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Removal of heavy metals from wastewater using granular coal Saravanabawan, Thirugnana 1980

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REMOVAL OF HEAVY METALS FROM WASTEWATER USING GRANULAR COAL  by  TH-SRUGNANA B.Sc,  SARAVANABAWAN  U n i v e r s i t y o f Wales,  A THESIS SUBMITTED IN PARTIAL  1973  FULFILMENT OF  THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE  in THE FACULTY OF GRADUATE STUDIES (Department of C i v i l  We accept t h i s  Engineering)  t h e s i s as conforming  to the r e q u i r e d  standard  THE UNIVERSITY OF BRITISH COLUMBIA January  1980  (^Thijrugnana Saravanabawan,  1980  In presenting this thesis in p a r t i a l fulfilment of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of this  thesis  for scholarly purposes may be granted by the Head of my Department or by his representatives.  It  is understood that copying or publication  of this thesis for f i n a n c i a l gain shall not be allowed without my written permission.  Department of  E^iNEEfQrJg,  The University of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  MMLtU-  \4 , WZo  A B S T R A C T  Batch t e s t s were performed to e v a l u a t e the r e l a t i v e performance of f o u r B.C. special  coals  plant  (Hat Creek O x i d i s e d , K a i s e r - s t o c k  feed and Cominco Ash)  pile  refuse,  in removing heavy metals c o p p e r ,  z i n c and mercury from f i l t e r e d primary sewage treatment p l a n t Emphasis  Kaiser-  was p l a c e d on metal c o n c e n t r a t i o n s of  10 mg/1  effluent.  and l e s s .  Creek coal was found to be much s u p e r i o r to the o t h e r t h r e e and efficiency  Hat its  is comparable to t h a t o f Darco a c t i v a t e d carbon 12 x 20.  Hat Creek and K a i s e r - s t o c k column t e s t s  p i l e r e f u s e c o a l s were f u r t h e r used  to e v a l u a t e the r e l a t i v e performance o f these c o a l s  removing copper,  lead and z i n c under dynamic c o n d i t i o n s .  was p l a c e d on i n f l u e n t metal c o n c e n t r a t i o n s of  10 mg/1  Again  T e s t s with a c t i v a t e d carbon  c o m p e t i t o r f o r use  in  in emphasis  and l e s s and once  more the performance o f Hat Creek coal was much s u p e r i o r to that of coal.  lead,  i n d i c a t e Hat Creek coal  Kaiser  to be a c l o s e  in advanced waste treatment f o r heavy metal  removal.  -iii-  TABLE OF CONTENTS Page  ABSTRACT  ii  TABLE OF CONTENTS  iii  LIST OF TABLES  v  LIST OF FIGURES  vi  ACKNOWLEDGEMENT  ix  CHAPTER 1 INTRODUCTION AND RESEARCH RATIONALE  1  CHAPTER 2 MATERIAL AND PROCEDURE  5  2.1  Type of Coal  5  2.2 2.3 l.k 2.5  Coal P r e p a r a t i o n Wastewater Measurement o f C o n c e n t r a t i o n Batch T e s t i n g Procedure  5 6 7 7  2.6  2.5-1 2.5.2  D e t e r m i n a t i o n of Optimum Contact Time D e t e r m i n a t i o n of Required Coal Q u a n t i t y  7 9  2.5.3  Adsorption  9  Isotherms  Column T e s t i n g Procedure  2.6.1 2.6.2  Col umn Set Up Experimental Procedure  11  11 12  CHAPTER 3 RESULTS AND DISCUSSION 3. 1  Batch T e s t s 3.1.1  E f f e c t of pH on E f f i c i e n c y  '7 17 17  - i v-  Page 3.1.2 3.1.3 3.1.4 3.1.5  3.2  C a p a c i t y of Coals O v e r a l l Ranking of the Coals General Comments Comparison of Hat Creek Coal A c t i v a t e d Carbon  Column T e s t s 3.2.1  Copper, Lead and Z i n c  20 37 39 with kO kl kl  CHAPTER k CONCLUSIONS  Ik  CHAPTER 5 RECOMMENDATIONS  77  REFERENCES  79  LIST OF TABLES Page  TABLE  3. 1  Summary o f Copper A d s o r p t i o n C a p a c i t i e s  24  3.2  Summary of Lead A d s o r p t i o n C a p a c i t i e s  28  3. 3  Summary of Z i n c A d s o r p t i o n C a p a c i t i e s  32  3.  Summary of Mercury A d s o r p t i o n C a p a c i t i e s  3-5  Summary of Comparison Between A c t i v a t e d Carbon and Hat Creek Coal  ...  36 46  LIST OF FIGURES Page FIGURE 2.1  E f f e c t of Contact Time on A d s o r p t i o n of Copper  2.2  E f f e c t o f Coal  2.3  Breakthrough Curves f o r Copper Using Depths o f Hat Creek Coal  l.k  3.1  3.2  Dosage on Metal  Adsorption  Breakthrough Curve f o r Copper with S o r b s t c s •••• •••• •••• E f f e c t of pH on Metal Concentration  Removal  E f f e c t of pH on Metal  Removal  at  ....  8  ,  10  Various 14  Different •••• • > •«  ••••  Lower ....  Concentration  at  15  18  Higher ,  19  3.3  Copper A d s o r p t i o n  Isotherms  21  3.4  Copper A d s o r p t i o n  Isotherms  22  3.5  Copper A d s o r p t i o n  Isotherms  23  3.6  Copper Removal  3.7  Lead A d s o r p t i o n  3.8  Lead Removal  3.9  Zinc Adsorption  Efficiency  25  Isotherms  27  Efficiency Isotherms  Efficiency  30 31  3.10  Z i n c Removal  3.11  Mercury A d s o r p t i o n  3.12  Mercury Removal  3.13  Copper A d s o r p t i o n  3.H  Lead A d s o r p t i o n  Isotherms  kl  3.15  Zinc Adsorption  Isotherms  kk  Isotherms  Efficiency Isotherms  J,k 35 38 k]  —vi ! —  Page FIGURE 45  3.16  Mercury A d s o r p t i o n  3.17  Breakthrough  Curve f o r Copper . . .  3.18  Breakthrough  Curve f o r Copper  3.19  Breakthrough  Curve f o r Copper  3.20  Comparison of A d s o r p t i o n C a p a c i t y f o r Copper Primary E f f l u e n t at D i f f e r e n t Flow Rates  3.21  3.22  Isotherms  **8 ;  50 51  Comparison of Breakthrough Curve f o r Copper Primary E f f l u e n t and Water S o l u t i o n Comparison of A d s o r p t i o n C a p a c i t y  in ....  52  in 56  f o r Copper  in  Primary E f f l u e n t and D i s t i l l e d Water  57  3.23  Breakthrough  Curve f o r Copper  58  3.2A  Breakthrough  Curve f o r Copper  59  3.25  Comparison of A d s o r p t i o n C a p a c i t y  3.26  in Primary E f f l u e n t at D i f f e r e n t Flow Rates . . . . Comparison of A d s o r p t i o n C a p a c i t y f o r D i f f e r e n t Copper  f o r Copper  Influent Concentrations  60  61  3.27  Breakthrough  Curve f o r Lead  63  3.28  Breakthrough  Curve f o r Lead  64  3.29  Comparison of A d s o r p t i o n C a p a c i t y  f o r Lead  in  Primary E f f l u e n t at D i f f e r e n t Flow Rates  ....  65  3.30  Breakthrough  Curve f o r Z i n c  67  3.31  Breakthrough  Curve f o r Z i n c  68  3.32  Comparison of A d s o r p t i o n C a p a c i t y f o r Z i n c in Primary E f f l u e n t at D i f f e r e n t Flow Rates  ....  69  -vi i i -  Page FIGURE 3.33  Breakthrough  Curve f o r Z i n c  70  3.3^  Breakthrough  Curve f o r Z i n c  71  3.35  Comparison of A d s o r p t i o n C a p a c i t y f o r Z i n c in Primary E f f l u e n t at D i f f e r e n t Flow Rates ....  72  Comparison of A d s o r p t i o n C a p a c i t y f o r Zinc Influent Concentrations  73  3.36  Different  ACKNOWLEDGEMENT I am g r a t e f u l for his  to my r e s e a r c h s u p e r v i s o r ,  p a t i e n c e and encouragement  throughout  support and guidance were o f the utmost appreciated. critical  My thanks  Dr. W.K. this  Oldham,  study.  His  importance and are s i n c e r e  are a l s o due to Dr.  K. H a l l  f o r making a  survey of my t y p e s c r i p t and weeding out some a n a l y t i c a l  errors. This  study was supported by Grants  Environment of  the P r o v i n c e o f B r i t i s h  from the M i n i s t r y Columbia.  of  1  Chapter 1  INTRODUCTION AND RESEARCH RATIONALE  I n c r e a s i n g p o p u l a t i o n and i n d u s t r i a l e f f e c t s on the environment and human l i f e tamination of f i s h  growth has produced adverse such as  the mercury c o n -  and the subsequent human h e a l t h h a z a r d s .  i n c i d e n t s have focused a t t e n t i o n on the p o l l u t i o n p o t e n t i a l s heavy metals  in wastewater  e f f l u e n t s and r e c e i v i n g waters.  concern f o r the p r e s e r v a t i o n of and P r o v i n c i a l standards  the environment has  effluent  of The p u b l i c ' s  f o r c e d the Federal  Governments of Canada to enact s t r i c t  f o r m u n i c i p a l and i n d u s t r i a l  Similar  pollution control  discharges.  1 2 A review of  literature '  indicates  c o n t r i b u t e the bulk o f the heavy metal mercury with  its  that copper, z i n c and  loading  lead  to r e c e i v i n g w a t e r s ,  inherent cumulative nature and m u l t i p l y i n g e f f e c t  the food c h a i n poses the utmost concern in the a q u a t i c  and in  environment.  Crushed a n t h r a c i t e coal has been used f o r many years as a filtering  medium f o r water s u p p l i e s .  medium f o r p u r i f y i n g wastewater  However  its  use as a s o r p t i o n  has been examined o n l y  r e c e n t l y with  3 special  emphasis  A significant is s t i l l  towards  advantage  the removal of o r g a n i c s is  p o t e n t i a l l y useful  that  coal exhausted of  as an energy s o u r c e .  from domestic sewage . its  sorption  A U.S.  capacity  Department  2  of  Interior  report"' recommends the use of coal  treatment of secondary sewage treatment p l a n t The a b i l i t y of c e r t a i n B r i t i s h  for post,  or " t e r t i a r y "  effluent.  Columbia c o a l s  to remove  dissolved  k constituents  from water has been i n v e s t i g a t e d  and t h e i r f i n d i n g s out with  are e n c o u r a g i n g .  by C o u l t h a r d  However, most of  5 and Hendren  the work was c a r r i e d  r e l a t i v e l y high metal c o n c e n t r a t i o n s and with o n l y two c o a l s  found in B r i t i s h  Columbia.  