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Treatment of a low strength landfill leachate with peat Corbett, John Richard Ernest 1975

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TREATMENT OF A LOW STRENGTH LANDFILL LEACHATE WITH PEAT by JOHN RICHARD ERNEST CORBETT B.A.Sc., University of British Columbia, 1972 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in the Department of C i v i l Engineering We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1975 In present ing th is thes is in p a r t i a l fu l f i lment o f the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make it f r ee ly ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th is thes is for s c h o l a r l y purposes may be granted by the Head of my Department or by h is representa t ives . It is understood that copying or p u b l i c a t i o n of th is thes is fo r f i n a n c i a l gain sha l l not be allowed without my wri t ten permiss ion. Department of C i v i l E n g i n e e r i n g The Un ivers i ty of B r i t i s h Columbia 20 75 Wesbrook Place Vancouver, Canada V6T 1W5 Date A p r i l 28, 1975 ABSTRACT The Burns Bog l a n d f i l l i s the largest solid waste l a n d f i l l in the province of British Columbia. It i s situated on a peat bog in the Municipality of Delta. Leachate is generated by the passage of rainwater through the layers of refuse. Due to consolidation of the underlying peat bed the leachate rises to the ground surface near the toe of the l a n d f i l l where i t enters peripheral ditches and subsequently flows into Crescent Slough and the Fraser River. The purpose of this research was to investigate the treatment of this leachate to an acceptable quality for release to the receiving environment using peat as an adsorption/filtration medium. The peat used in this research was obtained from the Burns Bog peat bog near the l a n d f i l l site. Column tests were run in the laboratory using a 29.2 cm I.D. plexiglass column containing 793 gm of dry peat. Leachate was pumped to the top of the column and allowed to percolate through the peat. The effluent from the column was then collected and analyzed. Six column runs were made to determine the effects of influent pH, influent concentration, and 'resting' the peat on the removal of pollutants by the peat. The removal of pollutants from the leachate by the peat is believed to occur through a combination of adsorption or exchange of dissolved pollutants and f i l t r a t i o n of precipitated and suspended mat-erials. The optimum pH for the adsorption of metals, was 7.1. At pH 4.8, adsorption decreased dramatically. At pH 8.4, adsorption was not i i i i i as great as at pH 7.1, however, the total removal of metals was greater due to the precipitation and f i l t r a t i o n of metal complexes. At the 95 per cent treatment level (i.e. 95 per cent of the metals entering the column are removed) the removal capacity of the peat at pH 7.1 was 11.4 mg/gm of dry peat. In order to treat the Burns Bog leachate to the proposed P.C.B. 'AA' level guidelines for specific discharges, a treat-ment level of 94.0 per cent would be required at the optimum pH of 7.1. This would require a dry weight of approximately 159 kg of peat per 1000 l i t e r s of leachate. Resting the peat for one month following i n i t i a l leachate throughput appeared to slig h t l y restore some of the adsorptive capacity of the peat. However, this restoration was not sufficient to allow re-use of the peat for leachate treatment. Reuse may be possible i f longer rest periods (6 to 12 months) are used. Desorption of pollutants does occur by the percolation of water through the expended peat. This may cause a pollution problem following the termination of leachate treatment and should be studied in greater detail before a full-scale treatment system is constructed. Chemical treatment using lime and f e r r i c chloride produced Fe, Mn, and Ca removals of greater than 90 per cent but did not reduce the N or Cl concentrations. Combined chemical and peat treatment did not produce any advantage over peat treatment alone. The 96 hr. TLm value for the natural.leachate was 7.0 per cent vol/vol. Rapid Toxicity Assessments (RTA) run on the treatment effluents i v showed that i t i s possible to treat the leachate to a noh-tbxic level using peat treatment. Ammonia nitrogen and pH are believed to be major factors affecting leachate toxicity. It i s f e l t that pe.at treatment may be an effective and economi-cal method of treating the Burns Bog leachate. A spray-irrigation treat-ment system u t i l i z i n g the f i n a l peat/clay cover of the l a n d f i l l i s con-sidered to be the most suitable full-scale treatment method. P i l o t -scale research at the l a n d f i l l site i s thought to be the logical next step in determining the f e a s i b i l i t y of peat treatment of the Burns Bog leachate. . TABLE OF CONTENTS CHAPTER Li s t of Tables . v i i Lis t of Figures x Acknowledgement x i i i I Introduction . . . . . . . . . . . . . . . 1 A. Leachate 1 B. Burns Bog Landfill . . . . . . 3 II Research Rationale 7 III. Leachate Characteristics, Peat Column-Operations, and Analytical Procedures. . . . . . . . . . . 11 A. Leachate Analysis . 11 B. Peat Column Operation. 16 C. Analytical Procedures 23 IV Effect of pH on the Removal Capacity of Peat 25 A. General. . 25 B. Treating the Burns Bog Leachate to the Proposed P.C.B. -'AA' Level-Guidelines 44 V The Effects of a One Month Rest Period on Adsorptive Capacity 51 VI Desorption of Pollutants from the Peat . . . . . . . . . 60 VII Chemical Treatment and Peat Treatment 66 A. Selection of the Optimum Chemical Treatment 66 B. Chemical Treatment Followed by Peat Treatment. . . . 71 VIII Toxicity Assessment. 82 IX Summary. . 91 v vi CHAPTER . X Conclusions and Recommendations. 7 J A. Conclusions. ..' 95 B. Peat Treatment Schemes at the Burns Bog Landfill . . . 97 C. Pilot-Scale Studies. 100 List of References . 104 Appendix A - Breakthrough Data for Peat Columns at pH 4.8, 7.1, 7.8, 8.4 106 Appendix B - Breakthrough Data Showing the Effects of a One Month Rest Period on Peat Adsorption 130 Appendix C - Breakthrough Data for Desorption Test . . . . 148 Appendix D - Breakthrough Data for Combined Chemical Treatment and Peat Treatment 158 1 LIST OF TABLES TABLE PAGE I Municipal Refuse Components - City of Vancouver 1 II Leachate Analysis. . 12 III Proposed P.C.B. Receiving Water Quality Maintenance Objectives . . . . . 13 IV Proposed P.C.B. Guidelines for Specific Discharges . . . 15 V Comparison of Typical Landfill Leachates with the Burns Bog Leachate 1? VI Analysis of the Natural Peat . 18 VII Cumulative Metal Removal: pH 4.8 26 VIII Cumulative Removals: pH 4.8 27 IX Cumulative Metal Removal: pH 7.1. V 28 X Cumulative Removals: pH 7.1 29 XI Cumulative Metal Removal: pH 7.8. . 30 XII Cumulative Removals: pH 7.8 31 XIII Cumulative Metal Removal: pH 8.4. 32 XIV Cumulative Removals: pH 8.4 . 3 3 XV Peat Removal Capacities. . 43 XVI Breakthrough Data Summary: pH 4.8 45 XVII Breakthrough Data Summary: pH 7.1 46 XVIII Breakthrough Data Summary: pH 7.8 47 XIX Breakthrough Data Summary: pH 8.4 . . . 48 XX Peat Requirements for Treatment of the Bums Bog Leachate to the Proposed P.C.B. 'AA' Level Guidelines. . 49 v i i v i i i m B L E PAGE XXI • Cumulative Metal Removal Before the Rest Period. . . . . 53 XXII Cumulative Metal Removal After the Rest Period 54 XXIII Total Metal Removal . 55 XXIV Desorption of Pollutants . . . . . . . . . 6 1 XXV Analysis of the Burns Bog Leachate After Chemical Treatment - Test Series II . . . 69 XXVI Dosage Used - Test Series II . 69 XXVII Removal Efficiencies - Test Series II 69 XXVIII Analysis of the Burns Bog Leachate after Chemical Treatment - Test Series III 70 XXIX Dosage Used - Test Series III 70 XXX Chemical Treatment 72 XXXI Cumulative Metal Removal: Chemical Treatment Followed by Peat Treatment . 73 XXXII Cumulative Removal: Chemical Treatment Followed by Peat Treatment . 7 4 XXXIII Peat Removal Capacities. . . . . . . . . . . . . . . . . 78 XXXIV Breakthrough Data Siimmary: Chemical Treatment Followed by Peat Treatment 80 XXXV 'RTA and TLm. Results. 84 XXXVI Effluent Analysis for RTA and TLm Samples 85 XXXVII Comparison of 6 - 12 Liters of Throughput Volume . . . . 89 A- I Breakthrough Data for Peat Columns at pH 4.8, 7.1, 7.8, 8.4 .107 A- II Breakthrough Data For Peat Columns at pH 4.8, 7.1, 7.8, 8.4 .109 i x TABLE PAGE A-III Breakthrough Data for Peat Columns at pH 4.8, 7.1, 7.8, 8.4. . I l l A- IV Breakthrough Data for Peat Columns at pH 4.8, 7.1, 7.8, 8.4. 113 B-I Breakthrough Data Showing the Effects of a One Month Rest Period on Peat Adsorption 131 C-I Breakthrough Data for the Desorption Test. 149 D-I Breakthrough Data for Combined Chemical Treatment and Peat Treatment 159 LIST OF FIGURES FIGURE 1 . . . . 5 2 . . .. . 20 3 . . . . 22 4 . . . . 34 5 . . . . 35 6 . . . . 36 7 . . . . 37 8 38 9 56 10 75 11 88 A- 1 115 A- 2 116 A- 3 117 A- 4 . H8 A- 5 . . . . 119 A- .6 . . . 120 A- 7 . . 121 A- 8 . . . 122 A- 9 . 123 A-10 . . . . 124 A - l l . 125 x i FIGURE PAGE A-12 . Breakthrough Curve for Total Kjeldahl Nitrogen (TKN) . . 126 A-13 ' Breakthrough Curve for P . . . . . . . . . 127 A-14 Breakthrough Curve for C l . . . . . . 128 A-15 Breakthrough Curve for Alkalinity (pH=4.5) . . 129 B- 1 Breakthrough Curve for Fe. . . . . . . . . . . . . . . . 133 B- 2 . Breakthrough Curve for Mn. 134 B- 3 Breakthrough Curve for Zn. . . 135 B- 4 Breakthrough Curve for K . . . . . 136 B- 5 Breakthrough Curve for Na. 137 B- 6 . Breakthrough Curve for Ca. . . . . . 138 B- 7 Breakthrough Curve for Mg. 139 B- 8 Breakthrough Curve for Pb. . . . . . . . . 140 B- 9 Breakthrough Curve for COD . 141 B-10 Breakthrough Curve for Total Solids. . . . . . 142 B - l l Breakthrough Curve for Suspended Solids 143 B-12 Breakthrough Curve for Total Kjeldahl Nitrogen (TKN) . . 144 B-13 Breakthrough Curve for Cl. . 145 B-14 Breakthrough Curve for P . . 146 B-15 Breakthrough Curve for Alkalinity (pH =4.5) 147 C- 1 Breakthrough Curve for Fe and Zn 150 C- 2 Breakthrough Curve for Ca and Mg 151 C- 3 Breakthrough Curve for Pb and Mn . . 152 x i i FIGURE PAGE C- 4 Breakthrough Curve for Na and COD 153 C- 5 Breakthrough Curve for Total Kjeldahl Nitrogen (TKN) and K . 154 C- 6 Breakthrough Curve for Alkalinity (pH=4.5) and Cl, . . . 155 C- 7 Breakthrough Curve for Total Solids. . 156 C- 8 Breakthrough Curve for P . . . . . . . . . . . . . . . . 157 D- 1 Breakthrough Curve for Fe 160 D- 2 Breakthrough Curve for Mn 161 D- 3 Breakthrough Curve for Zn . 162 D- 4 Breakthrough Curve for K . . . . . . . . . . . . . . . 163 D- 5 Breakthrough Curve for Na . . . 164 D- 6 Breakthrough Curve for Ca 165 D- 7 Breakthrough Curve for Mg . . . . . . 166 D- 8 Breakthrough Curve for Pb . . . . . . 167 D- 9 Breakthrough Curve for COD. 168 D-10 Breakthrough Curve for Total Solids 169 D - l l Breakthrough Curve for Suspended Solids . . . 170 D-12 Breakthrough Curve for Total Kjeldahl Nitrogen (TKN) . . 171 D-13 Breakthrough Curve for Cl . 172 D-14 Breakthrough Curve for P 173 D-15 Breakthrough Curve for Alkalinity (pH=4.5). . 174 ACKNOWLEDGEMENT The author would like to express his gratitude to Dr. R. D. Cameron for his guidance and encouragement i n the preparation of this thesis. He would also lik e to thank Elizabeth McDonald and Susan Harper for their assistance i n the laboratory. This research was supported by a research grant from the City of Vancouver. x i i i CHAPTER I INTRODUCTION A. Leachate One of the major problems presented by the operation of a solid waste l a n d f i l l i n high r a i n f a l l climates i s the production of leachate. Leachate is produced when surface or groundwater becomes contaminated as i t passes through the layers of refuse in a l a n d f i l l . If the leachate enters surface or groundwaters, a serious pollution problem may result. The magnitude of the pollution problem depends largely on the strength and quantity of leachate produced as well as the dilution afforded by the receiving waters. The quantity and quality of leachate depends on the amount and composition of the refuse, the hydrogeology of the si t e , the age of the l a n d f i l l , and the climate. Deleterious effects of leachates on receiving waters has been well documented in the literature (1, 2). Table I shows the composition of municipal refuse' for the city of Vancouver (3). TABLE I MUNICIPAL REFUSE COMPONENTS - CITY OF VANCOUVER Component Percentage by Weight Paper 36.4 Metals 8.2 Glass 7.2 Rubber 0.5 Plastic 1.7 Food Wastes 25.0 Wood 14.9 Textiles 2.5 Inerts 3.6 1 2 Paper i s a major component of refuse accounting for approx-imately 36 per cent of the weight. This paper is one of the major sources of the inorganic and organic pollutants found in leachate. Decomposition of cellulose produces organic compounds such as tannins and lignins, while the f i l l e r materials and chemicals employed in paper manufacture add inorganic materials such as sodium, calcium, magnesium, and trace metals. Other components of the refuse such as garbage, metal wastes, and industrial wastes add large amounts of COD, BOD, nitrogen, chlorides, sodium, magnesium, potassium, and certain heavy metals to the leachate. In recent years, two schools of thought have emerged con-cerning the control of l a n d f i l l leachates. The f i r s t suggests mini-mizing leachate production by proper site selection and design. This entails diverting surface water from the l a n d f i l l s i t e , preventing contact of groundwater with the refuse, and sealing and sloping the surface to minimize or eliminate precipitation i n f i l t r a t i o n . This method of control is very effective in arid or semi-arid climates where precipitation is minimal. However, in a high r a i n f a l l climate, keeping a l a n d f i l l free of water forever may be d i f f i c u l t and eventual uncontrolled leachate production w i l l probably occur. The second method of leachate control is to allow precipi-tation i n f i l t r a t i o n and collect and treat the leachate produced. The percolation of water through the refuse greatly increases the rate of biochemical stabilization of the l a n d f i l l . Consolidation and 3 settling of the l a n d f i l l thus occurs in a much shorter time than in a sealed .landfill, and thus allows the use of the l a n d f i l l site for building construction or recreational purposes at an early date. Collection of the leachate before i t enters ground or surface waters can be accomplished by careful l a n d f i l l design and site selection. Treatment of the collected leachate can then be done either at municipal treatment plants or at on-site f a c i l i t i e s . This method of leachate control i s considered to be better suited to high rain-f a l l climates such as the Lower Mainland area of British Columbia. The possible on-site treatment of leachate at a high r a i n f a l l l a n d f i l l i s the purpose of this research. B. Burns Bog La n d f i l l The Burns Bog l a n d f i l l , operated by the City of Vancouver, is the largest l a n d f i l l in the Province of British Columbia. It i s situated on a 1000 acre site located in the Municipality of Delta. In the nine years that the l a n d f i l l has been operating, approximately 90 acres of land have been partially u t i l i z e d . The l a n d f i l l i s operated on a 24 hour per day, seven days a week basis. It receives approximately 650 tons per day of refuse from the City of Vancouver, the Municipality of Delta, the Municipality of White Rock, the University of British Columbia and Endowment Lands, and commercial haulers and private citizens (4). The l a n d f i l l i s being built in three successive stages or l i f t s to provide a f i n a l height of 20 feet. The l i f t s are constructed by spreading three to four feet of refuse on a sloping working face and compacting the refuse to approximately two feet in thickness be-fore the next layer of refuse is spread (4). A covering of sand approximately six inches thick i s spread over the completed top of the l i f t as the working face moves forward. When the f i n a l l i f t i s completed, a f i n a l cover of approximately two feet of a peat/clay mixture i s placed on the refuse. The l a n d f i l l i s situated on a peat bog averaging nine feet in thickness, underlain by approximately four feet of relatively impervious clay. Below the clay layer i s a deposit of sand and s i l t several hundred feet in depth. The area receives approximately 45 inches of precipitation per annum, of which about 30 inches enters the l a n d f i l l following evaporation losses (4). The water table is generally at or near the surface of the peat bog in the November to March rainy season and drops to about one foot below the surface in the dry season. Runoff from the area i s picked up in shallow ditches, approximately two feet deep, around the existing l a n d f i l l on the north, west, and south sides (Fig. 1). While tides,may temporarily reverse the direction, of flow in these' ditches, the leachate inevitably runs into Crescent Slough and subse-quently into the Fraser River. A study prepared by Golder, Brawner, and Associates (4) in 1973 indicated that because of the consolidation of the underlying peat, at least 95 per cent of the leachate which leaves the l a n d f i l l Leachate Sampling Location Scale: 1" - 1000" Figure 1 Burns Bog Landfill 6 discharges within 10 feet of the toe of the l a n d f i l l , enters the drain-age ditches, and is transported to the Fraser River. It was also con-cluded that a portion of the remaining 5 per cent also enters the ditches due to the hydraulic, gradient which normally exists between the water level in the ditches and the groundwater level. After the Golder, Brawner study was done the depth of the ditches was increased to ensure collection of nearly 100 per cent of the leachate seepage, thus virtually eliminating the possibility of groundwater contamination. The leachate in the ditches however contains concentrations of pollutants which exceed the values considered to be acceptable. Some means of reducing these concentrations to less than the maximum acceptable levels was therefore considered necessary. It was f e l t that u t i l i z a t i o n of the local peat as an adsorbing or f i l t e r i n g medium would be the logical f i r s t step in the development of an efficient, low cost treatment system. CHAPTER II RESEARCH RATIONALE The purpose of this research was to investigate the effective-ness of peat as an adsorption - f i l t r a t i o n medium to treat the Burns Bog leachate to acceptable levels. Peat consists of decomposed organic matter derived from past vegetation. For centuries peat has been used as a fuel, a building material, and a s o i l conditioner(5). In recent years, i t has been used in pollution abatement in mop-up operations for o i l s p i l l s . The effectiveness of peat as an o i l adsorbent i s due to i t s highly porous, sponge-like structure and large surface area of approximately 200 2 meter /gram (5). Peat also contains cationic exchange properties be-lieved due i n part to humic acids produced during humification (5). The cationic exchange capacity (CEC) of peat has been estimated at between 50 to 400 milliequivalents of exchangeable cations per 100 grains of peat (6) . This combination of large surface area and cation exchange properties make peat an excellent potential f i l t r a t i o n and " adsorption medium for the treatment of l a n d f i l l leachates. Other features that make peat attractive as a treatment media are i t s abundance and low cost. Canadian deposits of peat are e s t i -mated at 225 million tons over an area of 37,000 square miles (5). Many Lower Mainland l a n d f i l l s such as the Burns Bog l a n d f i l l in Delta, 7 8 the Port Mann dump in Surrey, and the Terra Nova dump in'Fraser Mills are situated on peat bogs. Burns Bog alone has been estimated to have 5000 acres of peat, ranging from two to ten feet in depth (7). The low cost of peat (3 to 4 cents per lb.) compared to conventional activated carbon (40 to 60 cents per lb.) (5) indicates that examination of the use of peat for leachate treatment is indeed merited. Previous research has indicated that peat has the a b i l i t y to remove a wide variety of pollutants. Studies done at B.C. Research (4) have shown that peat has the potential to treat kraft pulp m i l l effluents, o i l refinery effluents, and specific industrial wastes due to i t s ab i l i t y to adsorb or f i l t e r out certain heavy metals, o i l s , suspended solids, phenols, and detergents. Other studies (8, 9, 10) have also indicated that peat i s effective in removing o i l , mercury, dyes, sur- , factants, and proteins from wastewaters. Laboratory studies at the University of Bri t i s h Columbia (7) have shown that peat w i l l effectively remove metal ions from solutions containing high concentrations of specific metals. These studies also indicated that peat has a reason-able capacity tp remove metal ions from a very high strength leachate produced from a simulated l a n d f i l l . It was concluded that peat had an excellent potential to economically treat low strength leachate such as the leachate from Burns Bog or from other Lower Mainland l a n d f i l l s (11). The question then arose of how to use peat to treat leachate in a full-scale system. Prefabricated f i l t e r s have been suggested for 9 use with wastewaters having sporadic or low flows such as those arising from small industrial plants. However for large flows, operational costs due to the necessary frequent replacement and disposal of f i l t e r s could be prohibitive. At the Burns Bog l a n d f i l l , a novel solution was f e l t possible. Since peat i s used as a f i n a l cover material, a logical treatment scheme would involve collecting the leachate and spraying i t over the peat cover in a similar fashion to a spray-irrigation treatment system for a municipal wastewater (6). In addition to the benefit gained by peat treatment, the concentrations of pollutants in the leachate might also be reduced by the recirculation of leachate through the refuse. Studies done at the Georgia Institute of Technology (12) have indicated that recirculation of leachate through the refuse reduces the strength of the leachate and increases the rate of stabilization of the l a n d f i l l . An alternate system to spray-treatment would be to pass the leachate through special peat beds separate from the l a n d f i l l . Another possibility would be to spray the leachate on the existing peat bog allowing treatment to occur as leachate percolates through the in - s i t u peat. In view of the foregoing i t was f e l t that peat treatment had excellent potential. This research was therefore established to study the f e a s i b i l i t y of peat treatment of the Burns Bog leachate with the following objectives in mind: 1. To determine i f i t was indeed possible to treat the Burns Bog leachate to a quality level that could be safely discharged 10 to the receiving environment. 