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Coal treatment of wastewaters Hendren, Murray K. 1974

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COAL TREATMENT OF WASTEWATERS  by  Murray K. Hendren B . A . S c , U n i v e r s i t y o f B r i t i s h Columbia, 1969  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE  i n the Department of Civil  Engineering  We accept t h i s t h e s i s as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1974  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 the requirements f o r  an advanced degree at the U n i v e r s i t y o f B r i t i s h Columbia, I agree the L i b r a r y s h a l l make 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  and  that  study.  I f u r t h e r agree 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 purposes may by h i s r e p r e s e n t a t i v e s .  be granted by  permission.  Department  The U n i v e r s i t y o f B r i t i s h Vancouver 8, Canada  Date  flprd  Department or  I t i s understood t h a t c o p y i n g or p u b l i c a t i o n  of 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 written  the Head o f my  Columbia  2.5, \314-  s h a l l not be  allowed without  my  A B S T R A C T  The  c a p a c i t y o f two  metals, organics tests.  One  B r i t i s h Columbia c o a l s to remove heavy  and phosphates was  c o a l was  evaluated  a l i g n i t e from the Hat  u s i n g b a t c h and  Creek a r e a ,  medium v o l a t i l e bituminous from the Crowsnest a r e a . was  were p o s s i b l e w i t h both c o a l s .  Hat  Hat  The of 0.5  c a p a c i t y o f Hat  to 1.0%  weight o f the c o a l . c o a l would be copper.  tested.  ( l e s s than 0.05  mg/l) completely  cadmium from s o l u t i o n .  Creek c o a l f o r copper i o n s was  by weight of the c o a l and  i n the range  f o r l e a d i o n s was  2 to 3%  A sample c a l c u l a t i o n showed t h a t 20 l b s . o f  required  to t r e a t 1,000  a  Creek c o a l  Creek c o a l removed almost  a m i x t u r e of copper, z i n c , l e a d , n i c k e l and  0.2  the o t h e r  s u p e r i o r to Crowsnest c o a l f o r removal of a l l metals  Removals o f heavy m e t a l s to t r a c e v a l u e s  column  crushed  g a l l o n s o f waste c o n t a i n i n g  Average e f f l u e n t c o n c e n t r a t i o n  u s i n g t h a t dosage would  by  10  mg/l  be  mg/l.  I t was  shown t h a t the  t e s t e d v a r i a b l e s had  the  following effects  on the column c a p a c i t y f o r removal of heavy m e t a l s : (1)  Increasing  g r a i n s i z e of c o a l decreased  (2)  Increasing  flow  (3)  D e c r e a s i n g pH  (4)  D e c r e a s i n g wastewater temperature had capacity.  capacity;  r a t e of wastewater decreased  of wastewater decreased  capacity;  capacity; no  e f f e c t on  column  iii  T e s t s performed on o r g a n i c s and  s o l u b l e phosphates showed  the  c o a l s to be u n a b l e t o produce a h i g h q u a l i t y e f f l u e n t from e i t h e r a b e e f e x t r a c t or a sodium phosphate s o l u t i o n , thereby i n d i c a t i n g t h a t the e f f e c t i v e n e s s adsorption  o f the  coals  an  p r o c e s s would p r o b a b l y be v e r y l i m i t e d .  I t i s recommended t h a t of heavy metals by (i)  i n t r e a t i n g m u n i c i p a l waste by  coal.  further research  be  performed on  A suggested course o f a c t i o n i s as  Lab-scale t e s t i n g of s e v e r a l B r i t i s h  removal  follows:  Columbia c o a l s  to  f i n d which ones are most e f f e c t i v e i n heavy m e t a l removal, (ii) (iii)  Comprehensive l a b - s c a l e t e s t i n g o f the b e s t c o a l s i n ( i ) . D e t e r m i n a t i o n of the o f procurement and  (iv)  Pilot  t e c h n i c a l and  d i s p o s a l of  economic f e a s i b i l i t y  coal,  s c a l e t e s t i n g o f the most e f f e c t i v e c o a l s on  wastewaters, i f d a t a from ( i i ) and treatment to be  ( i i i ) indicates  an economic p r o c e s s .  actual coal  TABLE OF CONTENTS  Page ABSTRACT  i i  LIST OF TABLES  ' vi  LIST OF FIGURES  v i i  ACKNOWLEDGEMENT  viii  CHAPTERS I II  III  INTRODUCTION  1  PROCEDURE  4  2il  Introduction  4  2.2  Wastewaters Used  4  2.3  T e s t i n g Procedure  4  2.4  Coal Preparation  7  2.5  Batch T e s t s  8  2.6  Column T e s t s  9  PRESENTATION OF DATA  15  3.1  Composition  15  3.2  Batch T e s t Data  16  3.2.1  General  16  3.2.2  Heavy M e t a l Removal  16  3.2.3  Beef E x t r a c t Removal  22  3.2.4  Phosphate Removal  22  3.2.5  Summary o f Batch T e s t Observations  24  i v  o f the Coals  3.3  Column T e s t Data  26  3.3.1  General  26  3.3.2  Copper Removal - Hat Creek Coal  2g  3.3.3  Copper Removal Crowsnest C o a l  39  Removal o f Lead - Hat Creek C o a l  42  Removal o f Heavy M e t a l Mixture  43  3.3.6  Regeneration  45  3.3.7  Beef E x t r a c t Removal  47  3.3.8  Phosphate Removal  47  3.3.9  Summary o f Column T e s t s  49  3.3.A  3.3.5  IV  V  POSSIBLE USES  51  4.1  I n d u s t r i a l Heavy M e t a l Removal  51  4.2  Treatment o f M u n i c i p a l Sewage  52  CONCLUSIONS AND RECOMMENDATIONS  54  5.1  Conclusions  54  5.2  Recommendations  56  GLOSSARY OF TERMS  58  BIBLIOGRAPHY  59  APPENDIX I II  III  T y l e r Mesh S e r i e s  60  Sample D e t e r m i n a t i o n o f C o a l C a p a c i t y from a Breakthrough Curve  62  Batch T e s t Data  64  LIST OF TABLES  TABLE  I  II  III  IV  PAGE  Solutions Tested  Composition  5  o f Coals  16  Summary o f T e s t s and Capacities  C a p a c i t y o f 28/48 Hat Creek C o a l  vi-  31  LIST OF FIGURES Figure  Page  1.  A d s o r p t i o n Isotherms f o r Copper  18  2.  A d s o r p t i o n Isotherms f o r Lead  20  3.  A d s o r p t i o n Isotherms f o r Z i n c  21  4.  A d s o r p t i o n Isotherms f o r Beef E x t r a c t  23  5.  A d s o r p t i o n Isotherms f o r PO^  25  6.  Breakthrough Curve u s i n g Hat Creek C o a l and 100 mg/l Copper S o l u t i o n  30  7.  Breakthrough Curves f o r Three G r a i n S i z e s o f Hat Creek C o a l  32  8.  Breakthrough Curves showing E f f e c t s o f Adsorbate pH and A d s o r b a t e Flow Rate  34  9.  Breakthrough Curves f o r Hat Creek and Crowsnest Coals T r e a t i n g a 10 mg/l S o l u t i o n o f Copper  36  10.  Breakthrough Curves f o r Hat Creek and Crowsnest C o a l s T r e a t i n g a 0.7 mg/l S o l u t i o n o f Copper  38  11.  Breakthrough Curves f o r Hat Creek and Crowsnest C o a l s , I n f l u e n t C o n c e n t r a t i o n 100 mg/l Copper  40  12.  Breakthrough Curves f o r Crowsnest C o a l , Showing E f f e c t s of Flow Rate  41  13.  Breakthrough Curve f o r Hat Creek C o a l , Showing C a p a c i t y f o r Lead  44  14.  Breakthrough Curves f o r Hat Creek and Crowsnest C o a l s T r e a t i n g a 10 mg/l S o l u t i o n o f Copper.  46  15.  Breakthrough Curves f o r Beef E x t r a c t S o l u t i o n u s i n g Hat Creek and Crowsnest Coals.  48  vii  A C K N O W L E D G E M E N T  The h e l p  o f Mr. Cy Jones o f I n t e r p r o v i n c l a l P a t e n t s L t d .  f o r the s u p p l y o f t h e c o a l s Also  the help  t e s t e d i s g r a t e f u l l y acknowledged.  and encouragement o f Dr. W.K. Oldham, Dr. R.D. Cameron,  Mrs. E. MacDonald, Mr. R.D. Wetter, Mr. J.W. Atwater and Mrs. A.M. MacGillivray.  viii  T h i s t h e s i s i s d e d i c a t e d to my  wife  Marg, w i t h o u t whose encouragement and s u p p o r t , the study would n o t have been p o s s i b l e .  ix  C H A P T E R  I  INTRODUCTION  Anthracite  c o a l has been i n use f o r s e v e r a l decades as a  i n g medium f o r water s u p p l i e s .  Only r e c e n t l y , however, has the use o f  c o a l as an adsorbent f o r p u r i f y i n g wastewaters been examined. to the study d e s c r i b e d been t e s t e d  filter-  Prior  i n t h i s t h e s i s , no B r i t i s h Columbia c o a l s  comprehensively f o r t h e i r a b i l i t y  to remove  have  impurities  from wastewaters, even though the use o f c o a l f o r t r e a t i n g wastewaters i n B r i t i s h Columbia seems p a r t i c u l a r l y worthy o f r e s e a r c h . population,  Increasing  i n d u s t r i a l growth, and p u b l i c p r e s s u r e a r e f o r c i n g the  P r o v i n c e to enact h i g h e r p o l l u t i o n c o n t r o l standards thereby the need f o r i n e x p e n s i v e b u t e f f e c t i v e treatment methods. possibility  that  reported  There i s a  c o a l c o u l d be used f o r t r e a t i n g wastewaters  p r i o r to o r i n s t e a d o f b e i n g used as a f u e l . i n t h i s t h e s i s was  The r e s e a r c h  undertaken to examine  increasing  either  program  this possibility.  C o a l , which i s a v a i l a b l e i n the P r o v i n c e i n l a r g e , e a s i l y mined deposits, several  has been r e p o r t e d  types o f i m p u r i t i e s  [1,2,3,4] to have the c a p a b i l i t y o f removing from wastewaters, i n c l u d i n g :  (1)  C o l l o i d a l organic  (2)  Dissolved  (3)  Solids normally separable i n conventional filtering  material  inorganic  material  processes.  1  2  The materials  p o s s i b i l i t y e x i s t s t h a t c o a l can remove using a s i n g l e contacting  u n i t , thereby r e q u i r i n g a minimum  l a n d o r f l o o r area f o r t r e a t i n g a complex waste. tively  cheap compared w i t h o t h e r  little  as $15 p e r ton.  C o a l , which i s r e l a -  adsorbent m a t e r i a l s , may s e l l f o r as  A c t i v a t e d carbon, on the o t h e r hand  approximately $500 f o r the same amount. if  a l l the above-named  Further  savings  costs  might be e f f e c t e d  t h e c o a l c o u l d be used f o r f u e l a f t e r use i n a wastewater treatment  process.  I n v e s t i g a t o r s have found t h a t most c o a l s e x h i b i t a c a p a b i l i t y t o remove i m p u r i t i e s from waste streams b u t t h a t t h e magnitude o f the removal c a p a c i t y v a r i e s from c o a l t o c o a l .  Johnson and Kunka [1] r e p o r t e d  t h a t c e r t a i n c o a l s had the c a p a c i t y  to remove up to 4% o f t h e i r weight i n oxygen demanding m a t e r i a l s , measured i n terms o f C.O.D., from s e t t l e d raw sewage.  The c o a l s used by Johnson  and Kunka were ground to a p p r o x i m a t e l y 50/70 mesh* and c o n t a c t e d  with  the sewage i n a b a t c h system.  