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Treatment of sanitary landfill leachate with peat Lidkea, Thomas Roy 1974

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TREATMENT OF SANITARY LANDFILL LEACHATE WITH PEAT by THOMAS ROY LIDKEA B . A . S c , University of Bri t i sh Columbia, 1969 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 July, 19 74 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e H e a d o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f Civil Engineering The U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8, C a n a d a D a t e August 20, 1974 A B S T R A C T Leachate is generated by the action of water on the sol id wastes deposited in sanitary landf i l l s or dumps. In this research, peat was investigated as a means of removing metal ions from leachate. The leachate used in the investiga*-tion was obtained from a project at the University of Bri t i sh Columbia in which leachate is generated under controlled con-ditions. Two different types of local ly available peat were used in i n i t i a l batch tests. These were a fibrous peat derived mainly from sphagnum moss and in a middle stage of humification, and a well humified sample of woody peat from the surface. These samples were used to treat d i s t i l l e d water solutions of Fe, Cr, Zn, AI, Cd, and Pb, The fibrous peat was found to be superior and was used in subsequent tests. In the batch tests performed on d i s t i l l e d water solu-tions of the above metals, i t was found that the fibrous peat adsorbed between 12 and 38 mg of metal per gm of peat. In the batch treatment of leachate, the fibrous peat was found to have a capacity of 55 mg/gm. A test conducted to investigate the dependence of ad-sorption on pH showed that adsorbance was best in the range be-tween pH 3,0 and 4.0, i i i Column tests were performed on d i s t i l l e d water solu-tions of Cr in order to optimize the column's design. Based on these tests, 60 gm of wet fibrous peat were packed in a column 12 inches high and 0.75 inches in diameter. A flow rate of 0.100 gpm/ft was used in treating two different samples of leachate. In treating the f i r s t leachate, which had a high strength (total metal concentration was 5,360 mg/1) and a pH of 4.84, i t was found that the treatment capacity of the peat was about 48 mg/gm. At treatment efficiencies of 90 per cent and 75 per cent, peat capacities were 31.4 and 43.3 mg/gm, respectively. The test of a low strength leachate (total metal concentration was 1,830 mg/1) of pH 5.35 was not val id for assessing the performance of the column since many of the metals were present as solids which were simply f i l tered out in the column. The usefulness of peat in treating leachate depends on the type and concentration of the leachate. In order to be effective, large amounts of peat may have to be used. For example, to remove 90 per cent of metal ions from 1,000 gal. of the high strength leachate would require roughly 0.77 tons (dry) of peat. TABLE OF CONTENTS Page LIST OF TABLES vi LIST OF FIGURES v i i ACKNOWLEDGEMENT v l i i CHAPTER I. INTRODUCTION 1 1. Peat 1 2. Leachate 3 II. RESEARCH RATIONALE 5 III. PEAT AND LEACHATE USED 8 IV, BATCH TESTS 10 1. Metal Concentration Versus Contact Time. . . . 10 2. Adsorption Isotherms 14 3. pH Dependence 21 4. Leachate Adsorbance 21 V. COLUMN TESTS 25 1. Chromium in D i s t i l l e d Water 25 2. Leachate Treatment 30 VI. REPRODUCIBILITY OF RESULTS 40 VII. SUMMARY AND CONCLUSIONS 42 LIST OF REFERENCES 46 iv V Page APPENDIX A BATCH. TESTS 48 APPENDIX B COLUMN TESTS , 55 LIST OF TABLES Table Page I. METAL CONCENTRATION VERSUS CONTACT TIME 12 II. pH DEPENDENCE 22 III. LEACHATE BATCH TEST 23 IV. COLUMN TESTS TREATING CHROMIUM IN DISTILLED WATER. . 2 7 V. EFFICIENCY OF PEAT UTILIZATION 2 8 VI. LEACHATE ANALYSES 31 VII. METAL REMOVAL AS A FUNCTION OF VOLUME THROUGHPUT . . 32 VIII. TOTAL METAL REMOVAL 35 IX. REPRODUCIBILITY OF RESULTS 40 A - I . ADSORPTION ISOTHERMS FOR Zn 49 A-II . ADSORPTION ISOTHERMS FOR Cd 5 0 A-III . ADSORPTION ISOTHERMS FOR Fe 51 A-IV. ADSORPTION ISOTHERMS FOR Cr 52 A-V. ADSORPTION ISOTHERMS FOR AI 53 AWI. ADSORPTION ISOTHERMS FOR Pb 54 B-I. BREAKTHROUGH DATA FOR HIGH STRENGTH LEACHATE . . . . 56 B-II. BREAKTHROUGH DATA FOR LOW STRENGTH LEACHATE 57 v i LIST OF FIGURES Figure Page 1. M'ETAL CONCENTRATION" VERSUS CONTACT TIME 13 2. ADSORPTION ISOTHERMS FOR Zn 15 3. ADSORPTION ISOTHERMS FOR Cd 17 4. ADSORPTION ISOTHERMS FOR Fe 17 5. ADSORPTION ISOTHERMS FOR Cr 18 6. ADSORPTION ISOTHERMS FOR A l 18 7. ISOTHERMS COMPARING ADSORPTION OF Zn, Fe, A l , Cr, Cd AND Pb USING FIBROUS PEAT 20 8. BREAKTHROUGH CURVES FOR CHROMIUM IN DISTILLED WATER. 2 9 9. PER CENT REMOVAL OF Fe, Zn, A l , Pb, AND Cr 33 10. PER CENT REMOVAL OF Mn, Mg, Ca, Na, AND K 34 11. TOTAL METAL REMOVAL „ 36 B - l . BREAKTHROUGH CURVES FOR Zn, Mg, AND Fe 58 B-2. BREAKTHROUGH CURVES FOR Al AND Mn 59 B-3. BREAKTHROUGH CURVES FOR Pb AND Cr 60 B-4. BREAKTHROUGH CURVES FOR Ca, Na, AND K 61 v i i A C K N O W L E D G E M E N T The author would l ike to acknowledge the help and encouragement given by Dr. R. D. Cameron. He would also like to give thanks to Mrs. Elizabeth McDonald and Mr. Gary Birtwistle for their help in the laboratory. This research was supported by Grant No. A6102 from the National Research Council of Canada. v i i i CHAPTER I INTRODUCTION 1. Peat: The origin of the name peat is obscure, but i t is supposed to be of North German or Anglo-Saxon extraction from a word signifying bog or pond. As used today the word refers to organic deposits produced by the incomplete anaerobic decomposition of vegetable matter in the presence of water. Marshes, bogs, and swamps provide conditions suitable for the accumulation of these deposits. Plants grow, die, and sink down to be covered by the water in which they grow. They then decay slowly through the agency of fungi, anaero-bic bacteria, algae, and certain types of microscopic aqua-t ic animals. As one generation of plants succeeds another, layers of organic residue are deposited. The constitution of these successive layers changes as time goes on since a sequence of different plant l i f e is l ikely to occur. Thus, deep-water plants may be succeeded by reeds and sedges, these by various mosses, and these in turn by shrubs, with trees f ina l ly gain-ing a foothold. Peat, regardless of its state of decomposition (or humification) may conveniently be c lass i f ied according to 1 2 i ts parent materials under three general headings. 