2. To determine the removal capacity of the peat at an effluent level suitable for discharge and thus establish design c r i t e r i a for a full-scale system. 3. To determine i f the adsorptive capacity of the peat could be economically increased by leachate pretreatment techniques such as pH adjustment or chemical treatment. 4. To determine i f chemical treatment i t s e l f would be a feasible treatment method. 5. To determine i f the removal capacity of the peat following leachate treatment could be restored by 'resting' the peat for a prac-t i c a l length of time. This might enable the reuse of the peat and thus reduce the total peat volume required. 6. To determine the extent of desorption of adsorbed pollu-tants from the peat. Desorption might occur when surface water percolates through the peat after leachate treatment has ceased. 7. To determine the potential toxicity of the natural leachate and of the treated effluent to aquatic l i f e in the receiving environment. CHAPTER III LEACHATE CHARACTERISTICS, PEAT COLUMN OPERATIONS, AND ANALYTICAL PROCEDURES A. Leachate Analysis As mentioned in the previous chapter leachate rises to the ground surface within ten feet of the toe of the l a n d f i l l and i s collected in peripheral ditches. A leachate spring on the northern boundary of the l a n d f i l l was chosen as a collection site (Fig. 1). It was chosen because i t appeared to have the highest consistent flow (approximately 5 - 1 0 l i t e r s per minute (1/m)) of any of the known leachate springs, was relatively easy to get at, and was free from possible interference by l a n d f i l l operations. A ;small wooden weir was constructed between the spring and the ditch enabling undiluted leach-ate to be collected. The flow from this spring reached a minimum of about two 1/m i n September but rose again to about ten 1/m in late f a l l . Analysis of the leachate collected over a seven month period i s shown in Table II. The i n i t i a l leachate sample was analyzed for a l l of the pollutants shown in order to determine the values that were i above acceptable levels. The proposed Pollution Control Board (P.C.B.) objectives for municipal type waste discharges state only that leachate from l a n d f i l l s must meet the receiving water quality maintenance objec-tives (Table III). Since in this research i t was necessary to define a specific effluent quality in order to determine the effectiveness of 11 12 TABLE II LEACHATE ANALYSIS Leachate Parameter col l e c t e d c o l l e c t e d c o l l e c t e d Average June 17/74 Sept. 21/74 Nov. 28/74 Iron 30.3 27.2 13.8 23.8 Manganese 0.57 0.56 0.64 0.59 Zinc 0.43 0.40 0.78 0.54 Potassium 600 435 438 491 Sodi um 840 820 725 795 Calcium 175 164 173 171 Magnesium 126 128 39 98 Lead 0.055 0.046 0.052 0.054 COD 903 733 760 799 Phosphorus 1.56 0.86 1.38 1.27 Total Solids 4636 4264 4340 4413 Suspended Solids 134 146 104 128 Total Kjeldahl Nitrogen 494 408 435 • 446 Chloride 2400 2500 1975 2291 pH 7.1 7.5 7.8 7.5 A l k a l i n i t y (pH=4.5) . 3400 3510 3290 3400 B0D5 120 V o l a t i l e Solids 1092 Sulphate 5.3 Fluoride 0.27 Ammonia Nitrogen 427 A c i d i t y 185 Tannin-like cpd. 62.4 Aluminum 0.27 Arsenic 0.038 Barium 0.08 Beryl 1i um 0.025 Boron 4.5 Cadmium 0.0037 Chromium 0.053 Cobalt N.D. Copper 0.024 Molybdenum 0.013 Nickel 0.069 S i l i c o n 9.80 Si 1 ver N.D. Tin N.D. Titanium N.D. Vanadium N.D. N.D. = Not Detectable - a l l values except pH as mg/1; Alk. and A c i d i t y i n mg/1 as CaCO * Parameters exceeding P.C.B. 'AA' le v e l guidelines. - a l l metals as t o t a l concentrations. 13 TABLE III PROPOSED P .C .B . RECEIVING WATER QUALITY MAINTENANCE OBJECTIVES Parameter Object ive Dissolved Oxygen Decrease not to exceed 10% Residual Chlor ine. Below detectable l i m i t s (ampero-metr ic method) Nutr ients No detectable increase i n s i t e -speci f i c producti v i ty-1i mi t i ng parameters Col i f o r m s — r e c e i v i ng waters Total co l i fo rm MPN 1000/100 m l . Fecal co l i fo rm MPN 200/100 m l . Toxi c i ty No increase above background S e t t l e a b l e So l ids N e g l i g i b l e increase F loatab le So l ids and Scum N e g l i g i b l e increase O i l None v i s i b l e on water surface Organisms No change i n p r o d u c t i v i t y or development of nuisance condi t ions Heavy Metals N e g l i g i b l e increases 14 peat treatment and to determine design c r i t e r i a for a full-scale treatment system, i t was decided to adopt the proposed P.C.B. 'AA' level guidelines for specific discharges (Table IV) as an acceptable effluent quality. It was believed that i f the treated leachate satis-fied the proposed 'AA' level guidelines then the proposed receiving water quality maintenance objectives would also be satisfied. The pollutants that exceeded the proposed 'AA' level guidelines were found to be Fe, Mn,Zn, Pb, BOD , and suspended solids. Those parameters, with the exception of BOD , plus K, Na, Ca, Mg, COD, P, total Kjeldahl nitrogen (TKN), total solids, Cl, pH and alkalinity were chosen to monitor the effectiveness of the proposed treatment schemes and to try to achieve an overall picture of the changes occurring in the leachate with various treatment methods. BOD5 was not monitored because of the inaccuracy of the test in this research due to long periods of sample storage prior to analysis. It was f e l t that the COD test would closely reflect the changes occurring in BOD^  with the various treatment schemes. Table II shows that there was about a ten per cent variation in the concentrations of the majority of the pollutants over the seven month collection period. The concentrations of Mn, Zn, K, Ca, Pb, COD, P, TKN, and total solids appeared to reach a minimum in Sept-ember, the low flow period. However, Fe, Na, and Mg concentrations decreased over the collection period. It i s also interesting to note that the pH of the leachate increased steadily from 7.1 to 7.8 over the collection period. Unfortunately, with the limited data i t is d i f f i c u l t 15 TABLE IV PROPOSED P .C .B . GUIDELINES FOR SPECIFIC DISCHARGES Parameter Maximum Concentrations mq/1 (except pH and TLm) Level AA BOD- 45 Suspended S o l i d s 60 Methylene Blue Act i ve Substances 5 Oi1 and Grease 15 pH 6 . 5 - 8 . 5 Phenol 0.2 TL (96 h r . ) 100X Aluminum [Total) 2.0 Arsenic [Total) 0.05 Barium [Dissolved) 1.0 Boron Dissolved) 5 Cadmium Dissolved) 0.005 Chromi um [Total) 0.1 Cobalt [Dissolved) 0.1 Copper [Dissolved) 0.2 Cyanide [Total) . 0.1 Fluor ide [Dissolved) 5 .0 Iron [Dissolved) 0.3 Lead (Total ) 0.05 Manganese [Dissolved) 0.05 Mercury (Total ) 0.0006 Molybdenum (Total) 0.2 Nickel [Dissolved) 0.3 Nitrogen -Resin Ac id Soaps 5 Selenium (Total) 0.05 S i l v e r (Total ) 0.1 Sulphate 'Dissolved) 50 Sulphide [Dissolved) 0.5 T in (Total ) 5 Zinc (Total ) 0.5 16 to determine i f this trend i s a seasonal variation or a long term phenomenon. This variation i n concentrations while tending to com-plicate the analysis of the results did not prevent definite conclusions from being drawn.-• Table V shows the composition of various l a n d f i l l leachates and the average composition of the Burns Bog leachate. The high pH of the Burns Bog leachate (7.5 compared to an average 6.5) and the much lower concentrations of Fe, Ni, Cu, and COD i n the Burns Bog leachate are worthy of note. In the operation of the Burns Bog land-f i l l , construction debris such as broken concrete, plaster, wall-board, tires, lumber, etc. i s f i r s t l a i d down on the peat in order to provide adequate support for the heavy equipment depositing and compacting the refuse. The refuse i s then deposited and compacted on this layer. The leachate that i s generated as water passes through the refuse i s normally acidic. This weak acid solution is thought to attack the con-crete, plaster and wall-board in the layer of construction debris, dissolving lime, and hence raising the pH. This increase in pH tends to precipitate heavy metals present in the leachate and is f e l t to be the reason for the low concentrations of Fe, Ni, and Cu. Removals of some pollutants by adsorption onto the peat may also occur as the leachate moves from the refuse through the peat to the springs at the toe of the f i l l . B. Peat Column Operation The peat used in this research was obtained from two to three TABLE V COMPARISON OF TYPICAL LANDFILL LEACHATES (2) WITH THE BURNS BOG LEACHATE LANDFILL LEACHATES Average Cone. Burns Bog Leachate Parameter 1 2 3 4 5 6 7 8 PH 4 . 0 - 8 . 5 5 . 8 - 6 . 3 - 7.1 - 5.6 5.9 8 .3 7 .5 Fe 200-1700 175-860 - 20.3 5,500 305 336 219 23 .8 Cl 100-2400 951-2310 773 23.7 1697 2240 - 300 2291 Na 100-3800 584-1439 ' 652 - 900 1805 350 600 795 COD 100-5100 - - - 39,680 7130 - 760 BOD5 -14,760 -33,360 - 24 54,610 32400 7050 120 * Ni 0.01 -0 . 8 - - - - - 0.069 * Cu 0 . 1 - 9 . 0 ' - - - - - - - 0.024 * TKN 20-500 - - - - - - - 446 A l k a l -i n i t y -10,630 -20,850 740 257 -i - - 3400 > •sing le sample June 17/74. A l l values except pH as mg/1. A l k a l i n i t y as mg/1 as CaC03-18 f e e t below t h e ground s u r f a c e n e a r the n o r t h w e s t c o r n e r o f t h e l a n d -f i l l s i t e . T h i s a r e a was chosen because t h e p e a t r e q u i r e d f o r a f u l l -s c a l e t r e a t m e n t p r o c e s s w i l l have t o be o b t a i n e d n e a r t h e l a n d f i l l t o m i n i m i z e t r a n s p o r t a t i o n c o s t s and t h i s a r e a was thought to be r e p r e -s e n t a t i v e o f t h e s u r r o u n d i n g peat.bog. The p e a t i t s e l f i s an a m o r p h o u s - g r a n u l a r pe a t w i t h woody-f i n e f i b e r s (13). I t i s dark brown i n c o l o r w i t h a m o i s t u r e c o n t e n t r o f 91.0 t o 91.6 p e r c e n t and an ash c o n t e n t o f a p p r o x i m a t e l y 5.5 p e r c e n t . T a b l e VI shows the c o n c e n t r a t i o n s o f m e t a l s i n t h e n a t u r a l p e a t . TABLE VI ANALYSIS OF THE NATURAL PEAT M e t a l I o n C o n c e n t r a t i o n - mg/100 gm p e a t (wet) e x c e p t pH I r o n 7.0 Manganese 0.17 Z i n c 0.015 P o t a s s i u m 3.3 Sodium 8.0 C a l c i u m 55.0 Magnesium 30.3 L e a d 0.031 pH 4.5 I n o r d e r t o d e t e r m i n e the e f f e c t i v e n e s s o f t h e t r e a t m e n t o f l e a c h a t e by p e a t , a p e a t a d s o r p t i o n column was s e t up i n the l a b . P r e v i o u s r e s e a r c h (7) i n d i c a t e d t h a t t h e minimum c o n t a c t time r e q u i r e d to a c h i e v e e q u i l i b r i u m between a h i g h - s t r e n g t h l e a c h a t e and p e a t was i n t h e o r d e r o f 20 min. L i d k e a (7) a l s o f o u n d t h a t the t o t a l a d s o r p -t i v e c a p a c i t y o f t h e p e a t was i n the range o f 10 t o 50 mg. o f m e t a l s 19 per gm. of dry peat. From this information a 29.2 cm. I.D. plexiglass column with a cone bottom was constructed (Fig. 2). The cone was f i l l e d with stone ranging from about 3 cm. diameter at the bottom to 1 cm. dia-meter at the top. Peat (793 gm. dry weight) was placed on top of the stone as a slurry to minimize air voids. The peat was allowed to settle overnight and the excess water was drained off. Leachate was then pumped to the top of the column and allowed to percolate through the peat. The effluent from the column was collected at the bottom of the cone. Individual 2.0 l i t e r samples were collected and analyzed. The total volume of effluent collected varied from 14.0 to 32.0 l i t e r s . The flow rate through the column was maintained at 70 l i t e r s / h r . / 2 meter . This flowrate was chosen because i t was the maximum gravity flow that could be obtained i n the i n i t i a l column run using leachate at i t s collected pH of 7.1. This flow rate gave a contact time of 2.9 hr., well in excess of the minimum contact time found by Lidkea (7). The permeability coefficient of the peat for the column run -4 at pH 7.1 was estimated at 1.6 x 10 cm/sec. This value decreased for column runs with high influent suspended solids concentrations due to plugging of the top few millimeters of peat. When this occurred, aspiration of the column was necessary to maintain the flowrate of 2 70 liters/hr./meter . Some dilution of the column effluent is believed to have occurred due to the.free water present in the peat. The maximum vol-ume of free water in the peat column was estimated at 6 l i t e r s . This F i g u r e 2: Peat Column 21 was based on the assumption that free water represents 70 per cent of the total water content of the peat (14, 15). This represents a max-imum dilution effect of approximately 20 per cent i f uniform mixing of the leachate throughput and the free water in the peat column i s assumed. The actual dilution effect i s believed to be less than 20 per cent for two reasons. F i r s t , there i s evidence to indicate that pollutants were already present in the natural peat (Table VI). This indicates that the free water might have also contained pollutants and hence the actual dilution effect would be less than 20 per cent. Second, the estimate of the free water i n the peat column was based on saturated conditions. Since the peat remained in the column over-night, some loss of free water might have occurred due to evaporation or drainage. This would also reduce the dilution effect. Since this dilution effect i s relatively small and since in a full-scale treatment system a similar dilution would occur, the dilution effect of the free water in the peat was ignored in the analysis of the results. The results obtained were plotted as breakthrough curves. Breakthrough curves are a plot of the effluent concentration versus the volume of leachate passed through the column (Fig. 3). The ideal curve w i l l begin at zero or a very low effluent concentration, rise sharply as breakthrough of the pollutant occurs, and then level off as the influent concentration is reached. The amount of material removed by the column at any throughput volume can be determined from this plot. The amount removed i s equal to 22 the a r e a bounded by the v e r t i c a l a x i s , t h e i n f l u e n t c o n c e n t r a t i o n , the b r e a k t h r o u g h c u r v e , and the v e r t i c a l l i n e p a s s i n g t h r o u g h t h e t h r o u g h p u t volume d e s i r e d . T h i s i s shown i n F i g u r e 3. 0 Throughput Volume ( l i t e r s ) F i g u r e 3 I d e a l B r e a k t h r o u g h Curve Amount o f p o l l u t a n t removed = shaded a r e a (mg) a f t e r t h r o u g h p u t V^ P e r c e n t removal o f p o l l u t a n t = shaded a r e a x 100 C o X V l a f t e r t h r o u g h p u t V'^  The c u m u l a t i v e removals and p e r c e n t removals f o r each 2.0 l i t e r sample can t h e n be c a l c u l a t e d f r o m t h e b r e a k t h r o u g h c u r v e f o r each p o l l u t a n t . In o r d e r t o compare the removal e f f i c i e n c y o f column r u n s , i t was n e c e s s a r y t o sum up t h e i n d i v i d u a l p o l l u t a n t r e m o v a l s . T h i s was done by summing t h e c u m u l a t i v e removals f o r e a c h 2.0 l i t e r sample f o r 23 the following metals: Fe, Mn, Zn, K, Na, Ca, Mg and Pb. From these results, curves of total metal removal versus volume throughput were plotted. Similarily, curves of total per cent removal of these metals versus volume throughput were plotted. The removal efficiency for each column run was then compared using the total per cent removal curves. In this research a series of six column runs were made to determine the effects of influent pH, influent concentration, and 'resting' the peat on removal efficiency. The results are discussed in the succeeding chapters. C. Analytical Procedures Analysis of the leachate, the effluent samples, and the nat-ural peat was done in accordance with the procedures set out in STANDARD METHODS FOR THE EXAMINATION OF WATER AND WASTEWATER, 13th ED. (16). Ten times concentration of the leachate and effluent samples was necessary to detect certain heavy metals. Digestion of the leachate and effluent samples was also necessary to ensure that a l l metals were in solution so that the total concentrations were measured. The digestion procedure outlined in STANDARD METHODS was modified in accordance with past analytical experience using leachate (17). The digestion procedure used was as follows: 1. Concentrated HC1 and HNO^  were added to 500 m i l l i l i t e r s (ml) of leachate such that the f i n a l concentrated sample contained 1 per cent HN0„ and 5 per cent HC1. 24 2. The samples were then boiled down to approximately 30 ml, fil t e r e d , and brought up to 50 ml with d i s t i l l e d water. This gave a 10:1 concentration and ensured that a l l metals were in solution. 