Recent s t u d i e s  c a r r i e d out with  relatively  lower copper, z i n c ,  c e n t r a t i o n s and the r e s u l t s column t e s t s  are  by R i a z ^ and T i n Tun^ were lead and mercury c o n -  o b t a i n e d from both batch and l a b o r a t o r y  scale  promising.  R i a z ^ c a r r i e d out batch t e s t s with s i x Kaiser  coal  - Special  Kaiser  coal  - Stock  waste  pile  lagoon  refuse  samples:  sample  sample  Kaiser coal  - Special  Kaiser  - O x i d i s e d stock p i l e  coal  plant  coal  feed sample sample  Northern coal mines - U n o x i d i s e d sample and Northern coal mines - O x i d i s e d  sample.  On the b a s i s of batch t e s t data o b t a i n e d , the best (Kaiser  coal  were t e s t e d  - stock  pile  r e f u s e and K a i s e r  in a continuous  flow  coal  laboratory  flow r a t e through  f o r mercury.  and l e s s  The e f f e c t o f  the column ( c o n t a c t  - special  - s c a l e column.  was p l a c e d on metal c o n c e n t r a t i o n s o f 2 mg/1 and z i n c and 5 yg/1  two  coals plant  The emphasis  for copper,  i n f l u e n t , and mixture  of metals on the a d s o r p t i v e c a p a c i t y of c o a l were i n v e s t i g a t e d .  found to be the best o f s i x c o a l s  tested.  - Stockpile Its  lead  influent concentration,  t i m e ) , pH o f  basis of adsorptive capacity, Kaiser coal  feed)  metal  On the  r e f u s e sample was removing e f f i c i e n c y  3  was compared with a c t i v a t e d carbon and n i t r o h u m i c a c i d and  results  i n d i c a t e that c o a l may be a f e a s i b l e a l t e r n a t e to remove heavy from waste  metals  effluents.  T i n Tun^ c a r r i e d out batch t e s t s  with f i v e coal  samples:  Hat Creek o x i d i s e d Hat Creek  unoxidised  Cominco o x i d i s e d Cominco ashwaste and Cominco p r o d u c t i o n . Based on batch t e s t  results,  the Hat Creek and Cominco groups,  the best  flow l a b o r a t o r y - s c a l e column.  The i n f l u e n t c o n c e n t r a t i o n was 2 mg/1  and l e s s  in the case o f copper,  and l e s s f o r mercury.  The e f f e c t of pH,  i n f l u e n t metal c o n c e n t r a t i o n , flow r a t e and the s y n e r g i s t i c m u l t i p l e metals were i n v e s t i g a t e d . s u p e r i o r to o t h e r s with  Hat Creek o x i d i s e d was  effects  of  found to be  regard to a d s o r p t i v e c a p a c i t y and a l s o compared  f a v o u r a b l y with Darco a c t i v a t e d The study  from each of  namely Hat Creek o x i d i s e d and Cominco  ashwaste were t e s t e d on a continuous  z i n c and lead and was 5 yg/1  performing coal  reported in t h i s  carbon. thesis  c a r r i e d out by Riaz^ and T i n Tun^.  is an e x t e n s i o n of the work  Readers  are s t r o n g l y  refer  to these r e f e r e n c e s f o r f u r t h e r background  metal  p o l l u t i o n problems, t h e i r magnitudes,  recommended to  i n f o r m a t i o n on heavy  and methods  presently  a v a i l a b l e and used to c o n t r o l them. S y n t h e t i c waste waters  produced by m i x i n g  metal  solutions  with  d i s t i l l e d water to d e s i r e d c o n c e n t r a t i o n s were used by the above workers in a d s o r p t i o n  studies.  In the study  reported h e r e i n , the performance of  coal was  in removing heavy metals investigated. 1.  from sewage treatment p l a n t  The s p e c i f i c o b j e c t i v e s of t h i s  To e v a l u a t e the r e l a t i v e e f f i c i e n c i e s and of four d i f f e r e n t B.C. from wastewater  2.  in batch  To e v a l u a t e heavy metal coals  3.  coals  in continuous  investigation  were  capacities  in removing heavy  metals  tests; removal c a p a c i t y of the best  flow column  To compare the metal  effluent  two  tests;  removing c a p a c i t y of c o a l  from waste-  water with that of Darco a c t i v a t e d carbon grade 12 x 20. During  the i n v e s t i g a t i o n ,  f l u e n c e s of the f o l l o w i n g a d s o r p t i o n c a p a c i t y of  i n f o r m a t i o n was o b t a i n e d on the  in-  c h a r a c t e r i s t i c s on removal e f f i c i e n c y and  coal;  1.  C o n c e n t r a t i o n of  adsorbate;  2.  Flow r a t e or c o n t a c t  3.  pH.  time;  5  Chapter 2  MATERIAL AND PROCEDURE  2.1  Types of  Coal  Four d i f f e r e n t c o a l from R i a z ' s ^  samples were used o f which two were chosen  study and the o t h e r two from T i n T u n ' s ^ work.  Kaiser  coal  - Stock p i l e  Kaiser  coal  - Special  Hat Creek o x i d i s e d  r e f u s e (K.C.  plant  (H.C.  feed (K.C.  SPF)  OX)  Cominco Ashwaste  (CO.  A c t i v a t e d carbon  (ACT. CARB.)  Abbreviations  SPR)"  ASH)  used throughout  the t e x t .  The performances of the above f o u r c o a l s were compared with a c t i v a t e d carbon grade  2.2  Coal  12 x 20 by p a r a l l e l  Darco  testing.  Preparation  Coal was f i r s t washed with water to remove a l l and subsequently d r i e d at  room temperature.  crushed to the d e s i r e d g r a i n  size  foreign  particles  The d r i e d c o a l was  (28/48 mesh) by p a s s i n g  it  then  first  through a T a y l o r G y r a t o r and then through a Massco cone c r u s h e r . Crushed coal was dry s i e v e d using shaker.  28/48 mesh screens and mechanical  6  The 28/48 mesh f r a c t i o n was then wet s i e v e d and back washed plexiglass at  column to remove f i n e s .  F i n a l l y , the g r a n u l a r  103°C f o r about 40 hours and s t o r e d  nitrogen  2.3  in sealed b o t t l e s  in a  coal was d r i e d flushed  with  gas.  Wastewater Wastewater was prepared from u n c h l o r i n a t e d e f f l u e n t from the Lions  Gate Primary Sewage Treatment p l a n t of the Greater Vancouver District.  The primary e f f l u e n t , which has t o t a l  ppm and suspended v o l a t i l e s g l a s s carboys  o f about 70 ppm,  o f about 200  was f i l t e r e d by vacuum  into  using Whatman No. 5^1 f i l t e r paper and stored under r e -  frigerated conditions. prevent s e t t l i n g  Removal  o f suspended s o l i d s  and entrapment o f these s o l i d s  w i t h i n the pore spaces o f the 28/48 mesh coal was p o s s i b l e  volatiles  Regional  to a c h i e v e throughput  was necessary  d u r i n g column  column.  to  testing  As a r e s u l t ,  volumes o f up to 10 l i t e r s  it  instead of  l e s s than one. The f i l t e r e d e f f l u e n t w i t h n o n - d e t e c t a b l e was " s p i k e d " with standard metal  solutions  initial  metal  to d e s i r e d c o n c e n t r a t i o n s , and  heated to room temperature (23°C) b e f o r e use as wastewater Standard  solutions  (ppm) metal  standard  (stock)  turned a c i d i c , the f i n a l  s o l u t i o n added.  are a c i d i c , the spiked  pH depending on the q u a n t i t y o f metal  to 4.0 by a d d i t i o n o f sodium hydroxide  which was shown by p r e l i m i n a r y t e s t s process.  with 1000  Whenever the prepared wastewater was found to have pH  l e s s than 4.0, and pH was a d j u s t e d  sorption  solutions  lead,  concentration.  Since the above standard metal s o l u t i o n s wastewater  for testing.  used to s p i k e the f i l t e r e d e f f l u e n t were copper,  z i n c and mercury atomic a b s o r p t i o n mg/1  concentrations  If  not to i n t e r f e r e with the a d -  the pH o f spiked wastewater was g r e a t e r  than 4.0,  7  pH adjustment was not c a r r i e d o u t .  2.k  Measurement A Jarrell  used f o r  of  Concentration  Ash MV - 500 atomic a b s o r p t i o n  the measurement of metal  concentration.  lead and mercury at c o n c e n t r a t i o n s absorption  technique was  used.  spectrophotometer  of 2 mg/1  was  For copper, z i n c and  and h i g h e r  the flame  atomic  For lower mercury c o n c e n t r a t i o n the c o l d  g vapour or f l a m e l e s s centrations  method  of 2 mg/1  Batch T e s t i n g  mechanical to f i n d study  of g r a n u l a t e d  in a f l a s k  shaker.  metal  2.5.1  known c o n c e n t r a t i o n s  f o r a predetermined c o n t a c t  The mixture was  the r e s i d u a l  from  of c o p p e r , z i n c ,  time using  then f i l t e r e d and the f i l t r a t e  concentration.  These t e s t s  the d i f f e r e n t c o a l s  a analysed  were u t i l i s e d in removing  to  heavy  Determination of Optimum Contact Time tests  were performed with d i f f e r e n t c o a l s  e q u i l i b r i u m copper c o n c e n t r a t i o n at d i f f e r e n t c o n t a c t  clusions  lead.  wastewater.  Batch  results  using  c o a l were mixed with one hundred  containing  the r e l a t i v e e f f i c i e n c i e s of  metals  to pH below 2.0  by the same method as c o p p e r , z i n c or  of wastewater  lead or mercury  mercury c o n -  Procedure  Known q u a n t i t i e s milliliters  Samples having  and h i g h e r were a c i d i f i e d  NHO^ and then analysed  2.5  was u t i l i s e d .  are shown in F i g u r e 2.1. were drawn.  From these  results  to determine  times  and the  the f o l l o w i n g  con-  8  0  1  F i g u r e 2.1  2  .  3  Contact  0  time - hours  I  2  E f f e c t of Contact Time on A d s o r p t i o n  3  of  Copper  9  (a)  Contact  time of 90 minutes w i l l  a c h i e v e about 35% of the  u l t i m a t e removal, and i t was thus chosen as c o n t a c t time f o r the r e s t of the (b)  Initial  study.  metal c o n c e n t r a t i o n and the pH of wastewater  not a p p r e c i a b l y  2.5.2.  