1. Sedimentary: Sedimentary peats usually accumulate in comparatively deep water, and are generally found well down in the pro-f i l e . They are derived from mixtures of water l i l i e s , pondweed, hornwort, pollen, plankton, etc. 2. Fibrous: These are derived from sedges, various types of mosses, reeds, cat-t a i l s , etc. The most common peat mosses are sphagnumand hypnum. They are a l l high i n water-holding capacity. 3. Woody: Woody peats are generally found at the surface of the organic accumula-t ion. They are brown or black in colour when wet, according to the degree of humification. Woody peats develop from the residue of decid-uous and coniferous trees, and shrubs and other plants that occupy the forest floor of the swamp. The water-holding capacity is lower than that of the fibrous peats. Peat is commonly used in one of the following ways, depending on i ts nature. 1. Nurseries, greenhouses and lawns: It makes a good so i l conditioner by effecting greater retention of moisture in the s o i l , and by improving the so i l ' s texture. Unhumified material i s pre-ferred. 2. Bedding for animals: It i s desireable because of i ts high absorbancy ( i . e . , of l iquid manure) and i ts ab i l i ty to suppress odours. 3. Packing and insulation: Peat is a good heat insulator, and is sometimes used as an insulating material in houses. It is also quite e last ic when dry, and so makes a good packing material. 4. Fuel: The ca lor i f i c value of Canadian peats is usually about 4500 cal/gm. Since evapor-ation of water requires 500 cal/gm, peat contain-ing as much as 90 per cent moisture can be used as fuel . Usually, however, moisture is removed to about 30 per cent by pressing before peat is used as a fuel . 3 In summary, the properties of peat which make i t a useful material are i ts absorbence, lightness, e las t i c i ty , combustibility, and i ts ab i l i ty to act as a heat insulator. For the purposesr.mentioned above, unhumified or s l ight ly humified peat is generally preferred, since humification causes peat to lose some of i t s absorbent capacity, and most of i ts e las t i c i ty . 2. Leachate: The volume of sol id wastes being generated in North America has been increasing at a tremendous rate. Consequent-l y , the number of garbage dumps and sanitary landf i l l s are increasing, since this means of disposal remains the most popular. Other methods of disposal are more costly, are subject to breakdowns, or present various pol lutional prob-lems. Methods such as incineration and composting require the use of a l a n d f i l l for the disposal of residues in any case. Therefore, i t i s unlikely that sanitary landf i l l s w i l l soon become outmoded or be replaced to a significant degree by other disposal methods. Landfi l ls can cause water contaminationproblems, par-t i cu lar ly in areas of high r a i n f a l l , and where the l a n d f i l l sites are not hydrologically isolated. Rainfal l and ground-water can dissolve large quantities of organic and inorganic materials in the solid wastes and transport these materials to receiving waters. One of the areas of concern is water 4 contamination by metals which may be toxic to aquatic l i f e and indirect ly toxic to man by concentration in f i sh , shel l -f i sh , livestock and crops. CHAPTER II RESEARCH RATIONALE In areas of high ra in fa l l and high water tables such as the Lower Fraser Valley i t is v ir tua l ly impossible to find a l a n d f i l l site which can be economically hydrologically iso-lated. The alternative leachate control measure then is collec-tion and treatment of the leachate. What are the reasons for examining the treatment capabil-i t i es of peat? F i r s t , there is l i terature to indicate that peat is an effective adsorber of metallic cations. Second, peat is cheap (two to four cents per pound) and readily available. Third, many landf i l l s sites in the Lower Mainland of Bri t i sh Columbia are situated on peat bogs. It is known (1) that peat contains humic and fulvic acids. It is thought that these acids make important contri-butions to the surface and sorption properties of peat. The amounts of these acids increase with humification and higher ion exchange capacity is associated with greater humification. Work done at the University of Sherbrooke (2) indicated that peat was effective in removing mercury from polluted water. There is an abundance of peat in the Lower Fraser Valley. Burns Bog has been estimated (3) to have 5,000 acres, with a depth of from two to 10 feet. There are peat 5 6 bogs in Richmond, Pi t t Meadows, and southwest of New West-minster on the north bank of the Fraser River. The Burns Bog landf i l l s i te , located centrally in Delta Dis tr ic t Municipality northeast of Highway 499, is the largest in Bri t i sh Columbia. The site is situated on a bed of peat averaging nine feet thick, underlain by about four feet of relat ively impervious clay. A depth of several hundred feet of sand and s i l t l i e beneath the peat. It has been estimated (4) that about 95 per cent of the seepage from the l andf i l l rises to the ground surface within 10 feet of the f i l l periphery. It is possible that the underlying layer of peat is providing some treatment of the leachate before i t surfaces in the collection ditches. Besides the Burns Bog l a n d f i l l , the Richmond dump, the Port Mann dump in Surrey, the Terra Nova dump in Fraser Mil ls north of the Fraser River and the Crown Zellerbach f i l l in Mai l lardvi l le are a l l situated on peat so i l s . Leachate treat-ment may therefore be occurring at these sites as the leach-ate moves through the underlying peat. With pollution control regulations becoming more s tr in -gent, leachate treatment is l ike ly to become necessary at many l a n d f i l l s i tes . Treatment with peat may be provided in two ways at Lower Mainland l a n d f i l l s i tes . The f i r s t way is "natural" treatment as. the leachate flows through the under-lying peat. The second way may be to spray leachate over 7 peat either when peat is used as a cover material or when i t is used in an adsorption bed separate from the l a n d f i l l . Because peat occursi: atimany l a n d f i l l sites and can be obtained economically, this research is therefore directed towards determining the effectiveness of peat as a leachate treatment material. CHAPTER III PEAT AND LEACHATE USED The peat used was obtained from Burns Bog, north of the l a n d f i l l s i te . Samples of fibrous peat and woody peat were obtained. The fibrous peat sample was obtained from a stockpile of recently mined peat. The peat was mined to a depth of about eight feet, excluding the top few inches which was f i r s t stripped off and discarded. It was then macerated and mixed to ensure homogeneity. This sample was primarily derived from sphagnum moss. The moisture content was 84.3 per cent and the ash content was about one per cent. The peat was dark brown when wet, and s l ight ly l ighter brown when dry. Unhumified or s l ight ly humified sphagnum moss peat is l ight greyish green or yellowish to l ight brown in colour. When humified, i t is dark brown to black. There-fore, the sample was in a middle stage of humification. A sample of black woody peat was taken from the sur^ face. Woody peats range in colour from dark brown to black, depending on the degree of humification, so the sample was well humified. It had a moisture content of 76>8 per cent and an ash content of about five per cent. It was not as homogeneous as the fibrous- sample, and contained pieces of undecayed wood and twigs. 