Shannon [ 2 ] , u s i n g found t h a t the b e s t  s i m i l a r g r a i n s i z e d c o a l and a s y n t h e t i c sewage,  c o a l t e s t e d had a c a p a c i t y o f removing o n l y 0.1% o f  i t s weight i n oxygen demanding m a t e r i a l s , measured i n terms o f C.O.D. Both Johnson's and Shannon's s t u d i e s were performed on a l a b o r a t o r y scale.  * T y l e r Mesh S e r i e s  (See Appendix I ) .  3  The Rand C o r p o r a t i o n [3] o p e r a t e d a 10,000 U.S.  gal/day p i l o t  p l a n t t h a t used 18/120 mesh c o a l as a consumable p r e c o a t f i l t e r t r e a t raw sewage and secondary e f f l u e n t . 90% decrease i n suspended  The r e s u l t s showed t h a t a  s o l i d s and a 40 to 60% decrease i n phosphates  and C.O.D. c o u l d be expected i f a c o a l f i l t e r was raw sewage o r secondary  to  used to t r e a t  either  effluent.  The L i n f i e l d Research I n s t i t u t e i n M c M i n n v i l l e , Oregon [4] has completed a p r e l i m i n a r y study on the removal o f i n o r g a n i c i o n s solutions with coal.  A l l cations tested  (copper, z i n c , barium,  manganese) were removed to some e x t e n t by the c o a l . as chromate  iron,  T o x i c a n i o n s such  and cyanide were a l s o removed.  A r e s e a r c h program was bility  from  t h e r e f o r e undertaken to examine the f e a s i -  o f u t i l i z i n g B r i t i s h Columbia c o a l s to t r e a t wastewaters.  reasons f o r u n d e r t a k i n g the program (1)  follows:  C o a l has been shown to remove a wide v a r i e t y o f m a t e r i a l s from  (2)  are summarized as  The  wastewaters.  The i n c r e a s e d p o p u l a t i o n and i n d u s t r i a l growth o f B r i t i s h Columbia d i c t a t e s h i g h p o l l u t i o n c o n t r o l s t a n d a r d s and t h e r e f o r e e f f e c t i v e treatment methods.  (3)  There are l a r g e r e s e r v e s of c o a l i n B r i t i s h Columbia  that  c o u l d p o s s i b l y be used f o r treatment p u r p o s e s . (4)  No B r i t i s h Columbia for  their ability  c o a l s have been t e s t e d  to r e n o v a t e wastewaters.  comprehensively  C H A P T E R  II  PROCEDURE  2.1  Introduction  Two  c o a l s were crushed, washed, s i e v e d to v a r i o u s g r a i n  and then t e s t e d f o r t h e i r c a p a b i l i t y to remove p o l l u t a n t s  sizes  from  s y n t h e t i c wastewaters.  Batch t e s t s were performed to p r o v i d e  g e n e r a l d a t a w i t h which  to d e s i g n column experiments.  Column  t e s t s were subsequently performed to e s t a b l i s h the c a p a c i t y o f the c o a l s to removal s e v e r a l i m p u r i t i e s from s o l u t i o n under c o n d i t i o n s o f f l o w r a t e , wastewater and g r a i n s i z e of c o a l . lead n i t r a t e ,  pH, wastewater  varying  temperature  S o l u t i o n s c o n t a i n i n g copper s u l p h a t e ,  z i n c s u l p h a t e , n i c k e l n i t r a t e , cadmium n i t r a t e ,  sodium phosphate  and b e e f e x t r a c t were used t o s i m u l a t e a c t u a l  wastewaters.  2.2  Wastewaters Used  T a b l e I i n d i c a t e s the s i m u l a t e d wastewaters, used i n the s y n t h e t i c wastewater, wastewaters  2.3  the m a t e r i a l s  and the major s o u r c e s o f the  amenable to p o t e n t i a l c o a l treatment.  T e s t i n g Procedure  T e s t i n g was  performed i n accordance w i t h Standard Methods f o r  4  TABLE  I  SOLUTIONS  ACTUAL WASTEWATER  Copper  ions  SYNTHETIC WASTEWATER  ions  Pb  Zinc  ions  ZnSO^  Cadmium  ions ions  Oxygen demanding materials  Phosphates  *  ratio  SOURCE OF A C T U A L WASTEWATER  CuSO^  Lead  Nickel  TESTED  (N0 ) 3  2  (N0 )  2  Cd  (N0 )  2  3  3  Extract*  S od ium Phosphate  o f COD: T K N : 9:1  finishing  Landfill  Ni  Beef  Metal  Mining  Industries  leachate effluents  Municipal sewage, I n d u s t r i a l waste  Municipal  sewage  6  Examination o f Water and Wastewater, 13th E d i t i o n .  Heavy m e t a l  c o n c e n t r a t i o n s were measured u s i n g an atomic a b s o r p t i o n s p e c t r o photometer.*  The K j e l d a h l t e s t r a t h e r than t h e C.O.D. o r B.O.D.  t e s t s was used to i n d i c a t e the amount o f oxygen demanding m a t e r i a l s present  i n a sample.  Other r e s e a r c h e r s  [2] found  that the f i n e s  added by the c o a l made the d e t e r m i n a t i o n  o f oxygen demanding  m a t e r i a l s by the C.O.D. t e s t i m p r e c i s e .  The B.O.D. t e s t was a l s o  inconvenient,  from a time s t a n d p o i n t .  P r e c i s e r e s u l t s were o b t a i n e d  u s i n g t o t a l K j e l d a h l n i t r o g e n (TKN) as an i n d i c a t i o n o f oxygen demanding m a t e r i a l s , although has  the use o f TKN as such an i n d i c a t o r  some drawbacks.  K j e l d a h l n i t r o g e n t e s t s g i v e a good i n d i c a t i o n o f p r o t e i n a c e o u s m a t e r i a l b u t do n o t g i v e any i n d i c a t i o n o f c a r b o h y d r a t e s . i f K j e l d a h l n i t r o g e n were used as an i n d i c a t o r f o r a c o a l  Therefore, treatment  p r o c e s s , the c o a l need o n l y remove a l a r g e p o r t i o n o f t h e p r o t e i n aceous matter to f a l s e l y  appear to be a c h i e v i n g e f f i c i e n t  Because c o a l does p r e f e r e n t i a l l y adsorb p r o t e i n a c e o u s carbohydrates  such as sugars  t h a t the degree o f treatment Kjeldahl tests i s falsely  treatment.  materials  [ 2 ] , the s t r o n g p o s s i b i l i t y  over  exists  measured i n t h i s study by u s i n g  optimistic.  Treatment e f f i c i e n c i e s c a l c u l a t e d by u s i n g data from K j e l d a h l t e s t s t h e r e f o r e w i l l p r o b a b l y be h i g h e r than those which would be  * J a r r e l l - A s h MV-500  7  c a l c u l a t e d u s i n g C.O.D. t e s t s .  The  conclusions  to be v a l i d , but  o f the r e p o r t , however, are s t i l l  considered  o n l y because the data showed t h a t the c o a l columns  were unable to e f f e c t i v e l y remove o r g a n i c m a t e r i a l from s o l u t i o n . As  explained  i s probably  above, the a c t u a l treatment of the o r g a n i c worse than t h a t measured.  I t can  materials  t h e r e f o r e be  t h a t the poor r e s u l t s n o t i c e d i n t h i s study a r e the b e s t be expected. the q u e s t i o n  Had  said  that  can  the r e s u l t s of the study been more o p t i m i s t i c  of u s i n g n i t r o g e n as an i n d i c a t o r o f o r g a n i c  materials  would have r e q u i r e d f u r t h e r c o n s i d e r a t i o n .  v  2.4  Coal  Preparation  All  c o a l used throughout the t e s t i n g program was  g r a i n s i z e and was a s e r i e s of jaw  and  three g r a i n s i z e s :  thoroughly  washed.  cone c r u s h e r s ,  The  then wet  c o a l was  of a  ground  s i e v e d to the  specific using following  ( T y l e r mesh s e r i e s ) * 14/28 28/48 48/65  A f t e r being  s i e v e d , the i n d i v i d u a l g r a i n s i z e s were back-washed  i n a p l e x i g l a s s column u n t i l a l l f i n e s were removed. was  then d r i e d at 103°C and  * See Appendix I .  The  coal  s t o r e d at room temperature u n t i l  used.  8  2.5  Batch  Tests  Batch  t e s t s were performed  d e s i g n continuous procedure (i)  flow column experiments.  f o r b a t c h t e s t i n g was  The  experimental  as f o l l o w s :  A measured amount o f wastewater of known c o n c e n t r a t i o n was  (ii)  to o b t a i n d a t a w i t h which to  added to each o f s e v e r a l f l a s k s ,  V a r y i n g b u t known amounts o f c o a l were added to each flask.  (iii)  The  coal-wastewater  m i x t u r e was  shaken f o r 24 hours t o  a s s u r e t h a t e q u i l i b r i u m c o n d i t i o n s were e s t a b l i s h e d , (iv)  The  e q u i l i b r i u m c o n c e n t r a t i o n of wastewater i n each  f l a s k was (v)  The  measured,  removal c a p a c i t y of the c o a l i n each f l a s k  was  calculated.  P l o t s were made of the c a p a c i t y o f the c o a l to remove an i m p u r i t y v e r s u s the e q u i l i b r i u m c o n c e n t r a t i o n of the i m p u r i t y i n c o n t a c t w i t h the c o a l .  Such p l o t s are c a l l e d a d s o r p t i o n i s o t h e r m s ,  as the d a t a f o r each graph temperature,  i s gathered a t a c o n s t a n t  solution  and because the mechanism of a d s o r p t i o n i s p r o b a b l y  i n v o l v e d i n the removal of p o l l u t a n t s by c o a l .  The  term a d s o r p t i o n  i s meant to i n c l u d e p h y s i c a l a d s o r p t i o n , c h e m i s o r p t i o n and i o n exchange.  A l l b a t c h t e s t s except those u s i n g beef e x t r a c t were at room temperature. at 4°C  The b e e f e x t r a c t removal t e s t s were  performed performed  to p r e v e n t b i o l o g i c a l d e g r a d a t i o n of the s o l u t i o n d u r i n g the  9  24 hour c o n t a c t  time.  The v a l u e o f b a t c h t e s t d a t a i s l i m i t e d by the f a c t t h a t d a t a i s gathered a t e q u i l i b r i u m c o n d i t i o n s . employing  Most treatment  units  i o n exchange o r adsorbent m a t e r i a l s , however, o p e r a t e  on a continuous  flow b a s i s .  The adsorbent  o r i o n exchange m a t e r i a l s  a r e p l a c e d i n a column through which wastewaters a r e passed the removal c a p a c i t y o f the m a t e r i a l s i s exhausted. on f a c t o r s such as flow r a t e , column depth  until  Depending  and column c r o s s  s e c t i o n a l a r e a , e q u i l i b r i u m c o n d i t i o n s may o r may n o t e x i s t i n such flow-through  operations.  In l i g h t of t h i s f a c t , batch  test  data s h o u l d n o t be used as a v a l i d i n d i c a t i o n o f how w e l l a m a t e r i a l t e s t e d would p e r f o r m  in a full  The most important  s c a l e column o p e r a t i o n .  use f o r b a t c h t e s t d a t a i s the d e s i g n o f  l a b - s c a l e column experiments.  Data from b a t c h t e s t s can save  and e f f o r t when d e s i g n i n g and running a l a b - s c a l e column. from the column t e s t s can then i n t u r n be used scale f a c i l i t y  2.6  time  Data  to design a p i l o t  i f the l a b s c a l e t e s t s a r e s u c c e s s f u l .  Column T e s t s  R e s u l t s from column t e s t s can be used t o d e s i g n a p i l o t - s c a l e column experiment  i f c o a l treatment  seems e c o n o m i c a l l y  feasible.  