i n f l u e n c e the optimum c o n t a c t  Determination of Required Coal  of c o a l .  c o n c e n t r a t i o n s of  time.  containing  the v a r i o u s m e t a l s , but with v a r y i n g  The volume of wastewater  used f o r each t e s t was  R e s u l t s o b t a i n e d are shown in F i g u r e 2.2.  do  Quantity  Batch t e s t s were c a r r i e d out with wastewaters initial  the optimum  constant quantities  100 ml.  From these r e s u l t s  the  minimum q u a n t i t y of c o a l necessary f o r e f f e c t i v e removal of heavy metals from 100 m i l l i l i t e r s of wastewater was determined to be one gram.  2.5.3-  Adsorption  An a d s o r p t i o n  Isotherms  isotherm which  can be d e f i n e d as a constant  is d e r i v e d from a s e r i e s o f batch  temperature p l o t of the adsorbent  tests  capacity  to remove a p a r t i c u l a r adsorbate from s o l u t i o n a g a i n s t the c o n c e n t r a t i o n of adsorbate  in e q u i l i b r i u m with the a d s o r b e n t .  Conditions were as  used in the batch t e s t s  f o r the p r e p a r a t i o n of  follows: Q u a n t i t y of Coal  coal  28/48  size  Volume of Contact  1 gram  wastewater  time  100 ml 90 min  Temperature  23 C (room temperature)  pH of wastewater  4.0  isotherms  10  0  0.5  I Coa I  F i g u r e 2.2  E f f e c t of Coal  1.5 dosage-q  Dosage on Metal  Adsorption  11  Initial  metal c o n c e n t r a t i o n s :  concentrations  (less  than 10 mg/1) so that c o n c e n t r a t i o n s are of  a s i m i l a r o r d e r of magnitude waters  Emphasis was p l a c e d on low metal  to those found in m u n i c i p a l  that c o n t a i n some i n d u s t r i a l wastes.  waste-  The s e n s i t i v i t y  and  minimum c o n c e n t r a t i o n d e t e c t a b l e by the atomic a b s o r p t i o n technique were taken  i n t o c o n s i d e r a t i o n when choosing  the minimum metal  c o n c e n t r a t ions. Isotherms so developed reveal u s e f u l  information  in that  they  p r o v i d e an easy comparison on the a b i l i t i e s of d i f f e r e n t absorbents remove a common adsorbate from s o l u t i o n , and g i v e some i n s i g h t design requirements f o r f l o w - t h r o u g h  2.6  to  into  columns.  Columns T e s t i n g Procedure Column Set Up  2.6.1.  The a b i l i t y of coal  to remove metals  from wastewater  flow c o n d i t i o n s was s t u d i e d using column t e s t s . simulates  This  under continuous  type of  testing  the use of packed, or s o r p t i o n towers which are designed  a c h i e v e mass t r a n s f e r between the l i q u i d and s o l i d The set  up used  is  similar  to  phases of the system.  to that employed by R i a z ^ and T i n Tun^  2 but with s l i g h t m o d i f i c a t i o n s .  2  (0.001 f t ) c r o s s  sectional  F i f t y m i l l i l i t e r b u r e t t e s of 0.9385 cm  area were used as columns.  It  has been shown  2 that f o r column c o n t a i n i n g 28/48 mesh s i z e p a r t i c l e s , 0.001 cross  sectional  column w a l l  area  is g r e a t e r than the c r i t i c a l  bed  a r e a below which the  i n f l u e n c e s the f l u i d flow c h a r a c t e r i s t i c s and thereby  significantly  reduces a d s o r p t i o n c a p a c i t y .  were packed under the c o a l trol  ft  valve with c o a l .  Glass beads and g l a s s wool  column to a v o i d p l u g g i n g the o u t l e t flow c o n -  The b u r e t t e i n l e t opening was connected to an a c i d  7  12  washed 5 g a l l o n g l a s s carboy which f u n c t i o n e d as a wastewater in the system.  Care was  frequent adjustments  2.6.2  taken to keep the r a t e of flow constant  to the o u t l e t  Experimental  valve.  intended to be c a r r i e d out  t o those o f Riaz^ and T i n Tun^ so that comparisons respect to the a b i l i t y of c o a l  in a manner  the wastewater  from d i f f e r e n t  c o n d i t i o n was  but at o t h e r times some d e v i a t i o n s were necessary  similar  c o u l d be drawn with  to remove heavy metals  Most of the time t h i s  d i f f e r e n t p r o p e r t i e s of  by  Procedure  The e n t i r e study was  types of wastewater.  reservoir  satisfied,  to accommodate  used, as d i s c u s s e d  later  the in  this  chapter. P r e l i m i n a r y column runs  r e v e a l e d that a column depth of  as chosen by Riaz^ and T i n Tun^ was not s u i t a b l e  f o r work with  sewage treatment p l a n t e f f l u e n t , s i n c e the column tends microbial  to plug due to  used  in t h i s  study,  simulated wastewater.  water to overcome t h i s  c h a r a c t e r i s t i c s of t h i s  after  the  S t e r i l i z a t i o n of the waste-  i n t e r f e r e n c e is one o f the more  type of  since  important  wastewater.  Since complete p l u g g i n g o c c u r r e d at about 40 h o u r s , column had o b v i o u s l y  With  problem was c o n s i d e r e d but not c a r r i e d out  a c t i v i t y and i t s  Tin  the column became c o m p l e t e l y plugged and  no flow o c c u r r e d a f t e r some 40 hours o f use.  microbial  primary  growth on the c o a l s u r f a c e was e v i d e n t  65 hours of c o n t a c t with h i s  wastewater  inches  growth on the s u r f a c e b e f o r e metal breakthrough o c c u r s .  Tun^ r e p o r t e d t h a t m i c r o b i a l about  10  the c o a l  been m i c r o b i a l l y a c t i v e f o r some time b e f o r e  that.  Hence 20 hours was c o n s i d e r e d to be the maximum time the column should be operated to keep t h i s throughput  i n t e r f e r e n c e to a minimum.  volume to 5-5.  liters  at 4.88 ml/cm  2  This min.  (l  r e s t r i c t e d the 2 gpm/ft )  flow  13  r a t e and 27.5  l i t e r s at 24.41 ml/cm . min. (5 gpm/ft  ).  To s e l e c t a s u i t a b l e column depth t e s t s were c a r r i e d out with coal columns with depths o f respectively).  19.1 > 12.7 and 6.4 c m .  ( 7 . 5 , 5.0 and 2.5  inch  Emphasis was p l a c e d on breakthrough c h a r a c t e r i s t i c s  Hat Creek o x i d i s e d coal which performed best 2 r a t e of 4.88 ml/cm . min.  in batch t e s t s .  2 ( l g p m / f t ) was chosen f o r these  of  A flow  tests. 2  F i g u r e 2.3  indicates  that f o r a flow r a t e of 4.88 ml/cm . min.  using Hat Creek c o a l : (1)  A column h e i g h t of no s i g n i f i c a n t had been passed  (2)  inches)  is  too. g r e a t  as  breakthrough had o c c u r r e d a f t e r 5 l i t e r s through the column.  A column h e i g h t o f 6.4 cm ( 2 . 5 . s i n c e metal  (3)  19-1 cm (7.5  inches)  is not adequate  p e n e t r a t i o n o c c u r r e d at an e a r l y  A column h e i g h t of  12.7 cm (5.0  inches)  stage.  is more s u i t a b l e  s i n c e metal c o n c e n t r a t i o n in the e f f l u e n t was constant  and  l e s s than o n e - t e n t h of the i n f l u e n t c o n c e n t r a t i o n upto a throughput  volume of  1 liter,  throughput  volume t h e r e a f t e r .  and  increased with  increasing  However complete breakthrough  was not achieved with a throughput volume of 5 l i t e r s , i n d i c a t i n g t h a t optimum column depth f o r Hat Creek c o a l smaller Test  than 12.7 cm. and g r e a t e r than 6.4. cm.  r e s u l t s with K a i s e r coal  F i g u r e 2.4  and a c t i v a t e d carbon p l o t t e d  i n d i c a t e that a column h e i g h t of  these adsorbates  it  in  12.7 cm is not adequate f o r  under s t a t e d o p e r a t i n g c o n d i t i o n s , s i n c e metal  p e n e t r a t i o n o c c u r r e d at e a r l y stages o f such runs. these t e s t s  is  is obvious  From r e s u l t s  that one column h e i g h t w i l l  a d s o r p t i o n c h a r a c t e r i s t i c s of the t h r e e adsorbates  not  of  satisfy  to be s t u d i e d .  Also,  0  I  2 Throughput  Figure  2.3-  Breakthrough  Curves  4  3 volume - liters  f o r Copper U s i n g Depths  o f Hat C r e e k C o a l  0  I  2 Throughput  3 volume - liters  4  5 vn  Breakthrough Curve f o r Copper With D i f f e r e n t Sorbates  16  d i f f e r e n t metals would r e q u i r e d i f f e r e n t h e i g h t s to e x h i b i t a d s o r p t i o n It  is extremely  and breakthrough important  of adsorbate  characteristics.  to note t h a t these column t e s t s  d e v i s e d and c a r r i e d out o n l y f o r the comparison of different  columns  c o a l s and not to o b t a i n a b s o l u t e  values  were  the performances f o r the  c a p a c i t y , minimum e f f l u e n t metal c o n c e n t r a t i o n , e t c .  of  adsorption  By a l t e r i n g  the  flow r a t e or column depth the e f f l u e n t metal c o n c e n t r a t i o n can be significantly  changed.  For comparative purposes,  the d i f f e r e n t  must be t e s t e d under e x a c t l y s i m i l a r  conditions.  That  column h e i g h t  coals  tests  should be used f o r a l l  the o t h e r parameters be examined. different If  Hence d i f f e r e n t column h e i g h t s  coals,  B,  if  the same the e f f e c t of  ( i n f l u e n t c o n c e n t r a t i o n , flow r a t e , e t c . )  to s u i t  their  individual  were to  should not be used  for  characteristics.  