8 9 In a study currently being conducted at the Univer-sity of Bri t i sh Columbia, leachate is being generated under controlled conditions in large metal tanks. The leachates have widely varying compositions, depending on the type of sol id waste used, temperature variations, amount of water added, age of the waste, etc. Examples of pollutant concen-trations and pH's of some of these leachates are given in Tables "3 and 4. CHAPTER IV BATCH TESTS Batch tests were carried out for the purposes of (a) determining how the concentration of metal ion in solution varied with time of contact with the peat; (b) constructing adsorption isotherms; (c) investigating the effect of pH on adsorptive capacity; and (d) determining the relative pref-erence of 14 metals present in a sample of leachate for ad-sorption on peat. In order to simplify testing, the f i r s t three phases mentioned above used d i s t i l l e d water solutions of single metal ions in order to eliminate interferences from the many ions and organic compounds present in the leachate. Solutions of the following six metal ions were used: Zn, A l , and Fe, which were chosen because of their high concentration in the leachate, and Pb, Cr , and Cd, which were chosen because of their toxic i ty . These six metals were added to d i s t i l l e d water in the following compounds: ZnSO^; Al 2 (SO^) 3 • U8H 2 0; FeS04 • 7H20; P b C N O ^ ; C r C l 3 • 6H20 and Cd(N0 3) 2 • 6H 20. 1. Concentration Versus Time: The f i r s t phase of testing was performed to determine the length of time required for the adsorption reactions to 10 11 achieve equilibrium and to obtain information regarding the extent of the adsorption. Seven tests were performed. In each test, 63.7 gm of fibrous peat at 84.3 per cent mois-ture (equivalent to 10.0 gm on a dry basis) was added to one l i t r e of water containing 100 mg of one of the above metals. Minor adjustments to a pH of 3.0 were made by add-ing NaOH. It had i n i t i a l l y been desired to adjust the pH of these solutions to correspond with the pH of the leach-ate (about 4.5) but i t was observed that 100 mg/1 solutions of Cr, Pb, or AI formed precipitates above a pH of about 3.8 in d i s t i l l e d water solutions. It was found to be possible to increase the pH of a 100 mg/1 solution of AI to above 4.0 without forming a precipitate, but only by adding large amounts (about 10,000 mg/1) of sodium acetate or sodium ci trate . It was judged that this addition would have unpre-dictable effects on adsorption. So, in order to keep the conditions for each test s imilar, i t was decided to keep the pH at 3.0. A l l tests were also performed with the solutions at room temperature. After adding the peat to the vessel containing the adsorbate, the mixture was agitated vigorously with an im-pe l ler . Samples of the mixture were removed at intervals , and immediately f i l t ered . The f i l t ra te was analyzed and plots of concentration versus time were obtained for each ion. These results , in tabular and graphical form, are shown in Table 1 and Figure 1. 12 TABLE I METAL CONCENTRATION VERSUS CONTACT TIME TIME CONCENTRATION (mg/1) (Miii. ) Pb Cr Zn Al Cd Fe 0 100 100 100 100 100 100 1 26.6 62.0 82.0 86 .0 76.0 5 9.0 2 61.5 81.0 82 .0 70.0 49.0 3 17.0 4 58.0 78.0 60.0 65.0 42 .0 5 14.0 8 9.0 57.0 77 .0 59.0 62.0 38.0 10 76.5 12 6.0 58 .0 61.0 55.0 37.0 15 6.0 • 20 6.0 55.5 76.5 59.0 56.0 35.0 30 6.4 55.5 77.0 58 .0 55.0 36.0 40 55.5 77.0 45 5.2 57 .0 53.0 37.0 50 • - - 55v5 78.0 • 60 4.1 7 8.0 58.0 53.0 38.0 Fig. I METAL CONCENTRAT ION VERSUS CONTACT TIME . 14 2. Adsorption Isotherms: The reasons for performing tests to obtain adsorp-tion isotherms were (a) to compare the adsorptive capacity of wet peat with dried peat; (b) to compare the capacity of dark, woody peat from the upper strata with the capacity of fibrous sphagnum peat representing about eight feet of depth and blended after mining; and (c) to find the total capacity of the peat for different ions investigated. These tests were performed by adding 6.37 gm of wet fibrous peat or 4.32 gm of wet woody peat (equivalent to 1.0 gm on a dry weight basis) to Erlenmeyer flasks contain-ing 100 ml of solutions of varying concentrations of the different metal ions. The flasks containing the above mix-tures were then agitated gently on a wrist shaker for one hour. (The results obtained in Part 1 indicated that a res i -dence time of one hour was ample to allow the reactions to achieve equilibrium). After removal from the shaker, the mixtures were f i l t ered , and the f i l t ra te analyzed. The re-sults of the analyses (the equilibrium concentrations) were then plotted against the amount of metal adsorbed. The curves thus obtained were then used to compare adsorptive capacities of wet or dry, woody or fibrous peat. The results given for Zn in Table A-1 in Appendix A and plotted in Figure 2 show that the dried peat does not work as well as the peat which has been allowed to retain its mois-F i g u r e 2 ' A D S O R P T I O N I S O T H E R M S F O R Z n 16 ture. This was expected, since i t was observed that when the peat was dried i t became very hydrophobic. It is poss-ible that with a longer retention time the dried peat would become suff iciently wetted for its adsorptive capacity to increase. No further testing of dried peat was done because of the lack of encouraging results. It is also apparent from Figure 2 that the dried woody peat does not work as well as the dried fibrous peat, although when wet the peats gave similar results. In order to investigate this , comparisons of the adsorptive capacities of wet woody and wet fibrous peat were carried out for the remaining five metals, at concentration ranges approximating the ranges found for those metals in the leachate. These re-sults , given in Tables A-2 to A-6 , in Appendix A and shown graphically in Figures 3 to 6, show that in most cases the fibrous peat is superior to the woody peat. Although slight*-) ly better Fe removal at low concentrations is shown for woody peat the overall results show that fibrous peat is better. Because of the inconsistent performance and lack of homogen-r eity of the woody peat, further testing was restricted to fibrous peat. The next phase of the batch testing was conducted to extend the ranges of the absorption isotherms by increasing the concentrations of the metal ions. The same amounts of peat and l iquid were used. It was desired to find the total I I I I I I !