3. Total metal concentrations were then determined using a Jarrel-Ash MV-500 atomic adsorption spectrophotometer. CHAPTER IV EFFECT OF pH ON THE REMOVAL CAPACITY OF PEAT A. General Four peat column runs were carried out at different pH in order to determine the optimum pH for the treatment of the Burns Bog leachate in terms of removal efficiency 1 and minimum cost. Removal efficiency was determined as described in Chapter I I I by f i r s t plotting breakthrough curves for each pollutant and then calculating the cumulative removals. The breakthrough curves are shown i n Appendix A. The cumulative re-movals for the individual pollutants are shown in Tables VII through XIV. The total metal removals and the total per cent removals based on the sum of the removals of Fe, Mn, Zn, K, Na, Ca, Mg, and Pb were then calculated. These are shown in Figures 4 to 7. Figure 8 shows a comparison of the per cent removals of total metals for the four column runs. The column runs were made using leachate at pH 4.8, 7.1, 7.8, and 8.4. The pH was adjusted using 0.070 equivalents of HCl per l i t e r of leachate for the pH 4.8 column run and 0.013 equivalents of NaOH per l i t e r of leachate for the pH 8.4 column run. The column runs at pH 7.1 and 7.8 were at the pH of the collected leachate. The optimum pH for leachate treatment i s determined by com-paring the total metal removal curves, the breakthrough curves, and the peat capacities at the four pH's. 25 26 TABLE VII CUMULATIVE METAL REMOVAL pH 4.8 VOLUME THROUGHPUT (LITERS) Fe Mn Zn K Na Ca Mg Pb T o t a l M e t a l Removal 2 mg. I n f . mg. rem. % rem. 53.6 41.0 76.4 1.04 0.72 69.2 0.86 0.41 47.6 1160 910 78.4 2800 2000 71.5 508 328 64.6 212 122 57.5 0.06 0.05 83.3 4736 3402 71.8 4 mg. I n f . mg. rem. % rem 107.2 73.0 68.1 2.08 1.11 53.4 1.72 0.27 15.7 2320 1470 63.4 5600 3200 57.2 1016 436 43.0 424 174 41.0 0.12 0.10 83.3 9471 5354 56.5 6 mg. I n f . mg. rem. % rem. 160.8 95.0 59.1 3.12 1.37 44.0 2.58 0.06 2.3 3480 1880 54.0 8400 3900 46.5 1524 484 31.7 636 201 31.7 0.18 0.15 83.3 14,207 6562 46.1 8 mg. I n f . mg. rem. % rem. 214.4 113.0 52.8 4.16 1.59' 38.2 3.44 -0.13 0 4640 2240 48.2 11,200 4,400 39.3 2032 512 25.1 848 213 25.1 0.24 0.20 82.3 18,942 7,480 39.4 10 mg. I n f . mg. rem. % rem. 268.0 129.0 48.0 5.20 1.78 34.2 4.30 -0.25 0 5800 2600 44.9 ' 14,000 4800 34.3 2540 522 20.9 1060 221 20.9 0.30 0.25 81.7 23,678 8274 34.9 12 mg. I n f . mg. rem. % rem 321.6 145.0 45.2 6.24 1.98 31.7 5.16 -0.30 0 6960 2960 42.4 16,800 5200 31.4 3048 527 17.3 1272 227 17.3 0.36 0.29 80.5 28,413 9061 31.8 14 mg. I n f . mg. rem. % rem. 375.2 162.0 43.2 7.28 2.20 30.3 6.02 -0.27 10 8120 3320 40.9 19,600 5,600 28.6 3556 531 15.0 1484 231 15.6 0.42 0.33 79.4 33,149 9846 29.7 16 mg. I n f . mg. rem. % rem. 428.8 180.0 42.0 8.32 2.43 29.3 6.88 -0.19 0 9280 3680 29.8 22,400 6,000 26.8 4064 533 13.1 1696 233 13.7 0.48 0.37 77.7 37,884 10,628 28.0 18 mg. I n f . mg. rem. % rem. 482.4 198.5 41.2 9.36 2.66 28.4 7.74 -0.07 0 10,440 4040 38.6 25,200 6400 25.4 4572 534 .11.7 1908 234 12.3 0.54 0.41 75.5 42,620 11,409 26.7 20 mg. I n f . mg. rem. % rem. 536.0 217.5 40.6 10.40 2.89 27.8 8.60 0.09 1.0 11,600 4400. 38.0 28,000 6800 24.3 5080 534 10.5 2120 234 11.0 0.60 0.44 73.5 47,355 12,188 25.7 22 mg. I n f . mg. rem. • % rem. . 589.6 236.5 40.2 11.44 3.13 27.3 9.46 0.27 2.8 12,760 4760 37.3 30,800 7200 23.4 5588 534 9.6 2332 234 10.0 0.66 0.47 71.2 52,090 12,968 24.8 24 mg. I n f . mg. rem. % rem. 643.2 254.5 39.5 12.48 3.36 26.9 10.32 0.48 4.6 13920 5120 36.8 33600 7600 22.6 6096 534 8.7 2544 234 9.2 0.72 0.50 68.8 56,826 13,746 24.1 mg. I n f . - mg. c o n t a i n e d i n t h e i n f l u e n t mg. rem. - mg. removed i n t h e column N-B- Removals a r e based on t h e t o t a l removal f o r t h e t o t a l volume t h r o u g h p u t . 27 TABLE V I I I CUMULATIVE REMOVALS pH 4.8 Volume t h r o u g h p u t (1 i t e r s ) T o t a l S o l i d s Suspended S o l i d s COD TKN p C l 2 mg. I n f . mg. rem. % rem. 16,004 11,600 72.5 320 230 71.9 1654 1054 63.7 10,800 7,800 72.2 4 mg. I n f . mg. rem. % rem. 32,008 18,000 56.2 640 360 56.3 3308 1748 52.8 21,600 12,600 58.4 6 mg I n f . mg. rem. % rem. 48,012 21,600 45.0 960 470 48.9 4962 2182 44.0 - 32,400 15,400 47.5 8 mg. I n f . mg. rem. % rem. 64,016 24,000 37.5 1280 590 46.1 6616 2476 37.4 43,200 17,700 41.0 10 mg. I n f . mg. rem. % rem. 80,020 25,800 32.1 1600 720 45.0 8270 2696 32.6 UJ LU 1 54,000 19,500 36.1 12 mg. I n f . mg. rem. % rem. 96,024 27,000 28.7 1920 870 45.3 9924 2870 28.9 CO •a: i—i > CQ -rJ t—1 s» 64,800 21,100 32.6 14 mg. I n f . mg. rem. % rem. 112,028 29,400 26.2 2240 1020 45.5 11,578 3024 26.1 t— o t— o 75,600 22,500 29.8 16 mg. I n f . mg. rem. % rem. 128,032 31,200 24.4 2560 1170 45.7 13,232 3168 23.9 86,400 23,800 27.1 18 mg. I n f . mg. rem. % rem. 144,036 33,050 23.0 2880 1310 45.5 14,886 3,302 22.2 . 97,200 25,000 25.8 20 mg. I n f . mg. rem. % rem. 160,040 34,850 21.8 3200 1450 45.3 16,540 3426 20.7 108,000 26,200 24.6 22 mg. I n f . mg. rem. % rem. 176,044 36,450 20.7 3520 1585 45.0 18,194 3540 19.5 118,800 27,300 23.0 24 mg. I n f . mg. rem. % rem. 192,048 37,650 19.6 3840 1715 44.7 19,848 3644 18.3 129,600 28,300 21.9 N.B. r e m o v a l s a r e based on t h e t o t a l removal f o r t h e t o t a l volume t h r o u g h p u t . 28 TABLE IX CUMULATIVE METAL REMOVAL pH 7.1 Volume t h r o u g h p u t (1 i t e r s ) Fe Mn Zn K Na : Ca Mg Pb T o t a l Removal 2 mg. I n f . mg. rem. % rem. 60.6 60.5 99,9 1.14 1.04 21.2 0.86 0.72 83.8 1200 1175 98.0 1680 1620 96.6 350 • 337 96.4 252 242 96.0 0.130 0.130 100 3544. 3436. 96.9 4 mg. I n f . mg. rem. % rem. 121.2 121.0 99.8 2.28 2.08 91.2 1.72 1.32 76.8 2400 2340 97.5 3360 3200 95.2 700 665 95.1 504 479 95.0 0.260 0.259 99.9 7089. 6808 96.0 6 mg. I n f . mg. rem. % rem. 181.8 181.3 99.8 3.42 3.11 91.1 2.68 1.66 62.0 3600 3440 95.5 5040 4680 92.8 1050 978 92.8 756 706 93.3 0.390 0.388 99.7 10,634 9,991 94.0 8 mg. I n f . mg. rem. % rem. 242.4 241.6 99.5 4.56 4.10 89.8 3.44 1.38 40.2 4800 4440 92.5 6720 5960 88.8 1400 1273 91.0 1008 913 90.5 0.520 0.517 99.5 14,178.9 12,834. . 90.5 10 mg. I n f . mg. rem. %, rem. 303.0 301.5 99.4 5.70 5.04 88.5 4.30 0.98 22.8 6000 5240 87.5 8400 7090 84.4 1750 1550 88.5 1260 1098 87.1 0.650 0.647 99.0 ' 17,723 15,286 86.3 12 mg. I n f . mg. rem. % rem. 363.6 358.3 98.6 6.84 5.93 86.7 5.16 1.54 30.0 7200 5790 80.5 10,080 7745 76.8 2100 1814 86.5 1512 1258 83.0 0.780 0.750 96.2 21,269 16,975 79.8 14 mg. I n f . mg. rem. % rem. 424.2 410.8 96.8 7.98 6.78 84.8 6.02 2.16 35.9 8400 ; 6190 73.8 11 ,760 8190 . 69.7 2450 2067 84.5 1764 1398 79.2 0.910 0.820 90.1 24,812 18,269 73.6 16 mg. I n f . mg. rem. • % rem. 484.8 462.5 95.4 9.12 7.59 83.0 6.88 2.76 40.3 9600 6490 67.6 13,440 8490 63.1 2800 2309 82.5 2016 1526 75.8 1.04 0.86 82.5 28,358 19,288 68.0 18 mg. I n f . mg. rem. % rem. 545.4 512.3 94.0 10.26 8.37 81.7 7.74 3.34 43.2 10,800 6740 62.4 15,120 8690 57.5 3150 2544 81.0 2268 1646 72.6 1.17 0.89 76.1 31,901 20,145 63.2 20 mg. I n f . mg. rem. % rem. 606.0 560.4 92.5 11.40 9.13 80.1 8.60 3.90 45.4 12,000 6,940 57.9 16,800 8845 52.6 3500 2771 79.2 2520 1760 70.0 1.30 0.91 70.0 35,447 20,890 58.9 22 mg. I n f . mg. rem. % rem. 666.6 606.1 91.0 12.54 9.87 78.6 9.46 4.40 46.5 13,200 7090 53.7 18,480 8940 48.5 3850 2994 77.7 2774 1872 67.5 1.43 0.92 64.3 38,994 21 ,518 55.2 24 mg. I n f . mg. rem. % rem. 727.2 648.6 89.1 13.68 10.57 77.4 10.32 4.80 46.4 14,400 7190 50.0 20.160 8980 44.5 4200 3212 76.5 3026 1976 65.4 1.56 0.93 59.6 42,539 22,022 51.8 TABLE X CUMULATIVE REMOVALS pH 7.1 Th ( Volume -oughput 1i t e r s ) T o t a l S o l i d s Suspended S o l i d s COD TKN P Cl 2 mg. I n f . mg. rem. % rem. 9272 8300 89.5 272 192 70.6 1806 1450 80.4 988 950 96.2 3.12 2.79 89.5 4800 4600 95.8 4 mg. I n f . mg. rem. % rem. 18,544 16,800 90.6 544 439 80.6 3612 3000 83.1 1976 1890 96.2 6.24 5.68 . 91.0 9600 9000 93.7 6 mg. I n f . mg. rem. % rem. 27,816 24,800 89.2 816 701 86.0 5418 4525 83.4 2964 2810 94.8 9.36 8.63 92.0 14,400 12,900 89.5 8 mg. I n f . mg. rem. % rem. 37,088 32,100 86.5 1088 958 88.2 7224 5950 82.1 3952 3660 92.7 12.48 11.53 92.6 19,200 16,100 84.0 10 mg. I n f . mg. rem. % rem. 46,360 38,400 82.9 1360 1205 88.6 9030 7175 • 79.3 4940 4410 88.5 15.60 14.35 92.0 -24,000 18,500 77.0 12 mg. I n f . mg. rem. % rem. 55,632 43,700 78.7 1632 1417 86.8 10,836 8125 75.0 5928 5010 84.5 18.72 17.07 91.2 28,800 20,300 73.9 14 mg. I n f . mg. rem. % rem. 64,904 48,100 74.2 1904 1604 84.2 12,642 8925 70.5 6916 5470 78.6 21.84 19.71 90.4 33,600 21,500 64.0 16 mg. I n f . mg. rem. % rem. 74,176 52,100 70.2 2176 1779 81.8 14,448 9625 67.6 7904 5870 74.2 24.96 22.31 89.5 38,400 22,300 58.2 18 mg. I n f . mg. rem. % rem. 83,448 55,400 66.4 2448 1944 79.5 16,254 10,225 63.0 8892 6230 70.2 28.08 24.88 80.6 43,200 22,800 52.8 20 mg. I n f . mg. rem. % rem. 92,720 58,400 63.0 2720 2104 77.3 18,060 10,825 60.0 9880 6540 66.2 21.20 27.42 88.0 48,000 • 23,100 48.1 22 mg. I n f . mg. rem. % rem. 101,992 61,100 60.0 2992 2264 75.7 19,866 11,350 57.2 10,868 6810 62.7 34.32 29.91 87.2 52,800 23,200 44.0 24 mg. I n f . mg. rem. % rem. 111,264 63,400 57.0 3264 2419 74.0 21,672 11,550 53.3 11,856 7030 59.3 37.44 32.38 86.4 57,600 23,220 40.4 30 TABLE XI CUMULATIVE METAL REMOVAL pH 7.8 Volume T h r o u g h p u t ( L i t e r s ) Fe Mn Zn K Na. Ca Mg Pb T o t a l Removal 2 mg. I n f . mg. rem. % rem. 27.6 27.4 99.3 1.28 1.18 92.3 1.56 1.32 84.1 876 836 95.5 1450 1360 93.8 345 308 89.3 78 66 84.6 0.090 0.040 44.4 2780 2599 93.5 4 mg. I n f . mg. rem. % rem. 55.2 54.7 99.2 2.56 2.32 90.6 3.12 2.32 74.5 1752 1640 94.0 2500 2660 89.7 690 614 89.0 156 130 83.3 0.180 0.072 .40.0 5559 5103 91.8 6 mg. I n f . mg. rem. % rem. 82.8 81.9 98.8 3.84 3.44 89.5 4.68 1.92 41.2 2628 2360 89.8 4350 . 3810 87.6 1035 902 87.1 234 190 81.2 0.270 0.102 37.8 8339 7349 88.1 8 mg. I n f . mg. rem. % rem. 1104 109.0 98.7 5.12 4.56 89.2 6.24 2.20 35.3 3504 2980 85.0 5800 4810 82.8 1380 1176 85.2 312 248 79.5 0.360 0.128 35.6 11,118 8,330 83.9 10 mg. I n f . mg. rem. % rem. 138.0 136.1 98.7 6.40 5.64 88.3 7.80 3.10 39.7 4380 3560 81.3 7250 5760 79.6 1725 1450 84.1 390 306 78.5 0.450 0.142 31.6 13,897 11,221 80.7 12 mg. I n f . mg. rem. % rem. 165.6 163.2 98.7 7.68 6.73 87.7 9.36 4.16 44.5 5256 4130 78.6 8700 6660 76.5 2070 1720 83.9 468 363 77.6 0.540 0.152 28.1 16,678 13,047 78.2 14 mg. I n f . mg,. rem. % rem. 193.2 190.3 98.7 8.96 7.81 87.0 10.92 5.26 48.1 6132 4670 76.1 10,150 7460 73.4 2415 1980 82.0 546 419 76.7 0.630 0.162 25.7 19,456 14,732 75.7 16 mg. I n f . mg. rem. % rem. 220.8 217.4 98.7 10.24 8.89 87.0 12.48 6.32 50.8 7008 5150 73.4 11,600 8210 70.9 2760 2230 80.9 624 473 75.8 0.720 0.168 23.3 22,235 16,295 73.3 31 TABLE X I I CUMULATIVE REMOVALS pH = 7.8 i/olume T h r o u g h p u t ( l i t e r s ) T o t a l S o l i d s S.S. COD TKN P C l I mg. I n f l u e n t mg. removed % 8780 8200 93.4 208 208 100.0 1520 1300 85.5 870 840 96.6 2.60 2.50 96.2 3350 3450 87.3 \ mg. I n f l u e n t mg. removed % 17560 16000 91.1 416 416 100.0 3040 2580 84.9 1740 1640 94.2 5.20 5.02 96.5 7900 6650 84.2 5 mg. I n f l u e n t mg. removed % 26340 23000 87.3 624 616 98.7 4560 3660 80.3 2610 2380 91.2 7.80 7.54 96.7 11850 9450 79.7 3 mg. I n f l u e n t mg. removed % 35120 29200 83.1 832 816 - 98.1 6080 4600 75.7 3480 . 3040 87.4 10.40 10.06 96.7 15800 11650 73.7 10 mg. I n f l u e n t mg. removed % 43900 35400 80.6 1040 1012 97.3 7600 5500 72.4 4350 3690 84.8 13.00 12.58 96.8 19750 13750 69.6 12 mg. I n f l u e n t mg. removed % 52680 41200 78.2 1248 1204 96.5 9120 6380 70.0 5220 4330 83.0' 15.60 15.10 96.8 23700 15750 66.5 14 mg. I n f l u e n t mg. removed % 61460 46800 76.1 1456 1390 95.5 10640 7180 67.5 6090 4930 81.0 18.20 17.60 96.7 27650 ' 17350 62.7 16 mg. I n f l u e n t mg. removed % 70240 51600 73.5 1664 1566 94.1 12160 . 7780 63.9 6960 5470 78.6 20.80 20.08 96.5 31600 18550 58.7 32 TABLE X I I I CUMULATIVE METAL REMOVAL pH 8.4 -Volume T h r o u g h p u t ( l i t e r s ) Fe Mn' Zn K Na Ca Mg Pb T o t a l Removal 2 mg. I n f . mg. rem. % rem. 49.0 48.8 99.6 0.90 0.78 86.7 0.60 0.32 53.3 1140 1010 88.6 2260 2040 90.2 162 134 82.7 246 221 90.0 .080 .036 45.2 3858 3454 89.5 4 mg. I n f . mg. rem. % rem. 98.0 97.6 99.5 1.80 1.58 87.8 1.20 0.72 60.0 2280 2020 88.6 4520 4080 90.2 324 270 83.5 492 444 90.0 .160 .068 42.5 7717 6920 89.7 6 mg. I n f . mg. rem. % rem. 147.0 146.4 99.5 2.70 2.38 88.2 1.80 • 1.16 64.5 3420 3030 88.6 6780 6120 90.2 486 404 83.1 738 664 90.0 .240 .092 38.3 11,575 10,367 89.6 8 mg. I n f . mg. rem. % rem. 196.0 195.1 99.5 3.60 3.16 87.8 2.40 1.58 66.0 4560 4030 88.4 9040 8130 90.0 648 524 80.9 984 875 88.8 .320 .110 34.4 15,434 13,759 89.1 10 mg. I n f . mg. rem. % rem. 245.0 243.8 99.5 4.50 3.91 87.0 3.00 2.00 66.6 5700 5000 87.7 11 ,300 10,050 89.0 810 612 75.5 1230 1071 87.2 ;400 .126 31.5 19,292 16,982 88.0 12 mg. I n f . mg. rem. % rem. 294.0 292.5 99.4 5.40 4.64 86.0 2.60 2.44 67.8 6840 5910 86.4 13,560 11 ,860 87.5 972 657 67.6 1476 1252 84.8 .480 .142 29.6 23,151 19,978 86.3 14 mg. I n f . mg. rem. % rem. 343.0 341.1 99.4 6.30 5.34 84.8 4.20 2.88 68.6 7980 6710 85.0 15,820 13,470 85.4 1134 677 59.6 1722 1413 82.3 .560 .157 28.0 27,010 22,619 83.7 33 TABLE XIV CUMULATIVE REMOVALS pH = 8.4 Volume Throughput Total - Suspended COD TKN P Cl (1 iters) Solids Sol ids 2 mg. Influent 9948 624 1308 804 1.84 4740 mg. removed 8648 609 1048 780 1.80 4140 % II 86.9 97.5 80.3 97.0 97.8 87.4 4 mg. Influent 19,896 1248 2616 1608 3.68 9480 mg. removed 17,298 1163 2086 1560 3.59 8280 % II 86.9 93.2 80.0 97.0 97.6 87.4 6 mg. Influent 29,844 1872 3924 2412 5.52 14,220 mg. removed 25,998 1687 .3104 2340 5.37 12,340 % II 86.9 90.3 79.0 97.0 97.3 86.8 8 mg. Influent 39,792 2496 5232 3216 7.36 18,960 mg. removed 34,498 2236 4092 3112 7.15 16,180 % ti 86.6 89.6 78.3 97.0 97.1 85.4 10 mg. Influent 49,740 3120 6540 4020 9.20 23,700 mg. removed 42,548 2825 5030 3876 8.93 19,520 % 85.6 90.6 78.2 96.8 97.1 82.3 12 mg. Influent 59,688 3744 7848 4824 11.04 28,440 mg. removed 49,898 3419 5878 4620 10.70 22,160 % 83.7 93.7 75.1 95.8 96.8 77.9 14 mg. Influent 69,636 4368 9156 5628 12.88 33,180 mg. removed 56,448 4009 6586 5334 12.46 24,100 % II 81.1 91.6 71.9 94.7 96.7 72.7 34 6 ca > o a cu Pi 9) a ca o H 20,000 16,000 12,000 -I 100% 8000 4000 h-12 16 20 24 Volume throughput - l i t e r s Figure 4 Total Metal Removal: pH 4.8 ca > o e Pi cu . a a) 35 \ 24,000 20,0001 16,000k 12,000L 8,000 4,000l 8 12 16 20 Volume throughput - l i t e r s Figure 5 Total Metal Removal: pH 7.1 -| 100 _| 20 24 36 4 8 12 16 20 24 Volume throughput - l i t e r s Figure 6 Total Metal Removal: pH 7.8 37 0 4 8 12 16 20 24 Volume throughput - l i t e r s Figure 7 Total Metal Removal: pH 8.4 38 F i g u r e 8 E e r c e n t Removal o f T o t a l M e t a l s 39 It i s clear from the total per cent removal curve (Fig. 8) that the removal efficiency at pH 4.8 i s significantly less than the removal efficiency at the higher pH's. This i s supported by the break-through curves at pH 4.8 (Appendix A) where the effluent concentrations of Fe and Mn always exceeded the proposed P.C.B. 'AA' level guidelines. The column runs at pH 7.1, 7.8 and 8.4 achieved much lower i n i t i a l effluent concentrations and much greater overall removals than the pH 4.8 run. The greatest per cent removal of total metals for the f i r s t 8.0 l i t e r s of leachate through the column occurs at pH 7.1 (Fig. 8). After this volume throughput, the pH 7.1 removal curve drops below the pH 8.4 curve. The per cent removal curve for pH 7.8 i n i t i a l l y exceeds that at pH 8.4 but then drops off and roughly parallels the pH 7.1 curve. The greater per cent removal at pH 8.4 after 8.0 l i t e r s throughput i s f e l t to have occurred through the removal of precipitated metal complexes by f i l t r a t i o n rather than by adsorption. In the pH 8.4 column run, as the pH of the influent leachate was increased to 8.4, precipitation of metal complexes occurred. This formation of very fine particles was confirmed by the increase in suspended solids concentra-tion from 105 mg/1 to 312 mg/1 upon the pH increase (Table A-III). During operation of the column the upper layers became clogged with this fine material, restricting the flow rate and increasing the removal of sus-pended particles. This restriction of flow was the reason for the term-ination of the column run after 16 l i t e r s throughput. It i s f e l t there-fore that even though better per cent removals occurred at pH 8.4 after 40 8.0 l i t e r s throughput, adsorption of metals i s better at pH 7.1. The greater adsorption of metals at pH 7.1 i s also verified when the breakthrough curves in Appendix A are examined. For the i n i t i a l 2.0 to 6.0 l i t e r s of leachate through the column, the lowest effluent concentrations generally occurred at pH 7.1. After this throughput, the pH 7.8 and 8.4 curves drop below the pH 7.1 curve as removal of pre-cipitated metal complexes became predominant. This trend i s evident in the breakthrough curves for Fe, Mn, Zn, Ca, Mg, Pb, and total solids. The breakthrough curves for COD, P, and total kjeldahl nitrogen (TKN) indicate that slightly lower i n i t i a l effluent concentrations and greater overall removals were obtained at pH 7.8 and 8.4 than at pH 7.1. This may be due to the increased removal of suspended organics at the higher pH's because of the column clogging mentioned above. The breakthrough curves for Zn at pH 4.8, 7.1, and 7.8 showed a sharp rise i n effluent concentration above the influent concentration at between 4 to 10 l i t e r s throughput. This phenomenon occurred only in the Zn breakthrough curves and i s believed to have been caused by the preferential adsorption of another pollutant. It appears that i n i t i a l l y when exchange sites are abundant, Zn is adsorbed onto the peat. However after a certain adsorptive capacity has been u t i l i z e d , the Zn that had been adsorbed or that was originally present i n the peat i s exchanged for another cation with stronger exchange properties. This would explain the sharp peak in the breakthrough curve. As the adsorp-tive capacity of the peat i s further u t i l i z e d and the concentration of 41 ions in solution becomes greater, Zn i s again adsorbed onto the peat. This peak was not observed i n the pH 8.4 curve. This may be because most of the Zn was removed by precipitation and f i l t r a t i o n due to the high pH and hence this effect was not as pronounced. The removal performance at different pH levels can also be compared by calculating the removal capacity of the peat for the total metals at arbitrary treatment levels. For example, the capacity of the peat at a treatment level of 85 per cent (i.e. removal of 85 per cent of the total metals entering the column)for the pH 7.1 column run can be determined from Figure 5 as follows. At 85 per cent treatment, 15,800 mg of metals have been removed by the peat column. This occurs at a volume throughput of 9.5 l i t e r s . Therefore the capacity of the peat is equal to the amount of metals removed divided by the weight of peat in the column: Capacity of the peat at the 85 per cent = amount of metals removed treatment level weight of peat in the column 15,800 mg 793 gm dry peat = 19.9 mg of metals/gm dry peat Similarily, the amount of peat required to remove 85 per cent of the total metals entering the column per volume of leachate can also be calculated: 42 Peat required per 1000 l i t e r s of leachate at the = weight of dry peat volume throughput at which 85 per cent treat- 85 per cent treatment occurs ment l e v e l = 793 gm dry peat 9.5 l i t e r s 83.5 kg of dry peat/1000 l i t e r s The capacity of the peat and the weight of peat required at the 75, 85, 90, and 95 per cent treatment levels at pH 4.8, 7.1, 7.8, and 8.4 are shown i n Table XV. Table XV shows that at the 90 per cent treatment l e v e l and above, the capacity of the peat i s greatest at pH 7.1. S i m i l a r i l y , the peat required to treat 1000 l i t e r s of leachate i s at a minimum at pH 7.1. Below the 90 per cent treatment l e v e l the capacity of the peat i s greatest at pH 8.4. This r e f l e c t s the conclusions reached i n the comparisons of the t o t a l per cent removal curves and the break-through curves. In summary, the optimum pH for peat treatment of leachate depends oh the treatment l e v e l desired. Above the 90 per cent treatment l e v e l or for the f i r s t 8.0 l i t e r s through the column, leachate at pH 7.1 produces the best metal removals. Adsorption of metals i s also best at pH 7.1. 43 TABLE XV PEAT REMOVAL CAPACITIES Treatment Level Capaci ty pH=4.8 pH=7.1 pH=7.8 pH=8.4 75% .... ; mg/gm: 3.5 22.8 19.4 32.8 Peat Required: 132 63.0 56.6 49.6 85% mg/gm: not 19.9' 11.1 27.7 Peat Required: possib le 83.5 122 64.0 90% mg/gm: not 16.9 8.2 not Peat Required possib le 107 189 possib le 95% mg/gm: not 11.4 not not Peat Required: possib le 180 possi ble possi ble Capacity as mg.of to ta l metals per gm. Dry Peat. Peat Required as kg. of Dry Peat per 1000 l i t e r s of Leachate. 44 Below t h e 90 p e r c e n t t r e a t m e n t l e v e l o r a f t e r 8.0 l i t e r s t h r oughput, l e a c h a t e a t pH 8.4 p r o d u c e s the b e s t m e t a l removals due t o p r e c i p i t a t i o n and f i l t r a t i o n o f m e t a l complexes. B. T r e a t i n g the Burns Bog L e a c h a t e t o the Proposed P.C.B. 'AA' L e v e l G u i d e l i n e s In o r d e r to de t e r m i n e t h e optimum pH f o r t r e a t i n g the Burns Bog l e a c h a t e t o t h e proposed P.C.B. 