f o r a p a r t i c u l a r column h e i g h t and flow r a t e , breakthrough  not o b t a i n e d with say, coal  in a l l  is,  coals  coal A and metal  i t goes t o prove t h a t  p e n e t r a t i o n was o b t a i n e d  in o r d e r to remove t h a t metal  water coal A is much more s u i t a b l e  than c o a l  B.  with  from waste-  F u r t h e r column  tests  with coal A would be r e q u i r e d in o r d e r to o b t a i n more i n f o r m a t i o n , as  the minimum e f f l u e n t c o n c e n t r a t i o n a t t a i n a b l e ,  breakthrough  c e n t r a t i o n , optimum flow r a t e and column depth e t c . to o b t a i n depth of  i n f o r m a t i o n such as 12.7 cm (5.0  Since t h i s  such  constudy  is  the former and not the l a t t e r , a column  i n c h e s ) , which  is between the requirements of  Creek and K a i s e r c o a l s , was c o n s i d e r e d s u i t a b l e and was used testing.  was  Hat  ih column  Chapter 3  RESULTS AND DISCUSSION  3.1  Batch  Tests  3.1.1  E f f e c t o f pH on E f f i c i e n c y  Batch t e s t s  were c a r r i e d out  e f f i c i e n c y of heavy metal and 3.2.  removal.  to examine the e f f e c t of pH on the The r e s u l t s  are shown in F i g u r e  Hat Creek c o a l was chosen f o r these t e s t s  since  it  3.1  had  c o n t i n u o u s l y d i s p l a y e d g r e a t e r a d s o r p t i v e e f f i c i e n c y than the o t h e r s . T e s t s were performed at pH v a l u e s of 3.0, creasing  pH, an i n c r e a s e  in metal  i n f l u e n c e of pH is g r e a t e r of copper or  lead, possibly  4 . 0 , 5 - 5 and 7.0.  With  removal e f f i c i e n c y is e v i d e n t .  in the a d s o r p t i o n of z i n c than  due to p r e c i p i t a t i o n of z i n c at higher pH.  removal e f f i c i e n c y has dropped s i g n i f i c a n t l y  for adsorption  sites,  heavy m e t a l s .  T h i s very  wastewater  metal  in t r e a t e d sewage e f f l u e n t ,  T h i s might be due to c o m p e t i t i o n with  resulting  is d i s c u s s e d  The  in the case  Compared to work c a r r i e d out by R i a z ^ and T i n Tun^, the o v e r a l l  as shown in F i g u r e 3.1.  in-  in fewer s i t e s  being a v a i l a b l e  organics for  important d i f f e r e n c e between pure s o l u t i o n in d e t a i l  later  in t h i s  chapter.  and  18  100 ]• Distilled water O Cu . ^ 2„ jPrimary effluent  20 Initial c o n e . Coa I u s e d  10  8  2mg/L - H.C. OX  C o a I weight * I g  7 Figure  6  pH 3-1  E f f e c t of pH on Metal Lower C o n c e n t r a t i o n  Removal  at  F i g u r e 3.2  E f f e c t of pH on Metal Higher C o n c e n t r a t i o n  Removal  at  20  3.1.2 (a)  C a p a c i t y of Copper  Coals  Copper a d s o r p t i o n  isotherms o b t a i n e d from batch  t e s t s are shown in F i g u r e s batch t e s t c o n d i t i o n s following Table (1)  coal  to 3-5.  Under  a l r e a d y d e f i n e d , the  p r o p e r t i e s were n o t e d .  (Refer  to  3.1).  The copper a d s o r p t i o n with  3-3  c a p a c i t y of c o a l  increased  i n c r e a s i n g 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  metal. (2)  By comparison  to R i a z ' s ^ work  in 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 range, greater effluent (3)  t r a c e metal  coals  have shown  removal c a p a c i t i e s  than from water  from sewage  solution.  Under much lower e q u i l i b r i u m c o n c e n t r a t i o n s  (0.1  1.0 m g / l ) , the a d s o r p t i v e c a p a c i t i e s of the  various  coals  have decreased s i g n i f i c a n t l y  o b t a i n e d with water s o l u t i o n s (4)  10 to 30 mg/1  Hat Creek coal residual  supernatant  detectable solution  had the a b i l i t y  from those  of copper. to produce a  c o n c e n t r a t i o n of  l i m i t of 0.03 mg/1  c o n t a i n i n g 0.1  to  from an  l e s s than the initial  mg/1 of copper.  (see  Figure  3.5). (5)  In d e c r e a s i n g o r d e r o f coals  removal e f f i c i e n c y the four  c o u l d be ranked (see F i g u r e 3.6)  Hat Creek o x i d i s e d c o a l  sample  Kaiser  -  Stock p i l e  refuse  Kaiser  -  Special  Cominco  -  Ash  as  follows:  j  / No s i g n i f i c a n t p l a n t feed r d i f f e r e n c e between j these three c o a l s . /  5  22  Equilibrium  F i g u r e 3.H  cone-  Copper A d s o r p t i o n  mg/L  Isotherms  0.018  o.oioO-  Coal  -  H.C. OX  Coa I weight  = Ig  pH = 4.0  0  Figure 3-5-  0.1 Equilibrium  0.2 conc.-mg/L  Copper A d s o r p t i o n  Isotherms  2k  TABLE  3-1  SUMMARY OF COPPER ADSORPTION  Coal  Type  |  E q u i 1 i b r i um  |  Concentration  j mg/1  CAPACITIES  mg A d s o r b e d / g W a t e r S<s l u t i o n Riaz^  H.C.OX Co.Ash K.C. SPR K.C. SPF  H.C.OX  H.C.OX  5  Co.Ash K.C. SPR K.C. SPF  H.C.OX  1.0  Co.Ash  K.C. SPR K.C. S P F  0. 10  Sewage  (primary) Effluent  3-7  5.5  I.A  2.3 2.5  0.7  2.9  Co.Ash  K.C. SPF  Treated  0.85  10  K.C. SPR  T i nTun ^  Coal  3-0  3-7  1.25  1.3  0.71  1-7  0.6  1.2  2.5  1.9  0.9  0.2  0.6  Q.k  0.5  0.2  1.0  0.32  0.5  0  0.2  0  0.15  0  100  80  —  •  •  u  n  H.C.OX  A  K.CSPF Cn • A<?H K.C.SPR  ® A  A  Q  ® A  60 /  O  40 C o a l weight - Ig 20  KJ  —  C)  1  1  1  10  20  30 Initial  Figure  3-6"  1  1  1  |  40  50  60  70  cone  Copper Removal  - mg / L Efficiency  26  The above  results  complex formation metal  ions  (M)  .  could be e x p l a i n e d using  Assuming  and o r g a n i c  that complex forming  reactant  they may be t r e a t e d as a system  M  +  L . =  * Hence K u  the p r i n c i p l e s  (L)  of  r e a c t i o n between  occur r a p i d l y and  reversibly,  in e q u i l i b r i u m .  ML ML  =  M . L Where K is Applying  the comp1 ex-format ion or s t a b i l i t y  Le C h a t e l i e r ' s  p r i n c i p l e ^ to the above system, when metal  ions a r e present  in high c o n c e n t r a t i o n s  equilibrium will  shift  organic  t o the r i g h t  complex c o n c e n t r a t i o n .  (as  in item 2 above)  resulting  Thus  in s i g n i f i c a n t  the h i g h e r  adsorption  o b t a i n e d with primary e f f l u e n t compared to pure s o l u t i o n to metal  adsorption  both d i r e c t l y and complexed with  However when metals item 3 above)  complexed o r g a n i c s organic  species  and the l a t t e r phenomenon  are present  the e q u i l i b r i u m w i l l  reduced meta1-organic  shift  to the  left  the metal-  capacity  is  probably  (as  resulting  Hence the metal  ions  ions a t t a c h e d , f o r a d s o r p t i o n  is favoured s i n c e they are v a s t l y  is comparable t o " c o m p e t i t i v e  more numerous.  inhibition"  in  in much  have to compete with high c o n c e n t r a t i o n s  that have no metal  due  organics.  in lower c o n c e n t r a t i o n s  complex c o n c e n t r t i o n .  will  constant.  and of sites (This  in enzymatic  react ions).  (b)  Lead Lead a d s o r p t i o n  F i g u r e 3.7. 3.2) .  isotherms  The f o l l o w i n g  coal  o b t a i n e d from batch t e s t s  are shown in  p r o p e r t i e s were n o t e d :  to  (Refer  table  Equilibrium  F i g u r e 3-7  cone -  Lead A d s o r p t i o n  mq/L  Isotherms  28  TABLE 3-2 SUMMARY OF LEAD ADSORPTION CAPACITIES  mg adsorbed/g c o a l  Equilibrium Coal Type  Concentration mg/1  H.C.OX  water s( l u t i o n Riaz  8  CO. Ash  H.C.OX  6  CO. Ash  H.C.OX  4  CO. Ash  6  Ti nTun ^  t r e a t e d (primary) sewage e f f l u e n t  5  0.17  2.1  0.35  5  0.125  2.0  0.01  5  0.085  1.9  0  K.C. SPR  1.45  0.01  K.C. SPF  1.55  0  H.C.OX  1  CO. Ash  4.65  0.02  1.7  0  K.C. SPR  1.9  0  K.C. SPF  1.07  0  (l)  The metal a d s o r p t i o n increasing  (ll)  c a p a c i t y of coal  increased with  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  By comparison  to R i a z ' s ^ work  lead;  in the l e s s than 10 mg/1  e q u i l i b r i u m c o n c e n t r a t i o n range the a d s o r p t i v e of K a i s e r as (ill)  coals  are much lower with Sewage than with water,  in item 3 above,  Lead removal with Hat Creek c o a l the o t h e r  (IV)  capacities  than with  coals.  In d e c r e a s i n g order of could be ranked as (Refer  is much g r e a t e r  to F i g u r e  removal e f f i c i e n c y the four  coals  follows: 3-8)  Hat Creek o x i d i s e d Kaiser  -  stock p i l e  Kaiser  -  special  refuse  plant  No s i g n i f i c a n t d i f f e r e n c e between these t h r e e c o a l s .  feed  Cominco ash  (c)  Zinc Zinc adsorption  F i g u r e 3-9-  isotherms o b t a i n e d from batch t e s t s  Under t e s t  p r o p e r t i e s were n o t e d : (l)  Metal with  (11)  conditions (Refer  adsorption  are shown in  a l r e a d y d e f i n e d the f o l l o w i n g  to T a b l e 3- 3) •  c a p a c i t y of c o a l s  increased  increasing equilibrium concentration.  Hat Creek c o a l had the a b i l i t y z i n c c o n c e n t r a t i o n o f 0.14 mg/1 c o n c e n t r a t i o n of 0.5  mg/1  t o produce a r e s i d u a l from an  initial  coal  100  80 Coal  o  |  we i g ht = I g  601  <v a.  ^  40  H.C.OX  20  Co'ASH.K.C.SPF.K.C.SPR  1 .2  3 Figure 3-8  4 5 6 7 Initial concentration - mg/L Lead Removal  Efficiency  8  10  0.20  •  • H.C.OX O Co'ASH A K.C. SPR x K.C.SPF pH = 4 . 0 Coal weight - Ig  I  2 Equilibrium F i g u r e 3-9  3 conc.-mg/L  Zinc Adsorption  Isotherms  32  TABLE  3-3  SUMMARY OF ZINC ADSORPTION  Coal  Type  H. C. OX  CAPACITIES  Equ i1i b r i um  mg A d s o r b e d / g  C o n c e n t r a t i on  W a t e r ' o1ut i o n  Treated  mg/1  Riaz  Sewage  It  Co.Ash  H.C.OX  2  Co.Ash  H.C.OX  0.4  Co.Ash  H.C.OX  H.C.OX  Coal  •3  6  T i nTun ^  0.19  0.4  0.06  0.6  0.17  0.3  0.01  0.28 •  0. 15  0.07  0  0.11  Co.Ash  .03  0.14  0. 13 0  K.C. SPR  0. 18  0  K.C. SPF  0. 