__! I I I I I 0 0 . 2 0 . 4 0 . 6 0 . 8 1.0 1.2 1.4 1.6 1.8 2 . 0 2 . 2 2 . 4 E q u i l i b r i u m c o n c e n t r a t i o n - m g / l i t e r F i g u r e 3 ! A D S O R P T I O N I S O T H E R M S F O R C d . 0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 E q u i l i b r i u m c o n c e n t r a t i o n - mg / l i t e r F i g u r e 4 • A D S O R P T I O N I S O T H E R M S F O R F e I I 1 1_ I I I I O 0.1 0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 E q u i l i b r i u m c o n c e n t r a t i o n - m g / l i t e r F i g u r e 5 s A D S O R P T I O N I S O T H E R M S F O R C r . F i g u r e 6 = A D S O R P T I O N I S O T H E R M S F O R A l 19 capacity of the fibrous peat, as indicated by the ultimate flattening of the isotherm curves. These results are shown in Tables A-2 to A-6 in Appendix A. The f u l l range iso-therms are plotted in Figure 7. The approximate capacity of the peat for each of the six metals is as follows: METAL CAPACITY ION (mg per gm of peat) Fe 12 Cr 15 Zn 16 Al 19 Cd 19 Pb 38 The above numbers represent the total capacity of the peat for the single metal ions at concentrations near 1,000 mg/1 in d i s t i l l e d water. Such high capacities would not be realized when dealing with solutions of lower concen-tration. Furthermore, adsorptive capacity in a d i s t i l l e d water solution may be completely different from the capacity in a more complex solution such as leachate. 3. pH Dependence: Solutions of Al and Fe were each made up at concentra-tions of 1,000 mg/1. The pH's of 100 ml samples were adjusted to between 1.0 and 6.0 with sulfuric acid, sodium hydroxide F i g u r e 7« I S O T H E R M S C O M P A R I N G A D S O R P T I O N O F Z n , F e , A I , C r , C d A N D P b U S I N G F I B R O U S P E A T . 21 and (for the AI) sodium ci trate . 6.37 gm of fibrous peat at 84.3 per cent moisture (1.0 gm dry) was added to flasks containing the samples. The flasks were then agitated on the wrist shaker for one hour. The samples were f i l t ered and the f i l t r a t e analyzed. These data are shown in Table II. It was found that adsorptive capacity was strongly affected by pH. Although the data points are rather scattered, i t is clear that adsorption was best in the range of about pH 3.0 to 4.0 for the d i s t i l l e d water solutions. While i t is possible that some of the adsorptive capacity of the peat was ut i l i zed by the Na added in pH adjustment, i t is fe l t that pH was the major factor which affected adsorptive capacity. 4. Leachate Adsorbance: One l i t r e of leachate was thoroughly mixed with 12 7.4 gm of wet fibrous peat (20 gm on a dry basis) and left for 24 hours. This long detention time was used because the mixture was too thick to agitate effectively. The mixture was then Vacuum f i l tered in a Buchner funnel. The results of the analysis of the f i l t r a t e , and of the original leach-ate, are shown in Table III. The relative adsorbance of the different metals present can be clearly seen. Per cent re-movals varied between 1.6% for K and 63.5% for Ca. These results should not be anticipated for a l l cases, since the per cent removal of any ion is based on factors such as concen-tration, ionic species and complexes present, and cannot be ex-trapolated to another, different system. TABLE II pH DEPENDENCE METAL . INITIAL * INITIAL EQUILIBRIUM REMAINING FINAL METAL CONCENTRATION pH CONCENTRATION IN 100 nil pH ADSORBED (mg/1) (mg/1) (mg) (mg) 1000 3.36 837 (x.1054) = 88.4 3.20 11.6 1000 3 -.00 837 (x.1054) = 88.4 3.05 11.6 999 2.50 860 (x.1054) = 90.9 2.74 9.0 Al 9 9 6 2. 00 923 (x.1054) = 97.5 2.26 2.1 A X 993 1.50 884 (x.1054) = 93.4 1.42 5.9 987 1.00 935 (x.1054) = 98.7 0.95 0.0 1000 6.80 910 (x.1054) = 96.1 6.00 3.9 999 6.00 920 (x.1054) = 97.2 5.63 2.7 998 5 .00 895 (x.1054) = 94.5 4.67 5.3 Fe 997 4.00 838 (x.1054) = 88.2 3.60 11.5 995 3.00 830 (x.1054) = 87.7 2.80 11.8 990 2 .00 840 (x.1054) = 88.7 1.90 10.3 Dilution due to pH adjustment 23 TABLE I I I LEACHATE BATCH TEST LEACHATE * BEFORE AFTER PER CENT PARAMETER TREATMENT TREATMENT REMOVAL P H 4 . 5 0 4 . 2 5 COD 3 3 , 6 0 0 2 9 , 2 0 0 1 3 . 0 TOC 1 3 , 3 4 0 9 , 3 5 0 2 9 . 9 Z n 3 4 0 324 4 . 7 Fe 6 4 0 4 9 1 2 3 . 4 Cr 3 . 6 9 2 . 0 4 5 . 8 Cd 1 . 3 0 0 . 7 1 4 5 . 4 Pb 3 . 2 0 1 . 8 1 4 3 . 4 A l 1 5 8 . 4 1 2 4 . 0 2 1 . 7 Ca 1 , 1 7 0 426 6 3 . 5 Na 1 , 0 9 0 1 , 0 3 0 5 . 5 K 9 0 5 8 9 0 1 . 6 Mg 238 2 0 8 1 2 . 6 Cu 0 . 1 7 0 . 2 0 N i 0 . 5 4 0 . 4 4 1 8 . 5 Mn 3 1 . 2 2 4 . 4 2 1 . 8 Ba 3 2 . 1 2 1 8 . 8 7 4 1 . 3 A l l values except pH given in mg/1. 24 The total concentration of metals (for which analyses were done) was about 4,600 mg/1 before treatment, and about 3,500 mg/1 after treatment. This means that about 1,100 mg of metal were removed by 20 gm of peat. Thus, the capacity of the peat in this case was about 55 mg of metal per gm of peat. Chemical oxygen demand (COD) was reduced by 13 per cent and the total organic carbon (TOC) was reduced by 29.9 per cent. Although these two parameters were not invest i -gated in subsequent column tests i t is possible that most of the COD and TOC could be removed i f large enough quanti-ties of peat were used. It is probable that there would be a l imit to COD and TOC removal due to the addition of organic acids to the water from the peat i t s e l f . CHAPTER V COLUMN TESTS The information obtained from column tests is usually-presented in the form of breakthrough curves. These curves:; are obtained by plotting the volume flowthrough on the horizon-tal axis versus the concentration of the impurity in the eff lu-ent. On an ideal curve the concentration of impurity in the effluent increases suddenly from a very low value to the con-centration of the impurity in the influent. If this break-through level is well defined, the amount of impurity which can be ef f ic ient ly removed can be found. This amount is equal to the area bounded by the Y-axis, the influent concentration, the breakthrough curve, and a vert ica l l ine through the break-through volume. The column tests were carried out in two parts. F i r s t , d i s t i l l e d water containing 1,0.00 mg/1 Cr was used to optimize the density of packing in the column, and to investigate the effect of flowrate on column efficiency. Second, two dif fer-ent types of leachate were treated. 