L a b o r a t o r y s c a l e column t e s t s were t h e r e f o r e performed  t o demon-  s t r a t e the a b i l i t y o f the c o a l t o remove i m p u r i t i e s from wastewater on a flow-through b a s i s and to g a i n i n s i g h t i n t o the f e a s i b i l i t y of establishing p i l o t scale  tests.  10  Column t e s t s were performed i n the f o l l o w i n g manner: (i) (ii)  A predetermined amount of c o a l was Wastewater was  p l a c e d i n a column,  passed through the c o a l at a c o n t r o l l e d  flow r a t e . (iii)  The  e f f l u e n t c o n c e n t r a t i o n was  measured at r e g u l a r i n t e r v a l s  based on through-put volume, (iv)  A p l o t was  made of e f f l u e n t c o n c e n t r a t i o n v e r s u s  through-  put volume.  In the e a r l y stages  of any  column o p e r a t i o n the e f f l u e n t  t r a t i o n o f i m p u r i t y w i l l be l e s s than the i n f l u e n t  concentration  an amount dependent on s e v e r a l f a c t o r s , i n c l u d i n g type and s i z e of c o a l i n the column, flow r a t e , pH, and  composition  o f the wastewater.  As  temperature,  grain  the time of o p e r a t i o n i n c r e a s e s ,  c o n c e n t r a t i o n approaches t h a t of the i n f l u e n t .  to the curve  by  concentrations,  the c a p a c i t y o f the adsorbent i s g r a d u a l l y exhausted and  concentration versus  concen-  A p l o t of  the  effluent  effluent  throughput volume i s g e n e r a l l y S-shaped, s i m i l a r  shown i n F i g u r e  6.  There are two parameters which must be measured to determine the e f f e c t i v e n e s s o f an adsorbent m a t e r i a l to p u r i f y wastewaters under any  g i v e n c o n d i t i o n o f flow r a t e , pH,  concentration. (i)  The  temperature and  impurity  These a r e :  i n f l u e n t and  e f f l u e n t concentrations  from which a %  treatment can be c a l c u l a t e d , (ii)  The  l e n g t h o f time an amount o f c o a l can produce an  effluent  o f a g i v e n q u a l i t y i . e . the weight c a p a c i t y o f the c o a l to remove an  impurity.  11  As p r e v i o u s l y mentioned, the c a p a c i t y of the adsorbent exhausted and  the e f f l u e n t  c o n c e n t r a t i o n approaches t h a t o f  i n f l u e n t as time of column o p e r a t i o n p r o g r e s s e s . when the i n f l u e n t and  spent.  When the e f f l u e n t  the  Presumably  e f f l u e n t c o n c e n t r a t i o n s are e q u a l  bent w i l l be completely  is  the  adsor-  concentration  i s l e s s than the i n f l u e n t , however, o n l y a c e r t a i n f r a c t i o n o f c o a l s c a p a c i t y w i l l have been u t i l i z e d . upon the v a l u e o f e f f l u e n t calculated.  The  the  T h i s f r a c t i o n would depend  c o n c e n t r a t i o n a t which the c a p a c i t y i s  e f f l u e n t c o n c e n t r a t i o n a t which we  a r e most  i n t e r e s t e d i n c a l c u l a t i n g the c a p a c i t y o f the c o a l i s t h a t above which we  can no l o n g e r use  the column.  Such a c o n c e n t r a t i o n i s  c a l l e d the breakthrough c o n c e n t r a t i o n and (i) (ii) (iii)  depends on f a c t o r s such as:  Pollution control regulations Water re-use  criteria  whether o r not another  column i s p l a c e d downstream o f  the  column i n q u e s t i o n .  Because of the d i f f e r e n t f a c t o r s i n v o l v e d , i t i s d i f f i c u l t  to p r e d i c t  o r assume a b r e a k t h r o u g h c o n c e n t r a t i o n t h a t would be a p p l i c a b l e to an a c t u a l i n s t a l l a t i o n . the c o r r e s p o n d i n g concentrations  T h e r e f o r e , i n most i n s t a n c e s i n t h i s  c o a l c a p a c i t i e s were g i v e n f o r t h r e e b r e a k t h r o u g h  f o r each column  test.  Another parameter sometimes r e p o r t e d i n t h i s study  i s the  average e f f l u e n t c o n c e n t r a t i o n p r i o r to b r e a k t h r o u g h , simply t o t a l weight o f i m p u r i t y passed through the column d i v i d e d by t o t a l throughput.  study,  the the  I t i n d i c a t e s the e f f l u e n t q u a l i t y a t t a i n a b l e on  12  an average b a s i s .  Sample c a l c u l a t i o n s are  shown i n Appendix I I .  O b t a i n i n g an a c c u r a t e breakthrough curve r e q u i r e s sampling o f the  column e f f l u e n t .  a t t e n d e d on a continuous b a s i s .  The  frequent  column must t h e r e f o r e  C o a l volumes used were  therefore  l i m i t e d to t h a t amount which would a l l o w e x h a u s t i o n of the removal c a p a c i t y would not be  so  were a v a i l a b l e ) .  a f t e r a r e a s o n a b l e time.  (The  c r i t i c a l i f automatic feed and The  amount of c o a l to be  volume o f sampling  used was  be  column's coal  devices  decided i n  the f o l l o w i n g manner: (i) (ii)  A maximum time of o p e r a t i o n Flow r a t e s  through the  was  chosen as b e i n g 16  columns were chosen i n l i n e w i t h  commercial treatment p r o c e s s e s . further i n this (iii) (iv)  hours,  (This i s  discussed  section).  Column s i z e s were chosen a c c o r d i n g to equipment a v a i l a b l e , Flow through the  column d u r i n g  the 16 h r . p e r i o d  was  calculated. (v)  Weight o f i m p u r i t y hour p e r i o d was  (vi)  The  capacity  p a s s i n g through the  column i n the  16  calculated,  o f the  c o a l f o r removing the  p a r t i c u l a r i n f l u e n t concentration  impurity  t e s t e d was  at  the  estimated  from b a t c h t e s t data, (vii)  The  weight o f c o a l r e q u i r e d  i n the  column was  calculated  from (v) and ( v i ) .  U s i n g r e a d i l y a v a i l a b l e 100  ml b u r e t t e s  as columns, i t was  found  t h a t a p p r o x i m a t e l y 30 grams of c o a l i n each column would permit most  13  runs to be t e r m i n a t e d w i t h i n 12 to 16 h o u r s . filled  T h i r t y grams o f c o a l  the columns to a depth o f a p p r o x i m a t e l y 1 f o o t .  r a t e through the columns was  The flow  2 a p p r o x i m a t e l y 1 g a l l o n / f t /min.  which,  3 in  the case o f t h i s s t u d y , was  also 1 g a l / f t  /min., as the column 2  depth was  one f o o t .  O c c a s i o n a l l y a flow rate of 5 g a l l o n s / f t  /min.  was  used t o show the e f f e c t s o f u s i n g such a r a t e o r to decrease  the  time to breakthrough to p r a c t i c a l For  comparison,  p r o c e s s e s are as  limits.  flow r a t e s f o r commercial  contact or  filter  follows: 1-5  Ion  1-10  gal/ft  1-10  gal/ft  Exchange  A c t i v a t e d Carbon A d s o r p t i o n  gal/ft  2  Rapid Sand F i l t r a t i o n  /min. 2 2  /min. /min.  Residence times o f a d s o r b a t e i n the columns, based on empty columns, were 7.5 minutes  1.5 minutes  f o r the flow r a t e o f 1 g a l / f t 2  f o r a flow r a t e of 5 g a l / f t  /min.  2  /min.  Based on a c t u a l v o i d  space i n the column the r e s i d e n c e times would be about 3.7 and 0.75  minutes  and  minutes  respectively.  The g r a i n s i z e s used i n the column t e s t s were 14/28, 28/48 and 48/65.  The m a j o r i t y o f t e s t i n g was  The i n f l u e n t and the i n f l u e n t  done w i t h 28/48.  c o n c e n t r a t i o n o f the i m p u r i t y , the i n f l u e n t  pH,  temperature were a d j u s t e d d u r i n g the column t e s t i n g  so t h a t the e f f e c t s o f these v a r i a b l e s on column o p e r a t i o n s c o u l d be determined.  Complete  d e t a i l s o f the column t e s t s as performed,  i n c l u d i n g type o f c o a l used, i m p u r i t y removed, i n f l u e n t  concentration  14  of Impurity, and  i n f l u e n t pH,  i n f l u e n t temperature,  g r a i n s i z e of  flow r a t e of wastewater are o u t l i n e d i n the f o l l o w i n g  coal  chapter.  C H A P T E R  III  PRESENTATION OF DATA-  3.1  Composition  Due  o f the Coals  to l a c k o f p r o p e r f a c i l i t i e s t o determine  compositions o f c o a l s , i t was  n e c e s s a r y to approximate  t i o n s w i t h v a l u e s from l i t e r a t u r e .  c o u l d be e s t i m a t e d  from  o f the g e n e r a l c o a l f i e l d as r e p o r t e d by the Canada  Department o f Mines.  [5] (See T a b l e I I )  Thus, the  compositions  r e p o r t e d are not e x a c t l y the same as the compositions used i n the experiments. purposes  the composi-  The o r i g i n s of the c o a l s were  known, and t h e r e f o r e the compositions samplings  the exact  of t h i s  o f the c o a l s  They a r e , however, s a t i s f a c t o r y  for_the  study.  The ash contents o f the c o a l s were checked by h e a t i n g the c o a l to 550°C f o r s i x hours.  Values o f ash content f o r the Crowsnest  agreed almost e x a c t l y w i t h p u b l i s h e d f i g u r e s .  coal  However, the ash  c o n t e n t o f the Hat Creek c o a l used f o r e x p e r i m e n t i n g was  twice t h a t  r e p o r t e d i n the l i t e r a t u r e , thereby i n d i c a t i n g t h a t c o a l samples v a r y i n c o m p o s i t i o n depending  on l o c a t i o n w i t h i n the c o a l f i e l d .  This  f a c t c o u l d be important when more comprehensive s t u d i e s are c a r r i e d out i n attempts  to f i n d the removal mechanism(s) i n v o l v e d i n c o a l  treatment o r to f i n d the most e f f i c i e n t S e v e r a l samples o f a g i v e n c o a l f i e l d may 15  coal for coal  treatment.  have to be t e s t e d to see  16  which g i v e s  the b e s t r e s u l t s . TABLE I I COMPOSITION OF COALS  Parameter  Hatcreek  Crowsnest  8  1  % v o l a t i l e matter  36  22  % f i x e d carbon  47  65  % moisture  % ash  9*  % sulphur  0.5+  * Actual Analysis  11 0.7+  o f c o a l showed 20% ash  + Data f o r c o a l a c t u a l l y used.  3.2  Batch T e s t 3.2.1  Data  General Batch t e s t s were performed u s i n g o f the two c o a l s .  two g r a i n s i z e s of each  Substances used s e p a r a t e l y  to approximate wastewaters were copper  i n solution  sulphate,  lead  n i t r a t e , z i n c s u l p h a t e , l e a d n i t r a t e , sodium phosphate and beef e x t r a c t .  Generally,  during  the b a t c h t e s t s , the water  was clouded due t o p a r t i c l e break-up o f the c o a l . Creek c o a l was p a r t i c u l a r l y s u s c e p t i b l e Phosphate samples, r e q u i r i n g  Hat  to p a r t i c l e break-up.  c o l o r i m e t r i c a n a l y s i s , were  centrifuged before testing.  