'AA' l e v e l g u i d e l i n e s f o r s p e c i f i c d i s c h a r g e s ( T a b l e I V ) , t h e t r e a t m e n t l e v e l r e q u i r e d must be d e f i n e d . T h i s i s a c c o m p l i s h e d by d e t e r m i n i n g the th r o u g h p u t volume a t wh i c h a p o l l u t a n t f i r s t exceeds t h e p r o p o s e d P.C.B. g u i d e l i n e c o n c e n t r a t i o n . T a b l e s XVI, XVII, X V I I I , and.XIX show a summary o f t h e b r e a k t h r o u g h d a t a at pH 4.8, 7.1, 7.8, and 8.4 r e s p e c t i v e l y . At pH 4.8, Fe and Mn d i d n o t meet t h e 'AA' l e v e l c o n c e n t r a t i o n s hence t r e a t m e n t a t t h i s pH i s n o t p o s s i b l e . At pH 7.1, Mn was t h e l i m i t i n g p o l l u t a n t a t a volume t h r o u g h p u t o f 5.0 l i t e r s . T h i s was f o l l o w e d by Zn a t 7.5 l i t e r s , Fe a t 9.3 l i t e r s , and Pb a t 16.5 l i t e r s throughput.; At pH 7.8, Mn was t h e l i m i t i n g p o l l u t a n t a t 2.0 l i t e r s . T h i s was a g a i n f o l l o w e d by Zn a t 3.7 l i t e r s . A t pH 8.4, Mn was a l s o t h e l i m i t i n g p o l l u t a n t a t a volume throughput o f 5.0 l i t e r s . S i n c e COD was s u b s t a n t i a l l y r educed a t pH 7.1, 7.8, and 8.4, i t was assumed t h a t BOD5 was a l s o r e d u c e d to below t h e p r o p o s e d P.C.B. 45 TABLE XVI_ BREAKTHROUGH DATA SUMMARY pH = 4.8 P a r a m e t e r I n f l u e n t C o n c e n t r a t i o n (mg/1) Lowest E f f l u e n t C o n c e n t r a t i o n (mq/1) P.CB. 'AA' l e v e l g u i d e ! i n e s (mq/1) Volume T h r o u g h p u t b e f o r e ' A A ' l e v e l i s r e a c h e d (1) Fe 26.8 4.8 0.30 < 2 Mn 0.52 0.17 0.05 < 2 Zn 0.43 0.23 0.50 2.5 K 580 170 - . -Na 1400 420 - -- Ca 254 87 -• -Mg 106 48 - -Pb 0.030 < 0.01 0.05 N.A. COD 827 282 - -P - - - -TKN . - - . - -T o t a l S o l i d s : 8002 2302 • - -Suspended S o l i d s 160 50 60 2.5 C l 5400 1550 - • N.A. n o t a p p l i c a b l e 46 TABLE XVII BREAKTHROUGH DATA SUMMARY pH = 7.1 Pa r a m e t e r I n f l u e n t C o n c e n t r a t i on (mg/1) Lowest . E f f l u e n t C o n c e n t r a t i o n (mg/1) P.C.B. ' A A ' l e v e l g u i d e l i n e s (mg/1) Volume Throughput b e f o r e 'AA' l e v e l i s r e a c h e d (1) Fe 30.3 0.17 0.30 9.3 Mn 0.57 0.05 0.05 5.0 Zn 0.43 0.06 0.50 7.5 K 600 10 - -Na 840 35 - _ Ca 175 9 Mg 126 5 - • _ Pb 0.065 < 0.01 0.05 16.5 COD 903 113 - _ P 1.56 0.08 - _ TKN 494 25.8 - _ T o t a l S o l i d s 4636 440 Suspended S o l i d s 134 7 , 60 22.0 Cl 1995 108 - -N.A. - n o t a p p l i c a b l e 47 TABLE WiU BREAKTHROUGH DATA SUMMARY pH = 7.8 Pa r a m e t e r I n f l u e n t C o n c e n t r a t i o n (mg/1) Lowest E f f l u e n t C o n c e n t r a t i o n (mg/1) P.C.B. 'AA' l e v e l q u i d e l i n e s (mg/1) Volume T h r o u g h p u t b e f o r e ' A A ' l e v e l i s r e a c h e d (1) Fe 13.8 0.13 0.30 16.0 + Mn 0.64 0.05 0.05 2.0 Zn 0.78 0.07 0.5 3.7 K 438 76 - -Na 725 40 - -Ca 173 19 - -Mg 39 6.3 - -Pb 0.045 0.025 0.05 N.A. COD 760 117 - -P 1.56 0.07 - -TKN 435 16.8 - -T o t a l S o l i d s 4390 348 _ _ Suspended So l i d s 104 0 60 16.0+ c i 1975 250 - -A l k a l i n i t y (as C a C 0 3 ) 3290 80 - -N.A. - n o t a p p l i c a b l e 48 TABLE X l X BREAKTHROUGH DATA SUMMARY pH = 8.4 P a r a m e t e r I n f l u e n t C o n c e n t r a t i o n (mg/1) Lowest E f f l u e n t C o n c e n t r a t i o n (mg/1) P.C.B. 'AA ' l e v e l g u i d e l i n e s (mg/1) Volume T h r o u g h p u t b e f o r e 'AA' l e v e l i s r e a c h e d (1) Fe 24.5 0.08 0.30 14.0+ Mn 0.45 0.05 0.05 5.0 Zn 0.30 0.08 0.50 N.A. K 570 63 - -Na 1130 110 - -Ca 81 12 - -Mg 123 12 - -Pb 0.040 0.021 0.05 N.A. COD 654 123 - -P 0.92 0.02 - -TKN 402 9.8 - -T o t a l S o l i d s 4974 668 _ _ Suspended S o l i d s 312 11 60 14.0+ Cl 2370 293 - -Al k a l i n i t y (as C a C 0 3 ) 2600 36 - -N.A. - Not A p p l i c a b l e 49 TABLE XX PEAT REQUIREMENTS. FOR THE TREATMENT OF THE BURNS BOG LEACHATE TO THE PROPOSED 'PCB 'AA' LEVEL GUIDELINES pH 4.8 7.1 7.8 8.4 Treatment level Required not possi ble 94.0% 93.0% 89.6% Removal Capaci ty mg/gm 12.6 5.0 13.1 Peat Requi red Kg (dry) / 1000 1 leachate - 159 397 159 50 'AA' level objective. Table XX shows the treatment level required, the capacity of the peat, and the peat required to treat the leachate to the proposed P.C.B. 'AA' guidelines at pH 7.1, 7.8, and 8.4. The same amount of peat is required to treat 1000 l i t e r s of leachate at both pH 7.1 and 8.4. There does not appear to be any advantage then in raising the pH of the leachate to above the naturally occurring pH prior to peat treat-ment . The approximate amount of peat required to treat the Burns Bog leachate to the proposed P.C.B. 'AA' guidelines for specific discharges i s 159 kg of dry peat per 1000 l i t e r s of leachate. On an 3 in-place basis, this represents about 1.5 meter of peat per 1000 l i t e r s of leachate at a in - s i t u moisture content of 91.0 per cent and an 3 assumed wet density of 1.2 gm/cm (13). This estimate may be slightly conservative since the concentrations of pollutants in this research were measured as the total concentrations whereas the proposed P.C.B. guideline for the limiting pollutant, Mn, i s as dissolved concentration. CHAPTER V THE EFFECTS OF A ONE' MONTH REST PERIOD ON ADSORPTIVE CAPACITY As determined in the preceding chapter, large quantities of peat are necessary to treat the leachate to below the proposed P.C.B. 'AA' level guidelines for specific discharges. If restoration of some of the adsorptive capacity of the peat could be achieved by 'resting' the peat following leachate application, reuse of the peat for further leachate treatment might be possible. This would greatly reduce the quantity of peat required over the l i f e of the treatment s cheme. It has long been recognized that resting a septic tank dis-posal f i e l d results in a restoration of the adsorptive capacity of the s o i l . This i s believed to be accomplished when ai r penetrates the s o i l and subsequent aerobic biological activity results i n solids degrada-tion. Since a portion of the adsorbed solids from the leachate are believed biodegradable, i t was thought that resting the peat between leachate applications might regenerate some of the adsorptive capacity of the peat. In order to determine i f resting the peat could improve or restore adsorptive capacity, 14.0 l i t e r s of leachate (pH8.4) was run through the peat column, with samples collected and analyzed every 2.0 l i t e r s . The peat was allowed to drain and l e f t in the column for one 51 52 month. Another 18.0 l i t e r s of leachate, at i t s collected pH of 7.5, was then run through the peat column. The breakthrough curves for each pollutant for the total leachate throughput of 32.0 l i t e r s are shown in Appendix B. Tables XXI, XXII, XXIII, and Figure 9 show the i n d i v i -dual and total metal removals as a function of volume throughput. A restoration of the adsorptive capacity of the peat during the rest period would be indicated by an increase in the slope of the total metal removal curve after the f i r s t 14.0 l i t e r s of leachate throughput. Figure 9 does not indicate this increase, in fact, there appears to be a decrease in the slope, indicating a decrease in the removal capacity over the rest period. It i s believed that this decrease i s due to the fact that the i n i t i a l 14.0 l i t e r s of leachate was at pH 8.4. As mentioned in Chapter IV, a significant increase in the total metal removal occurs at this pH, due to the precipitation and f i l t r a t i o n of metal complexes. Since the leachate throughput following the rest period was at pH 7.5, precipitation and f i l t r a t i o n of metal complexes did not occur and hence there appears to be a decrease in the removal capacity of the peat following the rest period. If the total metal removal curve after the rest period i s compared to the total metal removal curves at pH 7.1 and 7.8 from previous column runs (Fig. 3) there is a very slight increase in the slope of the curves following the rest period. This would indicate that there may be a slight increase in adsorptive capacity. There is no conclusive evidence from the total metal removal 53 TABLE XXI CUMULATIVE METAL REMOVAL BEFORE THE REST PERIOD Volume T h r o u g h p u t ( l i t e r s ) Fe Mn Zn K Na Ca Mg Pb T o t a l Removal 2 mg. I n f . mg. rem. % rem. 49.0 48.8 99.6 0.90 0.78 86.7 0.60 0.32 53.3 1140 1010 88.6 2260 2040 90.2 162 134 82.7 246 221 90.0 .080 .036 45.2 3858 3454 89.5 4 mg. I n f . mg. rem. % rem. 98.0 97.6 99.5 1.80 1.58 87.8 1.20 0.72 60.0 2280 2020 88.6 4520 4080 90.2 324 270 83.5 492 444 90.0 .160 .068 42.5 7717 6920 . 89.7 6 mg. I n f . mg. rem. % rem. 147.0 146.4 99.5 2.70 2.38 88.2 1.80 1.16 64.5 3420 3030 88.6 6780 6120 90.2 486 404 83.1 738 664 90.0 .240 .092 38.3 11,575 10,367 89.6 8 mg. I n f . mg. rem. % rem. 196.0 195.1 99.5 3.60 3.16 87.8 2.40 1.58 66.0 4560 4030 88.4 9040 8130 90.0 . 648 524 80.9 984 875 88.8 .320 .110 34.4 15,434 13,759 89.1 10 mg. I n f . mg. rem. % rem. 245.0 243.8 99.5 4.50 3.91 87.0 3.00 2.00 66.6 5700 5000 87.7 11 ,300 10,050 89.0 810 612 75.5 1230 1071 87.2 .400 .126 31.5 19,292 16,982 88.0 12 mg. I n f . mg. rem. % rem. 294.0 292.5 99.4 5.40 4.64 86.0 2.60 2.44 67.8 6840 5910 86.4 13,560 11,860 87.5 972 657 67.6 1476 1252 84.8 .480 .142 29.6 23,151 19,978 86.3 14 mg. I n f . mg. rem. % rem. 343.0 341.1 99.4 6.30 5.34 84.8 4.20 2.88 68.6 7980 6710 85.0 15,820 13,470 85.4 1134 677 59.6 1722 1413 82.3 .560 .157 28.0 27,010 22,619 83.7 54 TABLE XXII CUMULATIVE METAL REMOVAL AFTER THE REST PERIOD Volume Throu g h p u t ( l i t e r s ) Fe Mn Zn K Na . Ca Mg Pb T o t a l Removal 16 mg. I n f . mg. rem. % rem. 54.4 47.4 87.2 1.12 0.94 84.0 0.80 0.52 65.0 870 470 54.1 1640 680 41.5 328 252 76.9 256 180 70.3 .092 .034 37.0 3150.3 1630.8 51.8 18 mg. I n f . mg. rem. % rem. 108.8 93.8 86.4 2.24 1.86 82.0 1.60 1.03 64.4 1740 740 42.6 3280 1120 34.2 656 472 72.0 512 346 67.6 .184 .064 34.8 6300.8 2774.8 44.0 20 mg. I n f . mg. rem. % rem. 163.2 138.2 84.6 3.36 2.73 81.2 2.40 1.53 63.8 2610 940 36.0 4920 1520 30.9 984 672 68.3 768 492 64.0 .276 .092 34.3 9451.3 3766.5 39.9 22 mg. I n f . mg. rem. % rem. 217.6 179.6 - 82.5 4.48 3.53 - 79.0 3.20 2.02 63.2 3480 1110 31.9 6560 1830 27,9 1312 850 64.7 1024 620 60.5 .368 .116 32.5 12,601.7 4595.2 36.5 24 mg. I n f . mg. rem. % rem. 272.0 217.0 79.8 5.60 4.25 76.0 4.00 2.49 62.3 4350 1260 29.0 8200 2120 25.9 1640 1010 61.6 1280 732 57.2 .460 .138 30.0 15,752.1 5345.9 33.9 26 mg. I n f . mg. rem. % rem. 326.4 250.4 76.8 6.72 4.91 73.0 4.80 2.93 61.1 5220 1400 26.7 9840 2390 24.3 1968 1150 58.5 1536 832 54.1 .552 .158 28.6 18,902.5 6030.4 31.9 28 mg. I n f . mg. rem. % rem. 380.8 278.8 71.8 7.89 5.51 70.5 5.60 3.33 59.5 6090 1520 25.0 11,480 • 2640 23.0 2296 1278 55.7 1792 920 51.3 .644 .177 27.5 22,052.8 6645.8 30.1 30 mg. I n f . mg. rem. % rem. 435.2 302.2 69.5 8.96 6.07 67.8 6.40 3.68 57.6 6960 1620 23.3 13,120 2870 21.8 2624 1390 52.9 2048 996 48.6 .736 .195 26.3 25,203.3 7188.2 28.5 32 mg. I n f . mg. rem. % rem. 489.6 321.6 65.7 10.08 6.59 65.4 7.20 3.98 55.3 7830 1680 21.5 14,760 3080 20.8 2952 1486 50.4 2304 1060 46.0 .828 .212 25.7 28,353.6 7638.4 26.9 N.B. 14.0 l i t e r s i s e q u a l t o z e r o m e t a l removed i n t h i s t a b l e . 55 TABLE X X I I I TOTAL METAL REMOVAL Volume T h r o u g h p u t ( l i t e r s ) T o t a l M e t a l s Volume T h r o u g h p u t ( l i t e r s ) T o t a l M e t a l s 2 mg. I n f l u e n t mg. removed % 3559 . 3455 89.5% 18 mg. I n f l u e n t mg. removed % 33,311 25,395 76.2% 4 mg. I n f l u e n t mg. removed % 7718 6920 89.7% 20 mg. I n f l u e n t mg. removed % 36,461 26,387 72.4% 6 mg. I n f l u e n t mg. removed % 11,576 10,368 89.6% 22 mg. I n f l u e n t mg. removed % 39,611 27,215 68.7 8 mg. I n f l u e n t mg. removed % " . . 15,434 13,759 89.1% 24 mg. I n f l u e n t mg. removed % . " 42,762 27,966 65.4 10 mg. I n f l u e n t mg. removed % 19,293 16,983 88.0% 26 mg. I n f l u e n t mg. removed % 45,912 28,650 62.6 12 mg. I n f l u e n t mg. removed % 23,152 19,979 86.3% 28 mg. I n f l u e n t mg. removed % 49,063 29,266 59.6 14 mg. I n f l u e n t mg. removed % 27,010 22,620 83.7% 30 mg. I n f l u e n t mg. removed % 52,213 29,808 56.8 16 mg. I n f l u e n t mg. removed % 30,160 24,251 80.4% 32 mg. I n f l u e n t mg. removed % 55,363 30,258 54.7 N.B: The one month r e s t p e r i o d o c c u r s a f t e r 14.0 l i t e r s t h o u g h p u t . N.B. Actual Column Run Comparison of Total Metal Removal after the Rest Period with previous column runs at pH 7.1 and 7.8 Volume throughput - l i t e r s Figure 9 Total Metal Removal 57 c u r v e f o r e i t h e r an i n c r e a s e o r d e c r e a s e i n a d s o r p t i v e c a p a c i t y f o l l o w i n g t h e r e s t p e r i o d . However, f u r t h e r i n s i g h t i n t o the e f f e c t s o f t h e r e s t p e r i o d can be g a i n e d by s t u d y i n g t h e i n d i v i d u a l b r e a k t h r o u g h c u r v e s i n Appendix B. The b r e a k t h r o u g h c u r v e s f o r K, Ca, Mg, and Mnshow a r e s t o r -a t i o n o f t h e removal c a p a c i t y o f t h e p e a t f o l l o w i n g t h e r e s t p e r i o d . T h i s i s b e l i e v e d to be due to d e g r a d a t i o n o f p e a t i n t o s m a l l e r p a r t i c l e s t h r o u g h d e s s i c a t i o n o f t h e p e a t d u r i n g the r e s t p e r i o d . The d i s i n t e -g r a t i o n o f the p e a t i n c r e a s e d t h e s u r f a c e a r e a and hence t h e a v a i l a b l e a d s o r p t i o n s i t e s . The i n c r e a s e i n a d s o r p t i o n s i t e s thus r e s t o r e d some o f the a d s o r p t i v e c a p a c i t y o f t h e p e a t . T h i s h y p o t h e s i s i s s u b s t a n -t i a t e d by the t e n f o l d i n c r e a s e i n t h e suspended s o l i d s e f f l u e n t con-c e n t r a t i o n f o l l o w i n g t h e r e s t p e r i o d ( T a b l e B - I ) . The b r e a k t h r o u g h c u r v e s f o r Fe, Zn, P, TKN, and COD, however, do n o t show t h i s r e s t o r a t i o n i n r e m o v a l c a p a c i t y and a c t u a l l y show an i n c r e a s e i n e f f l u e n t c o n c e n t r a t i o n s f o l l o w i n g t h e r e s t p e r i o d . T h e re a r e s e v e r a l p o s s i b l e e x p l a n a t i o n s f o r t h i s o c c u r r e n c e . F i r s t , as mentioned above p r e c i p i t a t i o n and f i l t r a t i o n o f m e t a l complexes d i d n o t o c c u r f o l l o w i n g t h e r e s t p e r i o d due t o the l o w e r pH o f t h e i n f l u e n t l e a c h a t e . T h i s c o u l d e x p l a i n t h e h i g h e r e f f l u e n t c o n c e n t r a t i o n s o f Fe and Zn f o l l o w i n g t h e r e s t p e r i o d . Second, the i n c r e a s e i n t h e e f f l u e n t c o n c e n t r a t i o n s o f t h e above p o l l u t a n t s may be due to t h e l a r g e i n c r e a s e i n suspended s o l i d s f o l l o w i n g t h e r e s t p e r i o d . T h i s i n c r e a s e i n suspended s o l i d s was composed m a i n l y 58 o f p e a t p a r t i c l e s . The peat p a r t i c l e s may have c o n t a i n e d p o l l u t a n t s a d s o r b e d n e a r t h e b ottom o f the p e a t column. R e s e a r c h (6) has i n d i c a t e d t h a t c a t i o n s p r e s e n t i n l a r g e c o n c e n t r a t i o n s i n a l e a c h a t e , i e . Ca, K, Mg, were removed i n the upper l a y e r s o f t h e s o i l i n a s p r a y - i r r i g a t i o n s t u d y . I t i s b e l i e v e d a s i m i l a r phenomenon o c c u r r e d i n t h e p e a t column. Ca, K, and Mg a r e b e l i e v e d to have been removed i n the u p p er p o r t i o n o f t h e column w h i l e p o l l u t a n t s w i t h r e l a t i v e l y low c o n c e n t r a t i o n s s uch as t h e heavy m e t a l s a r e b e l i e v e d to have been removed n e a r t h e b o t t o m o f the column. Thus, the p e a t p a r t i c l e s removed i n t h e e f f l u e n t f o l l o w i n g t h e r e s t p e r i o d may have c o n t a i n e d a d s o r b e d Fe, Zn, and P, o v ershadowing any r e s t o r a t i o n i n a d s o r p t i v e c a p a c i t y o f the p e a t f o r t h e s e p o l l u t a n t s . The i n c r e a s e i n t h e e f f l u e n t c o n c e n t r a t i o n s o f TKN and COD f o l l o w i n g the r e s t p e r i o d i s b e l i e v e d to be due t o p e a t p a r t i c l e s t h e m s e l v e s , s i n c e p e a t i s composed to a l a r g e e x t e n t o f c a r b o n and o r g a n i c n i t r o g e n . A l t h o u g h e f f l u e n t c o l o r was n o t q u a n t i t a t i v e l y measured as a parameter, i t i s o f i n t e r e s t to n o t e t h a t an i n c r e a s e i n e f f l u e n t c o l o r was o b s e r v e d f o l l o w i n g the one month r e s t p e r i o d . I n o t h e r column r u n s , a v i s u a l r e d u c t i o n i n c o l o r was o b s e r v e d , r o u g h l y c o r r e s p o n d i n g t o the degree o f p o l l u t a n t removal. I t appears then t h a t f o r s h o r t c o n t a c t t i m e s , o r g a n i c c o l o r i s removed f r o m the l e a c h a t e by a d s o r p t i o n o n t o the p e a t , however, a t c o n t a c t times o f l o n g e r d u r a t i o n , i . e . days o r months, the l e a c h a t e appears t o absorb c o l o r f r o m the p e a t . I n c o n c l u s i o n , t h e r e appears t o be a s l i g h t r e s t o r a t i o n o f a d s o r p t i v e c a p a c i t y o f t h e p e a t f o l l o w i n g a one month r e s t p e r i o d be-59 l i e v e d t o be due to an i n c r e a s e i n p e a t s u r f a c e a r e a by p a r t i c l e d e g r a -d a t i o n . T h i s i n c r e a s e i n a d s o r p t i v e c a p a c i t y , however, may be o f f s e t by an i n c r e a s e i n suspended m a t e r i a l i n the e f f l u e n t which may a l s o r e s u l t i n an i n c r e a s e i n e f f l u e n t c o n c e n t r a t i o n s o f some p o l l u t a n t s . I f t h i s l o s s o f suspended m a t e r i a l can be p r e v e n t e d i n t h e f u l l - s c a l e t r e a t m e n t scheme, some r e s t o r a t i o n o f a d s o r p t i v e c a p a c i t y may be a c h i e v e d . However, f o r a one month r e s t p e r i o d r e u s e o f the p e a t t o t r e a t the Burns Bog l e a c h a t e t o the proposed P.C.B. 'AA' l e v e l g u i d e -l i n e s f o r s p e c i f i c d i s c h a r g e s i s not c o n s i d e r e d f e a s i b l e . CHAPTER VI DESORPTION OF POLLUTANTS FROM THE PEAT Previous chapters have shown that pollutants are adsorbed by the peat as the leachate percolates through the column. The next area to be examined was the permanence of the adsorption and what effects the expended peat would have on the environment i f l e f t exposed to pre-cipitation and groundwater. To study the possible desorption of pollutants from the peat following leachate throughput, 16.0 l i t e r s of leachate at i t s collected pH of 7.8 were run through the peat column at the normal flowrate of 2 70 l i t e r s / h r . meter . Tap water was then added to the top of the column and a further 41.0 l i t e r s of effluent was collected by gravity flow over a period of several days. The breakthrough data and the breakthrough curves for the total effluent volume of 57.0 l i t e r s are shown in Appendix If the breakthrough curves for the individual pollutants are studied, there appears to be a general trend to increasing effluent con-centrations after 16.0 l i t e r s of throughput as the remaining leachate within the peat voids was flushed out. The effluent concentrations then decrease in an exponential fashion. After about 40 l i t e r s of total throughput the remaining leachate in the peat i s believed to have been completely flushed out and the concentrations of pollutants in the effluent are representative of the desorption that would occur due to percolating water alone. The effluent concentrations after 40.0 l i t e r s throughput are shown in Table XXIV. 60 61 TABLE XXIV DESORPTION OF POLLUTANTS Parameter M i l l i g r a m s e n t e r i n g the Column 0-22 l i t e r s * Mi 11i grams removed i n the t a p w a t e r 22-56 l i t e r s P e r c e n t c o n t a i n e d i n th e t a p w a t e r (col.2TCO1 ,1) C o n c e n t r a t i o n o f p o l l u t a n t s i n the e f f l u e n t a f t e r 40 1 (mq/1) Fe 303.6 48.8 16.1 1.5 Mn 14.1 1.9 13.5 0.03 Zn 17.2 7.2 41.8 0.25 K 9636 2800 29.1 25 Na 15,950 5600 35.1 40 Ca 3806 880 23.1 10 Mg 854 280 32.8 2.0 Pb 1.08 4.1 380 0.18 COD 16,720 18,000 108 500 T o t a l S o l i d s 96,580 38,000 39.3 700 TKN 9570 2400 25.1 25 Cl 43,450 17,600 40.5 100 P 30.4 10.0 32.0 0.25 Al k a l i n i t y (as CaCOj) 72,380 - 19,200 26.5 220 * c o n t r i b u t i o n o f p o l l u t a n t s f r o m t ap w a t e r i s assumed to be n e g l i g i b l e . 