1. Chromium in D i s t i l l ed Water: Four tests were performed using the 1000 mg/1 Cr solutions. The solutions were made, up from C r C l , • 6H20 and had a pH of 3.05. Cr was chosen because the solution was bright green, and so the breakthrough could be detected v isual ly . In each test the column of peat was 12 inches high and the column diameter was 0.75 inches. Fibrous peat at 84.3 per cent moisture was used. The size of samples taken for analysis was 10 ml. The conditions and results of the four tests are given in Tables IV and V and the results are shown graphically in Figure 8. In the f i r s t three tests the adsorbate was allowed to flow freely through the column. There was no constrict ion. at the bottom of the column, and the flowrate was controlled at the inlet (top) of the column. There was a small amount of air trapped in the peat during operation of the column. In Test 4 the column was allowed to f i l l with the adsorbate by ins ta l l ing a valve at the outlet. Once the column had f i l l e d , the flowrate was controlled by this valve. The air was thus displaced from the interstices in the peat, and the detention time was increased by the 13 minutes i t took for the column to f i l l . It was expected that this would improve treatment e f f i -ciency . Test 4 did not improve efficiency. Perhaps diffusional mixing as the column f i l l e d increased the concentrations in the samples taken early in the test. Another poss ib i l i ty is that in the f i r s t three tests i n i t i a l samples were diluted by the TABLE IV COLUMN TESTS TREATING'CHROMIUM IN DISTILLED WATER 27 VOLUME THROUGHPUT (ml.) EFFLUENT CONCENTRATION] "•(mg/1) TEST 1 Flowrate: 0.360 gpm/fV 50 gm. of wet peat 5 15 25 35 45 55 65 75 85 95 6.50 34.2 112 222 408 548 685 805 905 885 TEST 2 Flowrate: 0.12 9 gpm/ft' 50 gm. of wet peat;: 5 15 25 35 45 55 65 75 85 95 0.65 14.4 82.0 200 376 476 600 660 800 905 TEST 3 Flowrate: 0.133 gpm/ft' 61 gm. of wet peat 5 15 25 35 45 55 65 75 85 95 0.0 5.40 30.0 72.0 180 375 543 667 773 85 3 TEST 4 Flowrate: 0.170 gpm/fV 61 gm. of wet peat 5 15 25 35 45 55 64 75 85 95 13.9 58 . 8 164 2 90 400 520 630 714 75 0 840 28 water in the peat. In any case, the packing and flow control used in Test 3 achieved the best results so they were used in treating leachate. TABLE V EFFICIENCY OF PEAT UTILIZATION (Assuming a breakthrough level at 10% of the influent concentration) TEST WEIGHT Wet OF PEAT (gm) Dry FLOWRATE (gpm/ft2) IMPURITY REMOVED (mg) EFFICIENCY (mg Cr/gm peat) 1 50 7.85 0.360 2 3.25 2 .96 2 50 7.85 0.129 25.40 3.40 3 61 9.58 0.133 36.12 3.76 4 61 9.58 0.170 19.20 2 .00 It was found that i f 70 gm of peat were packed into a column of the dimensions used above, the peat was prac t i -cal ly impermeable. With about 65 gm the highest flowrate obtain-2 able was about 0.010 gpm/ft . After many t r i a l s , 60 gm of peat were found to be best. It was also apparent from treating the Cr that the slower the flowrate the better the treatment. The flowrate chosen for treating the leachate was as slow as was convenient for per-forming the tests in a reasonable time. Further lowering the flowrate would probably not have improved treatment very much-as 1000 I n f l u e n t c o n c e n t r a t i o n : I Q O O m g / l i t e r V o l u m e t h r o u g h p u t - m l F i g u r e 8 * B R E A K T H R O U G H C U R V E S F O R C r IN D I S T I L L E D W A T E R . 30 in treating Cr, lowering the flowrate by 64 per cent only im-proved treatment efficiency by 8.65 per cent. 2. Leachate Treatment: Two tests were performed. The conditions for each test were as follows: Column: 12 inches high, 0.75 inches in diameter containing 60 gm of fibrous peat at 84.3 per cent moisture (10 gm of dry peat) Flowrate: 0.100 gpm/ft2 Samples: 10 ml aliquots were taken for analysis Two leachates were treated. One was high strength and the other was low strength. Their compositions are given in Table VI. The results of the analyses of the column effluent samples, and the breakthrough curves are given in Tables B-I and B-II, and Figures B- l to B-4. To consider a specif ic treatment level for each metal is not pract ical because this treatment level occurs at a di f fer-ent volume throughput for each metal. Therefore the data was analyzed as follows. The amount of each metal removed by the peat was found as a function of the volume throughput. For instance, the amount of Zn removed from the f i r s t 10 ml of leach-ate treated is equal to the area above the Zn breakthrough curve bounded by the Y-axis, the influent concentration, and a vert ica l 31 TABLE VI LEACHATE ANALYSES PARAMETER* HIGH STRENGTH LEACHATE LOW STRENGTH LEACHATE Zn 290 43.5 Al 68 0.9 Fe 1,2 40 185 Pb 2.3 0.049 Cr 10.8 0.19 Cd 0.04 0.014 Mn 44.7 9.0 Mg 240 84 Ca 1,630 595 Na 790 535 K 1,040 380 Ni 0.89 0.15 Cu 0.088 0. 043 COD 45,995 14,846 pH 4.84 5.35 A l l values except pH given in mg/1 line drawn through'10 ml. The amount of each metal removed at the volume throughputs considered is expressed in mg and as a percentage of the amount of each metal treated. This data is shown in Table VII and plotted in Figures 9 and 10. The total amount of metal removed at each par-t icu lar volume throughput and the 1 per : cent removals are shown in Table VIII and plotted in Figure 11. The total metal removals are found simply by summing the individual 32 TABLET V I I METAL REMOVAL AS A FUNCTION OF VOLUME THROUGHPUT VOLUME THROUGH (ml) METAL REMOVAL (mg and %) Zn AI Fe Pb Cr Mn Mg Ca Na K 10 ; g 2.89 99.8 .68 100.0 12.4 100.0 .022 95.7 .108 95.5 .446 99.8 2.31 96.3 16.22 99.6 7.82 99.0 10.4 LOO.O 20 ;* 5.79 99.7 1.36 100.0 24.77 99.9 .043 93.5 .196 90.8 .886 99.1 4.28 89.2 32.21 98.9 15.54 98.4 20.74 99.6 • 3 0 ? 8.67 99.6 2.02 99.0 37.11 99.7 .061 88.4 .271 83.7 1.315 98.1 5.53 76.8 47.81 97.8 23.04 97.3 31.01 99.4 40 ? 