3.2.2  Heavy M e t a l Removal The  b a t c h t e s t s showed t h a t  the c o a l s  t e s t e d had t h e c a p a c i t y  17  to remove heavy metals from s o l u t i o n . the  c o a l f o r metals depended on  g r a i n s i z e of the equilibrium  c o a l , the  concentration  The  capacity  of  the type o f c o a l used,  exact m e t a l i n v o l v e d  and  of the m e t a l s o l u t i o n .  the  the  Specific  b a t c h t e s t d a t a i s shown i n Appendix I I I .  The  isotherms p l o t t e d from the b a t c h t e s t s i n v e s t i g a t i n g  copper removal are shown i n F i g u r e  1.  The  curves show  the  following: - The  capacity  o f the c o a l i n c r e a s e d  with increasing  equili-  brium c o n c e n t r a t i o n  o f copper i n s o l u t i o n up  to a l i m i t  about 100  c o n c e n t r a t i o n s above 100  mg/1  capacity  does not  48/65 Hat to 300 - For  mg/1.  At  change s i g n i f i c a n t l y .  Creek c o a l , the  capacity  coal  exception i s  of which i n c r e a s e d  up  mg/1.  a p a r t i c u l a r g r a i n s i z e and  the Hat  An  the  of  Creek c o a l had  equilibrium  a higher capacity  concentration,  than the  Crowsnest  coal. - For  a p a r t i c u l a r c o a l and  smaller  equilibrium  g r a i n s i z e c o a l had  concentration,  the h i g h e r  capacity.  - The  maximum c a p a c i t y  a t t a i n e d was  was  measured f o r Hat  Creek c o a l , g r a i n s i z e 48/65, a t  equilibrium  concentration  o f 300  17 mg/gm of c o a l .  same trends as those p l o t t e d from the of coal increased  This an  mg/1.  Batch isotherms p l o t t e d from l e a d removal s t u d i e s  capacity  the  showed  copper s t u d i e s .  with increasing  equilibrium  The lead  the  20r D  O O  18  <+-  16  E  14  o  TJ  >  O  £  Crowsnest  12 Hat  10  Creek  48/65  28/48  CD  CJ-  E  —-  6 o QL O CJ  •O  8 6  Crowsnest  28/48  4  •-a  2 0  o  100  200  300  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/liter  FIG. I  ADSORPTION ISOTHERMS FOR C O P P E R .  400  500  19  concentration  and d e c r e a s i n g g r a i n s i z e .  was s u p e r i o r  t o Crowsnest c o a l .  C a p a c i t y as h i g h as 45 mg  of lead/gm o f c o a l was o b s e r v e d .  Similar  Hat Creek c o a l  (Figure 2).  trends a g a i n were o b t a i n e d when u s i n g  z i n c as t h e  adsorbate.  (Figure  in addition  to the Crowsnest c o a l i n the z i n c b a t c h t e s t s ,  but  the r e s u l t s were d i s c a r d e d  Figure -  3 ) . Hat Creek c o a l was o r i g i n a l l y  used  due t o s c a t t e r .  3 shows the f o l l o w i n g :  the c a p a c i t y equilibrium  - the h i g h e s t  o f the c o a l i n c r e a s e s concentration capacity  with  increasing  of zinc.  c a l c u l a t e d was e x h i b i t e d by the  48/65 g r a i n s i z e and amounted t o 14 mg Zn/gm o f c o a l . T h i s v a l u e was c a l c u l a t e d a t an e q u i l i b r i u m  concentra-  t i o n o f 425 mg/l.  The  flasks containing  the b a t c h t e s t m a t e r i a l s  were v i s u a l l y  examined c a r e f u l l y a f t e r each t e s t t o make sure p r e c i p i t a t i o n of the heavy metals was n o t o c c u r r i n g .  I n each case, no  t r a c e o f a p r e c i p i t a t e c o u l d be found on the bottom o f t h e flask.  There i s only  a minute p o s s i b i l i t y  t h a t any p r e c i p i t a t e  formed would s t i l l be i n s u s p e n s i o n and n o t measured i n t h e t e s t i n g procedure.  Such a s u s p e n s i o n would g i v e v e r y e r r a t i c  r e a d i n g s on the atomic a b s o r p t i o n phenomenon was n o t n o t i c e d  u n i t and such an e r r a t i c  i n t h i s study.  I t therefore  t h a t the c o a l removes the metals from s o l u t i o n by an process.  seems  adsorption  FIG. 2  ADSORPTION ISOTHERMS FOR LEAD  21  FIG.3 ADSORPTION ISOTHERMS FOR ZINC  22  3.2.3  Beef Extract Removal  Batch tests were performed on a beef extract solution kept at 4°C.  The low temperature was necessary to ensure  that no b i o l o g i c a l degradation occurred during the 24 hour contact time.  Figure 4 shows the results of the t e s t s .  The best results were obtained using Hat Creek coal, 48/65 grain s i z e .  Increasing the grain s i z e decreased the  capacity of the coal such that the capacity of the 48/65 Hat Creek coal was 1.8 times higher than the capacity of the 28/48 Hat Creek coal.  The maximum capacity of 48/65  Hat Creek coal was found to be 5 mg. of Total Kjeldahl Nitrogen/gm of coal at an organic nitrogen of 200 mg/l.  concentration  In terms of C.O.D.* this value would correspond  to approximately 45 mg C.O.D./gm of coal at an equilibrium C.O.D. concentration of 1,800 mg/l.  Crowsnest 48/65 coal  was also tested, but the removals were well below those found using Hat Creek coal.  The maximum capacity calculated  for Crowsnest coal was 15 mg C.O.D./gm of coal.  3.2.4  Phosphate Removal  I t was found that the capacity of Hat Creek and Crowsnest coals f o r a soluble phosphate solution was almost n e g l i g i b l e .  * r a t i o of C.O.D. to TKN f o r beef extract = 9:1.  23  FIG.  4  ADSORPTION ISOTHERMS FOR BEEF EXTRACT.  24  Figure 5 shows the isotherms plotted using 28/48 Hat Creek and Crowsnest coals.  The Hat Creek coal removed 0.1 mg PO ^/gm of coal (0.03 mg P/gm of coal), while the Crowsnest coal did not measurably remove any phosphate. 3.2.5  Summary of Batch Test Observations In general, i t was found that the coal tested had the a b i l i t y to remove both heavy metals and beef extract from solution.  Soluble phosphate was not removed to any extent  by either coal.  The batch tests showed that the capacity of the coal to remove impurities increased with increasing impurity t r a t i o n i n the wastewater, and that the capacity  concen-  increased  with decreasing grain size within the grain s i z e range tested. Hat Creek coal was superior to Crowsnest coal i n removal of heavy metals, beef extract and phosphates.  Capacities as  high as 45 mg of lead/gm of coal, 17 mg of copper/gm of coal, 15 mg of zinc/gm of coal, and 5 mg TKN/gm of coal were recorded using Hat Creek coal ground to a 48/65 grain size.  No precipitates were noticed on the bottoms of the flasks and no suspended metal precipitates were encountered during testing with the atomic absorption  unit.  FIG. 5  ADSORPTION ISOTHERMS FOR P 0 4 .  26  Data gathered i n the b a t c h t e s t s was  used as a  guideline  f o r d e s i g n i n g the column t e s t s , the r e s u l t s o f which r e p o r t e d i n the next  3.3  are  section.  Column T e s t Data 3.3.1  General Column t e s t s were performed to e s t a b l i s h how  much o f a  d i s s o l v e d i m p u r i t y the c o a l removes on a continuous f l o w through b a s i s .  The e f f e c t s o f the f o l l o w i n g  variables  were examined: (i) (ii) (iii) (iv) (v) (vi) (vii)  Grain s i z e of coal Flow  rate  pH o f adsorbate s o l u t i o n C o n c e n t r a t i o n o f adsorbate Temperature  of adsorbate s o l u t i o n  Composition of adsorbate Type o f c o a l  S p e c i f i c i n f o r m a t i o n c o n c e r n i n g the t e s t i n g and r e s u l t s i s shown i n T a b l e I I I .  As c a l c u l a t e d  from b a t c h t e s t d a t a ,  time to c o m p l e t i o n o f each column t e s t was  never more than  16 h o u r s .  Breakthrough the  capacity  c o a l was  curves were p l o t t e d and a n a l y z e d to c a l c u l a t e  o f the c o a l i n the column.  c a l c u l a t e d f o r each o f s e v e r a l  The  capacity  arbitarily  o f the  assumed  breakthrough c o n c e n t r a t i o n s i n the f o l l o w i n g manner:  TABLE  III  SUMMARY OF T E S T S Coal  Grain Size  1 2 3 4 5 6 7 8 9 10 11 12 13 14  IIC HC HC HC HC HC HC HC CN CN CN CN HC HC  28/48 14/28 48/65 28/48 28/48 28/48 2 8/48 28/48 28/48 28/48 28/48 28/48 28/48 28/48  15  HC  16  HC  Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Lead Beef Extract 28/48 B e e f Extract 28/48 N a H P 0  17  CN  28/48 N a H P 0  Test No .  impurity  2  2  Rate Flow Gal/Ft2/Min  Conc'n of Impurity  100 mg/l 100 mg/l 100 mg/l 100 mg/l 100 m g / l (pH-2} 100 mg/l 10 mg/l 0.7 mg/l 100 mg/l 100 mg/l 10 mg/l 0.7 mg/l 300 mg/l 2 3.5 m g / l T K N 23.5 mg/l  TKN  25 m g / l P 0 ~  3  4  4  27  AND C A P A C I T I E S  mg/l PO-3 4  Indicates values unable to be calculated.  Temperature  1 1 1 5 1 1 5 5 1 5 5 5 1 1  23°C 23°C 23°C 23°C 23°C 15°C 23°C 23°C 23°C 2 3°C 23°C 23°C 23°C 15°C  1 1  Capacity at following Breakthrough Concentrations (mg o f I m p u r i t y / g m o f c o a l ) 75% 50% 10% 4.3 3.4 6.1 3.6 1.0 4.4 5.3  6.1 5.7 7.7  0 6 7  4.7-  8 15  2.5 0.7 3.0  3.1 1.5  1.1 6.1  5.0 2.0  24.0 0.15  TKN  15°C  0 .1  TKN  23°C  0  22.5 0  23°C  ro  28  (i)  The weight o f i m p u r i t y t h a t e n t e r e d p r i o r to b r e a k t h r o u g h was  the column  c a l c u l a t e d by m u l t i p l y i n g  the throughput volume a t breakthrough by the i n f l u e n t concentration of impurity, (ii)  The weight o f i m p u r i t y breakthrough was  that l e f t  the column p r i o r to  c a l c u l a t e d by t a k i n g the a r e a  the breakthrough curve and to the l e f t  under  o f the through-  put volume a t b r e a k t h r o u g h , (iii)  The weight o f i m p u r i t y removed by the column was c a l c u l a t e d by s u b t r a c t i n g ( i i ) from ( i ) .  (iv)  The c o a l c a p a c i t y was  c a l c u l a t e d by d i v i d i n g the weight  of i m p u r i t y removed by the weight o f c o a l i n the column.  In some c a s e s , the average e f f l u e n t c o n c e n t r a t i o n breakthrough was  calculated.  T h i s c a l c u l a t i o n was  until performed  by d i v i d i n g the weight of i m p u r i t y l e a v i n g the column p r i o r to breakthrough to breakthrough. concentration  ( ( i i ) above) by the throughput volume p r i o r Average  e f f l u e n t concentration i s that  that would be expected i f a l l the throughput  from a g i v e n column t e s t p r i o r to b r e a k t h r o u g h were mixed together  and measured.  Sample c a l c u l a t i o n s o f c o a l c a p a c i t y  and average e f f l u e n t c o n c e n t r a t i o n a r e shown i n Appendix I I .  3.3.2  Copper Removal - Hat Creek  Copper s u l p h a t e was  Coal  the most f r e q u e n t l y used adsorbate i n  the column t e s t s , and was  used to r e p r e s e n t  a waste c o n t a i n i n g  29  dissolved  copper.  The breakthrough curve shown i n F i g u r e 6 r e p r e s e n t s a t i m e - p l o t o f Test 1 i n T a b l e I I I .  