62 The.concentrations of Mn, K, Na, Ca, Mg, TKN, Cl, and P in the effluent water are below levels of concern. However, Fe, Zn, Pb, and COD concentrations are relatively high, with Fe and Pb exceeding the'proposed'P.C.B.'..'AA' level guideline concentrations, It i s d i f f i c u l t to determine the actual amount of each pollu-tant desorbed from the peat by the tap water following leachate adsorp-tion. This i s because the volume throughput at which the leachate was flushed out of the column and at which: the.tap water emerged as effluent is not well defined due to mixing of the leachate and the tap water in the column. It i s possible however to determine the relative extent of desorption of individual pollutants by comparing the amount of each pollutant entering the column in the influent leachate to the amount of the pollutant removed by the tap water over a selected volume throughput. This was done by assuming that the volume of leachate remaining in the column after 16.0 l i t e r s throughput was equal to the volume of free water i n the void spaces of the peat. This volume was calculated in Chapter III to be approximately 6 l i t e r s . The amount of each pollutant that entered the column is then equal to the influent concentration of the pollutant in the leachate multiplied by 22 l i t e r s . The contribution of pollutants from the influent tap water is assumed to be negligible. The amount of each pollutant removed in the tap water i s assumed to be equal to the amount of the pollutant contained in the 22 to 56 l i t e r s of throughput as determined from the breakthrough curve. This estimate i s 63 b e l i e v e d t o be c o n s e r v a t i v e because the l e a c h a t e c o n t a i n e d i n t h e p e a t d i d n o t emerge as a p l u g f l o w b u t was mixed w i t h the tap w a t e r . The r e l a t i v e d e s o r p t i o n o f i n d i v i d u a l p o l l u t a n t s can be compared by d i v i d i n g the amount o f each p o l l u t a n t , i n t h e tap water, by the amount o f the p o l l u t a n t t h a t e n t e r e d t h e column. T h i s i s shown i n T a b l e XXIV. T a b l e XXIV shows t h a t t h e d e s o r p t i o n o f Pb and COD was s i g n i -f i c a n t l y g r e a t e r than the d e s o r p t i o n o f o t h e r p o l l u t a n t s . In f a c t , the amount o f Pb and COD removed i n t h e t a p w a t e r was g r e a t e r t h a n t h e amounts t h a t e n t e r e d t h e column i n the l e a c h a t e . T h i s apparent i n c o n g r u i t y can be e x p l a i n e d by r e f e r r i n g to T a b l e VI i n C h a p t e r I I I showing the a n a l y s i s o f t h e n a t u r a l p e a t . From t h i s t a b l e t h e amount o f Pb o r i g i n a l l y p r e s e n t i n t h e p e a t column was a p p r o x i m a t e l y 2 . 9 mg. I t i s r e a s o n a b l e t o assume th e n t h a t some o f the Pb removed by the tap w a t e r was f r o m Pb o r i g i n a l l y p r e s e n t i n t h e n a t u r a l p e a t . S i m i l a r i l y , o r g a n i c m a t e r i a l (COD) f r o m the n a t u r a l .peat was a l s o d e s o r b e d by th e u n c o n t a m i n a t e d tap w a t e r p e r c o l a t i n g t h r o u g h the p e a t . The heavy m e t a l s s u c h as Pb and t o a l e s s e r e x t e n t Zn and Fe were d e s o r b e d t o a much g r e a t e r e x t e n t than the o t h e r p o l l u t a n t s , w i t h t h e e x c e p t i o n o f COD. T h i s may be b e c a u s e o f an exchange e q u i l i b r i u m t h a t e x i s t s between the i o n s i n s o l u t i o n and t h e i o n s a d s o r b e d onto the p e a t . As the l e a c h a t e p e r c o l a t e s t h r o u g h the p e a t , t h e r e i s a g r e a t a f f i n i t y f o r c a t i o n s by the p e a t due.to t h e h i g h c o n c e n t r a t i o n s o f d i s s o l v e d m e t a l s i n th e l e a c h a t e and t h e l a r g e number o f exchange s i t e s a v a i l a b l e i n t h e peat.- T h i s exchange o r a d s o r p t i o n o f c a t i o n s onto the 64 peat c o n t i n u e s u n t i l t h e c a p a c i t y o f t h e p e a t i s e x h a u s t e d . When un-contamin'ated w a t e r p e r c o l a t e s through the column, a r e v e r s e r e a c t i o n o c c u r s . Ions a r e d e s o r b e d from the p e a t to f u l f i l t h e e q u i l i b r i a between the c o n c e n t r a t i o n o f i o n s i n t h e s o l u t i o n and t h e c o n c e n t r a t i o n o f a d s o r b e d i o n s . In a s y n t h e t i c ion-exchange p r o c e s s , the a f f i n i t y o f t h e media f o r s p e c i f i c i o n s depends upon the v a l e n c y o f t h e i o n and t h e a c t i v i t y o f the s o l u t i o n . The a f f i n i t y o f the media f o r b i v a l e n t . i o n s i s much g r e a t e r than f o r monvalent i o n s . However,-ion-exchange r e a c t i o n s a l s o obey the mass law f o r m u l a t i o n ( 1 8 ) , i . e . [ C a ^ R ] [ N a + ] 2 ~ ~ ~ ~ ~ = QNaR -S> CaR [Na Rr [Ca ] Where Q = s e l e c t i v i t y c o e f f i c i e n t R = c a t i o n exchanger Thus, i n a c o n c e n t r a t e d s o l u t i o n o f Na"*", the media may no ++ l o n g e r be s e l e c t i v e f o r b i v a l e n t Ca i o n s , a n d may s e l e c t i v e l y adsorb Na +. T h i s phenomenon c o u l d e x p l a i n why t h e heavy m e t a l i o n s , s u c h as Zn and Pb, were d e s o r b e d from the p e a t . The K, Ma, Ca, and Mg i o n s would be s e l e c t i v e l y a d s o r b e d onto the p e a t due to t h e i r v e r y h i g h c o n c e n t r a t i o n s i n the l e a c h a t e , compared t o t h e c o n c e n t r a t i o n s o f Zn and Pb. I n a s i m i l a r f a s h i o n , t h e Zn and Pb may be s e l e c t i v e l y d e s o r b e d from the p e a t i n t o the p e r c o l a t i n g water due t h e h i g h c o n c e n t r a t i o n s o f o t h e r p o l l u t a n t s competing f o r the a d s o r p t i o n s i t e s . 65 A l t h o u g h t h e e x a c t q u a n t i t i e s o f p o l l u t a n t s d e s o r b e d from t h e expended p e a t c o u l d n o t be d e t e r m i n e d t h e f o l l o w i n g c o n c l u s i o n s can be drawn f r o m t h e b r e a k t h r o u g h d a t a . 1. D e s o r p t i o n o f p o l l u t a n t s does o c c u r by p e r c o l a t i o n o f w a t e r t h r o u g h t h e p e a t f o l l o w i n g l e a c h a t e a d s o r p t i o n , however, the c o n c e n t r a t i o n s o f t h e m a j o r i t y o f p o l l u t a n t s i n t h e e f f l u e n t w a t e r a r e below l e v e l s o f c o n c e r n . 2. COD, Fe, Zn, and Pb a r e d e s o r b e d to a g r e a t e r e x t e n t than o t h e r p o l l u t a n t s . ^ T h e - c o n c e n t r a t i o n s - o f -Fe and-Pb i n the e f f l u e n t w a t e r exceeded t h e p r o p o s e d P.C.B. 'AA' l e v e l g u i d e l i n e c o n c e n t r a t i o n s . 3. The s i g n i f i c a n c e o f the d e s o r p t i o n o f p o l l u t a n t s w i l l depend upon the t y p e o f f u l l - s c a l e t reatment s e l e c t e d a t t h e Burns Bog l a n d f i l l . I n schemes where the p e a t i s d i s p o s e d o f a f t e r l e a c h a t e t r e a t m e n t , l e a c h a t e g e n e r a t e d from r a i n f a l l p e r c o l a t i n g t h r o u g h the e x h a u s t e d p e a t may p r e s e n t - a f u r t h e r p o l l u t i o n p r o b l e m . However, i n a s p r a y - i r r i g a t i o n t r e a t m e n t scheme u s i n g the f i n a l c o v e r o f the l a n d f i l l , t h e d e s o r p t i o n o f p o l l u t a n t s by r a i n f a l l p e r c o l a t i n g t h r o u g h the p e a t c o v e r may n o t be a s e r i o u s p r o b l e m as the c o n t a m i n a t e d w a t e r would n o t escape i n t o t h e environment b u t would be r e c i r c u l a t e d w i t h t h e l a n d f i l l l e a c h a t e . CHAPTER VII CHEMICAL TREATMENT AND PEAT TREATMENT The metal removal data presented i n Chapter IV indicates that Na, K, Ca, and Mg account for more than 98 per cent of the to t a l metals removed in the peat column. The heavy metals make up less than 2 per cent of the total metals removed. It seemed reasonable then that i f the influent concentrations of pollutants.such as Na, K, Ca,.and Mg could be reduced, more of the adsorptive capacity of the peat would be available for heavy metal removal, thus allowing a greater leachate throughput volume for a given treatment level. Chemical treatment of the leachate prior to peat adsorption was considered to be the main pretreatment method which could possibly achieve this goal. In add-itio n chemical treatment would also reduce the influent concentrations of certain heavy metals. The chemicals chosen for i n i t i a l testing were lime, alum, and ferric chloride. These are widely used in water treatment to remove Ca and Mg and in wastewater treatment to remove heavy metals, COD, and P (12, 19, 20). Previous experience also indicated that raising the pH to above 9.0 would induce precipitation and hence pH adjustment using sodium hydroxide was also included in the i n i t i a l tests. Jar testing was undertaken to determine the optimum combinations and dosages of the various chemicals. A. Selection of the Optimum Chemical Treatment Thirty-six jar tests were run using lime (Ca(0H) o), alum 66 67 (A]_2 (SO^)^' 18^0) , and f e r r i c chloride (FeCl^) , separately and in com-bination, in order to determine the optimum combinations and dosages. The procedure used in the j a r tests was as follows. The chemicals were added to the leachate as a powder or a slurry, rapidly mixed at 100 RPM for 1 min., followed by slow mixing at 20 RPM for 5 min. The solutions were then allowed to settle and optimum dosages were determined by visually observing color, turbidity, and the amount of precipitate or floe settled out and by measuring supernatant pH, Fe concentration, and alkalinity. The following conclusions were drawn from this series of tests: 1. Lime, at concentrations of approximately 2000 mg/1, reduces the Fe concentration but does not significantly alter the al k a l i n i t y . The floe settles very rapidly with a f i n a l volume of about 10 per cent. Color and turbidity are decreased. 2. Alum, at 500 mg/1, reduces the Fe concentration by 85 to 90 per cent and the alkalinity by 10 per cent. The rate of settling is very poor with a floe volume of about 20 per cent. At higher con-centrations (up to 7000 mg/1), the rate of settling improves but the solutions remain turbid. 3. Ferric chloride, at 200 mg/1, reduces Fe by up to 90 per cent. Settling i s very fast with very low floe volumes (5 per cent). However color and alkalinity are not substantially altered. 4. Combinations including alum produced very poor settling and large floe volumes. Combinations of lime and f e r r i c chloride do not produce any distinct advantage over either individual chemical. 68 A second series of jar tests was then run using the best s ix dosages and combinations from the f i r s t series and a comprehensive analysis of the supernatant was-carried out. The results are presented in Tables XXV, XXVI, and XXVII. From these results i t is evident that 2000 mg/1 of lime or a combination of about 2000 mg/1 of lime and 300 mg/1 of fer r i c chloride produced the best total removals for the pollutants monitored. A third series of jar tests was run using lime and f e r r i c chloride to determine the optimum dosages for this combination. Five tests were run using lime dosages of 2000, 2500, 3000, 3500, and 4000 mg/1. From these results, 2500 mg/1 of lime was found to be the optimum dosage and five more tests were run using 2500 mg/1 of lime and 0, 200, 400, 600, and 800 mg/1 of f e r r i c chloride. Four jar tests using sodium hydroxide to adjust the pH to 9.0, 9.5, 10.0, and 11.0 were also under-taken to determine what removals could be obtained by pH adjustment alone. The results of these tests are shown in Tables XXVIII and XXIX. Table XXVIII shows that pH adjustment to above 9.5 reduced the Fe concentration approximately the same amount as the combined lime and f e r r i c chloride treatment. However Ca and Mn concentrations were not as effectively reduced and alk a l i n i t y and Na were substantially increased using straight pH adjustment with sodium hydroxide. A combination of 2500 mg/1 of lime and either 200 or 400 mg/1 of f e r r i c chloride provided the best removals. Since only a negligible increase in removals occurred at the higher f e r r i c chloride 69 TABLE XXV ANALYSIS OF THE BURNS BOG LEACHATE AFTER CHEMICAL TREATMENT - TEST SERIES I I ( a l l v a l u e s e x c e p t pH i n mg/1) ( a l k a l i n i t y i n mg/1 as CaCO,) •. P a r a m e t e r T e s t # K Na Ca Mg Fe A l Mn Ba A l k . pH O r i g i n a l Sample 330 880 224 119 21.4 0.45 0.5 0.53 3167 7.3 1 326 808 0.8 77 4.5 0.35 0.2 0.05 1760 8.9 2 326 856 74 107 1.4 0.10 0.2 0.05 2416 8.3 3 325 856 - 154 112 0.6 0.35 0.5 0.05 610 7.2 4 325 864 86 113 2.4 66.0 . .0.5 0.28 ' 0 4.5 5 300 784 14 74 1.4 0.55 0.2 0.05 1900 8.8 6 324 820 14 79 0.8 1.85 0.2 0.05 1780 8.6 TABLE XXVI DOSAGE USED - TEST SERIES I I ( v a l u e s as mg/1) T e s t # C a ( 0 H ) 2 F e C l 3 A 1 2 ( S 0 4 ) 3 - 18H 20 1 2000 0 0 2 0 300 o -3 0 0 3000 4 0 0 5000 5 2000 300 0 6 2000 300 200 TABLE TWIT REMOVAL EFFICIENCIES - TEST SERIES I I T e s t # P e r c e n t Removal o f p a r a m e t e r s e x c e p t a l k a l i n i t y and pH 1 22.7 2 13.3 3 8.0 4 7.4 5 25.4 6 21.2 70 TABLE mTTT ANALYSIS OF THE BURNS BOG LEACHATE AFTER CHEMICAL TREATMENT -TEST SERIES I I I a l l . v a l u e s e x c e p t pH i n mg/1) a l k a l i n i t y i n mg/1 as CaCO,) T e s t # PARAMETER % Removal• e x c e p t A l k . & pH pH A l k a l i n i t y Fe Ca . Mn. Na O r i g i n a l 7.9 3180 20.7 156 0.72 940 1 8.7 2830 10.0 72 0.10 NA 53.6 2 8.7 2830 9.4 71 0.09 NA 54.5 3 8.9 2997 11.2 205 0.39 NA 0 4 9.0 3014 10.7 183 0.35 NA 0 5 NA N A " 9.5 : 19.0 0.32 NA ~ 0 6 8.7 2830 10.9 90 0.13 NA 42.9 7 8.8 2531 1.4 12 0.03 NA 92.4 8 8.7 2348 1.1 12 0.02 NA 92.6 9 8.4 2224 1.0 20 0.02 NA 88.1 10 NA NA 0.8 45 0.03 NA 74.0 11 8.9 3779 7.9 76 0.24 1315 0 12 9.5 NA 1.3 15 0.07 2125 0 13 10.0 5761 2.1 55 0.21 2610 0 1.4 10.5 7326 1.2 _ 72 0.09 3750 0 NA - Not A v a i l a b l e TABLE XXIX DOSAGE USED - TEST SERIES I I I T e s t # DOSAGE USED Ca(OH), (mg/1) F e C l 3 (mg/1) 6N NaOH (ml) 1 2000 0 0 2 2500 0 0 3 3000 0 0 4 3500 0 0 5 4000 .0 0 6 2500 0 0 7 2500 200 0 8 2500 400 0 9 2500 600 0 10 2500 800 0 11 0 0 2.0 12 0 0 . 3.5 13 0 • 0 5.5 14 0 0 8.4 71 dosage, 2500 mg/1 of lime and 200 mg/1 of f e r r i c chloride was chosen as the optimal chemical pretreatment prior to peat adsorption. B. Chemical Treatment Followed by Peat Treatment Following the selection of the optimum combination and dosages of chemicals, batch treatment of 48 l i t e r s of leachate was carried out. Lime and f e r r i c chloride, 2500 mg/1 and 200 mg/1 respectively, were added to the leachate in a large tub, rapidly mixed for 1 min. and then slowly mixed for 5 min. by hand. After overnight-settling, the supernatant was drawn off and a sample analyzed. Table XXX shows the removals-obtained in the batch treatment. The collected supernatant was then run through the peat column. Individual 2.0 l i t e r effluent samples were collected and analyzed. The breakthrough data and the breakthrough curves are presented in Appendix D. In order to compare the combined treatment with peat treatment alone, cumulative removals -as a function of volume throughput were calculated and are shown in Tables XXXI and XXXII. Figure 10 shows the total per cent removal curves for both the combined chemical and peat treatment and peat treatment alone at pH 7.1. A l l removals for the combined treatment are based on the original leachate before chemical treatment. The t o t a l per cent removal curve (Fig. 10), indicates that for the f i r s t 7 l i t e r s of leachate throughput, peat treatment alone produced .slightly better removals than the combined treatment. However after 7 l i t e r s of throughput, the removals from the combined treatment 72 TABLE XXX CHEMICAL TREATMENT N.B. Chemical Treatment using 2500 mg/1 Ca(0H) 9 and 200 mg/1 F e C l 3 L Parameter Concentration before Chemical Treatment Concentration a f t e r Chemical Treatment Percent Removal Fe 13.8 0.83 94.0 Mn 0.64 0.01 98.4 Zn 0.78 0.39 50.0 . K 438 430 1.8 Na 725 706 2.6 Ca 173 11 93.6 " Mg 38.8 13.8 64.4 Pb 0.045 0.019 57.7 Total.Metals 1389.6 1162.0 16.3 COD 760 670 11.8 Total S o l i d s 4340 3688 15.0 Suspended S o l i d s 104 8 92.3 TKN 435 416 4.4 Cl 1975 2300 0 P 1.38 0.18 87.0 pH 7.8 9.0 -A l k a l i n i t y (pH=4.5) 3290 2410 26.7 Concentrat ions as mg/1; except pH) ( a l k a l i n i t y as mg/1 as CaCO-J 73 TABLE XXXI CUMULATIVE METAL REMOVAL: CHEMICAL TREATMENT FOLLOWED BY PEAT TREATMENT Volume T h r o u g h p u t ( l i t e r s ) Fe Mn Zn K Na Ca Mg Pb T o t a l M e t a l Removal 2 mg. I n f . mg. rem. % rem. 27.6 27.5 99.6 1.28 1.18 92.2 1.56 1.32 84.6 876 840 95.9 1450 1400 96.6 345 310 89.9 78 66 84.6 0.090 0.040 44.4 2779 2646 95.2 4 mg. I n f . mg. rem. % rem. 55.2 55.0 99.6 2.56 2.34 91.4 3.12 2.58 82.7 1752 1680 95.9 2900 2800 96.6 690 616 89.3 156 130 83.3 0.180 0.066 36.6 5559 5286 95.1 6 mg. I n f . mg. rem. % rem. 82.8 82.4 99.4 3.84 3.46 90.1 4.68 3.94 82.1 2628 2500 95.1 4350 4140 95.2 1035 906 87.5 234 189 80.8 0.270 0.078 28.9 8339 7825 93.8 8 mg. I n f . mg... rem. % rem. 110.4 109.7 99.4 5.12 4.48 87.5 6.24 5.10 " 81.7 3504 3240 " 92.5 .5800 5360 92.4 1380 1176 85.2 312 241 77.2 0.360 0.078 21.7 11,117 10,137 91.2 10 mg. I n f . mg. rem. % rem. 138.0 136.9 99.2 6.40 5.44 85.0 7.80 6.36 81.5 4380 3960 90.4 7250 6480 89.4 1725 1411 81.8 390 287 73.6 0.45 0.062 13.8 13,897 12,286 88.4 12 mg. I n f . mg. rem. % rem. 165.6 164.0 99.0 7.68 6.38 83.1 9.36 7.60 81.2 5256 4630 88.1 8700 7480 85.0 2070 1626 78.6 468 333 71.1 0.54 0.036 6.7 16,677 14,247 85.4 14 mg. I n f . mg. rem. % rem. 193.2 191.1 98.9 8.96 7.33 81.8 10.92 8.80 - 80; 6 6132 5250 85.6 -10,150 8360 82.4 2415 1841 76.2 -546 381 69.8 0.63 0.002 0.3 19,456 16,039 82.4 16 mg. I n f . mg.-rem. % rem. -: 220.8 218,2 : 98.8. 10.24 8.35 - 81 .'5.". 12.48 10.04 80.4 •7008 " 5790 -82.6 11 ,600 -- 9080 -78.3 2760 2087 75.6 624 433 69.4" 0.72 -0.044 0 22,235 17,626 79.3 18 mg. I n f . mg. rem. % rem. 248.4 245.2 98.7 11.52 9.41 81.7 14.04 11.32 80.6 7884 6290 79.8 13,050 9710 74.4 3105 2347 75.6 702 489 69.7 0.81 -0.098 0 25,015 19,101 76.4 20 mg. I n f . mg. rem. % rem. 276.0 272.2 98.6 12.80 10.51 82.1 15.60 12.62 80.9 8760 6720 76.1 14,500 10,250 70.8 3450 2627 76.1 780 549 70.4 0.90 -0.16 0 27,795 20,451 73.6 22 mg. I n f . mg. rem. % rem. 303.6 299.1 98.5 14.08 11.63 82.6 17.16 13.92 81.1 9636 7120 73.8 15,950 10.740 67.8 3795 2917 76.9 858 611 71.2 0.99 -0.24 0 30,574 21,712 71.0 24 mg. I n f . mg. rem. % rem. 331.2 325.9 98.4 15.36 12.77 83.1 18.72 15.12 80.8. 10,512 7460 71.0 17,400 11,140 64.0 4140 3213 77.6 936 . 677 72.3 1.08 -0.34 0 33,354 22,844 68.5 N.B. removals i n c l u d e b o t h c h e m i c a l t r e a t m e n t and p e a t t r e a t m e n t and a r e based on the t o t a l removal f o r t h e t o t a l volume t h r o u g h p u t . 74 TABLE XXXII CUMULATIVE REMOVALS: CHEMICAL TREATMENT FOLLOWED BY PEAT TREATMENT \ Thr /olume 'oughput i t e r s T o t a l S o l i d s Suspended S o l i d s COD TKN P C l 2 mg; I n f . mg. rem. % rem. 8780 8000 91.1 208 200 96.1 1520 1300 85.5 870 860 98.9 . 2.76 2.72 98.6 3950 3710 93.9 4 mg. I n f . mg. rem. % rem. 17,560 16,000 91.1 416 400 96.1 3040 2620 86.2 1740 1710 98.3 5.52 5.44 98.6 7900 7320 92.7 6 mg. I n f . mg. rem. % rem. 26,340 23,600 89.6 624 598 95.8 4560 3880 85.1 2610 2540 97.3 8.28 8.17 98.7 11,850 10,670 90.0 8 mg. I n f . mg. rem. % rem. 35,120 30,500 86.8 832 786 94.5 6080 4980 81.9 3480 3340 96.0 11.04 10.83 98.1 15,800 13,420 84.9 '"lO mg. I n f . mg. rem. % rem. 43,900 36,900 84.1 1040 960 .92.3 7600 5980 78.7 4350 4110 94.5 13.80 13.41 97.2 19,750 15,570 78.8 12 mg. I n f . mg. rem. ' % rem. 52,680 42,600 80.9 1248 1116 89.4 9120 6780 74.3 5220 - 4820 92.3 16.56 15.97 96.4 23,700 16,920 71.4 14 mg. I n f . mg. rem. % rem. 61,460 47,300 77.0 1456 1276 87.6 10,640 7440 69.9 6090 5490 90.1 19.32 18.53 95.9 27,650 17,870 64.6 16 mg. I n f . mg. rem. % rem. 70,240 51,500 73.2 1664 1450 87.1 12,160 7900 65.0 6960 6090 87.5 22.08 21.09 95.5 31,600 18,320 58.0 18 mg. I n f . mg. rem. % rem. 79,020 55,500 70.2 1872 1634 87.3 13,680 8100 59.2 7830 6630 84.7 24.84 23.63 95.1 35,550 18,370 51.7 20 mg. I n f . mg. rem. % rem. 87,800 . 