10  0  H.C.OX  .1  Effluent  0.9  • 19  0.2  (primary)  .03  0.002  33  (ill)  By comparison with R i a z ' s work at 0.2 mg/1 equilibrium concentration, Kaiser significantly  (IV)  reduced metal a d s o r p t i o n  In d e c r e a s i n g o r d e r o f coals  coals  n  have shown capacities:  removal e f f i c i e n c y the four  c o u l d be ranked (Refer  to F i g u r e 3-10)  as  follows: Hat Creek o x i d ised Kaiser  - Stock p i l e  Kaiser  - Special  refuse  plant  j No s i gn i f i can t d i f f e r e n c e between these c o a l s .  feed  Cominco Ash (d)  Mercury Mercury a d s o r p t i o n  in F i g u r e 3 . 1 . 3 coal  isotherms o b t a i n e d from batch t e s t s  Under t e s t c o n d i t i o n s  p r o p e r t i e s were n o t e d ; (Refer (l)  Capacities  a l r e a d y d e f i n e d the  to T a b l e  3-4).  c o n c e n t r a t i o n of about kO mg/1  and a t t a i n e d c a p a c i t i e s o f 0.3 and 0.6 mg/g The r e l a t i v e  KC. SPF was a b l e to adsorb mercury o n l y at  The lowest  residual  and was 2.5 mg/1 No measurable initial  than 20 mg/1.  c o n c e n t r a t i o n was produced by H.C. OX  from an i n i t i a l  concentrations of  c o n c e n t r a t i o n o f 5 mg/1.  residual  l e s s than 5 mg/1.  concentrations  from pure s o l u t i o n of 0.03 mg/1 i t was  initial  r e d u c t i o n in c o n c e n t r a t i o n was o b t a i n e d with  a b l e to o b t a i n  while  respectively.  i n c r e a s e at higher c o n c e n t r a t i o n s were very  concentrations higher (ll)  following  of Cominco ash and KC. SPR to remove mercury  i n c r e a s e up to an i n i t i a l  small.  are shown  possible  initial  as  T i n Tun^ was  low as 0.005  mg/1  mercury c o n c e n t r a t i o n ,  down to o n l y 2.5 mg/1 with  treated  100  0  I Figure  2 3 Initial c o n c e n t r a t i o n - m g / L 3-10  Zinc Removal  4  5  Efficiency  -t-  Equilibrium  F i gure 3-11  cone-  Mercury A d s o r p t i o n  mg/L  Isotherms  ^  36  TABLE  3-4  SUMMARY OF MERCURY ADSORPTION CAPACITIES  Equilibrium Coal Type  Concentration mg/1  K.C.  SPR  40  K.C. SPF  K.C.  SPR  30  K.C. SPF  K.C.  SPR  10  K.C. SPF  H.C.  OX  .2  CO. Ash  H.C.  OX  .01  CO. Ash  H.C.  OX  mg adsorbed/g c o a l Water S o l u t i o n Riaz"  | TinTun^ |  sewage  0.6  0.55  1.2  1.2  0.55  0.5  1.1  0. 35  0.4  0  0.7  0  0. 145  0  0.015  0  0.0035 0.0026  .005  Treated  0.0008  (Primary) effluent  sewage e f f l u e n t ; (ill)  By comparison 40 mg/1  to R i a z ' s ^ work, w i t h i n a range of 30 to  mercury e q u i l i b r i u m c o n c e n t r a t i o n , K a i s e r  produced comparable a d s o r p t i o n  capacities  sewage e f f l u e n t and water s o l u t i o n . librium concentrations  (less  between t r e a t e d  Under lower e q u i -  than 10 mg/1)  greater  a d s o r p t i o n c a p a c i t i e s were o b t a i n e d w i t h water than from t r e a t e d sewage e f f l u e n t .  (IV)  removal e f f i c i e n c y the f o u r  could be ranked (Refer  to F i g u r e 3.12 as  Kaiser  - Stock p i l e  Kaiser  - Special  of  Ranking  of  coals  follows;  refuse feed)  show that of the four d i f f e r e n t  O x i d i s e d was f a r s u p e r i o r compared to the o t h e r three l e a d , z i n c and mercury from wastewater.  H.C.  d i f f e r e n c e was present between  OX seem to belong to a c l a s s of  i t s own.  Its of  T h i s o b s e r v a t i o n suggests t h a t H.C.OX has much g r e a t e r  s u r f a c e area per u n i t weight sites  in  K.C.SPF,  c a p a c i t y was o f t e n observed to be more than double that  any o t h e r used.  coals  removing e f f i c i e n c i e s very much  to each o t h e r and no s i g n i f i c a n t  these t h r e e .  tested.  (a).  the Coals  K.C.SPR, and CO. Ash e x h i b i t e d metal  sorption  in s e c t i o n  sample  plant  the batch t e s t s  the removal of c o p p e r ,  adsorption  results  In d e c r e a s i n g o r d e r of  The r e s u l t s  similar  these  the same theory as  Overall  t e s t e d , H.C.  Again,  solution  can be e x p l a i n e d using  Hat Creek o x i d i s e d  3.T.3  coals  per u n i t  and/or has g r e a t e r c o n c e n t r a t i o n of  s u r f a c e area than any of  the o t h e r t h r e e  active coals  100  Coo I weight  = Ig  •  Initial F i gure 3-12  co ncentra tion - mg / L  Mercury Removal  Efficiency CO  39  Hence in d e c r e a s i n g o r d e r of e f f i c i e n c y the f o u r could be ranked follows; Hat Creek O x i d i s e d Kaiser  - Stock  pile  ,, . Kaiser  . , - Special plant K  refuse , feed  No s i g n i f i c a n t d i f f e r e n c e , . , , between these t h r e e c o a l s  v  Cominco Ash  3.1.4.  General  Changes  in a d s o r p t i v e c a p a c i t y o r metal  coals w i l l  be d e s c r i b e d as " s l i g h t " ,  the use of a c t u a l cases.  Since t h i s  values  Comments  quantity, study  is  have no s i g n i f i c a n t  variables.  Riaz  c o n c e n t r a t i o n s of  removing e f f i c i e n c y of  "significant",  percentage, e t c , w i l l  "marked" e t c , and  be avoided  f o r comparative purposes o n l y ,  the a c t u a l  meaning s i n c e they are dependent on so many  chose to develop isotherms by changing the metal  the  The isotherms  be i d e n t i c a l w i t h i n a small outside that  it.  were t e s t e d isotherms K.C.  constant.  initial  developed by these methods w i l l  c o n c e n t r a t i o n range but w i l l  To be a b l e to make a c c u r a t e comparisons,  the data t a k i n g  initial  ions w h i l e keeping the coal weight  T i n Tun^ in most cases changed the c o a l weight and kept the concentration constant.  in most  procedures are c o n s i s t e n t .  in the same manner, the comparisons  As  it  be d i f f e r e n t is necessary  long as a l l  are v a l i d .  .  coals  Since  in t h i s  study were developed by changing  initial  SPR and K.C.  SPF can be compared w i t h R i a z ' s ^  r e s u l t s w h i l e H.C. OX  and CO. Ash cannot be compared with T i n T u n ' s ^ r e s u l t s initial  concentrations  are  similar.  concentrations,  except when  3.1.5Metal  Comparison o f Hat Creek,wjth A c t i v a t e d adsorbing  c a p a c i t y of H.C.  OX was compared with  a c t i v a t e d carbon grade 12 x 20, which adsorbent.  is a commercially  Batch t e s t s were performed with H.C.  c a r b o n , using metal d i s s o l v e d  Carbon Darco  available  OX and a c t i v a t e d  in both water and primary e f f l u e n t .  Copper: Adsorption and H.C. metal  isotherms  f o r copper removal using a c t i v a t e d  OX are shown in F i g u r e 3.13.  adsorption  capacity  than H.C.  carbon  A c t i v a t e d carbon e x h i b i t e d b e t t e r  OX under t e s t c o n d i t i o n s .  The  d i f f e r e n c e between the two is c o m p a r a t i v e l y u n i f o r m and the performance of H.C.  OX is c o n s i s t e n t l y  The i n c r e a s e  in a d s o r p t i o n  compared to that  lower over the c o n c e n t r a t i o n range t e s t e d . c a p a c i t y f o r copper  in primary e f f l u e n t  in water s o l u t i o n  is as much as  as  100%, p a r t i c u l a r l y  f o r higher e q u i l i b r i u m c o n c e n t r a t i o n s .  Lead: The a b i l i t y of both H.C.  OX and a c t i v a t e d carbon to adsorb  from both primary e f f l u e n t and water s o l u t i o n was are shown in F i g u r e 3.1**.  Within  removed lead from water s o l u t i o n  inferior  to a c t i v a t e d carbon  t e s t e d and the  isotherms  the c o n c e n t r a t i o n range t e s t e d , both completely.  lower f o r a c t i v a t e d carbon and tremendously used to t r e a t primary e f f l u e n t .  lead  The c a p a c i t y was reduced f o r H.C.  slightly  OX when  T h i s marked r e d u c t i o n makes H.C.  in removing  OX much  lead from primary e f f l u e n t .  Equilibrium  F i gure 3-13  c o n e -  Copper A d s o r p t i o n  mg/L  Isotherms  hi  Equilibrium F i g u r e 3- 14  cone. - mg/L  Lead Adsorption  Isotherms  ^3  Z i nc: Adsorption H.C.  isotherms are given  in F i g u r e 3 . 1 5 -  OX to remove z i n c from water s o l u t i o n  was b e t t e r than that of a c t i v a t e d carbon. capacities treating  of both H.C.  with  Thus H.C. regard  of  and from primary e f f l u e n t Furthermore, the metal  adsorption  OX and a c t i v a t e d carbon were higher when  primary e f f l u e n t than when t r e a t i n g a water s o l u t i o n of  These o b s e r v a t i o n s lead.  The a b i l i t y  are o p p o s i t e  OX seems  to what were observed with copper and  to be a b e t t e r c h o i c e than a c t i v a t e d  to z i n c removal  zinc.  carbon  from wastewater.  Mercury: The performance o f H.C. (see F i g u r e 3 - 1 6 )  OX was compared with a c t i v a t e d  in the removal of mercury from primary e f f l u e n t .  A c t i v a t e d carbon produced s i g n i f i c a n t l y The d i f f e r e n c e between the two was tion  range  tested.  carbon  better results  than H.C.  OX.  100% or g r e a t e r over the c o n c e n t r a -  3  0  Figure 3 . 1 P  2  4 6 8 10 Equilibrium cone.-mg/L Mercury Adsorption Isotherms  12  Summary:  Table  3-5*  Summary of Comparisons Between A c t i v a t e d Carbon and Hat Creek O x i d i s e d Coal  Act i vated Metal  Water Solut ion  Carbon  Hat Creek O x i d i s e d Coal  Pr imary Sewage E f f l u e n t  Water Solut ion  Coppe r  1  2  3  Lead  1  2  3  Z i nc  k  3  2  Mercury  1  2  3  Numbers 1 to k denote batch systems removal e f f i c i e n c y . (See F i g u r e s 3.13 to 3-16).  