The shape o f the curve  i s t y p i c a l f o r i o n exchange o r a b s o r p t i o n columns, and i s r e p r e s e n t a t i v e o f the breakthrough curves  found f o r most  of the t e s t s o u t l i n e d i n T a b l e I I I .  T a b l e I V shows the v a l u e s effluent  o f c o a l c a p a c i t y and average  c o n c e n t r a t i o n f o r Hat Creek c o a l t r e a t i n g a 100 mg/1  s o l u t i o n o f copper.  The  t a b l e shows c l e a r l y  t h a t the d e s i g n  capacity of a  column w i l l be dependent upon the a l l o w a b l e maximum e f f l u e n t o r water re-use  average and/or  c o n c e n t r a t i o n s t i p u l a t e d by r e g u l a t i o n s considerations.  For instance, i f the  average e f f l u e n t c o n c e n t r a t i o n r e q u i r e d i s 0.5 mg/1, then o n l y 1.9 mg/gm o f c a p a c i t y o r o n l y 25% o f the t o t a l c o a l c a p a c i t y c o u l d be u t i l i z e d . higher  I n o r d e r t o make use o f t h e  c o a l c a p a c i t i e s and s t i l l have a h i g h q u a l i t y e f f l u e n t ,  i t would be n e c e s s a r y  to use columns i n s e r i e s , the l a s t  column i n t h e s e r i e s a c t i n g as a p o l i s h i n g column.  I t was found t h a t the c a p a c i t y o f the c o a l i n column operation increased with  decreasing  grain size of coal,  c o n f i r m i n g e a r l i e r trends n o t i c e d i n t h e b a t c h  tests.  Breakthrough curves p l o t t e d u s i n g 14/28, 28/48 and 48/65 Hat  Creek c o a l a r e shown i n F i g u r e 7 t o i l l u s t r a t e the  O  FIG. 6  BREAKTHROUGH CURVE USING HAT CREEK COAL AND lOOmg/liter COPPER SOLUTION.  CAPACITY Adsorbate  Breakthrough Concentrat ion (% o f I n f l u e n t )  100  OF  TABLE  IV  28/48  HAT  mg/1  Cu.  Capacity of Coal (mg/gm)  CREEK  Flow  COAL  rate  1  gal./ft /min. 2  Average E f f l u e n t Concentration ( C a l c u l a t e d % of i n f l u e n t )  1  1.88  0.5  5  3. 7  1.6  10  4.3  2.4  25  5.3  5.8  50  6.1  11.5  75  7. 0  25.8  8 . 2  49  100  (est)  Influent concentration lOOmg/liter  Throughput volume in liters  F  I  G  7  B R E A K T H R O U G H CURVES FOR THREE GRAIN SIZES OF HAT CREEK C O A L .  33  grain s i z e e f f e c t . had 1.2  On the average the 28/48 grain s i z e  times the capacity of the 14/28; and the 48/65  grain s i z e had 1.3  times the capacity of the 28/48.  increase i n capacity obtained by using 48/65 over was  thus approximately 50%.  The  14/28  More d e t a i l s are shown i n  Table I I I .  Increasing the flow rate through the column had e f f e c t of s l i g h t l y decreasing through curves for the two  the  the column capacity.  Break-  column tests described i n  test 1 and 4, Table III and shown i n Figure 8, can be compared to show the e f f e c t .  Increasing flow rate by a  factor of f i v e decreased the column capacity by only (Table I I I ) .  Therefore,  a column can be of very  20%  small  size and s t i l l maintain 80% of the unit capacity of a column 5 times as large.  In i n d u s t r i a l situations where  f l o o r space i s at a premium, the f l e x i b i l i t y of s i z e may make a coal treatment process p a r t i c u l a r l y a t t r a c t i v e . The pH of the incoming waste was  shown to affect the  capacity of coal i n the columns considerably. of copper was  L i t t l e removal  obtained when the wastewater pH was  depressed to 2.  artificially  Data i n Table I I I , calculated from the break-  through curves i n Figure 8, show that the column treating^the influent having low pH had only 15 to 25% of the capacity of the column treating the influent having the higher natural pH of the copper sulphate solution.  pH adjustment may  therefore  ~ I 10!  Influent concentration  lOOmg/liter  £|00  1 90 Flow rate pH = 2  £ 80| UJ  I gal./ft./min  Flow rate 5gal./ft. /min pH = 5  •- 7 0  2  2. 6 0 CL °  Flow rate I gal./ft. /min pH = 5 2  I  <> - 5 4 00| c o  Depth of coal Wt. of coal  30  I ft. 32 gm  c 20 CD O  9  c o 10 (_>  0  >  0  ,0  FIG.  8  2.0 Throughput volume  3.0 (liters )  BREAKTHROUGH CURVES SHOWING EFFECTS OF ADSORBATE pH AND ADSORBATE FLOW RATE .  4.0  35  be n e c e s s a r y i n o r d e r to use c o a l s f o r t r e a t i n g a c i d mine d r a i n a g e , which i s u s u a l l y o f low pH.  No reasons can be g i v e n a t the p r e s e n t time f o r the f a c t t h a t low removals were observed a t a pH of 2. r e s e a r c h i s r e q u i r e d t o more f u l l y on heavy metal  More  determine pH e f f e c t s  removal.  I t was found t h a t c o a l had the c a p a b i l i t y o f removing h i g h percentages of copper from d i l u t e s o l u t i o n s . performed u s i n g a 10 mg/1 of  and a 0.7 mg/1  T e s t s were  influent  solution  copper, 28/48 g r a i n s i z e c o a l , and a flow r a t e o f 5 g a l / 2  ft  /min.  The h i g h flow r a t e was r e q u i r e d i n o r d e r to  t e r m i n a t e the run i n a r e a s o n a b l e time p e r i o d . through curve p l o t t e d u s i n g a 10 mg/1  The b r e a k -  copper s o l u t i o n as  the  wastewater ( F i g u r e 9) shows t h a t u s i n g Hat Creek  the  e f f l u e n t c o n c e n t r a t i o n was l e s s than 1% o f the i n f l u e n t  a f t e r 10 l i t e r s  o f throughput.  average e f f l u e n t c o n c e n t r a t i o n for  coal,  The c a p a c i t y o f the c o a l and (See d e f i n i t i o n on Page 58)  a 10% breakthrough c o n c e n t r a t i o n were 5.25 mg of  copper/gm o f c o a l and 0.2 mg/1  copper r e s p e c t i v e l y .  I t there-  f o r e appears t h a t Hat Creek c o a l i s c a p a b l e of t r e a t i n g d i l u t e s o l u t i o n s o f copper e f f e c t i v e l y w h i l e s t i l l m a i n t a i n ing of  a c a p a c i t y f o r copper i o n s i n the range o f 0.5% by weight coal.  I n a c t u a l f a c t , the removal c a p a c i t y o f the c o a l  when t r e a t i n g a 10 mg/1  s o l u t i o n i s b e t t e r than t h a t  when t r e a t i n g the 100 mg/1  found  s o l u t i o n , i f a breakthrough  concen-  r  II 10  £ c o  Influent concentration  column depth wt.of coal grain size flow rate influent pH  8 7 6  c a) o c o  o  9.9mg/liter  I ft. 32gm 28/48 5gal./ft /min. 5.8 2  5 4  Crowsnest  i  c a> 3  31  LU  21 I 0  L  7  0  8  9  Throughput  FIG. 9  10  II  volume  12 in  13 14  15  16 17 18  liters  BREAKTHROUGH CURVES FOR HAT CREEK AND CROWSNEST COALS TREATING A lOmg/liter SOLUTION OF COPPER .  19 2 0  37  t r a t i o n o f 10% o f i n f l u e n t i s used as a b a s i s . o f the c o a l  capacity  f o r t r e a t i n g the more c o n c e n t r a t e d waste was  o n l y 4.3 mg/gm a t 10% b r e a k t h r o u g h The  The  increased capacity  (Table I I I , T e s t 4 ) .  o f the c o a l n o t i c e d  when  treating  a d i l u t e s o l u t i o n was n o t expected because o f trends  noticed  i n the b a t c h t e s t s and i n a l l p r o b a b i l i t y would not e x i s t i f the  curve p l o t t e d  f o r the 10 mg/1 s o l u t i o n  c o u l d be completed  to show 100% breakthrough and then compared to the 100 mg/1 100%  breakthrough curve.  flow r a t e , g r a i n  I n other words, t h e column geometry,  s i z e o f c o a l , o r some combination o f these  f a c t o r s p r o b a b l y changed the shape o f the 10 mg/1 make treatment o f a d i l u t e s o l u t i o n point  The  curve t o  to a 10% breakthrough  appear p a r t i c u l a r l y a p p e a l i n g .  most important f a c t i s that  l o s s o f removal c a p a c i t y w i t h Hat Creek c o a l .  t h e r e i s no s i g n i f i c a n t  when t r e a t i n g a more d i l u t e waste  To i n v e s t i g a t e  this point  further,  a  t e s t was performed u s i n g a 0.7 mg/1 copper s o l u t i o n as the influent.  The  r e s u l t s o f the t e s t u s i n g Hat Creek c o a l t o t r e a t the  v e r y d i l u t e copper wastewater a r e shown i n F i g u r e 10. f i g u r e shows t h a t  effluent  0.05 mg/1 o f copper coal  treatment.  these t e s t s .  c o n c e n t r a t i o n s lower than  ( l i m i t of detection) are obtainable with  Because o f time o f running c o n s t r a i n t s  meaningful f i g u r e s  The  on c o a l c a p a c i t y  c o u l d be o b t a i n e d  no from  i.o 0.9 S  0.8 -  c o  0.7  c o c o  0.6 0.5  Influent concentration 0.7mg/liter column depth wt. of coal grain size flow rate  I ft. 32 gm 28/48 I gal./ft. / min. 2  0.4 c  CD3  0.3 -  £  0.2 h  Crowsnest  0.1 0.05  Hat Creek—9  7 8 9 10 II 12 13 14 Throughput (liters)  15  16 17 18  oo  FIG. 10  BREAKTHROUGH CURVES FOR HAT CREEK AND CROWSNEST COALS TREATING A 0.7mg/liter SOLUTION OF COPPER.  39  I t was  found t h a t d e c r e a s i n g the adsorbate temperature  to 15°C from 23°C produced no s i g n i f i c a n t c o a l ' s removal c a p a c i t y . o p e r a t i n g parameters t e s t 1.  A t e s t was  change i n the  performed w i t h a l l  except temperature the same as i n  The decreased temperature i n c r e a s e d the c a p a c i t y  o f the c o a l by about 2%.  T h i s d i f f e r e n c e can be  explained  by e x p e r i m e n t a l e r r o r .  3.3.3  Copper Removal - Crowsnest  The  Coal  t e s t s numbered 9 to 12 i n T a b l e IV were performed  using  Crowsnest  c o a l f o r the purpose o f comparing Hat Creek and  Crowsnest  c o a l i n column o p e r a t i o n .  The b r e a k t h r o u g h c u r v e  f o r T e s t 9 i s compared i n F i g u r e 11 to the Hat Creek b r e a k through c u r v e , which was  o b t a i n e d under i d e n t i c a l  conditions.  As shown i n T a b l e I I I the c a p a c i t y o f Hat Creek c o a l i s g r e a t e r than t h a t o f Crowsnest between 1.5  and 2.  c o a l by a f a c t o r r a n g i n g  T h i s o b s e r v a t i o n i s i n l i n e w i t h the  t r e n d s found d u r i n g the b a t c h t e s t s .  F i g u r e 12 shows t h a t i n c r e a s i n g the f l o w r a t e through a column o f Crowsnest and t h a t Crowsnest  c o a l decreases the c a p a c i t y o f the column c o a l has a l e s s e r c a p a c i t y than Hat  Creek  2 c o a l f o r copper i o n s a t e q u a l flow r a t e s o f 5 g a l / f t  /min.  The decrease i n c a p a c i t y caused by i n c r e a s i n g the flow r a t e was  a p p r o x i m a t e l y 60% i n the case o f Crowsnest  c o a l compared  w i t h o n l y a 20% decrease i n the case of Hat Creek c o a l  (Table I I I ) .  Throughput  FIG. II  volume  in  liters  BREAKTHROUGH CURVES FOR HAT CREEK AND CROWSNEST COALS, INFLUENT CONCENTRATION lOOmg/liter COPPER.  