11.52 99.5 2.66 97.8 49.39 99.5 .076 82.6 .325 75.2 1.731 97.0 6.03 62.8 62.71 96.2 30.01 92.3 40.76 97.9 50 ™ g 14.29 98.5 3.26 95.9 61.57 99.4 .086 74.8 .355 65.7 2.122 95.2 6.33 52.7 76.99 94.4 35.96 91.0 49.56 95.2 60 m g 16.81 96.6 3.80 93.1 73.63 99.0 .093 67.4 .365 56.3 2.502 93.5 6.53 45.4 90.29 92.3 40.55 85.5 56.76 91.0 70 ™ g A 19.21 94.2 4.29 90.1 85.55 98.6 .096 59.6 .369 48.8 2.852 91.4 6.65 39.6 101.99 89.4 43.99 79.4 62.08 85.3 80 " 8 n 21.23 91.5 4.71 86.5 97.31 98.0 .097 52.7 .372 43.1 3.141 88.0 6.70 34.9 111.71 85.6 46.55 73.5 65.77 79.1 90 m S 22.73 87.0 5.04 82.4 108.89 97.5 .097 46.8 .373 38.4 3.368 83.7 6.72 31.1 118.91 81.1 48.34 68.0 68.37 73.0 100 m g 23.75 82.0 5.30 78.0 120.24 97.1 .097 42.2 .375 34.7 3.726 83.4 6.72 28.0 123.93 76.0 49.44 62.6 70.52 67.8 110 " g 24.37 76.4 5.49 73.6 131.33 96.4 .097 38.4 .375 31.6 3.853 78.2 6.72 25.4 127.03 70.9 50.04 57.6 71.97 62.8 120 ™ g 24.74 71.1 5.63 69.0 142.11 95.7 .097 35.1 .375 28.9 3.934 73.3 6.72 23.3 128.63 65.8 50.24 52.9 73.26 58.7 130 m g 24.92 66.1 5.74 65.0 152.49 94.6 .097 32.4 .375 26.7 4.001 68.9 6.72 21.5 129.23 61.0 50.29 49.0 74.11 54.8 F i g u r e 9 s P E R C E N T R E M O V A L O F F e , Z n , A I , P b A N D C r 0 10 20 30 40 50 60 70 80 90 100 110 120 130 V o l u m e t h r o u g h p u t - m l F i g u r e 10 * P E R C E N T R E M O V A L O F M n , M g , C a , N a A N D K . 3 5 removals shown in Table VII , and the per cent removals are obtained by comparing the total amount of ^netal removed at a given volume throughput with the total amount of metal treated at that volume throughput. TABLE VIII TOTAL METAL REMOVAL VOLUME THROUGH (ml) TOTAL AMOUNT REMOVED (mg) TOTAL AMOUNT TREATED (mg) PER CENT REMOVAL 10 53.29 53.56 99.5 20 105.81 107.12 98.6 30 156.84 160.68 97.6 40 205.18 214.2 4 95.7 50 250.52 267.80 93.7 60 291.33 321.36 90.7 70 327.08 374.92 87.3 80 357.59 428.48 83.4 90 382.84 ^: 482. 04 79.4 100 404.10 535.60 75.5 110 421.27 589.16 71.5 120 435.74 642.72 67.7 130 447.97 696.28 64.3 From Figures 9 and 10, which show the per cent re-movals of the individual ions, i t can be seen that removals of Pb, Cr , and Mg were very poor. This was expected for Pb and Cr, since their i n i t i a l concentrations were low. The results from the batch treatment of a similar leachate indicated that F i g u r e II * T O T A L M E T A L R E M O V A L 37 Mg removal was poor, which agreed with the column test re-sults . The best removal was obtained for Fe, which had a very high i n i t i a l concentration. The removal of Na and K was better than expected from the batch test results , and Ca re-moval was worse. These inconsistencies can be explained by considering the variation in pH of the leachates, and the probability of some of the metals existing i n different ionic forms and in different complexes which would be adsorbed at different rates. Figure 11 shows that 90% treatment corresponds with the removal of 296 mg of metal from 61 ml. The useful capacity of the peat in this case is 31.4 mg of metal per gm of peat. Assuming a treatment level of 75%, at which 408 mg of metal are removed from 100 ml, gives a capacity of 43.3 mg/gm. The total amount of metal removed in the test was 448.0 mg. This gives a total capacity for the peat of 47.5 mg/gm for a throughput of 130 ml. This is in f a i r l y close agreement with the 55 mg/gm achieved in the batch test of a similar leachate. The treatment levels of 90 per cent and 75 per cent are arbitrary and may not be sufficient for meeting effluent standards for a particular metal. The breakthrough curves (Figures B - l to B-4) can be used to check that the effluent concentrations meet standards. The volume throughput which would meet a particular concentration requirement may be quite low. If so, the per cent treatment and metal removal for this 38 volume throughput can be found from Figure 11. Scaling up the figures for column treatment at 90 per cent and 75 per cent gives the following peat require-ments : 90% treatment: 0.774 Tons (dry) per 1,000 gal 75% treatment: 0.472 Tons (dry) per 1,000 gal At present the cost to the City of Vancouver of digging, transporting, and placing peat i n Burns Bog to cover the l a n d f i l l site is $1.30 per cubic yard, or approximately $15.30 per ton on a dry basis. Using this figure as a rough cost for unprocessed peat gives a cost of about $11.80 to achieve 90 per cent treatment of 1,000 gal of high strength leachate. To achieve 75 per cent treatment of 1,000 gal would cost about $7.25. It can be seen from the data for effluent concentra-tion versus volume throughput for the low strength leachate (Table B-II) that there is no breakthrough for Mn or Mg. The concentrations actually drop after an i n i t i a l increase. The concentration of suspended solids in the low strength leach-ate was high, probably due to the higher pH. However, the solids remained in a fa i r ly stable suspension, indicating that the sol id particles were co l lo ida l . These very small and co l -loidal particles were simply f i l tered out in the column. The reason for the f a l l of the effluent concentration was that f i l t ra t i on efficiency improved as the column became plugged 39 with sol ids , and increasingly smaller particles were removed. The data for Na and K behaved i n a more normal fashion although the treatment was better than expected. Since the in-fluent concentrations were low i t was thought that treatments ~' would be poorer than for the high strength leachate. Perhaps Na and K were adsorbed more eff ic ient ly at pH 5.35 than at pH 4.84 or perhaps they were present in large complexes that were par t ia l ly f i l tered out. CHAPTER VI REPRODUCIBILITY OF RESULTS A test was performed to determine the consistency of treatment provided by the peat.- Twelve 100 ml samples, each containing 100 mg/1 of lead, were each mixed with 6.37 gm of wet fibrous peat (1.0 gm on a dry basis) and agitated for one hour on the wrist shaker. The same procedure was fo l -lowed using twelve 100 ml samples each containing 500 mg/1 of lead. The samples were then f i l tered and the f i l t ra te analyzed. The analyses are given in Table IX. TABLE IX REPRODUCIBILITY OF RESULTS Concentrations: I n i t i a l (mg/1) I n i t i a l (mg/1) 500 100 Final (mg/1) Final (mg/1) 182 6.6 186 6.7 182 6.3 174 7.1 173 5.0 182 4.8 186 5.4 174 5.1 166 5.8 179 5.9 169 4.2 174 4.4 Mean: .1.7.7 Mean: 5.6 Standard Deviation: 6.5 S.D.: 0.942 40 41 The standard per cent error (standard deviation divided by mean x 100%) is 3.7 per cent at the higher concentration and 16.8 per cent at the lower concentration. It appears that ih j the treatment of> solutions of high concentration the results are more precise than in the treatment of solutions of lower concentration. CHAPTER VII SUMMARY AND CONCLUSIONS Peat can be effective in treating sanitary land-f i l l leachate, although characteristics of the leachate must be considered, and the type and degree of humification of the peat must be taken into account. The main points regarding treatment with peat that were brought out in the batch tests are as follows. 1. Approximately 2 0 minutes was sufficient time to allow the adsorption reactions to achieve equilibrium. 