Pr imary Sewage E f f l u e n t k  1  in d e c r e a s i n g metal  A c t i v a t e d carbon has much g r e a t e r s u r f a c e area per u n i t weight Hat Creek o x i d i s e d c o a l . in a c t i v a t e d carbon s m a l l e r percentage of v a r i o u s  than  A l s o a much g r e a t e r percentage of s u r f a c e area  is a v a i l a b l e f o r s o r p t i o n processes w h i l e o n l y is a v a i l a b l e  surface deposits.  in the case of coal due to the presence  Hence the former can be expected to show  g r e a t e r metal a d s o r p t i o n c a p a c i t y than the l a t t e r . Out of f o u r metals H.C.  t e s t e d , a c t i v a t e d carbon was s u p e r i o r  to  OX with regard to a d s o r p t i o n of c o p p e r , lead and mercury, and  inferior  to H.C.  OX w i t h regard to a d s o r p t i o n of z i n c .  due to the removal of z i n c from s o l u t i o n by chemical surface deposits  on c o a l , than by s o r p t i o n means.  This  is  possibly  r e a c t i o n s with  For reasons adsorption  discussed  earlier  in t h i s  can be expected to occur  sewage e f f l u e n t .  chapter, greater  in water s o l u t i o n  Out of four metals  tested, greater  than  metal in primary  adsorption  c a p a c i t i e s were o b t a i n e d with water s o l u t i o n of copper, lead and mercury, and primary sewage e f f l u e n t gave higher z i n c a d s o r p t i o n . Thus  in both cases z i n c behaved  three metals. this  (Refer T a b l e 3 5)•  differently.  nor d i d  T h i s behaviour  z i n c - o r g a n i c complex that organic  3.2  is  it  reveal  suggest any reason why z i n c might act  is p o s s i b l y  due to g r e a t e r  stability  of  the  formed, compared to the o t h e r three m e t a l -  complexes.  Column T e s t s : Compared to batch t e s t i n g ,  systems.  As  in batch t e s t s ,  can be c a l c u l a t e d .  adsorption  testing  column t e s t s  represent  the c a p a c i t y of coal  A p l o t of metal c o n c e n t r a t i o n  a g a i n s t volume passed metal  to o t h e r  L i t e r a t u r e research d i d not  _  type of anomaly,  in a manner o p p o s i t e  through.gives  capacities  to adsorb heavy  c u r v e " from which  Thus t h i s  method of  can a l s o be used to compare the performance of d i f f e r e n t  but t h i s  time  in a dynamic system.  metals  in column e f f l u e n t  the "breakthrough  can be c a l c u l a t e d .  continuous  Sample c a l c u l a t i o n s  showing  metals, the p r o -  6 cedure f o r c a l c u l a t i n g a d s o r p t i o n Adsorbing m a t e r i a l s Act.  Carb.  3.2.1  capacity  The f i r s t  shown in Appendix  f o r these t e s t s were H.C.  (Darco a c t i v a t e d Carbon grade  (a)  is  12 x  OX, K.C.  11.  SPR and  20).  Copper run was c a r r i e d out with an  i n f l u e n t copper c o n c e n t r a t i o n  2 of k mg/1  at a flow r a t e o f  1 gpm/ft  .  from t h i s  run are shown in F i g u r e 3-17.  The breakthrough curves Breakthrough was not  obtained  attained  Influent cone. pH*4.0 Flow rote * Igpm/ft. Column depth 5" Coal weight 1  ACT. CARB  K.C. SPR = 9.5g ACT. CARB = 5.0g H.CR. ' 7.75g  o—-  H.CR.  Throughput F i g u r e 3-17  Breakthrough  volume Curve f o r  liters Copper  10  II  h3  with H.C.  OX c o a l , due to b i o l o g i c a l  a f t e r a throughput  of  12  a c t i v i t y which plugged the column  liters.  From the breakthrough curves o b t a i n e d height of 5 inches  is  too great  f o r H.C.  it  is e v i d e n t that a column  OX, but not enough f o r K.C.  and A c t i v a t e d carbon to show metal breakthrough c h a r a c t e r i s t i c s . p l o t s o b t a i n e d with a c t i v a t e d carbon and K.C. paratively  low rates of a d s o r p t i o n  The reasons section  f o r choosing  SPR a l s o  SPR  The  i n d i c a t e com-  and low metal a d s o r p t i o n  capacities.  a column height of 5 inch are e x p l a i n e d  in  2.6.2.  In F i g u r e s  3- 18 and 3-19  are shown breakthrough curves  obtained  2 with 5 gpm/ft capacities  flow  rate.  f o r the c o a l s  From F i g u r e s  3.17,  3- 18 and 3.19  adsorption  and a c t i v a t e d carbon were c a l c u l a t e d and  a g a i n s t the r a t i o o f e f f l u e n t to i n f l u e n t metal c o n c e n t r a t i o n s in F i g u r e  it  concentration:  that; i n c r e a s e with  (higher  increasing  C/Co)  For the same e f f l u e n t c o n c e n t r a t i o n each coal adsorption  c a p a c i t y at  higher c o n t a c t (ill)  is e v i d e n t  A d s o r p t i o n c a p a c i t y of c o a l s effluent  (11)  (C/Co)  3.20.  From F i g u r e 3.20 (l)  plotted  the lower flow r a t e due to the  time:  Under column o p e r a t i n g c o n d i t i o n s , can be ranked efficiency  Hat Creek Coal  Kaiser  the t h r e e  in the d e c r e a s i n g order of  as:  Activated  has a higher  Carbon  - Stock P i l e  Refuse.  adsorbents  removal  Influent cone. ACT. CARB H pH = 4.0 Flow rate = 5gpm/ft Column depth 5" Coa I weight « K.C. SPR = 9.5g ACT. CARB =5.0g H. CR. = 7.75g 1.5 2 Throughput  F i gu re  3-18  Breakthrough  2.5 volume Curve f o r  3 liters Copper  3.5  4.5  Influent cone. K.C.SPR cn  ACT. CARB  I  o c o c 3  UJ  "pH = 4.0 Flow rate 5gpm/ft' Column depth * 5" C o a l weight' B  K.C. SPR = 9.5g ACT. CARB = 5.0g H.CR. = 7.75g  0.1  0.2  1  0.3  0.4 Throughput  F i g u r e 3- 19  Breakthrough  1  0.5  0.6  volume - liters Curve f o r  Copper  1  0.7  0.8  0.9  COAL ROW O H.CR. I  RATE gpm/ft  •  Q H.CR.  •  • ACT. CARS  I  O  O ACT.CARB  5  A  A KCSPR  I  A  A KCSPR  5  S  5  pH = 4.0 INFL.CONC  =  4mg/L  COLUMN DEPTH = 5 " COAL  WEIGHT :  K.C. S P R = 9 . 5 g A C T . C A R B = Sg H.CR. = 7.75g  / P »  0.50  0.25 C/ C  Figure  3.20  0.75  r  Comparison of A d s o r p t i o n C a p a c i t y f o r Copper in Primary E f f l u e n t at D i f f e r e n t Flow Rates  The e f f l u e n t metal c o n c e n t r a t i o n b e f o r e breakthrough  is a f u n c t i o  of the rate o f a d s o r p t i o n , where the r a t e of a d s o r p t i o n  is d e f i n e d as  the net q u a n t i t y of metal  s u r f a c e per  unit  time.  metal  This  ions which adsorb on the coal  r a t e of a d s o r p t i o n  c o n c e n t r a t i o n , form of metal  adsorption s i t e s , kept constant tion  u s u a l l y dependent on  influent  in s o l u t i o n , a v a i l a b i l i t y  temperature and pH.  Since a l l  of  other parameters are  throughout a column r u n , the e f f l u e n t metal c o n c e n t r a -  in our t e s t s Usually  is  is a f u n c t i o n of a v a i l a b l e a d s o r p t i o n  "Total  sites  originally  present"  a l r e a d y used"  i n c r e a s e s with  process s i t e s  a l r e a d y occupied are s t i l l  t r i b u t e to net a d s o r b t i o n .  increasing  sites.  is a c o n s t a n t .  time.  During  "Sites  the a d s o r p t i o n  a c t i v e though they d o n ' t  con-  By a process of a d s o r p t i o n and d e s o r p t i o n  s t a t e of e q u i l i b r i u m is approached on those s i t e s w h i l e unused s i t e s still  p r o v i d i n g a net a d s o r p t i v e t r e n d .  this  study  rich  in microorganisms  water  Since the wastewater used  is primary e f f l u e n t from a sewage treatment p l a n t , and b i o l o g i c a l l y very a c t i v e .  When t h i s  is passed through a column of c o a l , microorganisms w i l l  themselves  to coal and begin to m u l t i p l y  are f a v o u r a b l e .  i f environmental  growth  is u s u a l l y  in the form o f an expanding  waste-  attach  suitable  i n s i d e the coal  f o r growth and m u l t i p l i c a t i o n of microorganisms.  is  substrate  p r o v i d e d by the flow of wastewater, and the a v a i l a b i l i t y o f  ideal  in  conditions  Continuous supply of d i s s o l v e d oxygen and  growth s u r f a c e , make environmental c o n d i t i o n s  it  column  Microbial  l a y e r on the media  s u r f a c e , hence i t tends to reduce the a v a i l a b i l i t y of the s u r f a c e f o r adsorption continuously.  Common f e c a l b a c t e r i a  (Esh.  coli)  predominate among the a e r o b i c commensal organisms present  which  in the  12 healthy gut,  thus abundant  in the wastewater  a  used, are capable of  m u l t i p l y i n g once every 15 to 20 minutes  under  ideal  conditions.  With  2 a column flow of  1 gpm/ft , the time r e q u i r e d to pass 0 . 0 8  water through the column is present.  This microbial  f i l m , which due to  its  sufficient  d i f f u s i o n of the adsorbate  surfaces  nature, greatly 13  through  it.  results  reduces the rate of  Hence, by b i o l o g i c a l  s u r f a c e o c c u r s , and the r a t e o f  could be so reduced that a c o a l  s u r f a c e covered by m i c r o b i a l  originally  present" w i l l  for adsorption.  coli  in a m i c r o b i a l  an e f f e c t i v e b l a n k e t i n g of coal  a much reduced c a p a b i l i t y  waste-  to double the number o f Esh.  growth on s o l i d  viscous  1 of  Hence the " t o t a l  activity, diffusion  growth  has  sites  c o n t i n u o u s l y decrease and can be compared to a  s i t u a t i o n where the h e i g h t of column is being c o n t i n u o u s l y decreased by removing coal  and thereby making  the a d s o r p t i o n c a p a c i t y of  i t not a v a i l a b l e  the coal  for adsorption.  