o  Crowsnest cool 5gal./ft. /min. 2  Crowsnest coal lgal./ft /min. 2  /  Hat Creek coal 5gal./ft /min. 2  r  tf  Influent pH Depth of coal Wt. of coal Grain size  /  1.0 Throughput  FIG. 12  2.0 volume in liters  5 I ft. 32gm 28/48  3.0  BREAKTHROUGH CURVES FOR CROWSNEST COAL,SHOWING E F F E C T S OF FLOW R A T E .  42  The use o f Hat Creek c o a l o f f e r s two advantages use o f Crowsnest  c o a l f o r copper removal.  over the  Hat Creek  coal,  i n a d d i t i o n to h a v i n g a h i g h e r c a p a c i t y than Crowsnest c o a l , i s a l s o l e s s a f f e c t e d by changes  i n flow rates.  l a t t e r p o i n t may be important i n i n d u s t r i a l  The  situations  where unsteady f l o w r a t e s o c c u r .  F i g u r e 9 shows a comparison o f breakthrough curves f o r the two c o a l s t r e a t i n g an a d s o r b a t e o f 10 mg/l copper.  These  curves show t h a t both c o a l s can e f f e c t 99% removal o f copper from the 10 mg/l s o l u t i o n .  The Crowsnest  column i s exhausted  b e f o r e the Hat Creek column, a g a i n i n d i c a t i n g t h a t Hat Creek c o a l i s s u p e r i o r t o Crowsnest containing  Crowsnest  coal f o r treating  solutions  copper.  c o a l , l i k e Hat Creek c o a l , had the a b i l i t y to  decrease the c o n c e n t r a t i o n o f a 0.7 mg/l copper s o l u t i o n to a v a l u e l e s s than 0.05 mg/l.  The p l o t o f c o n c e n t r a t i o n v s .  throughput i s shown i n F i g u r e 10.  No v a l i d  c o n c l u s i o n s can  be drawn w i t h r e s p e c t to the c a p a c i t y o f the two c o a l s t r e a t i n g the 0.7 mg/l s o l u t i o n as the t e s t s were n o t run u n t i l breakthrough.  However, i t i s obvious t h a t v e r y h i g h  q u a l i t y e f f l u e n t s are p o s s i b l e when t r e a t i n g d i l u t e c o n t a i n i n g copper w i t h e i t h e r Hat Creek o r Crowsnest  3.3.4  Removal o f Lead - Hat Creek  solutions coal.  coal  Hat Creek c o a l was capable o f e f f e c t i v e l y removing  lead ions  43  from a l e a d n i t r a t e s o l u t i o n f o r a f i n i t e time p e r i o d d u r i n g a column t e s t .  The t e s t i s d e s c r i b e d i n T a b l e I I I ,  and the b r e a k t h r o u g h curve i s shown i n F i g u r e 13.  The c o a l , which was capable o f removing 99% o f t h e l e a d from a 300 mg/l l e a d n i t r a t e s o l u t i o n f o r a p p r o x i m a t e l y two l i t e r s o f throughput, had a c a p a c i t y f o r l e a d i o n s o f 22.5 mg/gm and 24 mg/gm f o r b r e a k t h r o u g h c o n c e n t r a t i o n s of  3.3.5  10% and 50% o f i n f l u e n t ,  respectively.  Removal o f Heavy M e t a l M i x t u r e  A t e s t was performed t o examine t h e a b i l i t y o f Hat Creek c o a l t o remove a v a r i e t y o f heavy metals mixed i n s o l u t i o n . A l l v a r i a b l e s , except i m p u r i t y type and c o n c e n t r a t i o n , were the  same as those used i n T e s t Number One (Table I I I ) .  and the i n f l u e n t c o n c e n t r a t i o n s were a r b i t r a r i l y  The metals  chosen as  follows: Copper Lead Zinc Nickel Cadmium  -  2.3 4.0 1.8 2.0 2.6  mg/l mg/l mg/l mg/l mg/l  I t was observed that the c o a l removed almost a l l the metal c o n t a i n e d i n a two l i t e r the  column.  sample o f m i x t u r e passed through  The c o n c e n t r a t i o n s of the metals i n the e f f l u e n t  were too low (<0.05 mg/l)  t o be measured by the atomic  a b s o r p t i o n spectrophotometer w i t h o u t u s i n g techniques.  concentration  (These techniques were not performed  because  220r ^200 CP  J  180  o  I60|  | c  140  0  120  <D  c  Coal type Hat Creek Grain size 28/48 Flow rate I gal. /ft./min Coal depth I ft. Weight of coal 32gm Influent concentration 300mg/liter  Lead  ° IOO  1  80  £  60 40 20 0 1.0  2.0 Throughput  FIG. 13  3.0  volume in liters  BREAKTHROUGH CURVE FOR HAT CREEK C O A L , SHOWING CAPACITY FOR L E A D  4.0  45  the t e s t was meant to be more q u a l i t a t i v e than q u a n t i t a t i v e . )  3.3.6  Regeneration  I t was observed t h a t by l e a v i n g the c o a l a t r e s t p e r i o d subsequent  to column breakthrough,  f o r a d s o r p t i o n was r e a l i z e d . breakthrough a 10 mg/1  a renewed c a p a c i t y  F i g u r e 14 shows the s e q u e n t i a l  curves o f Hat Creek and Crowsnest  s o l u t i o n o f copper.  (i)  coals  treating  The f i g u r e shows c l e a r l y  b o t h c o a l s e x h i b i t a f u r t h e r c a p a c i t y when l e f t the wastewater f o r two days.  for a  that  submerged i n  I n g e n e r a l , i t was found  that:  The renewed c a p a c i t y o f Hat Creek c o a l i s g r e a t e r than t h a t o f Crowsnest  (ii)  coal.  The minimum e f f l u e n t c o n c e n t r a t i o n i s h i g h e r a f t e r the two day p e r i o d than a t the b e g i n n i n g o f the p r e v i o u s run.  ( i i i ) The breakthrough  curves become s t e e p e r a f t e r each two  day " r e s t " p e r i o d . (iv)  The a d d i t i o n a l c a p a c i t y o b t a i n e d by two days o f b e i n g submerged i n wastewater decreases w i t h the number o f times the p r o c e s s i s r e p e a t e d .  The  c a p a c i t y o f Hat Creek c o a l was i n c r e a s e d by a p p r o x i m a t e l y  35% by a l l o w i n g a two day break a f t e r the column was run to a 20% b r e a k t h r o u g h c o n c e n t r a t i o n .  The time.  cause of t h i s phenomenon i s n o t understood a t the p r e s e n t  er  1 1 Influent concentration Cu = 9.9 mg/liter  E  8  Cu  9  7  ion  cn  10  6  pH = 5.8  NOTE  Crowsnest coal 28/48 32 gm flow rate = 5gal./ft /min.  VERTICAL LINES DENOTE 2 DAY PERIODS WHEN COAL WAS SUBMERGED BUT NO FLOW WAS TAKING P L A C E .  c  -4—  D  5  C <D O C  4  CO  —  3  c <u  2  »*—  LU  1 0  12  14 16  Throughput  FIG. 14  18 2 0 22 24 2 6 2 8 3 0 32 3 4 3 6 3 8 volume  in liters  BREAKTHROUGH CURVES FOR HAT CREEK AND CROWSNEST COALS TREATING A 10 mg / liter SOLUTION OF COPPER.  i  40  47  3.3.7  Beef E x t r a c t Removal  Column t e s t s performed on  a b e e f e x t r a c t s o l u t i o n showed  t h a t b o t h c o a l s were i n e f f i c i e n t  and  o f low  c a p a c i t y when  removing beef e x t r a c t on a continuous b a s i s . of the t e s t s i s shown i n T a b l e I I I , T e s t s  An  outline  14 and  15.  The b r e a k t h r o u g h curves f o r the t e s t are shown i n F i g u r e Both e f f l u e n t c o n c e n t r a t i o n s Within  0.2  of the Hat effluent 70%  The  Creek column has  concentration  reached 40%  immediately. concentration  o f i n f l u e n t and  o f the Crowsnest column has  Neither  reached  liter.  c a p a c i t i e s of c o a l i n the columns were c a l c u l a t e d  a higher  the  column i s c a p a b l e of p r o d u c i n g  removal f o r a throughput of 1  are shown i n T a b l e I I I . has  to i n c r e a s e  l i t e r s o f throughput, the e f f l u e n t  of i n f l u e n t .  even 50%  start  15.  The  t a b l e shows t h a t Hat  capacity f o r beef e x t r a c t .  and  Creek c o a l  I f a high q u a l i t y  e f f l u e n t i s r e q u i r e d , however, the c a p a c i t y i s zero  for a l l  p r a c t i c a l purposes.  3.3.8  Phosphate Removal  Phosphate removal on a continuous b a s i s was a s o l u t i o n of Na^PO^. 10 mg/1  as P.  The  other  The  concentration  t e s t e d by  of phosphorus  using was  t e s t parameters were the same as  those i n the t e s t s f o r Beef E x t r a c t Removal.  I t was  found t h a t n e i t h e r c o a l measurably removed phosphorus  81?  49  from s o l u t i o n .  Shannon [2] i n a s i m i l a r experiment a l s o found t h a t would n o t adsorb phosphates from s o l u t i o n . '  Corporation  The Rand  [3] o b t a i n e d phosphate removals o f up t o 40%  when o p e r a t i n g effluent.  coal  a 10,000 gpd p i l o t p l a n t  The r e p o r t  t r e a t i n g secondary  s t a t e d , however, t h a t a l a r g e  portion  of t h i s removal was p r o b a b l y due t o f i l t e r i n g o f suspended s o l i d s rather  3.3.9  than  adsorption.  Summary o f Column T e s t s  Both Hat Creek and Crowsnest c o a l e f f e c t i v e l y removed heavy metals from s o l u t i o n d u r i n g  column o p e r a t i o n .  c o a l was found t o be s u p e r i o r to u l t i m a t e  removal c a p a c i t y  at h i g h flow r a t e s .  d e c r e a s i n g the c a p a c i t y solution.  t o Crowsnest c o a l w i t h and a b i l i t y  Increasing  d e c r e a s i n g pH and i n c r e a s i n g  The Hat Creek  to treat  respect  solutions  the grain s i z e of c o a l ,  flow r a t e a l l had the e f f e c t o f  o f a c o a l column t o t r e a t a copper  Temperature d i d n o t seem t o have an e f f e c t on  column o p e r a t i o n .  G r e a t e r than 99% removal o f heavy metals  was p o s s i b l e . f o r f i n i t e p e r i o d s o f time w i t h s o l u t i o n s as d i l u t e as 0.7 mg/l o r as c o n c e n t r a t e d as 100 mg/l.  Capacity  of the Hat Creek c o a l f o r copper i o n s was a p p r o x i m a t e l y 0.5 to 1% by weight o f the c o a l and f o r l e a d i o n s was about 2% by weight o f the c o a l .  I f , a f t e r a c o a l column was exhausted  i t was a l l o w e d to remain submerged i n the wastewater  already  50  i n the column f o r 2 days a renewed c a p a c i t y o f 35% o f the o r i g i n a l c a p a c i t y was was  realized.  more pronounced w i t h Hat Creek  N e i t h e r c o a l produced  approximately  This effect  coal.  a h i g h q u a l i t y e f f l u e n t from a beef  e x t r a c t s o l u t i o n d u r i n g the column t e s t s , even though the b a t c h t e s t s p r e d i c t e d t h a t some a d s o r p t i o n o f o r g a n i c s would o c c u r .  N e i t h e r c o a l removed any phosphorus from a sodium phosphate solution.  The  column t e s t s were designed  were simple and  convenient  from b a t c h t e s t d a t a  to run.  and  A l l runs were t e r m i n a t e d  w i t h i n , about 14 hours as r e q u i r e d and hence designed f o r , using batch t e s t data.  In g e n e r a l the t r e n d s n o t i c e d i n the  b a t c h t e s t s w i t h r e s p e c t to the e f f e c t s of c o a l type, s i z e and i m p u r i t y type were a l s o n o t i c e d i n the column  grain tests.  