2. Peat which had been allowed to retain i ts moisture worked better than dried peat in the 6 0 minute contact time provided. 3. The fibrous peat derived primarily from sphagnum moss and i n a middle stage ofihumification was more effective than the well humified woody peat. 4. It was found that the adsorptive capacity of the peat was proportional to the i n i t i a l concentration of metal in solution, up to an ultimate capacity. In other words, no matter how high the i n i t i a l concentration, the adsorption 42 43 won't exceed this capacity. The approximate ultimate capa-city of fibrous peat for metal i n d i s t i l l e d water solution was as follows for each of the metals tested: METAL CAPACITY (mg/gm) Fe 12 Cr 15 Zn 16 Al 19 Cd 19 Pb 38 5. Adsorbance was strongly affected by pH, although in a somewhat erratic fashion. Adsorbance was best in the range pH 3.0 to 4.0. The range tested was 1.0 to 6.0. It was thought that perhaps the addition of Na when adjusting the pH upwards was using up some of the peat's capacity. However, subsequent tests indicated that the peat adsorbed Al and Fe much more strongly than Na, so the effect of the Na at the higher pH's was probably small. 6. It was found that the capacity of the peat was higher when treating leachate than when treating d i s t i l l e d water solutions of one metal. This leachate-treating capacity was 55 mg/gm. There was a wide variation in per cent removal of the - different metal ions-from the leachate. 44 7. In treating leachate, COD was reduced by 13 per cent and TOC by 30 per cent. Conclusions to be drawn from the column tests are as follows. 2 1. Lowering the flowrate from 0.360 gpm/ft to 0.129 2 gpm/ft improved the adsorptive capacity of the peat in the column by about 8.6 per cent. 2. Denser packing of the peat improved efficiency, but care had to be taken to ensure that the peat was not packed so t ightly as to be impermeable. 60 gm at 84.3 per cent moisture packed in a 12 inch high, 0.75 inch diameter column (about 4.3 lb / f t ) was found to be about right . The same column packed with 70 gm was pract ical ly impermeable. 3. In the best of four column tests performed on dis-t i l l e d water solutions of Cr , i t was found that, using a breakthrough level of 10 per cent of tlie influent concentra-t ion, the capacity of the peat was about 3.8 mg/gm. 4. In treating high strength leachate of pH 4.84, the total capacity of the peat was found to be about 47.5 mg/gm. The useful capacity of the peat depends on the treatment level desired. In achieving 90 per cent treatment the useful capa-city of the peat was about 31.4 mg/gm. For 75 per cent treat-ment the useful capacity was 43.3 mg/gm. As found in the batch 45 tests, the capacity'of the peat was higher when treat-ing leachate than when treating a d i s t i l l e d water solution of a single metal. 5. To treat to a level of 90 per cent, 0.774 tons of peat per 1,000 gal of the high strength leachate would be required, at a cost of about $11.80. To achieve 75 per cent treatment of 1,000 gal would require 0.472 tons, costing about $7.25. The results of treatment of a low strength leach-ate of pH 5.35 are not useful for evaluating adsorption by peat in a column. However, these results suggest another possible approach to leachate treatment. Perhaps simply rais ing the pH of the leachates would cause the metals to precipitate. This treatment could be effective by i t s e l f or useful as a preliminary treatment prior to anaerobic d i -gestion or adsorption. The effectiveness of peat treatment in a given application must be determined for the waste to be treated. The results of tests performed on three different leachates in this research showed that although roughly the same total capacity of the peat can be expected, the removal capacity for any given metal may vary considerably from leachate to leachate. LIST OF REFERENCES 1. Gamble, D. S., "Peat Humic Materials: A Review of the Chemistry," Soil Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Ontario, from Symposium on Peat Moss in Canada, University of Sherbrooke, Sherbrooke, Quebec, Canada, A p r i l 24-25, 1972 . 2. 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, University of Sherbrooke, Sherr brooke, Quebec, Canada, A p r i l 24-25, 1972. 3. Leverin, H. A . , "Peat Moss Deposits in Canada," Department of Mines and Resources, 1946. 4. BRIEF for presentation at the PUBLIC INQUIRY INTO MUNICIPAL TYPE WASTE DISCHARGES ON LAND, the City of Vancouver, February 19 73. 5. Kel ly , H. G . , and Cameron, R. D . , "Pollutants from Refuse Dumps," Faculty of Applied Science, Department of C i v i l Engineering, Pollution Control Engineering Group, University of Bri t i sh Columbia, December, 1971/ 6. Chalmers, R. , Mineral Resources of Canada Bullet in on Peat, 1904. 7. Haanel, B. F . , "Final Report of the Peat Committee Appointed Jointly by the Governments of the Dominion of Canada and the Province of Ontario," 1925. 8. Haanel, B. F . , Facts About Peat, Canada Department of Mines, 1924. 46 47 9. Buckman, H. 0., and Brady, N. C , The Nature and Proper-ties of Soi ls , The MacMillan Co. , New York, 1968. 10. Farnham, R. S., "Classification System for Commercial Peat," Proceedings of the Third International Peat Congress, Quebec, Canada, August 18-23, 1968. 11. MacFarlane, I. C , and Radforth, N. W., "Structure as a Basis of Peat Class i f icat ion," Proceedings of the Third International Peat Congress, Quebec, Canada, August 18-23, 1968. 12. Day, J . H . , "Classification of Organic Soils in Canada," Proceedings of the Third International Peat Congress, Qufebec, Canada, August 18-23, 1968. APPENDIX A BATCH TESTS 49 TABLE Arl ADSORPTION ISOTHERMS FOR Zn Zn Zn INITIAL INITIALLY Zn ADSORBED Zn PRESENT EQUILIBRIUM REMAINING PER gm. CONCENTRATION IN 100 ml, CONCENTRATION IN 100 ml. OF PEAT (mg/1) (mg,) (mg/1) (mg.) (mg.) 5 .5 1.56 (x,1054*)= 0.165 0 .335 T T« 4- 10 1.0 3.12 (x.l054^)= 0.33 0 .670 Wet 50 5.0 15.6 (x,1054 A)= 1.65 3.35 Fibrous 100 10.0 59.2 (x.l054^)= 6.25 3.75 500 50,0 367 (x,1054 A)= 38.8 11.20 1000 100.0 800 (x.1054 )= 84.5 15.50 5 .5 2.24 (x.l033^)= 0.232 0.268 10 1.0 2.64 (x.l033^)= 0.273 0.727 Wet 50 5.0 23.5 ( x . l 0 3 3 A ) = 2.43 2.57 Woody 100 10,0 59.3 (x.l033 A)= 6.17 3.83 500 50.0 367.0 (x.l033^)= 38.8 12.0 1000 100.0 815.0 (x.1033 )= 84.3 15.7 50 5.0 20.0 2.0 3.0 200 20.0 150 .0 15.0 5.0 Dry 500 50,0 400.0 40.0 10.0 Fibrous 750 75.0 625.0 62.5 12.5 1000 100.0 860.0 86.0 14.0 50 5,0 22.5 2.25 2.75 200 20,0 162.0 16.2 3.8 Dry 600 60,0 525.0 52.5 7.5 Woody 1000 100,0 890.0 89.0 11.0 The d i l u t i o n f a c t o r i s due to water added w i t h the