can be expected to be lower when  used to t r e a t sewage e f f l u e n t compared to pure metal Another very solution  is  that  (a)  the former c o n t a i n s  the presence of o r g a n i c s  adsorption c h a r a c t e r i s t i c s . charge, and s i z e )  dissolved organics  be i n f l u e n c e d .  in a r e l a t i v e l y  As d i s c u s s e d  in  section  can be expected to i n f l u e n c e metal  Depending on the type of adsorbate  type o f adsorbent  t i o n of metal and o r g a n i c s , capacity w i l l  solution.  important d i f f e r e n c e between sewage e f f l u e n t and metal  high c o n c e n t r a t i o n w h i l e the l a t t e r has none. 3.1.2  Hence  (pore s i z e s )  (ionic  and r e l a t i v e c o n c e n t r a -  the r a t e of a d s o r p t i o n and  adsorption  T h i s c o u l d be as a r e s u l t of d i r e c t com-  p e t i t i o n between o r g a n i c molecules and metal due to the formation o f organo-metal  complexes  complex)  having a much slower or f a s t e r  to s i t e s  w i t h i n the c o a l  particles.  ions (as  for adsorption  sites  opposed to aquo  r e a c t i o n r a t e f o r a d s o r p t i o n on  or  55  The combined e f f e c t s of c o m p e t i t i o n f o r a d s o r p t i o n s i t e s metal  ions, organo-metal  between  complexes and o r g a n i c molecules and the b l a n k e t -  ing e f f e c t of m i c r o b i a l growth w i t h i n the a d s o r p t i o n column on the breakthrough curve are unknown.  Perhaps  the gradual  and continuous  in the e f f l u e n t metal c o n c e n t r a t i o n as observed with H.Cr coal  rise  in  F i g u r e 3.18 was due to the i n f l u e n c e of above combined e f f e c t s .  Tests  c a r r i e d out with water s o l u t i o n produced constant e f f l u e n t metal  con-  centration t i l l  breakthrough was a c h i e v e d .  Column runs were a l s o c a r r i e d out with copper s o l u t i o n  in water  2 of k mg/1  c o n c e n t r a t i o n at  1 gpm/ft  , with the r e s u l t s  A d s o r p t i o n c a p a c i t i e s were c a l c u l a t e d and given  3.21. Results  shown in F i g u r e in F i g u r e  3.22.  i n d i c a t e that Hat Creek and K a i s e r c o a l s have reduced a d s o r p t i o n  capacities carbon.  in primary e f f l u e n t and i t  Hat Creek c o a l  is somewhat unchanged f o r a c t i v a t e d  performed b e t t e r than a c t i v a t e d carbon under  both c o n d i t i o n s . Column t e s t s were c a r r i e d out with sewage c o n t a i n i n g a copper 2 c o n c e n t r a t i o n of  10 mg/1 at  through curves are c a p a c i t i e s at 3.25.  1 and 5 gpm/ft  in F i g u r e 3-23  flow r a t e s , and the break-  and 3.2k r e s p e c t i v e l y .  Adsorption  these two flow rates were c a l c u l a t e d and shown in F i g u r e  Again Hat Creek coal has shown a d i s t i n c t s u p e r i o r i t y  a c t i v a t e d carbon at both flow r a r e s .  Comparison of metal  over  adsorption  c a p a c i t i e s f o r d i f f e r e n t copper i n f l u e n t c o n c e n t r a t i o n s are shown in F i g u r e 3.26.  G r e a t e r a d s o r p t i o n c a p a c i t i e s were o b t a i n e d with  i n f l u e n t metal (b)  higher  concentrations.  Lead Column runs were c a r r i e d out with an i n f l u e n t  lead c o n c e n t r a t i o n  2 of k mg/1  at  1.0 and 5.0 gpm/ft  flow r a t e s , with breakthrough  curves  Effluent c o n c . - m g / L — ro ui ro in oi c fD  3 IoO 3 QJ -< . —•  XI ~\  m O  -u  o  re  ZT  O < -1 ro rt O -ti 3 o-\ o c —•  c  c~>  O  Tro3 X)  3  95  —\ o c  |Q 3T3 C  vol  3 c ro -tl 3 CO rt Q J QJ 3 O -rt s: zr -i o c Q J rt ID -h  —•  —1  ZT  c 3  a  i  a -i  F i g u r e 3-22  Comparison of A d s o r p t i o n C a p a c i t y f o r Copper Primary E f f l u e n t and D i s t i l l e d Water  in  Influent cone. pH = 4.0 Flow rote lgpm/ft' Column depth * 5" Cool weight » K.C. SPR * 9.5g ACT. CARB = 5g H.CR.= 7.75g 5  ACT. CARB  H.CR.  2 2.5 3 3.5 Throughput vo Iu me - li ters Breakthrough  Curve f o r  Copper  4.5  Influent cone.  10  pH * 4.0 Flow rote 5gpm/ft' Column depth - 5" Coo I weight' K.C. SPR = 9.5g ACT.CARB - 5g H. CR.= 7.75g 3  ACT. CARB  I  2  2.5  Throughput Breakthrough  1 3  3.5  volume - liters Curve f o r Copper  4.5  "O— •-pH =  Cool Flow rote H.CR. "J ACT.CARB J Igpm/fl K.C.SPR H.CR H.CR. •> ACT.CARB J5gpm/(t' K.C.SPR J 4.0  Influent conc. = 4 m g / L  o o  Co Iu mn de pth  4|  Cool  = 5"  weight^  K.C.SPR  =9.5g  ACT.CARB s 5 g H. CR. = 7. 7 5 g  •o  2 31 •o o o> E  o  a  / 0.2 F i g u r e 3-25  0.3 c/c_  0.4  0.5  Comparison o f A d s o r p t i o n C a p a c i t y f o r Copper in Primary E f f l u e n t at D i f f e r e n t Flow Rates  0.6  o  -Cr-  H.CR.OX  — A C T . --Q—  CARB  H.CR.OX ACT.CARB  } 10 m g / L •( } 4mg 1  /L  pH = 4 . 0 Co Iu mn depth - 5" Flow  0  0.1  0.2  0.3  0.4  J 0.5  rote  I 0.6  :  I gpm/ft  I 0.7  L 0.8  0.9  1.0  C/C„ F i g u r e 3-26  Comparison of A d s o r p t i o n C a p a c i t y f o r D i f f e r e n t Copper Influent C o n c e n t r a t i o n s  being shown in F i g u r e 3-27  and 3-28  s l o p e was o b t a i n e d probably earlier.  due to m i c r o b i a l  For both a c t i v a t e d  of s c a t t e r with  regard  respectively.  Again,  growth  as  carbon and Hat Creek coal  to data  p o i n t s was o b t a i n e d .  an  explained a high degree  The s c a t t e r  rather c o n f i n e d at e a r l y stages but developed over a l a r g e r later stages. that  lead  The reason f o r t h i s  is  ions were complexed to a p a r t i c u l a r  used as a s u b s t r a t e absorbed  behaviour  t i o n by osmotic  cells,  processes  Rate of s u b s t r a t e  metal  phase etc)  characreristics  of  the c o a l s ,  is  from the  possible  time.  l i f e cycle.  Adsorption  from F i g u r e s  3.27  Answers  capacities and 3-28  and p l o t t e d  conditions,  Carbon  Hat Creek Coal Kaiser  effluent  micro-  in F i g u r e 3.29.  of best  this fit  Hat Creek coal  in a much s u p e r i o r manner to K a i s e r  in the d e c r e a s i n g o r d e r of  Activated  influence  coal,  carbon performing somewhat b e t t e r than Hat Creek c o a l .  Under column o p e r a t i n g ranked  phase,  are not known at  were c a l c u l a t e d from the l i n e s  and a c t i v a t e d carbon performed with a c t i v a t e d  to such q u e s t i o n s  regula-  cells.  that  c o n c e n t r a t i o n has a l s o been i n f l u e n c e d by the phase o f  organisms'  got  microorganisms  l i f e c y c l e (lag  it  which was  ionic  the m i c r o b i a l  and hence apart  at  could be  and thus  intake and c e l l u l a r metabolism of  phase, m u l t i p l y i n g  of a d s o r p t i o n  It  type of o r g a n i c s  were e x c r e t e d o u t s i d e  seemed  range  a f t e r which due to c e l l u l a r  are dependent on the phase of microorganisms' growth  unknown.  by c e r t a i n groups of microorganisms  into microbial  inclined  - Stock  Pile  Refuse  the three adsorbents  removal  efficiency  as:  can be  Influent  Throughput  F i g u r e 3-27  Breakthrough  cone.  volume - l i t e r s  Curve f o r  Lead  ON  Influent c o n e .  Q  H.CRACT. C A R B •a K . C S P R . pH = 4 . 0 •  E  Flow rote = 5gpm/It  I  Column Coo I  o u  depth - 5"  weight  :  K C S P R = 9.5g A C T . C A R B = 5g H.CR. = 7.75g  c  D  • •  3  I  Throughtput F i g u r e 3-28  1  2  Breakthrough  3  volume-  liters  Curve f o r Lead '  ON -E-  CA vn  F i g u r e 3-29  Comparison of Adsorption C a p a c i t y E f f l u e n t at D i f f e r e n t Flow Rates  f o r Lead in Primary  66  (c)  Zinc Column  of 0.5  mg/1  runs were c a r r i e d out with an i n f l u e n t at  1.0  shown in F i g u r e s calculated  and 5.0  gpm/ft  and 3-31  3-30  2  zinc  concentration  flow r a t e s , with breakthrough  respectively.  Adsorption  from these and are shown in F i g u r e 3-32.  Creek and a c t i v a t e d carbon performed much s u p e r i o r  curves  capacities  As expected Hat to K a i s e r  coal.  w i t h Copper, once again Hat Creek performed b e t t e r than a c t i v a t e d More column t e s t s  were performed with  were  influent zinc  As carbon.  concentration  2 of 2.0  mg/1  at  1.0  and 5.0  shown in F i g u r e 3-33  gpm/ft  performed much s u p e r i o r  conditions.  capacity  coal  calculated  o r d e r of  Carbon  - Stock  Pile  Refuse.  the t h r e e adsorbents  carbon  testing higher  removal  efficiency  as:  can be  are  from  and Hat Creek had much higher  c a p a c i t i e s were o b t a i n e d with  conditions  Hat Creek Coal  Kaiser  curves  concentrations.  in the d e c r e a s i n g  Activated  Capacities  than a c t i v a t e d carbon under these column  Under column o p e r a t i n g ranked  and breakthrough  Again Hat Creek and a c t i v a t e d  to K a i s e r  Greater adsorption  i n f l u e n t metal  rates  and 3.3** r e s p e c t i v e l y .  these are shown in F i g u r e 3-35.  adsorption  flow  Influent cone.  0.5 K.C.SPR.  _i 0.41  pH =4.0 Flow rate I g p m / ft Column depth 5" Coo I weight K.C. S P R * 9.5g ACT. CARB - 5g H.CR. « 7.75g ACT.CARB s  8  8  E I u c o o  0.3 0.2  c 3  5o.  H.CR.  UJ  I F i g u r e 3-30  2 Throughput  3 volume - liters  Breakthrough Curve f o r  Zinc  ON  Influent cone, pH = 4.0 Flow ro te = 5gpm/ft Column depth 5" C o o l weight* K . C . S P R = 9.5g ACT.CARB * 5g H.CR. = 7 . 7 5 g B  H.CR.  Throughput F i g u r e 3-31  volume - liters  Breakthrough Curve f o r  Zinc  0.3  Cool Flow rote - O - H.CR. , — • — ACT.CARB I g p m / f t * —Cr- K.C.SPR J --D-- H.CR. -, ACT.CARB 5 gpm/ft - • 6 — K.C.SPR J pH = 4.0  o o u  1  Influent c o n c . - 0 . 