59,300 67.5 2080 1822 87.6 15,200 8200 53.9 8700 7140 82.1 - 27.60 26.15 94.7 39,500 18,020 45.6 22 mg. I n f . mg. rem. % rem. 96,580 62,800 65.0 2288 2008 87.8 16,720 8140 48.7 9570 7610 79.5 30.36 28.65 94.3 43,450 17,470 40.2 24 mg. I n f . mg. rem. % rem. 105,360 65,900 62.5 2496 2184 87.5 18,240 7980 43.8 10,440 8010 76.7 33.12 31.10 93.9 47,400 16,870 35.6 N.B. r e m o v a l s i n c l u d e b o t h c h e m i c a l t r e a t m e n t and p e a t t r e a t m e n t and a r e based on t h e t o t a l removal f o r t h e t o t a l volume t h r o u g h p u t . 24,000 Volume throughput - l i t e r s Figure 10 Total Metal Removal: Combined Treatment 76 exceed the removals from peat treatment alone as was expected. The combined treatment then did not produce any overall increase i n total metal removal at the lower throughput volumes even though the chemical treatment alone removed 16.3 per cent of the total metals from the influent leachate. Further insight into the effectiveness of the combined chemical and peat treatment can be gained by referring to the breakthrough curves in Appendix D. If the individual breakthrough curves for the combined treatment and the peat treatment alone at pH 7.1 (Appendix A) are com-pared, the general trend observed i s that the effluent concentrations are approximately equal for the i n i t i a l few l i t e r s of throughput. As the throughput volume increases, the effluent concentrations for the combined treatment remain about 20 per cent lower than for the peat treatment alone. This reflects the same trend observed in the total per cent removal curves (Fig. 10) where the removals for the combined treatment surpass the removals for the peat treatment alone after about 7 l i t e r s of throughput. Also of interest from the breakthrough curves i s that the effluent concentrations of Mn, Ca, Mg, and Pb are higher than their influent concentrations prior to peat treatment. This explains •why no increase in total per cent removal was observed for the combined treatment for the f i r s t 7 l i t e r s of throughput. Although significant reductions of Ca, Mg, Mn, and Pb were achieved by chemical treatment, they were desorbed-from the peat during percolation of the chemically treated leachate through the column, 77 n u l l i f y i n g any o v e r a l l increase i n t o t a l metal removal. This desorption was probably due to the phenomenon previously described. In t h i s case, the influent concentrations of Mn, Ca, Mg, and Pb were very low following chemical treatment (Table XXX) . In order to restore the exchange vi e q u i l i b r i a between the cations i n solution and the cations adsorbed onto the peat, desorption of the cations from the peat to the solution occurred, increasing the effluent concentrations of these cations to ab ove t h e i r i n f l u e n t concentrations. The drop i n the effluent concentrations of Mg, Ca, and Mn after about 12 l i t e r s throughput i s f e l t to be caused by the increase i n pH of the effluent as throughput volumes increased (Table D-I). As the pH increased desorption i s thought to have ceased and p r e c i p i t a t i o n and f i l t r a t i o n of Mg, Ca, and Mn complexes to have occurred. The peat capacity for t o t a l metals and the peat requirements to treat 1000 l i t e r s of leachate for the combined treatment and for the peat treatment alone are compared i n Table XXXIII. Table XXXIII indicates that for treatment l e v e l s above 90 per cent, i . e . 90 per cent of the t o t a l metals entering the column are removed, peat treatment alone provides better treatment. At treatment levels of less than 90 per cent, combined chemical and peat treatment offers some reduction i n the peat required. For example, at the 75 per cent treatment l e v e l , the reduc-tion i n peat weight required with combined treatment i s 18.9 kg. of dry peat per 1000 l i t e r s of leachate. In order to determine i f chemical pretreatment i s j u s t i f i e d at t h i s treatment l e v e l , the savings i n peat 78 TABLE XXXIII PEAT. REMOVAL CAPACITIES Treatment Level Capaci t y Peat Treatment Alone (pH = 7.1) Chemi c a l Treatment and Peat Treatment 75% mg/gm: Peat Req'd: 22.8 63.0 . 25.0 44.1 85% mg/gm: Peat Req'd: 19.9 83.5 18.0 72.0 90% mg/gm: Peat Req'd: 16.9 107 13.5 107 95% mg/gm: Peat Req'd: 11.4 . 180 6.8 264 Proposed P.C.B. 'AA' Level Guide-1 i nes Treatment Level mg/gm: Peat Req'd: 94.0% 12.6 159 95.2% 5.0 397 Capacity as mg. of metals per gm. dry peat. Peat Requirements as kg. of dry peat per 1000 l i t e r s of lea c h a t e . 79 costs must be compared to the increased capital costs, the increased operational costs, and the sludge disposal costs for the chemical pre-treatment. Table XXXIV presents a summary of the breakthrough data and the limiting throughput volumes for the individual pollutants for the combined chemical and peat treatment. Mn i s the limiting pollutant at a volume throughput of 2.0 l i t e r s when the leachate i s treated to the proposed P.C.B. 'AA'level guidelines. This represents a peat require-ment of 337 kg. dry peat per 1000 l i t e r s of leachate, well in excess of the peat requirements for peat treatment alone (Table XXXIII). In conclusion, chemical treatment followed by peat treatment does not provide any advantage over peat treatment alone when treating the Burns Bog leachate to the proposed P.C.B. 'AA' level guidelines for specific discharges. Combined treatment actually produces a lower quality effluent due to the desorption of Pb and Mn from the peat. At lower treatment levels (less than 90 per cent), the com-bined treatment does reduce the peat requirements. The significance of this w i l l depend upon the reduction in peat costs compared to the increased costs for chemical pretreatment. These costs w i l l vary depend-ing upon the type of full-scale treatment scheme selected. Since the chemically-treated leachate was run through the peat column at the resultant pH of 9.0, i t i s reasonable to assume that peat adsorption may be. improved and hence the peat requirements reduced i f the pH was adjusted to 7.1. Chapter IV indicated that optimum adsorp-80 TABLE XXXIV BREAKTHROUGH DATA SUMMARY Chemical Treatment f o l l o w e d by Peat Treatment Parameter I n f l u e n t Concentration (mg/1) (before C.T.) Lowest E f f l u e n t Concentration (mg/1) P.C.B. 'AA' l e v e l guide!ines (mg/1) Volume Throughput before 'AA'level i s reached (1) Fe 13.8 0.05 0.30 19.0 Mn 0.64 0.05 0.05 2.0 Zn 0.78 0.10 0.50 24.0+ K 438 15 - -Na 925 30 - -Ca 173 17 - -Mg 38.8 6.3 - -Pb 0.045 0.021 0.05 8.0 COD 760 80 - -P 1.38 < 0.02 - -TKN 435 5 - -Total Sol i d s 4390 340 - -Suspended Sol i d s 104 4 60 24.0+ ci 1975 120 - -Al kal i ni t y (as CaC0 3) 3290 44 — — 81 t i o n o c c u r r e d a t t h i s pH. I t i s b e l i e v e d , however, t h a t d e s o r p t i o n o f Mn, Pb, Ca, and Mg would s t i l l o c c u r and s i n c e Mn r e p r e s e n t s the l i m i t i n g p o l l u t a n t , no s i g n i f i c a n t i n c r e a s e i n t h r o u g h p u t volume would o c c u r . C h e m i c a l t r e a t m e n t a l o n e r e d u c e d a l l o f t h e m e t a l s p r e s e n t i n t h e Burns Bog l e a c h a t e t o below the p r o p o s e d P.C.B. 'AA' l e v e l g u i d e l i n e s w i t h t h e e x c e p t i o n o f Fe ( T a b l e XXX). However COD and t o t a l k j e l d a h l n i t r o g e n were n o t s u b s t a n t i a l l y a l t e r e d and C l c o n c e n t r a t i o n s were a c t u a l l y i n c r e a s e d . I n a d d i t i o n to t h e r e l a t i v e l y p o o r p e r f o r m ance o f c h e m i c a l t r e a t m e n t , -very c a r e f u l c o n s i d e r a t i o n , would have :.to be g i v e n to s l u d g e d i s p o s a l and e f f l u e n t pH a d j u s t m e n t i f t h i s • t r e a t m e n t method were t o be c o n s i d e r e d . CHAPTER VIII TOXICITY ASSESSMENT In recent years, bioassay tests to evaluate the toxicity of a wastewater to the biological l i f e in the receiving water have gained increasing popularity. It is f e l t that toxicity assessments, using the native species of the receiving water, provide a better understanding of the impact of a wastewater on the receiving environment than the often arbitrary effluent standards set by regulatory agencies. Toxicity tests were run on the original leachate and on the treated leachate to determine i f there i s a potential toxicity problem from the Burns Bog leachate and i f i t can be reduced by the proposed treatment methods. The standard toxicity test used i s the 96 hr. TLm bioassay or the concentration of the waste (volume/volume) that w i l l k i l l 50 per cent of the test organisms in 96 hr. Pollutech Pollution Advisory Ser-vices Limited of North Vancouver carried out a 96 hr. TLm bioassay on the natural Burns Bog leachate, in accordance with the procedures set down in the Federal Government Standardization Program (21). Ten gallon test tanks were used containing 30 l i t e r s of test solution with a fish density of 1.2 gram of fish per l i t e r of test solution (10 fish per tank). Rainbow trout were used as the test species. Dissolved oxygen was main-tained at approximately 90 per cent saturation using glass bubblers connected to an oil-free compressed air source. Dechlorinated city tap water was used for both dilution and control purposes. The TLm value is obtained by plotting concentration of leachate (per cent vol/vol) 82 83 versus the percentage survival of the test fish after 96 hr. on semi-logarithmic paper, then determining the concentration of leachate lethal to 50 per cent of the test fish. A second toxicity assessment called the Rapid Toxicity Asses-ment (RTA) developed by Pollutech, was used to evaluate the toxicity of the natural leachate and the treatment effluents. The advantage of the RTA over the 96 hr. TLm i s that i t i s much faster, cheaper, and considerably less sample volume i s required. The RTA is performed by placing fish in sealed containers (500 ml.) containing seria l dilutions of leachate, then measuring residual oxygen in the container after death of the fish. High levels of residual oxygen indicate that death was due to the toxic effects of the leachate, whereas low dissolved oxygen levels indicate death from asphyxiation. The RTA threshold level i s obtained by plotting f i n a l dissolved oxygen versus leachate concentration on logarithmic paper. The intersection of the resulting lines ('effect' line having a positive-slope and the--'no effect-' line-having zero slope)--i s the threshold level. Studies done by Pollutech (22) indicate that for pulp m i l l wastewaters, the RTA threshold level and the 96 hr. TLm value are essentially equal with the RTA slightly higher than the TLm for values less than 40 per cent vol/vol and the opposite occurring for values greater than 40 per cent. Table XXXV shows the RTA and TLm results for the tests run on the natural leachate, the chemically-treated leachate,the effluents from 84 TABLE XXXV RTA AND T L m RESULTS m Sample # > Sample I n i t i a l pH RTA *pH u n a d j u s t e d RTA *pH = 7.0 96 HR TL m *pH u n a d j u s t e d P e a t T r e a t m e n t 1 I n f l u e n t 7.5 4.9 16.7 7.0 2 0 - 2 1 7.3 n o t t o x i c 3 2 - 4 1 7.4 70 4 4 - 6 1 7.8 50 5 6 - 8 1 7.9 28 6 8 - 1 2 1 7.7 26 7 12 - 16 1 7.7- 21 Ch e m i c a l T r e a t m e n t and -P e a t T r e a t m e n t 8 I n f l u e n t ( c h e m i c a l l y t r e a t e d ) 9.2 2.34 15.7 9 0 - 6 1 6.9 n o t t o x i c 10 6 - 12 1 7.4 90 11 12 - 18 1 7.4 43 i 12 18 - 24 1 7.9 16 E f f l u e n t f r o m 13 t h e D e s o r p t i o n t e s t (Chap. VI) 7.8 no t t o x i c * A l l r e s u l t s e x p r e s s e d i n p e r c e n t volume/ TABLE XXXVI EFFLUENT ANALYSIS FOR RTA AND JL SAMPLES Sample No. .Fe Mn Zn K Na Ca Mg Pb COD TKN Cl P Total Sol ids Alk. 1 13.8 0.64 0.78 438 725 173 38.8 0.045 760 435 1975 1.38 4390 3290 • 2 0.13 0.05 0.16 16 40 19 6.3 0.025 117 16.8 250 0.07 348 80 ' 3 0.14 0.07 0.07 37 75 20 6.9 0.029 119 29 350 0.002 480 164 4 0.25 0.08 1.5 . 88 156 29 8.8 0.030 231 67 600 0.03 872 390 5 0.27 0.08 0.23 144 256 37 9.6 0.030. 301 113 863 0.04 1304 700 6 0.19 0.10 0.43 142 259 38 11.1 0.041 319 112 969 0.03 1366 655 7 0.20 0.11 0.29 187 350 46 11.9 0.041 413 146 1369 0.08 1846 820 8 0.83 0.01 0.39 430 706 - 11 13.8 0.020 670 416 2300 0.18 '3688 2410 9 0.07 0.06 0.14 18 44 22 7.9 0.036 100 11.6 203 0.02 427 53 10 0.21 0.16 0.15 81 168 54 15.1 0.053 277 56 920 0.11 1238 163 11 0.27 0.13 0.17 168 352 53 12.9 0.058 542 130 . 1771 0.11 2243 416 12 0.34 0.08 0.15 246 461 28 7.9 0.084 778 205 2213 0.13 2579 727 13 1.5 0.03 0.28 21 36 13 1.5 0.18 572 22 80 0.25 716 220 (All values as mg/1) (Alkalinity as mg/1 as CaCO.,) 86 peat treatment alone and from combined chemical and peat treatment, and the effluent from the desorption test discussed in Chapter VI. Table XXXVI shows the concentrations of pollutants in the above tests. The RTA threshold level i s slightly lower than the 96 hr. TLm value (4.9 per cent compared to 7.0 per cent) for the natural leachate at the unadjusted pH of 7.5 (Table XXXV). This i s as predicted from the Pollutech studies and indicates that the RTA threshold levels for the leachate effluent samples closely reflect the 96 hr. TLm values. Table XXXV also shows the dramatic effect of pH on leachate toxicity. The RTA toxicity for the natural leachate decreased from 4.9 per cent vol/vol to 16.7 per cent vol/vol upon adjustment of the pH from 7.5 to 7.0. Similarily, the RTA toxicity of the chemically-treated leachate shows a seven times decrease from 2.3 per cent to 15.7 per cent upon adjustment of the pH from 9.2 to 7.0. There are several possible causes for this increased toxicity of pH's above 7.0. One explanation may be due to the increased toxicity of ammonia nitrogen at higher pH's. McKee and Wolf (23) point out that the toxicity of a given concentration of ammonium compounds i s increased by 200 per cent upon an increase in pH from 7.4 to 8.0 due to the increase in the more toxic ammonium hydroxide form. Since both the natural leachate and the chemically-treated leachate contain very high ammonia nitrogen concentrations (approximately 400 mg/1), this may be the major cause of the increased toxicity. Another possibility for the increased toxicity is the pre-cipitation of heavy metals that occurs as the pH increases. Research (23) 87 has indicated that much of the k i l l i n g action in bioassays using trout has been attributed to coatings of iron oxides or hydroxide precipitates on the g i l l s . A third possible cause may be due.to the increased toxicity of the zinc complexes formed at high pH's (24). Figure 11 shows a comparison of RTA versus volume throughput for peat treatment alone and for combined chemical and peat treatment. The figure shows that i t i s possible to run approximately 6.0 l i t e r s of chemically-treated leachate through the peat column before the effluent becomes toxic,- whereas after only about 2.0 l i t e r s of throughput, the peat treated effluent becomes toxic. Table XXXVII presents a comparison of the peat treatment effluent and the combined treatment effluent over 6 to 12.liters of throughput. The concentrations of the heavy metals are approximately the same in both samples, however, the RTA toxicity of the peat treatment alone i s 27 per cent vol/vol whereas the RTA toxicity of the combined treatment is-90 per-cent vol/vol.- It appears then that toxicity may not be entirely due to heavy metals. The greater toxicity of the peat treatment effluent i s believed to be due to a combination of the sl i g h t l y higher pH and the higher TKN concentration. This hypothesis can be further substantiated by comparing the RTA values for the natural leachate and the chemically-treated leachate at pH 7.0. The RTA values are approximately the same (16.7 per cent for the natural leachate and 15.7 per cent for the chemically-treated leachate) even though the heavy metal concentrations were significantly reduced by the chemical treatment. This again indicates that the toxicity may be caused by pollutants other 88 Volume throughput - l i t e r s Figure 11 RTA versus Volume Throughput 89 TABLE XXXVII COMPARISON OF 6-12 LITERS OF THROUGHPUT VOLUME PARAMETER PEAT TREATMENT 6-12 1 COMBINED TREATMENT 6-12 1 RTA 27% 90% Fe 0.23 0.21 Mn 0.09 0.16 Zn 0.33 0.15 K 143 81 Na 258 168 Ca 37.5 54 Mg 10.3 15.1 Pb 0.036 0.053 COD 310 277 TKN 112 56 Cl 916 920 P 0.04 0.11 Total S o l i d s 1335 1238 . A l k a l i n i t y .677 163 pH 7.8 7.4 ( a l l values except pH and RTA as mg/1) ( a l k a l i n i t y as mg/1 as CaCOo) 90 than heavy metals, possibly ammonia nitrogen. An RTA was also run on the f i n a l 10 l i t e r s of collected effluent from the desorption test. The effluent proved to be non-toxic even though the concentrations of Fe and Pb exceeded the proposed P.C.B. 'AA' level guidelines for specific discharges (Table XXIV). This again indicates that leachate toxicity may not be entirely due to the high heavy metal concentrations. Although i t i s d i f f i c u l t to determine the mechanisms of toxicity in a complex wastewater such as a l a n d f i l l leachate, i t i s possible to draw several conclusions from the toxicity assessments. F i r s t , pH has a major effect on the toxicity of the Burns Bog leachate. At pH's above 7.0, toxicity increases dramatically. Past research at U.B.C. using a high strength lysimeter leachate has shown that toxicity also increases as pH is reduced below 6.0. Second, i t appears that toxicity may not be entirely due to the high heavy metal concentrations present. Ammonia nitrogen appears to play a significant role in determining leachate toxicity. Third, i t is.possible to treat the Burns Bog leachate to a non-toxic level using either peat treatment alone or combined chemical treatment and peat treatment. Chemical treatment alone did not reduce the toxicity of the natural leachate. CHAPTER IX SUMMARY A sanitary l a n d f i l l leachate, such as the Burns Bog leachate, can be! effectively treated to a quality considered acceptable for re-lease to the environment by using peat as an adsorptive medium. Chemical treatment also proved to be effective i n reducing the concentrations of heavy metals present in the leachate. The key points in"the peat treatment of the Burns Bog leachate can be summarized as follows: 1. The Burns Bog leachate i s a relatively low strength leachate. It i s similar to many of the leachates found at other l a n d f i l l s in the Lower Mainland. The concentrations of most of the pollutants varied only about 10 per cent over the seven month collection period with the minimum concentrations occurring"during the low flow period i n September. 2. The peat used in the research was an amorphous - granular peat containing woody-fine fibres obtained from the Burns Bog peat bog near the l a n d f i l l site. The natural peat contained significant quantities of Pb, Zn, Fe, and Mn. 3. The optimum pH for peat adsorption was 7.1. At pH 4.8, adsorption dropped off dramatically. The total removal of pollutants increased at pH 8.4 due to the precipitation and removal by f i l t r a t i o n of metal complexes, however, i n i t i a l effluent concentrations were higher than those at pH 7.1. 91 92 4. At the 95 per cent treatment level (i.e. 95 per cent of the total metals entering the column are removed), the removal capacity of the peat at pH 7.1 is 11.4 mg. of metals per gram of dry peat. The peat required to treat 1000 l i t e r s of leachate to this level i s 180 kg. of dry peat. At the 85 per cent treatment le v e l , the removal capacity and the peat requirements are 19.9 mg/gm. of dry peat and 83.5 kg./lOOO l i t e r s of leachate respectively. At the 75 per cent treatment le v e l , the removal capacity and the peat requirements are 22.8 mg./gm. of dry peat and 63.0 kg./lOOO l i t e r s of leachate. 5. In order to treat the Burns Bog leachate to the proposed P.C.B. 'AA' level guidelines for specific discharges, a treatment level of 94.0 per cent would be required at pH 7.1, the natural pH of the leachate. The amount of peat that would be required i s 159 kg. of dry 3 peat per 1000 l i t e r s of leachate or approximately 1.5 meters of i n -place peat at a moisture content of 91.0 per cent and an assumed i n -3 place density of 1.2 gm./cm. . 6. Resting the peat for one month following i n i t i a l leachate addition appears to slightly restore some of the adsorptive capacity of the peat. However, an increase in effluent suspended solids containing adsorbed pollutants following the rest period, offsets any gain in adsorptive capacity. 