peat. 6.37 gm of wet f i b r o u s peat and 4,32 gm of wet woody peat were used, which means that 5.37 and 3.32 ml of water per 100 ml were added r e s p e c t i v e l y , 50 TABLE A-II ADSORPTION ISOTHERMS FOR Cd ... Cd Cd INITIAL INITIALLY Cd ADSORBED Cd PRESENT EQUILIBRIUM REMAINING PER gm /~\T3 TiT~> A rn CONCENTRATION IN 100 ml CONCENTRATION IN 100 ml OF PEAT (mg/1) (mg) (mg/1) (mg) (mg) 0.5 0.05 0.14 (x.l054)= 0.0148 0.0352 1.0 0.10 0.20 (x.l054)= 0.0211 0.0789 Wet 2.5 0.25 0.26 (x.l054)= 0.0274 0.223 Fibrous 5.0 0.50 0.80 (x.l054)= 0.0844 0.416 7.0 0.70 1.24 (x.l054)= 0.1310 0.569 10.0 1.00 1.93 (x.l054)= 0.2020 0.798 0.5 0.05 0.03 (x.l033)= 0.0031 0.0469 1.0 0.10 0.335 6c .1033) = 0.0346 0.0654 Wet 2.5 0.25 0.25 (x.l033)= 0.0258 0.2242 Woody 5.0 0.50 1.03 (x.l033)= 0.1065 0.3945 7.0 0.70 1.32 (x.l033) = 0.1366 0.5634 10.0 1.00 2.22 (x.l033)= 0.230 0.7700 103.0 10.3 28 (x=.1054) = 2.96 7.34 206.0 20.6 102 (x.l054)= 10.75 9.85 Wet 309.0 30.9 180 (x.l054) = 19.0 11.90 Fibrous 412.0 41,2 260 (x.l054) = 27.4 13.80 515.0 51.5 364 (x.l054) = 38.4 13.10 618.0 61.8 450 (x.l054) = 47.5 14.30 721.0 72.1 530 (x,1054) = 55.9 16.20 824.0 82.4 620 (x.l054) = 65.4 17.00 927.0 92.7 682 (x,1054) = 71.9 20.80 1030.0 103.0 800 (x.l054) = 84,4 18.60 51 TABLE A-III ADSORPTION ISOTHERMS FOR Fe Fe INITIAL INITIALLY Fe ADSORBED Fe PRESENT EQUILIBRIUM REMAINING PER gm CONCENTRATION IN 100 ml CONCENTRATION IN 100 ml OF PEAT (mg/1) (mg) (mg/1) (mg) (mg) 102.8 10.28 58.5 (x J.054) = 6.17 4.11 257.0 25.70 216.5 (x.l054) = 22.85 2.85 Wet 411.5 41.15 341.0 (x.l054) = 36.00 5.15 Fibrous 617.0 61.70 508.0 (x.l054) = 53.60 8.10 822.0 82.20 684.0 (x .1054) = 72.2 10.0 1028.0 102.8Q 865.0 (x.l054) = 91.30 11.5 102.8 10.28 55.0 (x.l033) = 5.68 4.6 257.0 25.70 220.0 (xJ033) = 22.75 2.95 Wet 411.5 41.15 336.0 (x.l033) = 34.75 - 6.40 Woody 617.0 61.70 503.0 (x.l033) = 52.00 9.70 822.0 82.20 728.0 (xJ033) = 75.40 6.80 1028.0 102.80 897.0 (x.l033) = 92.80 10.00 52 TABLE A-IV ADSORPTION ISOTHERMS FOR :Cr INITIAL Cr CONCENTRATION (mg/1) Cr INITIALLY PRESENT IN 100 ml (mg) EQUILIBRIUM CONCENTRATION (mg/1) Cr REMAINING IN 100 ml (mg) ADSORBED PER gm OF PEAT (mg) Fibrous 1. 2. 3. 4. 5. 6. 05 10 15 20 25 30 0.105 0.210 0.315 0.420 0.525 0.630 0.00 (x,1054)= 0.00 (x.l054)= 0.00 (x.l054)= 0.07 (x.l054)= 0.07 (x.l054)= 0.15 (X.1054)= 0.0 0.0 0.0 0.0074 0.0074 0.0158 0.105 0.210 0.315 0.4126 0.5176 0.6142 Woody 1. 05 2.10 3.15 4.20 5.25 6.30 0 .105 0.210 315 0.420 0.525 0.630 0.35 (x.l033)= 0.35 (x.l033)= 0.50 (x.l033)= (x.l033)= (x.l033) = (x.l033) = 0.62 0.62 0.65 0.0362 0.0362 0.0517 0.0642 0.0642 0.0672 0.0688 0.1738 0.2633 0.3558 0.4608 0.5628 Fibrous 100 200 300 400 500 600 700 800 900 1000 10 20 30 40 50 60 70 80 90 100 49.6 (x,1054)= 141 (x.l054) = 208 (x.l054)= 289 (x.l054)= 417 (x.l054) = 458 (x.l054)= 544 (x.l054)= 628 (x,1054) = 719 (x.l054) = 810 (X.1054) = 5.23 14.85 21.94 30.54 44.00 48.30 57.40 66.30 75.80 85.50 6 11 4.77 6.15 8.06 9.50 00 70 12.60 13.70 14.20 14.50 53 TABLE A-V ADSORPTION ISOTHERMS FOR AI AI AI INITIAL INITIALLY AI ADSORBED AI PRESENT EQUILIBRIUM REMAINING PER gm CONCENTRATION IN 100 ml CONCENTRATION IN 100 ml OF PEAT (mg/1) (mg) (mg/1) (mg) (mg) 98.8 9.88 33.5 (x.l054) = 3.53 6.35 197.5 19.75 106 (x.l054) = 11.2 8.55 Fibrous 395.0 39.50 268 (x.l054) = 28.3 11.20 593.0 59.30 428 (x,1054)= 45.2 14.10 790.0 79.00 594 (x.l054)= 62.6 16.40 988.0 98.80 720 (x.l054)= 76.0 22.80 98.8 9.88 26 (x.l033)= 2.69 7.21 197.5 19.75 113 (x.l033)= 11.70 8.05 Woody 395.0 39.50 286 (x.l033)= 29.60 9.90 593.0 59.30 498 (x.i033)= 51.50 7.80 790.0 79.00 612 (x.l033)= 63.20 15.80 988.0 98.80 798 (x.l033)= 82.50 16.30 54 TABLE A-VI ADSORPTION ISOTHERMS FOR Pb Pb Pb INITIAL INITIALLY Pb ADSORBED Pb PRESENT EQUILIBRIUM REMAINING PER gm CONCENTRATION IN 100 ml CONCENTRATION IN 100 ml OF PEAT (mg/1) (mg) (mg/1) 1 (mg) (mg) 2 0.2 ' 0.0 0.0 0.2 4 0.4 0.0 0.0 0.4 5 0.5 0.0 0.0 0.5 Fibrous 6 0.6 0.0 0.0 0.6 8 0.8 0.0 0.0 0.8 10 1.0 0.0 0.0 1.0 2 0.2 0.0 0.0 0.2 4 0.4 0.0 0.0 0.4 5 0.5 0.0 0.0 0.5 Woody 6 0.6 0.0 0.0 0.6 8 0.8 0.0 0.0 0.8 10 1.0 0.0 0.0 1.0 200 20 18 (x.l054)= 1.9 18.1 400 40 115 (x.l054)= 12.1 27.9 Fibrous 500 50 186 (x.l054)= 19.6 30.4 700 70 350 (x.l054)= 36.9 33.1 800 80 435 (x.l054)= 45.9 34.1 900 90 508 (x.l054)= 53.6 36.4 1000 100 567 (x,1054)= 59.8 40.2 1200 120 777 (x,1054)= 82.0 38.0 1500 150 1060 (x.l054)= 111.8 38.2 E N D I X COLUMN TESTS TABLE B - I BREAKTHROUGH DATA FOR HIGH STRENGTH LEACHATE VOLUME THROUGH (ml) EFFLUENT CONCENTRATION (mg/1) Zn A l Fe Pb Cr 5 15 25 •35 45 55 65 75 85 95 105 115 125 INFLUENT 0.50 0.67 0.93 2.88 13.0 28.6 48.8 81.0 147.5 188 220 254 272 290 0.0 0.0 1.8 4.2 8.6 13.0 19.5 26.4 35.5 42.0 48.5 53.6 57.2 68.0 1.10 2.0 4.4 8.6 19.4 33.0 57.5 60.0 62.0 100 128 170 194 1,240 0.28 0.58 0.71 1.30 1.66 1.84 2.30 2.30 2.30 0.57 1.40 3.30 5.4 7.9 9.9 10.4 10.4 10.2 10.8 VOLUME THROUGH (ml) EFFLUENT CONCENTRATION (mg/1) Mn Mg Ca Na K 0.13 9.8 7.7 7.9 0.0 0.67 43.0 30.5 15.0 6.0 1.95 115.5 78.4 39.5 13.0 3.17 190.0 152 95.0 63.0 4.55 210 200 197.5 165 6.65 220 268 375 325 9.75 230 447 440 490 15.80 — 640 500 670 22.0 — 920 630 780 26.8 — 1,120 680 845 32.0 — 1,340 730 890 36.6 — 1,500 — 925 38.0 — — — 960 44.7 240 1,630 790 1,040 5 15 25 35 45 55 65 75 85 95 105 115 125 INFLUENT TABLE B-II BREAKTHROUGH DATA FOR LOW STRENGTH LEACHATE VOLUME THROUGH (ml) EFFLUENT CONCENTRATION (mg/1) Zn Mh Mg Na K 5 0.70 0.00 3.65 9.0 1.43 15 1.05 0.05 8.65 13.5 2.08 25 2.10 0.35 22.10 24.0 3.63 35 0.70 0.67 43.80 49.5 7.15 45 0.35 0.89 55.5 83.5 15.60 55 — 0.89 56.0 124 30.50 65 — 0.70 48.8 150 43.60 75 — 0.62 40.0 200 58.30 85 — 0.43 30.0 220 75.00 95 — 0.35 22.5 260 97.00 INFLUENT 43.5 9.00 84.0 535 380 F i g u r e B - l B R E A K T H R O U G H C U R V E S F O R Z n , M g A N D F e 8 0 7 0 I n f l u e n t c o n c e n t r a t i o n : 6 8 m g / l i t e r A I F i g u r e B - 2 : B R E A K T H R O U G H C U R V E S F O R A I A N D M n I n f l u e n t c o n c e n t r a t i o n 1 I 0 . 8 m g / l i t e r C r 0 10 20 30 40 50 60 70 80 90 100 110 120 130 V o l u m e t h r o u g h p u t - m l Figure B-3 * BREAKTHROUGH CURVES FOR Pb AND Cr. 1700 1600 ^ I 500 .t: 1400 o»l300 E l 1200 c .2 I 100 t 1000 c g 900 o 800 u £ 700 CD 3 600 500 400 300 -200 -100 -0 I n f l u e n t c o n c e n t r a t i o n : I 6 3 0 m g / l i t e r C a I n f l u e n t c o n c e n t r a t i o n 1 I 0 4 0 m g / l i t e r K I n f l u e n t c o n c e n t r a t i o n 1 7 9 0 m g / l i t e r N a 10 20 30 40 50 60 70 80 90 100 110 120 V o l u m e t h r o u g h p u t - m l F i g u r e B - 4 1 B R E A K T H R O U G H C U R V E S F O R C a , N a A N D K . 130 

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