5 m g / L C o l u m n depth 5" C o a l , weight^  0.2|  :  o in •o o  K.C. SPR = 9.5g ACT. CARB = 5g H . C R . : 7. 75 g  CP  E  "  o  0.1  a.  o O  0.1  Figure  3-32  0.2  0.3  0.4 C/C  0.5  0.6  0.7  0.8  r  Comparison of A d s o r p t i o n Capacity f o r Z i n c Primary E f f l u e n t at D i f f e r e n t Flow Rates  in  ON  Throughput  volume - ii*ers —i o  F i g u r e 3-33  Breakthrough  Curve f o r  Zinc  0  0.15  0.3  0.45  0.6 Throughput  F i gure 3-34  0.75  0.9  volume - liters  Breakthrough Curve f o r  Zinc  1.05  1.2  0  0.1  F i g u r e 3.35  0.2  0.3  0.4  0.5 C/C  0.6  0.7  0.8  0.9  0  Comparison of A d s o r p t i o n Capacity E f f l u e n t at D i f f e r e n t Flow Rates  for.Zinc  in Primary  1.0  0.35  0.30  t  o o  »  r  i  0.25  •o  H.CR.OX  JO  I o  } 2 mg/L ACT. CARB --Q-- H. CR.OX 1 _ .. f 0.5 m g / L  0.20  n  cn E  - - • — ACT. CARB pH = 4 . 0  0.15  C o l u m n depth = 5" Flow rate -  o  a.  «  Igpm/ft  0.10  0.05  / 0  0.1  Figure 3 - 3 6  0.2  0.3  0.4  0.5 C / C'o ,  0.6  Comparison of Adsorption Capacity Influent Concentrations  0.7  0.8  for Different  0.9  Zinc  1.0  7k  Chapter k  CONCLUSIONS  Under batch t e s t  c o n d i t i o n s with c o n c e n t r a t i o n ranges  specified  in the t e x t ; 1.  Of f o u r c o a l s Kaiser coal  (Hat Creek O x i d i s e d , K a i s e r  - special  plant  had the a b i l i t y  f e e d , Cominco-Ash)  - stock p i l e  refuse,  t e s t e d , Hat Creek  to remove heavy metals  from f i l t e r e d  primary sewage treatment p l a n t e f f l u e n t b e t t e r than the other th r e e ; 2.  With  regard to removal of copper, Hat Creek c o a l was  able  to a t t a i n about 80% removal e f f i c i e n c y w h i l e the o t h e r s managed about 3.  60%;  With regard to l e a d , removal e f f i c i e n c i e s o b t a i n e d were very  low.  Hat Creek o x i d i s e d was about  the o t h e r s were about k.  With  17% e f f i c i e n t w h i l e  5%;  regard to removal o f z i n c , Hat Creek c o a l was able  a t t a i n 80% removal e f f i c i e n c y w h i l e the o t h e r s about 5.  attained  15%;  With regard to mercury Hat Creek c o a l had about 65% e f f i c i e n c y w h i l e the o t h e r s had about  15%;  to  76  6.  The a d s o r p t i o n  affinities  towards Hat Creek coal copper, z i n c , 7-  of the four metals  ranked  tested  in a descending o r d e r were  lead and mercury;  When Hat Creek c o a l ' s  performance was compared with  that  of a c t i v a t e d carbon the l a t t e r was found to possess capacity  to adsorb  copper,  was s u p e r i o r with 8.  All  four coals  regard  had  primary e f f l u e n t 9.  All  coals  Under.column in the t e x t , 10.  increasing  the former  zinc; capacities  test  conditions with  the f o l l o w i n g  Of the two c o a l s  solution.  adsorption  capacity  with  conclusions  influent concentrations  t e s t e d , Hat Creek coal had b e t t e r  organisms on coal  ability  from f i l t e r e d priamary e f f l u e n t  s u r f a c e and eventual  micro-  plugging; is compared to  of a c t i v a t e d c a r b o n , the l a t t e r was found to possess  regard 13.  lead w h i l e the former was s u p e r i o r  to a d s o r p t i o n  A five-fold adsorption  increase capacities  of copper and  in flow r a t e through of both c o a l s  Greater adsorption i n f l u e n t metal  capacities  concentrations;  that greater with  zinc; the column  and the  activated  carbon; 14.  better  sample;  When the performance o f Hat Creek coal  to adsorb  specified  were drawn;  Column t e s t s were i n f l u e n c e d by the growth of  capacity  from  pH.  than the K a i s e r c o a l  12.  of  adsorption  than from water  to remove heavy metal  11.  to removal  lower metal  indicated  increasing  lead and mercury w h i l e  greater  were o b t a i n e d at  higher  reduced  76  15-  Adsorption a f f i n i t i e s  towards Hat Creek c o a l  ranked  in  the descending order are copper, z i n c , and l e a d ; 16.  Of the four c o a l s  s t u d i e d Hat Creek coal  most e f f e c t i v e in heavy metal its  removal  proved to be the  from wastewater  a d s o r p t i o n c a p a c i t i e s were comparable to that of  a c t i v a t e d carbon t e s t e d .  and the  77  Chapter 5  RECOMMENDATIONS  1.  Hat Creek coal was proven to be much s u p e r i o r t e s t e d with  regard to heavy metal  removal  to o t h e r B.C.  from wastewater  hence any f u r t h e r d e t a i l e d study should be r e s t r i c t e d to  coals  and this  coa 1 .  2.  3.  Further studies  with Hat Creek coal  parallel  with d i f f e r e n t grades  parative  purposes.  Comparative s t u d i e s  should be c a r r i e d out  of a c t i v a t e d carbon f o r com-  between c h l o r i n a t e d and u n c h l o r i n a t e d  waters must be c a r r i e d out to e v a l u a t e the e f f e c t of on m i c r o b i a l  k.  Studies  in  waste-  chlorination  activity.  should be c a r r i e d out to i d e n t i f y the type of m i c r o -  organisms most predominant  in the column and  its  i n f l u e n c e on  column p r o p e r t i e s .  5.  If  p o s s i b l e microorganisms  should be made to a s s i s t  removal s i n c e some forms have the a b i l i t y  in heavy metal  to absorb heavy  metals.  78  6.  The a b i l i t y of Hat Creek c o a l  to remove d i s s o l v e d  organics  from t r e a t e d sewage e f f l u e n t should be i n v e s t i g a t e d , as the i n f l u e n c e of m i c r o b i a l growth on that  7.  If  microorganisms  removal  should  process.  cannot be made to work to advantage,  methods  of s t o p p i n g or c o n t r o l l i n g t h e i r growth on c o a l s u r f a c e be  8.  investigated.  Work should be d i r e c t e d to a r r i v e at optimum flow r a t e , column d e p t h , and p a r t i c l e s i z e to y i e l d high a d s o r p t i o n  9.  should  capacities.  Minimum e q u i l i b r i u m e f f l u e n t metal c o n c e n t r a t i o n s and maximum a d s o r p t i o n c a p a c i t i e s o b t a i n e d at optimum o p e r a t i n g  conditions  should be determined and compared with that f o r a c t i v a t e d carbon.  10.  I n f l u e n c e of pH on column performance should be s t u d i e d , into consideration activity  its  e f f e c t on microorganisms.  is s e n s i t i v e tc pH c o n d i t i o n .  taking  Microbial  A l s o a f f e c t of pH on com-  p l e x a t i o n and p r e c i p i t a t i o n of d i f f e r e n t metals should be c o n s i d e r e d .  11.  12.  An economic f e a s i b i l i t y study o f using Hat Creek coal  in advance  waste treatment should be c a r r i e d out t a k i n g  into consideration  possible  treatment.  If  coal  use as an energy source a f t e r waste  is  to be burned as a f u e l ,  be d e t e r m i n e d .  If  f a t e of metals adsorbed  metals escape with s t a c k gases,  of a i r  p o l l u t i o n c o n t r o l d e v i c e s may be n e c e s s a r y .  in ash  its  leaching.  disposal  should  installation If  metals  remain  method should minimise escape o f metal by  These f a c t s  any f e a s i b i l i t y  its  study.  should be taken  i n t o account when conducting  79  REFERENCES  1.  B u h l e r , D.R., Environmental Contamination by T o x i c M e t a l s . Heavy metals in the Environment. Water Resources Research Oregon S t a t e U n i v e r s i t y , SEMN WR016 73:1-36, January 1973.  Institute,  2.  Argo, D.G. and G.L. C u l p , Heavy Metals Removal in Wastewater Treatment Processes : Part 1 Water and Sewage Works 119(8):62-65» August 1972.  3.  Development of Coal Based Sewage Treatment P r o c e s s . Research and Development Report No. 55. O f f i c e of Coal Research, U.S. Department of I n t e r i o r , Washington, D.C. 1971.  4.  C o u l t h a r d , T . L . and Mrs. Samia F a d l , The A d s o r p t i o n of Water P o l l u t a n t s by a Coal S o r p t i o n P r o c e s s . Paper No. 73 506 presented at Can. Soc. Agr. Eng. Annual Meeting at V i c t o r i a , B.C. August 1973-  5.  Henren, M.K., Heavy Metals Removal by Using C o a l . Unpublished M.A.Sc. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B.C.  1974.  6.  R i a z , M. , Removal o f Heavy Metals Using Granular C o a l . Unpublished M.A.Sc. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B.C., 1974.  7.  T i n Tun, U., A d s o r p t i o n o f Heavy Metals at Low C o n c e n t r a t i o n Using Granular C o a l . Unpublished M.A.Sc. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B.C., 1974.  8.  Determination o f Mercury by Flameless Atomic A d s o r p t i o n J a r r e l l Ash - Atomic A b s o r p t i o n A n a l y t i c a l Method. No Hg-1, August 1970.  9.  F a i r , G.M., J . C . Geyer and D . A . O k u n , Water and Wastewater E n g i n e e r i n g , Volume 2, Chapter 28. John Wiley and Sons Inc. New York, 1968.  10.  Sawyer, C.N. and P.L. McCarty, Chemistry f o r S a n i t o r y Chapter 2. McGraw-Hill Book Company, New York 1967.  Engineers,  80  11.  Lehniger, A . L . , Biochemistry. New York, 1971.  12.  Cruickshank, Livingstone,  13.  A t k i n s o n , B., London, 197**.  Chapter 8.  R., Medical M i c r o b i o l o g y , London, 1972. Biochemical R e a c t o r s ,  \  Worth P u b l i s h e r s ,  Chapter  Inc.  18, C h u r c h i l l  Chapter 7, Pion L i m i t e d ,  

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