7. Desorption of pollutants from the peat used for leachate treatment does occur by the percolation of water through the peat. 93 Heavy metal ions, such as Fe, Zn, and Pb, and COD are desorbed to a greater extent than pollutants such as Ca, Na, K, Mg, TKN, P, and Cl. However, a Rapid Toxicity Assessment run on the effluent from the desorption test proved to be non-toxic even though Fe and Pb concentra-tions exceeded the proposed P.C.B. 'AA' level guidelines. Chemical treatment and combined chemical treatment and peat treatment, of the Burns Bog leachate were also studied as possible treat-ment alternatives. The results are summarized as follows: 1. Lime and f e r r i c chloride at concentrations of 2500 mg/1 and 200 mg/l respectively, produced optimum treatment for the removal of Fe, Ca, and Mn. 2. Chemical treatment alone produced substantial removals of Fe, Mn, Zn, Ca, Mg, Pb, and P, however, COD, K, Na, TKN, and Cl were not significantly altered. 3. Combined chemical treatment and peat treatment did not provide any distinct advantage over peat treatment alone at treatment levels greater than 90 per cent. At treatment levels less than 90 per cent, some saving i n the peat volume required could be realized. 4. In order to treat the Burns Bog leachate to the proposed P.C.B. 'AA' level guidelines, a treatment level of 95.2 per cent i s required. The amount of peat required to treat the leachate to this level i s 397 kg. dry peat per 1000 l i t e r s , which greatly exceeds the peat requirements for peat treatment alone. 5. An exchange or adsorption e q u i l i b r i a exists between the 94 c o n c e n t r a t i o n o f i o n s i n t h e l e a c h a t e and the c o n c e n t r a t i o n o f a d s o r b e d i o n s i n the p e a t . I n d i v i d u a l p o l l u t a n t s a r e e i t h e r a d s o r b e d from s o l u -t i o n onto the peat o r d e s o r b e d f r o m the p e a t i n t o s o l u t i o n d e pending upon a number o f f a c t o r s s uch as the i n f l u e n t c o n c e n t r a t i o n o f t h e p o l l u t a n t , t h e a v a i l a b l e a d s o r p t i o n c a p a c i t y i n the p e a t , and the t o t a l i o n i c s t r e n g t h o f the l e a c h a t e . T h i s phenomenon i s b e l i e v e d r e s p o n s i b l e f o r t h e i n c r e a s e i n the e f f l u e n t c o n c e n t r a t i o n s o f Mn, Pb, Ca, and Mg above t h e i r i n f l u e n t c o n c e n t r a t i o n s a f t e r c h e m i c a l t r e a t m e n t i n th e combined t r e a t m e n t column ru n . T o x i c i t y assessments u t i l i z i n g the R a p i d T o x i c i t y Assessment (RTA) and the 96 h r . TLm b i o a s s a y were run on t h e n a t u r a l l e a c h a t e and the t r e a t m e n t e f f l u e n t s . The f o l l o w i n g i s a summary o f t h e r e s u l t s : 1. I t i s p o s s i b l e to t r e a t the Burns Bog l e a c h a t e to a n o n - t o x i c l e v e l u s i n g e i t h e r p e a t t r e a t m e n t a l o n e o r combined c h e m i c a l and p e a t t r e a t m e n t . The t h r o u g h p u t volume p o s s i b l e b e f o r e t h e e f f l u e n t becomes t o x i c i s about t h r e e times g r e a t e r f o r t h e combined t r e a t m e n t than f o r t h e p e a t t r e a t m e n t a l o n e . 2. The pH o f the l e a c h a t e i s a major f a c t o r i n d e t e r m i n i n g i t s t o x i c i t y . Above pH 7, t o x i c i t y i n c r e a s e s d r a m a t i c a l l y . P r e v i o u s r e s e a r c h has i n d i c a t e d t h a t t o x i c i t y a l s o i n c r e a s e s below pH 6. 3. The t o x i c i t y o f t h e l e a c h a t e does n o t appear t o be due e n t i r e l y to t h e h i g h heavy m e t a l c o n c e n t r a t i o n s p r e s e n t i n the l e a c h a t e . Ammonia n i t r o g e n may a l s o p l a y a s i g n i f i c a n t r o l e i n d e t e r m i n i n g l e a c h a t e t o x i c i t y . CHAPTER X CONCLUSIONS AND RECOMMENDATIONS Peat treatment appears to be a practical method of treating the Burns Bog leachate to a quality considered acceptable for release to the receiving environment. The preceeding chapter presented a summary of the key results found i n this research. The purpose of this chapter i s to examine the implications of these results, to explore possible full-scale peat treatment schemes at the Burns Bog l a n d f i l l , and to suggest the direction of pilot-scale research considered necessary to answer many of the questions raised. A. Conclusions The major conclusions drawn from the research are as follows: 1. There is no advantage in raising the pH of the leachate prior to peat treatment when treating the leachate to the proposed P.C.B. 'AA' level guidelines for specific discharges. At lower treatment levels (i.e. less than 90 per cent removal of the total metals) some reduction in the peat requirements may be realized i f the pH i s increased to 8.4. This i s due to the precipitation and the subsequent removal by f i l t r a -tion of metal complexes. 2. The peat removal capacities and hence the peat requirements determined in the research are believed to be conservative for the two reasons. F i r s t , contact times in the f i e l d w i l l l i k e l y be greater. The flowrate or application rate used in a full-scale treatment system 95 96 w i l l be significantly lower than the laboratory flowrate of 70 liters/hr./ 2 meter . The depth of peat w i l l probably also be greater than the depth used in the laboratory column (15 cm.). The lower flowrate should also eliminate the clogging problems encountered in the laboratory column when high concentrations of influent suspended solids occurred. Second, wall-effects leading to short-circuiting of the leachate through the peat column w i l l be eliminated in the f i e l d . This may also increase the actual removals obtained i n a full-scale treatment scheme. The peat used in this research contained a f a i r l y high natural metal content (Table VI). A significant fraction of the adsorptive capacity of the peat had therefore been exhausted before leachate was applied. It i s not known i f the metal concentrations present in the peat used are representative of the metal concentrations found in the entire Burns Bog peat bog, but i t i s reasonable to assume that an increase in the adsorptive capacity of the peat could be obtained, i f peat with a lower natural metal content could be utilized-for the -treatment of the leachate. The f i n a l cover material used at the Burns Bog l a n d f i l l i s composed of a mixture of peat and clay. The effect of the clay on the removal capacities determined in this research i s not known. However since clay is known to have a reasonable adsorptive capacity for cations (6), i t i s believed that the clay w i l l not significantly affect the overall removal capacity of the cover material. 3. It i s believed that restoration of the adsorptive 97 capacity of the expended peat by resting the peat does have some possib i l i t y . However f i e l d studies using longer rest periods and natural climatic conditions are necessary to determine i f reuse of the peat for leachate treatment i s feasible. 4. Desorption of some pollutants may occur due to rainwater percolating through the expended peat. The design of a full-scale treatment scheme should be such that percolating water can be controlled and treated.if required before release to the receiving water. 5. Combined chemical treatment and peat treatment does not offer any advantage over peat treatment alone at the treatment levels required to satisfy the proposed P.C.B. 'AA' level guidelines for specific discharges. At lower treatment levels, combined treatment does offer some reduction in the peat requirements, however, i t i s believed that the savings would be offset by the increase in capital and operational costs and the added problem of sludge disposal with chemical -pretreatment. 6. Chemical treatment alone using lime and f e r r i c chloride reduces the heavy metals concentrations but does not reduce the toxicity of the leachate. This toxicity i s believed due to the high ammonia nitrogen concentration remaining i n the chemically-treated leachate. For this reason chemical treatment i s not considered to be.an accept-able treatment method. B. Peat Treatment Schemes at the Burns Bog L a n d f i l l The f i r s t step i n the design of a f u l l - s c a l e treatment scheme 98 at the Burns Bog l a n d f i l l i s the collection of the leachate. For-tunately, this step is relatively simple since the leachate emerges within ten feet of the toe of the f i l l due to consolidation of the underlying peat layer. A series of ditches could be constructed around the l a n d f i l l s i t e to allow the leachate to be.collected before i t has been diluted with the water in the drainage ditches (Fig. l ) . The collected leachate could then be stored in a holding pond or treated directly. Aeration of the leachate i n order to reduce the ammonia con-centrations could be incorporated at this point. Three major types of peat treatment schemes have been pro-posed: a peat bed separate from the l a n d f i l l s i t e , spraying the leachate over the bog, or spraying the leachate over the f i n a l cover of the l a n d f i l l . 1. Separate Peat Bed This type of peat treatment scheme would u t i l i z e a peat bed separate from the l a n d f i l l . Contact between the leachate and the peat could be accomplished either.by spraying the leachate_over the peat or by constructing storage ponds and allowing the leachate to percolate through peat dikes. The advantage of this type of system is that i t allows complete control of the treated leachate and any rain water that may contain desorbed pollutants. The disadvantages of this system are that a large land area eparate from the l a n d f i l l i s required, disposal of the exhausted peat in such a way that i t does not present a further pollution problem is required, and the capital and operating costs may be substantially higher than for the alternate schemes. s 99 2. S p r a y - I r r i g a t i o n U t i l i z i n g t h e P e a t Bog The advantage o f t h i s scheme i s . s i m p l i c i t y . a n d low c o s t . The c o l l e c t e d l e a c h a t e c o u l d . b e s p r a y e d o v e r the e x i s t i n g p e a t bog, a l l o w i n g t r e a t m e n t o f the l e a c h a t e t o o c c u r as i t p e r c o l a t e s t h r o u g h t h e i n - s i t u p e a t . However, t h i s t y p e o f t r e a t m e n t i s n o t c o n s i d e r e d to be a c c e p t -a b l e a t the Burns Bog l a n d f i l l f o r s e v e r a l r e a s o n s . F i r s t , t h e r e i s no c o n t r o l o v e r the degree o f l e a c h a t e t r e a t m e n t t h a t o c c u r s and no a c c u r a t e method o f d e t e r m i n i n g e f f l u e n t q u a l i t y . Second, d e s o r p t i o n of p o l l u t a n t s by e i t h e r p r e c i p i t a t i o n o r groundwater i s i m p o s s i b l e t o c o n t r o l . T h i s c o u l d r e s u l t i n g r o s s c o n t a m i n a t i o n o f t h e groundwater due t o the p r o x i m i t y o f the water t a b l e t o the ground s u r f a c e . T h i r d , - f u t u r e r e u s e of the p e a t bog may be e f f e c t e d by the h i g h l e v e l s o f p o l l u t a n t s t h a t may be p r e s e n t i n t h e p e a t . The e f f e c t s o f l e a c h a t e s p r a y i n g on v e g e t a t i o n o r w i l d l i f e i s n o t known. F o u r t h , o d o r s and n u i s a n c e i n s e c t s may a l s o be a problem. 3. S p r a y - I r r i g a t i o n U t i l i z i n g t h e F i n a l Cover o f the L a n d f i l l S p r a y i n g t h e c o l l e c t e d l e a c h a t e o v e r the f i n a l p e a t / c l a y c o v e r o f the l a n d f i l l appears t o be t h e b e s t method o f l e a c h a t e t r e a t -ment a t the Burns Bog l a n d f i l l . Two methods o f o p e r a t i o n u t i l i z i n g t h e f i n a l c o v e r o f the l a n d f i l l have been p r o p o s e d depending upon the q u a n t i t y o f l e a c h a t e c o l l e c t e d and the d i l u t i o n a v a i l a b l e i n the r a i n y s e a s o n . One method i s to c o l l e c t and s p r a y the l e a c h a t e o v e r t h e f i n a l c o v e r i n the summer months, a l l o w i n g i t t o r e c i r c u l a t e t h r o u g h the r e f u s e . In t h e r a i n y s e a s o n , when s u f f i c i e n t d i l u t i o n i s a v a i l a b l e , the c o l l e c t e d 100 leachate could be.released to the drainage system. This method thus treats the leachate in two ways: peat treatment by the peat cover and treatment by recirculating the leachate through the refuse (12). The second method of operation is to spray the leachate over the peat cover year round. Collection of the treated leachate after i t passes through the peat cover would then be necessary. This 'could be accomplished by a series of collection pipes between the f i n a l cover and the refuse, allowing a portion of the treated leachate and rainwater, to percolate through the refuse and the remainder to be collected and released to the drainage system. This could serve the dual purpose of reducing the quantity of leachate produced and providing some dilution of the treated leachate prior to release. The f i r s t system is obviously the most attractive. Capital costs and operating costs would be much lower since the installation and maintenance of collection pipes i s not required. Power-costs would also be lower with the f i r s t method of operation-since-spraying would only be done in the dry season. The advantage of both these systems is . that desorption of pollutants from the expended peat by rainwater can be controlled. The disadvantage of using a spray-irrigation treatment system i s that problems with odors and nuisance insects may arise. Interference with future reuse of the site should also be considered since leachate treatment may be required for several years. C. Pilot-Scale Studies This research has shown that peat treatment appears to be a 101 practical method of treating the Burns Bog leachate to an acceptable quality prior to release to the receiving water. The optimum pH for adsorption and the approximate removal capacities of the peat at var-ious treatment levels have also been determined. Questions about the possible restoration of the adsorptive capacity of the expended peat by resting the peat and the possible desorption of adsorbed pollutants from the peat by percolating rainwater have been pa r t i a l l y answered in the laboratory. It is f e l t that the next logical step is to set up a pilot-scale peat treatment study at the Burns Bog l a n d f i l l site with the following objectives in mind: 1. To determine i f a spray-irrigation treatment scheme u t i l i z i n g the f i n a l cover of the l a n d f i l l i s feasible on a pilot-scale basis. 2. To determine the most effective and economical method of operation of a spray^irrigation treatment scheme. 3. To determine the peat- requirements per-volume—of -leachate at an acceptable effluent quality. 4. To examine the effectiveness of combined peat treatment and leachate recirculation through the refuse. 5. To determine i f restoration of the adsorptive capacity of the expended peat is possible by:. resting the expended peat for longer periods (6 to 12 months). 6. To determine the significance of the desorption of pollu-tants from the expended peat by percolating rainwater in the proposed treatment schemes. 102 7. To.determine the e f f e c t s t h a t v e g e t a t i o n has on the p r o -posed t r e a t m e n t schemes. This c o u l d i n c l u d e t h e - p o s s i b l e i n c r e a s e i n e v a p o t r a n s p i r a t i o n and.hence the p o s s i b l e r e d u c t i o n o f l i q u i d volumes p e r c o l a t i n g through the r e f u s e . The removal o f a d s o r b e d p o l l u t a n t s such as P, N, o r t r a c e m e t a l s from the p e a t by v e g e t a t i v e growth c o u l d a l s o be examined. The p o t e n t i a l t o x i c i t y o f this v e g e t a t i o n t o f o r a g i n g a n i m a l s s h o u l d a l s o be s t u d i e d . 8. To determine the l o n g term e f f e c t s o f the p r o p o s e d t r e a t -ment scheme. Is t h e r e s u f f i c i e n t c o v e r m a t e r i a l to t r e a t the l e a c h a t e over the l e n g t h o f time t h a t l e a c h a t e t r e a t m e n t may be n e c e s s a r y ? W i l l d e s o r p t i o n o f adsorbed p o l l u t a n t s cause a s e r i o u s p o l l u t i o n p r o b l e m a f t e r l e a c h a t e t r e a t m e n t has ceased? W i l l t h e h i g h l e v e l s o f p o l l u -t a n t s i n t h e p e a t c o v e r a d v e r s e l y a f f e c t the r e u s e o f t h e s i t e ? These q u e s t i o n s s h o u l d be answered b e f o r e a f u l l - s c a l e t r e a t m e n t system i s c o n s t r u c t e d . The p i l o t - s c a l e p r o j e c t c o u l d be s e t up by i s o l a t i n g o r con-s t r u c t i n g a p o r t i o n o f t h e l a n d f i l l s u c h t h a t t h e l e a c h a t e produced i n t h i s s e c t i o n c o u l d be c o l l e c t e d . C o l l e c t i o n p i p e s c o u l d be i n s t a l l e d u n d e r n e a t h t h e f i n a l c o v e r on one s e c t i o n o f t h e p r o j e c t t o s t u d y y e a r round s p r a y - i r r i g a t i o n . A n o t h e r s e c t i o n o f the p r o j e c t c o u l d b e . u t i l i z e d t o s t u d y s p r a y - i r r i g a t i o n i n t h e summer months o n l y . T h i s s e c t i o n would r e c i r c u l a t e t h e t r e a t e d l e a c h a t e t h r o u g h the r e f u s e l a y e r . P r e c i p i t a -t i o n c o u l d a l s o be m o n i t o r e d to d e t e r m i n e the e f f e c t s o f d i l u t i o n and d e s o r p t i o n on b o t h methods of o p e r a t i o n . H y d r o l o g i c d a t a on t h e q u a n t i t y 103 o f l e a c h a t e p r o d u c e d and the d i l u t i o n w a t e r a v a i l a b l e a t v a r i o u s t i m e s i o f the y e a r i s a l s o r e q u i r e d i n o r d e r t o determ i n e t h e optimum method o f o p e r a t i o n . T h i s r e s e a r c h has shown t h a t p e a t t r e a t m e n t may be an e f f e c -t i v e and e c o n o m i c a l method o f t r e a t i n g l e a c h a t e from t h e Burns Bog l a n d -f i l l . I t i s f e l t t h a t t h e use o f p e a t as a t r e a t m e n t medium a t o t h e r s a n i t a r y l a n d f i l l s where l e a c h a t e g e n e r a t i o n p r e s e n t s a p o l l u t i o n p r o b l e m may-also be f e a s i b l e . C o n t i n u e d r e s e a r c h i n t o the use o f p e a t i n p o l l u t i o n abatement i s i n d e e d m e r i t e d . 104 LIST OF REFERENCES. 1. Hughes, G., Tremblay, J., Anger, H., D'Cruz, J., "Pollution of Groundwater Due to Municipal Dumps", Technical Bulletin No. 42, Inland Waters Branch, Department of Energy, Mines and Resources, Ottawa, Canada, 1971, 98 pp. 2. Zanoni, A. E., "Groundwater Pollution From Sanitary Landfills and Refuse Dump "Grounds - A C r i t i c a l Review", Department of Natural Resources, Madison, Wisconsin, 1971, 43 pp. 3. Hannigan, T., City of Vancouver, Personal Communication, March, 1975. 4. BRIEF for presentation-at-the-PUBLI-C INQUIRY- INTO-MUNICIPAL TYPE-WASTE DISCHARGES"ON LAND,"the City of Vancouver, February 1973. 5. "Peat Moss: An Alternative Adsorption Medium", Water and Pollution Control, 112, No. 8, p. 18, August 1974. - 6. Bramble, G. M., "Spray Irrigation of Sanitary La n d f i l l Leachate", M.Sc. Thesis, Department of C i v i l and Environmental Engineering, University of Cincinnati, 1973, 135 pp. 7. Lidkea, T.R., "Treatment of Sanitary L a n d f i l l Leachate with Peat", M.A.Sc. Thesis, Department of C i v i l Engineering, University of Br i t i s h Columbia, September 1974, 61 pp. 1 8. Tinh, V. Q. , Leblanc, R. ,._Janssens,-J. M. , and Ruel, M. , "Peat Moss, A Natural-Adsorbing Agent for^the Treatment of Polluted Water", The Canadian Mining and. Metallurgical Bulletin, 64, No. 707, pp. 99-104,. March 1971. 9. D'Hennezel and Coupal.B., "Peat Moss: A Natural Adsorbent for Oil S p i l l , "The Canadian Mining and Metallurgical Bulletin, 65, No. 717, pp. 51-53, 1972. " 10. Lalancette, J. M.. and Coupal, B., "Recovery of Mercury from Polluted Water Through Peat Treatment", University of Sherbrooke, Sherbrooke, Quebec, from Symposium on Peat Moss in Canada, Univer-s i t y of Sherbrooke, A p r i l 24-25, 1972. 11. Kelly, H. G. and Cameron, R. D., "Pollutants from Refuse Dumps, Solid Wastes Technical Report No. 2", University of Brit i s h Colum-bia, Department of C i v i l Engineering, Pollution Control Group, December 1971, 47 pp. 105 12.. Pohlandy F. G. , "Sanitary L a n d f i l l Stabilization with Leachate Recycle and Residual Treatment",- School of C i v i l Engineering, Georgia Institute of Technology, Atlantaj Georgia, 1975, 102 pp. 13. MacFarlane, I. C., Muskeg Engineering•Handbook, University of Toronto Press, 1969.. 