C H A P T E R  IV  POSSIBLE USES  4.1  I n d u s t r i a l Heavy Metal Removal Heavy metals are present i n the effluents of metal f i n i s h i n g industries, mine concentrators and sanitary l a n d f i l l leachates. The use of coal could be an e f f e c t i v e means of treating these effluents.  Wastewater from the sources mentioned may contain metals i n one or more of the following forms: (i)  Ionic - metals dissolved i n true solution (or, more correctly, complexed with water molecules),  (ii)  Complexed - with compounds such as cyanide or natural organics.  (iii)  Suspended - i n the form of insoluble metal compounds.  The r e s u l t s of t h i s and other studies show that coal has the p o t e n t i a l to remove metals i n a l l three forms mentioned The weight of coal required to treat 1,000 10 mg/1 0.2 mg/1  above.  gallons of a  solution of copper to an average effluent concentration of (breakthrough concentration 1.0 mg/1)  be 20 l b s . as follows:  51  was calculated to  52  Cap.  of c o a l  (Table  III)  =5.3 mg/gm = 0.53% by wt. o f = 1,000 gallons = 10,000 l b . = 10 mg/l = 10 lb/106 l b s .  V o l . of wastewater Wt. o f wastewater C o n c e n t r a t i o n of Copper Wt.  of Copper  Weight of c o a l  coal  = 10 lb/106 l b . x l O ^ l b . = 0.1 l b s . = 0.1 l b . x 100 0.53% = 20 l b s .  required  At an assumed c o a l c o s t of $15/Ton, the c o s t o f c o a l for  t r e a t i n g 1,000  copper waste would be  approxi-  mately $0.15.  I t must be n o t e d , however, t h a t the above c a l c u l a t i o n  i s preliminary  as i t assumes t h a t a l l the c o a l w i l l be  form a f t e r g r i n d i n g .  I n a c t u a l f a c t , t h e r e w i l l be  i n grinding.  Further  t e s t s are r e q u i r e d to see  significant.  More r e s e a r c h  process,  before  conventional  4.2  g a l l o n s of 10 mg/l  required  a l o s s of f i n e s  i f this loss i s  to the economics o f  the  a r e a s o n a b l e c o s t comparison can be made w i t h  treatment  Treatment o f M u n i c i p a l  The  i s r e q u i r e d as  i n a useful  processes.  Sewage  poor removals of beef e x t r a c t measured i n t h i s study i n d i c a t e  t h a t n e i t h e r Hat properties  Creek nor  Crowsnest c o a l have s u f f i c i e n t  to enable them to be  used e f f e c t i v e l y i n an  p r o c e s s t r e a t i n g domestic sewage.  adsorptive  adsorptive  Furthermore, the n e g l i g i b l e removal  of sodium phosphate i n d i c a t e s t h a t the e f f e c t i v e n e s s o f c o a l i n t r e a t ing  a waste c o n t a i n i n g i n o r g a n i c phosphate u s i n g  t i o n treatment p r o c e s s e s would be very the  c o a l s t e s t e d i s not  low.  conventional  Therefore,  recommended f o r the treatment of  adsorp-  the use  of  municipal  53  waste or secondary  e f f l u e n t by an a d s o r p t i o n p r o c e s s when e i t h e r  removal o f o r g a n i c m a t e r i a l s o r i n o r g a n i c phosphate i s r e q u i r e d . There i s the p o s s i b i l i t y , as mentioned i n the p r e v i o u s s e c t i o n , t h a t treatment  of heavy metals  p r e s e n t from i n d u s t r i a l s o u r c e s i n  m u n i c i p a l sewage c o u l d be e f f e c t e d by a c o a l p r o c e s s , but economics o f such a p r o c e s s ,  The for  r e q u i r e f u r t h e r study.  f a c t t h a t n e i t h e r c o a l t e s t e d i n t h i s study was  use i n a d s o r p t i o n p r o c e s s e s  o t h e r waste treatment  the  suitable  does not p r e c l u d e t h e i r use i n  processes.  F o r example, c o a l c o u l d be  used  as a f i l t e r medium o r as a medium to support b i o l o g i c a l growth so e f f e c t a c e r t a i n degree of treatment  on a m u n i c i p a l waste.  However, use of c o a l i n such circumstances  s h o u l d be preceded  economic comparison between c o a l and o t h e r a v a i l a b l e f i l t e r biological trickling  filter  media.  and  by and  an  C H A P T E R  V  CONCLUSIONS AND RECOMMENDATIONS  5.1  Conclusions The conclusions of the study are as follows: (i)  Both Hat Creek and Crowsnest coal had the a b i l i t y to e f f e c t i v e l y remove heavy metal from solution,  (ii)  The capacity of 28/48 grain size Hat Creek coal f o r removal of copper ions was approximately 0.5% to 1% of the weight of the coal.  This capacity was measured using column  tests. (iii)  Hat Creek coal had the a b i l i t y to remove 99% of copper from i n f l u e n t waste streams containing as l i t t l e as 0.7 mg/l  Cu and as much as 100 mg/l Cu. E f f l u e n t concentra-  tions lower than 0.05 mg/l were recorded, (iv)  Crowsnest coal also had the a b i l i t y to remove high percentages of copper from solution but i t s ultimate capacity for removal of metal ions was less than that of Hat Creek coal.  The capacity of Crowsnest coal f o r copper ions was  approximately 0.2% to 0.5% by weight of the coal, (v)  Decreasing  the grain size of Hat Creek coal i n the column  operation increased the capacity of the coal.  The increase  i n capacity f o r copper ions using 48/65 coal instead of 14/28 coal was approximately 50%.  54  55  (vi)  Increasing  flow  of d e c r e a s i n g  r a t e through the columns had  the  c a p a c i t y of both Hat  c o a l f o r removal o f copper i o n s . in  flow  Creek and  A five fold  20%  and Crowsnest by  D e c r e a s i n g i n f l u e n t pH decreasing  the  Crowsnest  increase  r a t e decreased the u n i t c a p a c i t y o f Hat  c o a l by (vii)  the e f f e c t  Creek  60%.  to 2 had  c a p a c i t y o f Hat  the e f f e c t of g r e a t l y Creek c o a l f o r removal of  copper i o n s . (viii)  The  c a p a c i t y o f Hat  Creek c o a l f o r removing copper i o n s  n o t decreased when the i n f l u e n t copper c o n c e n t r a t i o n reduced from 100 (ix)  Hat  mg/1  Creek c o a l was  than 0.05  mg/1  I f a Hat  mg/1.  time run,  the f o l l o w i n g metals  copper, z i n c , l e a d , cadmium, and n i c k e l ,  Creek c o a l column i s exhausted o f i t s heavy m e t a l  removal c a p a c i t y , and  i f the c o a l i s l e f t  days i n the wastewater p r e s e n t then a renewed c a p a c i t y available.  submerged f o r  f o r heavy m e t a l removal i s made  T h i s renewed c a p a c i t y can  amount to a p p r o x i m a t e l y A Crowsnest c o a l  column w i l l e x h i b i t the same p r o p e r t i e s , but c a p a c i t y to be  (xi)  g a i n e d i s not  the i n c r e a s e  as much as t h a t g a i n e d by  in  a  Creek c o a l column,  Neither  c o a l was  a b l e t o produce a good q u a l i t y e f f l u e n t  from a b e e f e x t r a c t s o l u t i o n d u r i n g is  two  i n the column at shutdown,  35% o f the o r i g i n a l removal c a p a c i t y .  Hat  was  s u c c e s s f u l i n removing to amounts l e s s  f o r a short  mixed i n s o l u t i o n : (x)  to 10  was  i n agreement w i t h o t h e r  studies  the column t e s t s . (2).  This  56  (xii)  N e i t h e r c o a l was  able  to measurably remove any  from a sodium phosphate s o l u t i o n d u r i n g (xiii)  O b s e r v a t i o n s made throughout the  responsible  f o r the  column t e s t s .  study i n d i c a t e d t h a t  mechanism o t h e r than p r e c i p i t a t i o n and t i o n was  the  phosphate  subsequent  a  filtra-  removal of heavy metals from  solution.  C o n c e i v a b l y , c o a l c o u l d be  used to p u r i f y e f f l u e n t s  containing  heavy metals from metal f i n i s h i n g i n d u s t r i e s , mining  operations,  s a n i t a r y l a n d f i l l s or i n d u s t r i a l i z e d m u n i c i p a l i t i e s .  I t was  culated  t h a t a waste stream c o n t a i n i n g  treated  to an average c o n c e n t r a t i o n  10 mg/1  of 0.2  copper c o u l d  mg/1  l b s of coal/1000 g a l l o n s  a c o a l c o s t of $15/ton,  the  treated,  The  per  1000  r e s u l t s of the  phosphate s o l u t i o n s  o f water.  gallons  f o r the c o a l used i n treatment would be  be  w i t h a c o a l consump-  t i o n o f a p p r o x i m a t e l y 20  cost  cal-  Assuming  o f wastewater  a p p r o x i m a t e l y $0.15.  t e s t s performed u s i n g b e e f e x t r a c t and  sodium  i n d i c a t e d t h a t c o a l would not be p a r t i c u l a r l y  e f f e c t i v e i n removing e i t h e r phosphates o r oxygen demanding  materials  from m u n i c i p a l sewage.  5.2  Recommendations  (i)  Several coals  (ii) (iii)  The  B r i t i s h Columbia c o a l s s h o u l d be  are  t e s t e d to f i n d which  the most e f f e c t i v e i n removal o f heavy m e t a l s ,  f e a s i b i l i t y o f r e g e n e r a t i n g the c o a l s h o u l d be  E f f e c t s o f flow r a t e , pH, of i m p u r i t y  s h o u l d be  g r a i n s i z e and  studied  influent  i n more d e t a i l u s i n g  investigated, concentration lab  scale  57  column t e s t s . (iv)  The types and amounts o f m a t e r i a l s  added by the c o a l s to  the wastewater s h o u l d be determined.  Such a d d i t i o n s  make the e f f l u e n t i m p o s s i b l e f o r re-use (v)  could  industrially,  D e t e r m i n a t i o n o f the t e c h n i c a l and economic  feasibility  o f procurement and d i s p o s a l o f c o a l s h o u l d be c a r r i e d o u t . (vi)  P i l o t s c a l e t e s t i n g o f the most e f f e c t i v e c o a l s wastewaters s h o u l d be undertaken.  on a c t u a l  GLOSSARY OF TERMS  mg/l  -  wt  - dry weight  milligrams/liter  breakthrough  curve  p l o t o f e f f l u e n t c o n c e n t r a t i o n vs volume o f throughput i n a column t e s t  breakthrough  concentration  t h a t c o n c e n t r a t i o n o f e f f l u e n t from a column o p e r a t i o n which n e c e s s i t a t e s t h a t the column be r e p l a c e d .  batch  test  a t e s t o f the c a p a c i t y o f c o a l to remove an i m p u r i t y from wastewater under nonflow-through c o n d i t i o n s  column t e s t  a t e s t o f the c a p a c i t y o f c o a l to remove an i m p u r i t y from wastewater under f l o w through c o n d i t i o n s  average e f f l u e n t concentration  the t o t a l weight o f i m p u r i t y passed through a column d i v i d e d by t h e t o t a l h y d r a u l i c throughput  adsorption  the removal o f i m p u r i t i e s from s o l u t i o n by a p h y s i c a l a d s o r p t i o n , chemical adsorpt i o n o r i o n exchange process  B.O.D.  Biochemical  Oxygen Demand  C.O.D.  - Chemical Oxygen Demand  TKN  - Total Kjeldahl Nitrogen  58  BIBLIOGRAPHY  1.  