14. Buckman, H. 0. .. and Brady, N. C. , The Nature and Properties of  Soils, The MacMillan Co., New York, 1968. 15. Baver, L. D., Soil Physics, 3rd Ed., J. Wiley and Sons Inc., New York, 1956. 16. Standard Methods for the Examination of Water arid Wastewater, 13th Edition, American Public Health Association, 1971. 17. - Cameron, R. D. and McDonald, E. C. , "Investigation of Leaching From Simulated Landfills, Interim Report No. 2, Procedures for the Analysis of Leachate", University of B r i t i s h Columbia, Department of C i v i l Engineering, Pollution Control Group, March 1974, 33 pp. 18. Fair, G. M. , Geyer, J. -C. . and 0kun,_ D. A. , Water and Wastewater  Engineering, Vol. 2, J. Wiley and Sons, Inc., New York, 1968. 19. Ho, S., Boyle, W. C. and Ham, R. K., "Chemical Treatment of Leachates from Sanitary Lan d f i l l s " , Journ. Water Pollution Control  Fed., 46, No. 7, pp. 1776-1791, 1974. 20. Thornton, R. J. and Blanc, F. C. , "Leachate Treatment by Coagu-lation and Precipitation", Journ. Environmental Engineering Div., Proc. Amer. Soc. C i v i l Engineers,- 99, No.. EE4-, pp. 535-544, 1973. 21. Davis, J. C. and Hoos, R. A. W., "Standardization.of Salmonid Bioassay Procedures Using Sodium Pentachlorophenate and Dehydroabietic Acid as Reference Toxicants", Inter-laboratory Cooperative Study, Journ. Fish Research Board, Canada,. 32, No. 3, pp. 411-416, 1975. 22. "Applicability of the Rapid Toxicity Assessment Procedure as an Environmental Monitoring Parameter for the Pollution Control Branch", Pollutech Pollution Advisory Services Limited, June 1973. 23. McKee, J. E. and Wolf, H. W., Water Quality Criteria, 2nd Ed., California State Water Resources Control Board, 1971. 24. Mount, D. I., "The Effect of Total Hardness and pH on Acute Toxicity of Zinc to Fish", Air and Water Pollution Int. Jour., 10, No. 1, pp. 49-56, 1966. 106 APPENDIX A BREAKTHROUGH DATA FOR PEAT COLUMNS AT pH 4.8,7.1, 7.8, 8.4 TABLE A-I Breakthrough Data f o r Peat Columns at pH 4.8, 7.1, 7.8, 8.4 Vol ume Throughput (1 i t e r s ) E f f l u e n t concent ;ra t i o n (mq/1) F e Mn pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 2.0 • 4.8 0.35 0.13 .0.08 0.17 0.06 0.05 0.06 4.0 14.0 0.17 0.14 0.09 0.38 0.05 . 0.07 0.05 6.0 12.2 0.19 0.25 0.13 0.35 0.05 0.08 0.05 8.0 19.2 0.17 0.27 0.13 0.42 0.08 0.08 . . 0.06 10.0 18.7 0.26 0.19 0.08 0.42 . 0.10 0,10 0.07 12.0 18.8 2.00 0.18 0.31 0.44 0.12 0.09 0.09 14.0 17.3 3.83 0.20 0.12 0.42 0.15 0.10 0.10 16.0 17.2 4.70 0.21 0.41 0.16 • 0.11 18.0 17.8 5.82 0.41 0.19 20.0 18.0 5.00 0.41 0.18 22.0 18.5 5.95 0.41 0.20 24.0 16.0 ,' 9.10 0.41 . 0.22 I n f 1 26.8 30.30 13.8 24.5 0.52 0.57 0.64 0.45 Inf. 2 30.3 30.30 13.8 26.5 0.57 0.57 0.64 0.60 (Continued...) TABLE A-I ( C o n t i n u e d ) Volume E f f l u e n t C o n c e n t r a t i o n (ma/1) Th r o u g h p u t ( l i t e r s ) Zn pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 2.0 0.23 0.12 0.16 0.14 , 170 10 16 65 4.0 0.60 0.06 0.07 0.10 410 12 37 63 6.0 0.48 0.36 1.5 0.08 405 50 88 63 8.0 0.51 0.31 0.23 0.09 • 505 100 144 65 10.0 0.46 0.96 0.65 0.09 505 190 137 82 12.0 0.46 0.12 0.20 0.09 505 320 146 102 14.0 0.39 0.14 0.13 0.07 500 415 175 155 16.0 0.35 0.14 0.44 500 410 200 18.0 0.38 0.15 503 480 20.0 0.34 0.14 505 490 22.0 0.34 0.14 510 520 24.0 0.32 0.27 , 501 550 I n t ^ 0.43 0.43 0.78 0.30 580 600 438 570 I n f 0 0.43 0.43 0.78 0.30 600 600 438 595 I n f 1 - I n f l u e n t t o the column I n f 2 - I n f l u e n t a t the c o l l e c t e d pH TABLE A-11 B r e a k t h r o u g h Data f o r P e a t Columns a t pH 4.8, 7.1, 7.8, 8.4 Volume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t ;ion (mq/1) Na Ca pH = 4.8 pH = 7.1 pH =7.8 pH = 8.4 pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 2.0 420 35 ; 40 120 87 10 19 14 4.0 805 40 75 110 204 9 20 12 6.0 980 115 156 n o 219 18 29 12 8.0 1260 185 256 120 244 30 37 18 10.0 1240 340 250 160 244 34 36 ; 36. 12.0 1220 . 515 268 225 252 42 39 58 14.0 1195 625 325 310 250 52 44 75 16.0 1220 690 • 375 256 53 48 18.0 1220 730 • i 256 60 20.0 1225 740 256 57 22.0 1240 795 258 63 24.0 1245 815 256 66 I n ^ 1400 840 725 1130 254 175 173 81 I n f 2 840 840 725 900 175 175 173 80 O vo ( C o n t i n u e d . . . ) TABLE A - I I ( C o n t i n u e d ) Volume T h r o u g h p u t (1 i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mq/1) V g Pb pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 pH = 4.8 pH = 7.1 pH = 7 . 8 pH = 8.4 2.0 48 5 6.3 14 <0.005 <0.005 0.025 0.021 4.0 88 6 6.9 12 0.020 <0.005.. 0.029 0.025 6.0 88 13 8.8 13 0.010 <0.005 0.030 0.028 8.0 102 23 9,6 18 <0.005 <0.005 0.030 0.040 10.0 102 33 9.6 23 <0.005 <0.005 0.041 0.028 12.0 104 47 10.6 33 <0.005 0.010 0.040 0.032 14.0 103 58 11.5 42 <0.005 0.042 0.040 0.030 16.0 106 62 12.2 0.010 0.042 0.042 18.0 106 67 0.010 0.070 20.0 106 67 0.020 0.050 22.0 102 72 0.010 0.060 24.0 74 0.020 0.065 I n f ^ 106 126 39 123 0.030 0.065 0.045 0.040 I n f 2 126 126 39 127 0.065 0.065 0.045 0.048 H 1 Inf.] :- I n f l u e n t t o t h e column I n f ? - I n f l u e n t a t the c o l l e c t e d pH TABLE A - I I I B r e a k t h r o u g h Data f o r P e a t Columns a t pH 4 .8 , 7 .1 , 7 .8 , 8.4 Vol ume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mg/1) CO D T o t a l S o l i d s pH = 4 . 8 pH = 7.1 pH =7 .8 pH = 8.4 pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 2.0 282 173 117 129 2302 474 .'348 672 4.0 . 587 113 119 133 5756 440 480 668 6.0 575 135 231 165 5736 670 872. 692 8.6 732 180 301 158 7176 932 1304 • 760 10.0 700 277 310 179' 7118 1424 1320 960 12.0 732 416 327 229 7092 2136 1412 1328 14.0 . 678 509 368 . 299 7050 2230 1688 . 1676 16.0 815 572 458 7018 2858 2004 18.0 735 599 7142 3076 20.0 746 596 7268 3158 22.0 853 623 7502 3280 24.0 694 800 7232 3474 Int^ 827 903 760 654 8002 4636 4350 4974 I n f 2 903 903 760 672' 4636 4636 4390 4474 ( C o n t i n u e d . . . ) TABLE A - I I I ( C o n t i n u e d ) Volume Th r o u g h p u t ( l i t e r s ) / • . E f f l u e n t C o n c e n t r a t i o n (mg /1 ) Suspended S o l i d s TK N pH = 4 . 8 pH = 7.1 . pH = 7 . 8 pH = 8 . 4 pH = 4 . 8 pH = 7 . 1 pH = 7 . 8 pH = 8 . 4 2 . 0 50 37 , o,. 11 2 5 . 8 1 6 . 8 1 4 . 0 4 . 0 100 13 0 26 o 2 6 . 9 2 8 . 8 1 1 . 2 . 6 . 0 94 . 7 4 58 —i 4 2 . 0 6 7 . 0 , 9 . 8 8 . 0 88 8 4 32 7 3 . 9 . 113 1 6 . 8 1 0 . 0 100 10 10 16 1 2 3 . 2 109 1 7 . 9 1 2 . 0 80 . 30 6 16 < 2 0 8 . 3 115 31 .1 1 4 . 0 84 43 12 23 > 2 7 1 . 6 132 4 5 . 4 1 6 . 0 . 84 66 16 2 9 1 . 2 161 1 8 . 0 80 50 3 3 2 . 4 2 0 . 0 104 54 3 3 8 . 8 2 2 . 0 104 54 bo 3 6 4 . 0 2 4 . 0 76 224 . rr 3 8 7 . 0 I n f ] 160 134 104 312 494 435 402 I n f 2 134 134 104 105 494 435 414 Inf-j - I n f l u e n t t o the column I n f 0 - I n f l u e n t a t t h e c o l l e c t e d pH TABLE A-IV B r e a k t h r o u g h Data f o r P e a t Columns a t pH 4 .8 , 7 .1 , 7.8, 8.4 Volume E f f l u e n t C o n c e n t r a t i o n (ma /1) T h r o u g h p u t Cl . i ' P ( l i t e r s ) pH = 4.8 pH = 7.1 pH = 7.8 pH = 8.4 pH = 4.8 pH = 7.1 pH = 7.8 pH.= 8.4 2.0 1550 108 250 293 . 0.14 0.066 0.02 4.0 3450 170 350 295 o . 0.10 0.002 0.19 6.0 3650 460 600 313 —I 0.07 • 0.026 N.D. 8.0 4450 630 : 863 445 0.10 0.044 N.D. 10.0 4550 1160 938 683 0.13 0.026 0.04 12.0 4600 1500 1000 1038 < 0.20. 0.002 N.D. 14.0 4620 1750 125b 1386 0.26 0.090 0.02 16.0 4700 2050 ' 1488 l-H 0.26 0.066 18.0 4900 2180 r— 0.3.2 20.0 4800 2240 > 0.22 22.0 5000 2400 CO 0.27 24.0 4800 2300 I— 0.34 I n ^ 5400 2400 1975 2370 m 1.56 1.30 0.92 -I n f 2 2400 '2400 1975 2300 1.56 1.30 1.15 N.D. Not D e t e c t a b l e ( C o n t i n u e d . . . ) TABLE A-IV ( C o n t i n u e d ) Vol ume T h r o u g h p u t (1 i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mq/1 e x c e p t pH) P H A l k a l i n i t y (pH=4.5) . pH = 4 . 8 pH = 7.1 pH = 7 . 8 pH = 8 . 4 pH = 4 . 8 pH = 7.1 pH = 7 . 8 pH = 8 . 4 2 . 0 ZZ 7.1 6 , 9 • ZZ ZZ. \ 80 40 4 . 0 O o 7 . 5 6 . 6 o o 164 40 6 . 0 —1 —1 7 . 8 6 . 7 —1 —1 . 390 36 8 . 0 8 . 0 6 . 9 700 60 1 0 . 0 > > 7 . 8 . 7 . 2 > > 650 90 1 2 . 0 < 7 . 8 7 . 4 < < 660 120 1 4 . 0 > 7 . 8 7 . 7 > 740 - 220 1 6 . 0 I - H 7 . 8 1—1 1—1 900 1 8 . 0 r~ -1— r- r-2 0 . 0 > > • > > 2 2 . 0 co co CD CO. 2 4 . 0 r~ m m r— r~ I n t ^ 4 . 8 7.1 7 . 8 ' 8 . 4 m m 3290 2600 I n f 2 7.1 7.1 7 . 8 7 . 8 3290 3126 I—1 Inf-j - I n f l u e n t t o the column E I n f 2 - I n f l u e n t a t the c o l l e c t e d pH ( a l k a l i n i t y i s mg/1 as CaCO,) Figure A-l : Breakthrough Curves for Fe 0.8 r -Influent Concentration: 0.64 mg/1 _(pH = 7.8) I.C. - 0.57 mg/1 (pH I.C. = 0.52 mg/1 (pH I.C. = 0.45 mg/1 (pH = 7.1 0 7.1) 4.8) 8.4) 8 1 0 1 2 l«t 1 6 1 8 2 0 2 2 2«t Volume Throughput - l i t e r s Figure A-2: Breakthrough Curve for Mn Figure A-3: Breakthrough Curves for Zn 60 6 ti o u c a ti o u c cu rH MH CH W 600 500 400 U 300 200 L_ 100 Influent Concentration = 600 mg/1 (pH =7.1) I.C. = 580 mg/1 (pH = 4.8) I.C. = 570 mg/1 (pH = 8.4) I.C. = 438 mg/1 (pH - 7.8) 8 10 12 14 16 18 20 22 2H Volume throughput - l i t e r s Figure A-4: Breakthrough Curves for K Volume throughput - l i t e r s Figure A-5: Breakthrough Curves for Na h-' Influent Concentration = 254 mg/1 (pH = 4.8) o 0 2 i+ 6 8 1 0 1 2 Ik 1 6 1 8 2 0 2 2 2k Volume throughput- l i t e r s Figure A-6: Breakthrough Curves for Ca 120 Influent Concent^ I.C. _= 123 mg/.l (pH = 8.4) 0 2 k 6 8 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2k Volume throughput - l i t e r s Figure A-7: Breakthrough Curve for Mg Figure A-8: Breakthrough Curves for Pb E Z T Volume throughput- l i t e r s . Figure A-10: Breakthrough Curve for Total Solids 400 360 6 320 1 C 280 o • H J-i n) M 240 •U C CU a c 200 o o •U 160 c <u 3 r H UH 120 M-l W 80 40 Influent Concentration = 312 mg/1 (pH =8.4) I.C. = 160 mg/1 (pH = 4.8) I.C. = 134 mg/1 (pH = 7.1) = 104 mg/1 (pH =7.8) Volume throughput "'liters Figure A - l l : Breakthrough Curve for Suspended Solids 500 Influent Concentration = 494 mg/1 (pH = 7.1) I.C. = 435 mg/1 (pH - 7.8) 2 4 6 8 10 12 Ik 16 18 20 22 2k Volume throughput - l i t e r s Figure A-12: Breakthrough Curves for Total Kjeldahl Nitrogen (TKN) 2.0 _ c o CO U u c (1) O c o u c 01 3 tH cw CH W 1.8 I 1.6 S i 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 Influent Concentration = 1.56 mg/1 (pH = 7.1) I.C. = 1.30 mg/1 (pH = 7.8) pH = 7.1 I.C. = 0.92 mg/1 (pH = 8.4) Figure A-13: Breakthrough Curve for P Volume throughput- l i t e r s NJ Influent Concentration = 5400 mg/1 (pH =4.8) tt 6 8 10 12 Ik 16 18 20 22 2k Volume throughput- l i t e r s Figure A-14: Breakthrough Curve for Cl I 4000 Volume throughput - l i t e r s Figure A-15: Breakthrough Curves for Alkalinity (pH =4.5) N> VO APPENDIX B BREAKTHROUGH DATA SHOWING EFFECTS OF A ONE MONTH REST PERIOD ON PEAT ADSORPTION 131 TABLE B-I B r e a k t h r o u g h Data Showing t h e E f f e c t s o f a One Month R e s t P e r i o d on P e a t A d s o r p t i o n N.B. R e s t p e r i o d o c c u r s a f t e r 14.0 l i t e r s Volume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mg/1) Fe Mn Zn K Na Ca Mg Pb 2.0 0.08 0.06 0.14 65 120 14 14 0.021 4.0 0.09 0.05 0.10 63 no 12 12 0.025 6.0 0.13 0.05 0.08 63 no 12 13 0.028 8.0 0.13 0.06 0.09 65 120 18 18 0.040 10.0 0.08 0.07 0.09 82 160 36 23 0.028 12.0 0.31 0.09 0.09 102 225 58 33 0.032 14.0 0.12 0.10 0.07 155 310 75 42 0.030 I n f 24.5 0.45 0.30 570 1130 •81 123 0.040 16.0 2.6 0.08 0.14 185 480 38 13 0.024 18.0 5.7 0.12 0 J 5 325 650 65 54 0.040 20.0 5.0 0.13 0.16 325 648 58 56 0.046 22.0 7.1 0.13 0.14 353 660 75 67 0.051 24.0 8.8 0.21 0.16 355 670 83 74 0.034 26.0 11.2 0.23 0.22 370 675 94 80 0.026 28.0 13.2 0.27 0.19 380 700 98 . 82 . 0.040 30.0 15.9 0.28 0.23 395 710 111 91 0.034 32.0 17.4 0.30 0.25 400 720 116 95 0.026 I n f 27.2 0.56 0.40 435 820 . 164. 128 0,046 ( C o n t i n u e d . . . ) 132 TABLE B-I ( C o n t i n u e d ) Volume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mg/1 e x c e p t pH) COD T.S. S.S. TKN Cl P pH Al k. 2.0 129 672 11 14.0 293 0.02 6.9 40 4.0 133 668 26 11.2 295 0.19 6.6 40 6.0 165 692 58 9.8 313 N.D. 6.7 36 8.0 158 760 32 16.8 445 N.D. 6.9 60 10.0 179 960 16 17.9 683 0.04 7.2 90 12.0 229 1328 " 16 31.1 1038 N.D. 7.4 120 14.0 299 1676 32 45.4 1386 0.02 7.7 220 I n f 654 4974 312 402 2370 0.92 8.4 2600 16.0 N/A 2472 490 152 950 0.29 7.5 890 18.0 N/A 3414 540 275 1525 0.31 8.0 1915 20.0 N/A 3150 320 274 1575 0.24 8.2 1962 22.0 805 3244 172 292- 1900-7- 0.28 - 8.2 2130 24.0 745 3268 92 :: 3 0 3 - 1750 . 0.25 8.2 2160 26.0- . 725 _ 3430- 126 314-. 1950 0.31 8.2 2260 28.0 723 3452 : 146 ," 320" 2125 0.31 8.2 2330 30.0 767 3616 232 333 2100 N/A 8.2 . 2495 32.0 740 3656 194 351 2425 0.34 8.1 2495 I n f 733 4264 146 408 2500 0.86 7.5 3160 A l k . as mg/1 as CaCO Volume Throughput - l i t e r s F i g u r e B - l ; B r e a k t h r o u g h Curve f o r Fe 0.4 Influent Concentration 14-32 1 = 0.40 rog/1 0.3 Influent Concentration 0-14 1 = 0.30 mg/1 0.2 — O ry. O 0 ^ j y ^ " ^ o 0 0.1 — i 0 I 1 1 i i i i i i i i i i • i \ 1 | 4 8 12 16 20 24 28 32 Volume Throughput- ^liters Figure B-3: Breakthrough Curve for Zn co Cn F i g u r e B - 4 : B r e a k t h r o u g h C u r v e f o r K 1200 Influent Concentration 0-14 1 = 1130 mg/1 •1000 r -Figure B-5: Breakthrough Curve for Na F i g u r e B - 6 : B r e a k t h r o u g h C u r v e f o r C a V o l u m e T h r o u g h p u t " - ' l i t e r s F i g u r e B - 8 : B r e a k t h r o u g h C u r v e f o r Pb Volume Throughput- li t e r s Figure B-9: Breakthrough Curve for COD Figure B-10 : Breakthrough Curve for Total Solids Volume T h r o u g h p u t - l i t e r s F i g u r e B - l l : B r e a k t h r o u g h Curves f o r Suspended S o l i d s Influent Concentration 14-32 1 = 2500 mg/1 Volume Throughput - l i t e r s Figure B-13: Breakthrough Curve for Cl Volume Throughput •*liters Figure B-14 : Breakthrough Curve for P 4 0 0 0 Influent Concentration 14-32 1 = 3160 mg/1 3200 L_ 6 Influent Concentration 0-14 1 = 2600 mg/1 2400 1600 U 800 0 4 8 ! 12 16 20 24 28 32 Volume Throughput - l i t e r s Figure B-15: Breakthrough Curve for Alkalinity (pH = 4.5) APPENDIX C BREAKTHROUGH DATA FOR THE DESORPTION TEST TABLE C-I B r e a k t h r o u g h Data f o r t h e D e s o r p t i o n T e s t Volume T h r o u g h p u t E f f l u e n t C o n c e n t r a t i o n (mg/1) ( l i t e r s ) F e : - Mn ~ " Zn K Na Ca Mg Pb 0-2 0.13 0.05 0.16 16 40 19 6.3 0.025 2-4 0.14 0.07 0.07 37 75 20 6.9 0.029 4-6 0.25 0.08 1.5 . .88 156 29 8.8 0.030 6-8 0.27 0.08 .0.23 144 256 37 9.6 0.030 8-10 0.19 0.10 0.65 137 250 36 9.6 0.041 10-12 0.18 0.09 0.20 146 268 39 10.6 0.040 12-14 0.20 - 0.10 0.13 175 325 44 11.5 0.040 14-16 0.21 -• O.H 0.44 - 200 375 48 12.2 0.042 I n f 13.8 0.64 0.78 - 438 725 173 38.8 0.049 16-23 0.26 0.15 0.93 212 425 71 12.5 . 0.080 23-43 1.25 0.04 0.09 104 162 19 5.0 0.081 43-47 1.63 0.03 0.21 25 44 9 2.7 - 0.135 47-57 1.50 0.03 0;28 21 36 13 1.5 0.184 Volume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mg/1 e x c e p t pH) COD T.S. S.S. TKN Cl P pH A l k . 0-2 117 348 0 16.8 250 0.066 7.1 80 2-4 119 480 • 0 '•' 28.8 350 ._ . 0.002, -7.5 164 . 4-6 - 231 ~- 872 4 67 600 0.026 7.8 390 6-8 301 1304 4 113 863 0.044 8.0 700 8-10 310 1320 10 109 938 0.026 7.9 650 10-12 327 1412 6 115 1000 <0.002 7.9 660 12-14 368 1688 1.2 132 1250 0.090 7.9 740 14-16 458 2004 16 161 1488 0.066 7.9 900 I n f 760 4390 104 435 1975 1.38 7.8 3290 16-23 513 . 2224 — ' 171 1638 0.29 7.5 1020 23-43 480 1044 — 81 525 0.26 7.2 540 43-47 480 628 — 35 150 . 0.30 7.5 230 47-57 572 716 — 22 80 0.25 7.6 220 . l e a c h a t e used as i n f l u e n t ; 0-16.0 l i t e r s , t a p w a t e r used as i n f l u e n t a f t e r . 16.0 l i t e r s . ( A l k a l i n i t y as mg/1 as CaCO-J. Fe Influent Concentration = 13.8 mg/1 I F i g u r e C - 2 : B r e a k t h r o u g h C u r v e s f o r C a a n d Mg Mn Influent Concentration - 0.64 mg/1 8 16 24 32 40 48 _ 56 Volume Throughput - l i t e r s Figure C-3: Breakthrough Curves for Pb and Mn V o l u m e T h r o u g h p u t - l i t e r s F i g u r e C - 4 : B r e a k t h r o u g h C u r v e f o r N a a n d COD 60 0 o rfl w 4J a CU a o u 4J c a) 3 500 r-400 L_ 300 H 200 L_ 100 K Influent Concentration = 438 mg/1 TKN Influent Concentration = 435 mg/1 Volume Throughput - l i t e r s Figure C-5: Breakthrough Curves for Total Kjeldahl Nitrogen (TKN) and K Cn V o l u m e T h r o u g h p u t - l i t e r s F i g u r e C - 6 : B r e a k t h r o u g h C u r v e s f o r A l k a l i n i t y ( p H = 4 . 5 ) a n d C l F i g u r e C - 7 : B r e a k t h r o u g h C u r v e f o r T o t a l S o l i d s APPENDIX D BREAKTHROUGH DATA FOR COMBINED CHEMICAL TREATMENT AND PEAT TREATMENT 159 TABLE D-I B r e a k t h r o u g h Data f o r Combined C h e m i c a l T r e a t m e n t and P e a t T r e a t m e n t Volume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mg/1) Fe Mn Zn K Na Ca Mg Pb 0-2 0.05 0.05 0.12 15 31 17 6.3 0.026 2-4 0.06 0.06 0.15 15 38 19 6.9 0.028 4-8 0.10 0.08 0.15 25 62 29 10.6 0.053 6-8 0.17 0.14 0.16 56 118 37 12.5 0.049 8-10 0.21 0.16 0.14 81 162 58 16.3 0.041 10-12 0.26 0.17 0.15 106 225 67 16.3 0.065 12-14 0.24 0.17 0.19 131 281 65 15.0 0.046 14-16 0.25 0.12 0.17 168 362 51 12.0 0.068 16-18 "0.31 0.11 0.14 206 412 42 11.6 0.058 18-20 0.30 0.09 0.13 225 450 32 8.8 0.076 20-22 0.32 0.08 0.13 244 481 29 7.5 0.090 22-24 0.40 0.07 0.18 268 512 24 6.5 0.091 I n f l u e n t 0.83 0.01 •0.39 430 706 - 11 - 13.8 0.019 I n f l u e n t B e f o r e C.T. 13.8 0.64 0.78 438 725 173 38.8 0.045 Volume T h r o u g h p u t ( l i t e r s ) E f f l u e n t C o n c e n t r a t i o n (mg/1 e x c e p t pH) COD T . S . - S.S. - TKN c i - P PH A l k . 0-2 91 346 4 5.6 121 .0.02 6.3 56 - 2 " 4 ' 80 - 368 11.2 175 <0,02 - 6.0 44 4-6 127 566 8 17.9 313 <0.02 6.2 60 6-8 215 910 16 37 600 0.13 6.6 110 8^10 262 1260 4 52 862 o.n 6.9 160 10-12 353 1644 36 80.- 1300 0.09 7.0 220 12-14 433 2284 32 100 1525 0.12 7.5 304 14-16 534 2136 12 132 1725 0.07 7.6 410 16-18 658 2310 12 160 2063 0.13 7.8 540 18-20 708 2460 12 182 2113 0.11 7.8 632 20-22 790 2572 8 203 2250 0.16 7.8 710 22-24 834 2704 16 230 2275 0.13 7.9 840 I n f l u e n t I n f l u e n t B e f o r e C.T. 670 760 3688 4340 8 104 416 435 2300 1975 0.18 1.38 9.0 7.8 2410 3290 . C h e m i c a l T r e a t m e n t was w i t h 2500 mg/1 C a ( 0 H ) ? a n d 200 mq/1 F e C l Calk, as mg/1 as CaCO-,) /. 1.0 influent Concentration = 13.8 mg/1 Before Chemical Treatment Figure D-l: Breakthrough Curve for Fe Influent Concentration = 0.64 mg/1 Before C.T. 60 S ti o •H 4-J RJ H J-l ti 0) a ti o CJ ti a) 3 i— I <4-l w 0.6 L_ 0.5 0.4 0.3 0.2 0.1 Influent Concentration After C.T. = 0.01 mg/1 1" 1 1 H H 1 1 1 h r 1 4 8 12 16 20 24 Volume Throughput - l i t e r s Figure D-2: Breakthrough Curve for Mn _ 0.6 0.2 0 — Influent Concentration .= = 0.78 mg/1 Before C.T. — Influent Concentration = 0.39 mg/1 — After C.T. i o o_Q o - ^ ^ ' l I I l I I 1 1 1 1 1 4 8 12 16 20 24 Volume Throughput - l i t e r s Figure D-3: Breakthrough Curve for Zn F i g u r e D - 4 : B r e a k t h r o u g h C u r v e f o r K i 1000 I Volume Throughput - l i t e r s £ F i g u r e D-5: B r e a k t h r o u g h Curve f o r Na 60 B 2 0 0 F i g u r e D - 6 : B r e a k t h r o u g h C u r v e f o r C a I n f l u e n t C o n c e n t r a t i o n B e f o r e C . T . = 3 8 . 8 mg/1 F i g u r e D - 7 : B r e a k t h r o u g h C u r v e f o r Mg Figure D-8: Breakthrough Curve for Pb 1000 Volume Throughput - l i t e r s cr> CO Figure D-9: Breakthrough Curve for COD 5000 60 6 C O • H 4-1 w 4J C cu CJ C o C CU 3 rH C M W 4000 3000 2000 1000 Influent Concentration Before C.T. = 4340 mg/1 Influent Concentration After C.T. = 3688 mg/1 8 12 1 I Figure D-10: 16 20 24 Volume Throughput - l i t e r s Breakthrough Curve for Total Solids Influent Concentration Before C.T. = 104 mg/1 O O Influent Concentration After C.T. = 8 mg/1 4 8 12 16 20 24 Volume Throughput - l i t e r s Figure D - l l : Breakthrough Curve for Suspended Solids o Influent Concentration Before C.T. = 435 mg/1 Influent Concentration After C.T. = 416 mg/1 4 .8 12 16 20 24 Volume Throughput - lit e r s Figure D-12: Breakthrough Curve for Total k j e l d a h l Nitrogen (TKN) Figure D-13: Breakthrough Curve for Cl Figure D-14: Breakthrough Curve for P 3500 60 6 C o •H 4-J tfl M 4-1 c cu o c o u c CU 3 CH w 3000 2500 2000 1500 1000 500 Influent Concentration Before C.T. = 3290 mg/1 •Influent Concentration After C.T. = 2410 mg/1 Figure D-15: 8 12 16 20 24 Volume Throughput - l i t e r s Breakthrough Curve for Alkalinity (pH* 4.5) 

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