G.E. Johnson and L.M. Kunka, "The Use o f Coals as Adsorbents f o r Removing O r g a n i c Contaminants from Wastewater", U.S. Dept. of the I n t e r i o r , Bureau o f Mines, Report o f I n v e s t i g a t i o n 6884, U.S. Government P r i n t i n g O f f i c e , Washington, D.C.  2.  E. Shannon, "The Use o f C o a l as an Adsorbent f o r the Treatment of Wastewaters", M. Sc. t h e s i s , U n i v e r s i t y o f W a t e r l o o , W a t e r l o o , O n t a r i o , (1967).  3.  "Development  o f a C o a l Based Sewage Treatment P r o c e s s " , O f f i c e  of Coal Research, U.S. Dept. o f the I n t e r i o r , U.S. Government P r i n t i n g O f f i c e , Washington, D.C. (1972).  4.  C H . H i n r i c h s , Grant A p p l i c a t i o n , U.S. P u b l i c H e a l t h L i n f i e l d Research I n s t i t u t e , M c M i n n v i l l e , Oregon  5.  Service,  (1971).  J.B. P o r t e r and R.J. D u r l e y , "An I n v e s t i g a t i o n o f the C o a l s o f Canada w i t h R e f e r e n c e t o T h e i r Economic Q u a l i t i e s " , Department  Canada  o f Mines, Government P r i n t i n g Bureau, Ottawa,  59  (1912).  APPENDIX I  TYLER MESH SERIES  60  MESH SIZE  SCREEN OPENING (MM)  14  1.2  28  0.6  48  0.3  65  0.2  APPENDIX I I  SAMPLE DETERMINATION OF COAL CAPACITY FROM A BREAKTHROUGH CURVE  63  Influent concentration lOOmg/liter  1.0 Throughput  0  E  2.0 volume in liters  Choose breakthrough concentration  10% of influent or 10 mg/l  Mg of impurity removed  Area ABCDA 147 mg of Cu  Mg of impurity removed/gm of coal  147 mg/32 gm 4.3 mg/gm  Average effluent  concentration  Weight of impurity passed through column divided by throughput Area ABEA/throughput 3.36 mg per 1.4 1 2.4 mg/l  APPENDIX I I I  BATCH TEST DATA  64  Batch  Initial Concentration of impurity (mg/l)  .  Initial weight of i m p u r i ty (mg)  Final Concentration of impurity (mg/l)  Test  Data  Final weight of i m p u r i ty (mg)  Weight, of impurity removed (mg)  Dosage coal (mg)  of  Wt. of impurity removed /gm of c o a l (mg/gm)  925  92.5  515  51.5  41  5.0  8.2  460  46  165  16. 5  29.5  4.0  7.4  210  21  54  5-4  15 . 6  2.0  7.8  161  16.1  39  3.9  12.2  2.0  6.1  90  9.0  20  2.0  7.0  2.0  3.5  46  4.6  14  1.4  3.2  2.0  1.6  20  2.0  0.2  1.8  2.0  0.9  Copper' A d s o r b a t e Hat Creek C o a l 28/48 G r a i n S i z e 24 h r . c o n t a c t t i m e .  2.2  ON  Batch  Initial Concentration of impurity (mg/1)  500  Initial weight of i m p u r i ty (mg)  Final Concentration of impurity (mg/1)  Test  Final weight of impurity (mg)  50  330  33  200  20  126  12. 6  100  10  42 10  i  52  5.2  20  2.0  Copper Adsorbate Hat Creek C o a l 48/65 G r a i n S i z e 24 h r . c o n t a c t t i m e  2.8  Data  Weight of impurity removed (mg)  17  Dosage coal (mg)  of  Wt. of impurity removed /gm of c o a l (mg/gm)  1.0  17  7.4  0.5  14. 8  4.2  5.8  0.5  11.6  1.0  4.2  0.5  8.4  0.3  1.7  0.5  3.4  Batch  Initial loncentration of i m p u r i t y (mg/1)  Initial weight of i m p u r i ty (mg)  Final Concentration ' of impurity (mg/1)  Test  Data  Final weight of impurity (mg)  622  62.2  490  49  190  19  120  12  Weight of impurity removed (mg)  13. 2  Dosage coal (mg)  of  Wt. of impurity r e m o v e d /gm of c o a l (mg/gm)  4.0  3.3  7  2.0  3.5  90  9.0  42  4.2  4.8  2.0  2.4  90  9.0  40  4.0  5.0  2.0  2.5  46  4.6  16  1.6  3.0  2.0  1.5  20  2.0  1.0  0.1  1.9  2.0  0.9  20  2.0  1.0  0.1  1.9  2.0  0.9  Copper Adsorbate Crowsnest Coal 28/48 G r a i n S i z e 24 h r . c o n t a c t t i m e  Batch  Test  Data  Initial Concen t r a t i o n of impurity (mg/l)  Initial weight of i m p u r i ty (mg)  500  50  390  39  11  1.0  11  335  33.5 '  205  20.5  13  1.0  13  200  20  150  15  5  0.5  10  Final Concentration of impurity (mg/l)  Final weight of impurity (mg)  Weight of impurity removed (mg)  Dosage coal (mg)  of  Wt. of impurity removed /gm of c o a l (mg/gm)  59  5.9  18  1.8  4.1  0.5  8.2  50  5  10.8  1.1  3.9  0.5  7.8  45  4.5  2.0  0.2  4.3  1.0  4.3  Copper Adsorbate Crowsnest Coal 48/65 G r a i n S i z e 2 4 h r . c o n t a c t t;Lme  Batch  Initial Concentration of impurity (mg/1)  1000  Initial weight of i m p u r i ty (mg)  Final Concentration' of impurity (mg/1)  Test  Data  Final weight of impurity (mg)  Weight of impurity removed (mg)  Dosage coal (mg)  of  Wt. of impurity r e m o v e d /gm of c o a l (mg/gm)  220  22.0  78  2.0  39  500  100 1 50  165  16.5  33.5  1.0  33  500  50  35  3.5  46.5  2.0  23  20Q  20  3.0  0.3  19. 7  2. 0  10  200  20  3.0  0.3  19.7  2.0  10  100  10  1.0  0.1  9.9  2.0  5  0.5  0.5  5  2.0  2  50  5.0  Lead Adsorbate Hat Creek C o a l 28/48 G r a i n S i z e 24 h r . c o n t a c t t i m e  Batch  Initial Concentration of impurity (mg/1) '  20  Test  Data  Initial weight of impurity (mg)  Final Concentration of impurity (mg/1)  Final weight of impurity (mg)  2.0  0.5  0.5  Weight of impurity removed (mg)  2  Dosage coal (mg)  of  Wt. of impurity r e m o v e d /gn of c o a l (mg/gm)  2.0  1  540  54  314  31.4  22. 6  0.5  45  540  54  310  31.0  23 .0  0.5  46  540  54  234  23.4  30.6  0 . 75  41  540  54  180  18  36  1.0  36  540  54  176  17.6  36.4  1.0  36  540  54  70  47  1-5  30  Lead Adsorbate Hat C r e e k C o a l 28/48 G r a i n S i z e 24 h r . c o n t a c t t i m e  7  Batch  Initial Concentration of impurity (mg/l)  Initial weight of Impurity (mg)  Final Concentration of impurity (mg/l)  Test  Data  Final weight of impurity (mg)  Weight of impurity removed (mg)  Dosage coal (mg)  of  Wt. of impurity r e m o v e d /g of c o a l (mg/gm)  520  52  285  28.5  23.5  0.5  47  520  52  210  21.0  31  0 . 75  41.2  520  52  154  15.4  36.6  1.0  36.6  520  52  144  14.4  37.6  1.0  37.6  520  52  50  47  1.5  31.5  Lead Adsorbate Hat Creek C o a l 48/65 G r a i n S i z e 24 H r . c o n t a c t t i m e  5  Batch Test  Initial Concen t r a t i o n of i m p u r i t y (mg/1)  Initial weight of . impurity (mg)  Final Concentration of i m p u r i t y (mg/1)  Data  Final weight of impuri ty (mg)  Weight o f impurity removed (mg)  Dosage o f coal (mg)  Wt. o f impurity removed /g of c o a l (mg/gm)  540  5 4.0  374  37.4  16.6  0.5  33  540  54.0 ,  286  28.6  25.4  0.75  34  5 40  54.0  216  21.6  32. 4  1.0  32  24  30.0  1.0  30  10.4  43.6  1.5  29  •  540  54.0  240  540  54.0  104  500  50.0  4.0  0.4  49.6  2.0  25  200  20.0  1.0  0.10  19.9  2.0  10  100  10.0  0.5  0.05  10  2.0  5  50  5.0  0.5  0.05  5  2.0  2.5  20  2.0  0.1  0.001  2  2.0  1  Lead Adsorbate Crowsnest Coal 28/48 G r a i n S i z e 24 h r . c o n t a c t time  •  Batch T e s t Data  Initial Concentration of i m p u r i t y (mg/l) '  Initial weight of impurity (mg)  Final Concentration of i m p u r i t y (mg/l)  Final weight of impurity (mg)  Weight of impurity removed (mg)  Dosage of coal (mg)  Wt. of impurity removed /gm of c o a l (mg/gm)  32.0  20  0.5  520  320  40  52.0  31.5  20.5  0.5  520  315  41  52.0  24.0  28  0.75  520  240  37  52.0  16.0  36  1.0  36  52.0  160  15.0  37  1.0  37  52.0  150  3.2  48.8  1.5  33  52.0  32  520 520 520  Lead Adsorbate Crowsnest C o a l 48/65 G r a i n S i z e 24 h r . C o n t a c t time  »  Batch T e s t  Initial Concentration of i m p u r i t y (mg/l)  Initial weight of Impurity (mg)  Final Concentration of i m p u r i t y (mg/l)  Data  Final weight of i m p u r i ty (mg)  Weight o f impurity removed (mg)  Dosage o f coal (mg)  Wt. of impurity removed /gm of c o a l (mg/gm)  560  56  420  42  14  1.0  14  560  56  375  37. 5  18.5  1.5  12. 3  560  56  325  32. 5  23.5  2.0  11. 7  120  •  12  45  60  6.0  25  68  6.8  18  29  2.9  4.3  7.5  1  7.5  3.5  0.5  7.0  1.8  5.0  1  5.0  0.4  2.5  1  2.5  4.5 .  2.5  Zinc Adsorbate Crowsnest C o a l G r a i n S i z e 48/65 24 h r . c o n t a c t time  3  Batch Test  Initial Concentration of i m p u r i t y (mg/1)  Initial weight o f impurity (mg)  Final Concentration of i m p u r i t y (mg/1)  Data  Final weight of impurity (mg)  Weight of impurity removed (mg)  Dosage o f coal (mg)  Wt. o f impurity removed /gm of c o a l (mg/gm)  560  56  460  46  10  1.0  10  560  56  430  43  13  1.5  8.7  560  56  390  39  17  2.0  8.5  276  27.6  150  15.0  12.6  2.0  6.3  255  25.5  90  16.5  4.0  4.1  2.4  2.0  1.2  27.5  2. 75  3.5  .  9.0 0.35  Z i n c Adsorbate Corwsnest C o a l Grain S i z e 48/65 24 h r . c o n t a c t time  «-4 Ul  Batch  Initial Concentration of impurity (mg/l)  Initial weight of i m p u r i ty (mg)  Final Concentration of impurity (mg/l)  Test  Data  Final weight of i m p u r i ty (mg)  Weight of impurity removed (mg)  Dosage coal (mg)  of  Wt. of i m p u r i ty removed /gn of c o a l (mg/gm)  B  256  25.6  197  19.7'  5.9  1.2  4  157  15.7  113  11. 3  4.4  1.0  4.4  78  7.8  46  4.6  3.2  1.0  3.2  43  4.3  19  1  2.4  1.0  2.4  24  2.4  6  1.8  1.0  1.8  Beef e x t r a c t adsorbate Hat Creek Coal 48/65 G r a i n S i z e . 24 h r . c o n t a c t t i m e  1  •9  0.6  Batch T e s t  Initial Concentration of i m p u r i t y (mg/l)  Initial weight of impurity (mg)  Final Concentration of i m p u r i t y (mg/l)  Data  Final weight of impurity (mg)  Weight of impurity removed (mg)  Dosage o f coal (mg) y  Wt. o f impurity removed / g m of c o a l (mg/gm)  255 .  25.5  224  2 2.4  3.1  1.0  3.1  150  15  125  12.5  2.5  1.0  2.5  73  7.3  56  5.6  1.7  1.0  1.7  34  3.4  21  2.1  1.3  1.0  1.3  20. 5  2.0  0.8  1.2  1.0  1.2  Beef e x t r a c t a d s o r b a t e Hat Creek Coal 48/65 G r a i n S i z e 24 h r . c o n t a c t time  8.0  Batch Test  Initial Concentration of i m p u r i t y (mg/1)  Initial weight o f impuri ty (mg)  Final Concentration of i m p u r i t y (mg/1)  Data  Final weight of impurity (mg)  Weight o f impurity removed (mg)  Dosage o f coal (mg)  Wt. o f impurity removed /gi of c o a l (mg/gm)  255  25.5  240  24  1.5  1.0  1.5  150  15  136  13.6  1.4  1.0  1.4  73  7.3  63.5  6.3  1.0  1.0  1.0  34  3.4  26.5  2.7  0.7  1.0  0.7  20.5  2.0  10.5  1.0  1.0  1.0  1.0  Beef e x t r a c t adsorbate Crowsnest Coal 48/65 G r a i n S i z e 24 h r . c o n t a c t time  Initial Concentration of i m p u r i t y (mg/l)  Initial weight of imp u r i ty (mg)  Final Concentration of i m p u r i t y (mg/l)  Final weight of i m p u r i ty (mg)  Weight of impurity removed (mg)  100  5  87.5  4.37  0.63  100  5  90  4.5  0.5  75  3. 75  62  3.1  0.65  75  3. 75  64  3.2  0.55  50  2.5  33  1.65  0.85  50  2.5  41  2.05  0.45  30  1.5  20  1.0  0.5  20  1.0  12  0. 6  0.4  20  1.0  8  0.4  0. 6  10  0.5  5  0.25  0.25 .  Phosphate A d s o r b a t e Hat Creek C o a l 28/48 G r a i n SizeContact time 24 h r s .  

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