United States
             Environmental Protection
             Agency
Health Effects Research
Laboratory
Cincinnati OH 45268
EPA-600/1 -80-023
May 1980
             Research and Development
             Water Treatment
             Project

             Observations on
             Use of  GAC  in
             Practice
s*
  EP 600/1
  80-023
                  T
                  U.S. SNVISOMUaiAL
                  EDISOM.H.J. f»817

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                RESEARCH REPORTING SERIES

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 tion Service, Springfield, Virginia 22161

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                                        EPA-600/1-80-023
                                        May 1980
       WATER TREATMENT PROJECT:
OBSERVATIONS ON USE OF GAC IN PRACTICE
                  by

           Tom  D. Reynolds
                 and
           Scott J.  Hawkins
         Texas A&M University
    College  Station, Texas   77843
       Contract No.  C 2557-NAEX
           Project Officer

          Herbert R. Pahren
        Field Studies Division
  Health Effects Research Laboratory
        Cincinnati, Ohio  45268
 HEALTH EFFECTS RESEARCH LABORATORY
 OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
       CINCINNATI, OHIO 45268

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                               DISCLAIMER


     This report has been reviewed by the Health Effects Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication.  Approval does not signify that the contents necessarily
reflect the views and policies of the U..S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.

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                                  FOREWORD
     The U.S. Environmental  Protection Agency was created because of increas-
ing public and  governmental  concern about  the  dangers of pollution  to the
health  and  welfare to  the  American people.   Noxious air, foul water, and
spoiled  land are  tragic testimony  to  the deterioration  of our  national
environment.   The complexity of that environment and the interplay between its
components require a concentrated and integrated attack on the problem.

     Research and development  is that necessary first step in problem solution
and it involves  defining the problem, measuring  its  impact, and searching for
solutions.  The  primary mission  of the  Health Effects Research Laboratory  in
Cincinnati (HERL) is to provide a sound health effects data base in support of
the regulatory activities of the EPA.  To this end, HERL conducts a research
program to identify, characterize, and quantitate  harmful  effects  of pollu-
tants that may result from exposure to chemical, physical, or biological agents
found in  the  environment.   In  addition  to the valuable  health  information
generated by these activities, new research techniques and methods  are being
developed that contribute to a better understanding of human biochemical and
physiological functions,  and  how  these  functions  are altered by  low-level
insults.

     This report provides an evaluation of nine water treatment plants which
use granular activated carbon in  the treatment  process.   Relating  the water
quality to the patterns of operation may provide a better understanding of what
to expect when granular activated carbon  is used.
                                   R.J. Garner
                                   Director
                                   Health Effects Research Laboratory
                                     in

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                                ABSTRACT


     The objectives of this project were:  (1) to determine if granular
activated carbon (GAC) adsorption beds applied in water treatment practice
slough-off organic materials during the spring warm-up and (2) to evaluate
the feasibility of the dilute or low-level COD procedure for the control
of GAC beds in water treatment applications.

     Nine water treatment plants were studied for a period of five months
during the spring of 1979.  An evaluation of the COD and TOC removals
versus water temperature showed that no temperature related trend in
removal existed.  It was found that the COD values determined by the low-
level or dilute procedure did correlate well  with the TOC values.

     This report was submitted in fulfillment of Contract C 2557-NAEX by
Texas A&M University under the sponsorship of the U.S. Environmental
Protection Agency.  This report covers a period from February 23, 1979
through August 31, 1979, and work was completed as of December 31, 1979.
                                   iv

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                                CONTENTS
Foreword	iii
Abstract	   iv
Figures and Tables	   vi
Abbreviations and Symbols  	  vii
Acknowledgements 	 viii

     1.  Introduction  	    1
     2.  Conclusions 	    2
     3.  Experimental Procedures 	    3
     4.  Experimental Results  	    5

References	   11
Appendix	   12

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                                FIGURES





Number                                                            Page



   1   Before GAC Temp. <10°C	   8



   2   After GAC Temp. <10°C  	   8



   3   Before GAC Temp. >14°C   	   9



   4   After GAC Temp. >14°C	   9





                                 TABLE



Number                                                            Page



   1   Results of Water Treatment  Plant Sampling  	   6
                                   vi

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      LIST OF ABBREVIATIONS AND SYMBOLS






<\

B0    -  slope intercept

A.

BI    -  slope of regression line



H     -  null hypothesis



H     -  alternative hypothesis
 a


LOS   -  level of significance



MSE   -  mean square error

 2

S:    -  variance of the slope
 PI


S"    -  standard deviation of the slope
 PI

 2

Sp    -  pooled variance



Sp    -  pooled standard deviation



SS    -  sum of the squared errors of prediction
  /\/\


TS    -  test statistic

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                             ACKNOWLEDGMENTS
     This report is the product of the coordinated effort of many individ-
uals.  Among those who deserve special recognition are Dr. Harold W. Wolf,
Head of the Environmental Engineering Division, Civil Engineering Depart-
ment, Texas A&M University and the participating personnel at the various
water treatment plants.  Their assistance to the project is sincerely
appreciated.
                                   vm

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                                 SECTION 1

                               INTRODUCTION
     In a recently completed report1 it was observed that the activated
carbon adsorption process applied in drinking water practice may have
contributed to the organic content of about 18 percent of the samples
examined.  About 80 percent of the increases were observed in April when
the water temperature averaged 12.93°C.  The average temperature was
sufficiently above the average water temperature for all other samplings
(3.92°C) to suggest a possible biological mechanism.  The same report
included a study of the monitoring methods used by the water utilities in
the control of their GAC beds.  Not one of the utilities reported the use
of the low-level or dilute COD procedure.

     The objectives of this project were:
          (1)  To determine if granular activated carbon (GAC) adsorption
beds applied in water treatment practice slough-off organic materials
during the spring warm-up and
          (2)  To evaluate the feasibility of the low-level COD procedure
for the control of GAC in water treatment.

     The scope of the study consisted of obtaining several water samples
before and after GAC filters from each of nine different water treatment
plants during the spring of 1979 and determining the COD and TOC values
of the collected samples.

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                                 SECTION 2

                                CONCLUSIONS
     Based on the results of the study the following conclusions have been
determined:

          (1)  The dilute or low-level COD procedure can be used for the
monitoring of GAC filters used in water treatment.
          (2)  There was no appreciable sloughing of bacterial growths
from the filters during the spring warm-up period.

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                                 SECTION 3

                          EXPERIMENTAL PROCEDURES
     The study involved the collection of samples from water treatment
plants that used GAC filtration and the determination of both COD and
TOC values for each sample.
SAMPLING

     A total of 15 water treatment plants were contacted and, out of the
15 plants, 12 agreed to participate.  Out of the 12 plants that agreed
to participate, nine actually became involved in the study.  The remaining
three plants that had agreed had operational problems which prevented
repeated sampling.

     Sample kits were mailed to the participating plants and after the
samples were collected the kits were returned by "Priority Mail" service
furnished by the U.S. Postal Service.  Each sampling kit mailed to the
plants contained:  (1)  two 500 ml TOC/COD-free glass sampling bottles
which contained 40 mg of sodium sulfite solution for chlorine neutralization,
(2)  gel-type freezing packs, (3)  sampling and shipping instructions and
(4)  a data sheet to be completed prior to shipping.  The time a sample kit
was en route was less than four days.  To help maximize the duration of time
the samples would remain cold, water treatment plant personnel were
instructed to precool the samples to 4°C and pack with frozen gel  cooling
packs prior to shipment.  Most of the samples arrived chilled although
some had reached room temperature.  Actually, the arrival temperature was
not important since the samples were disinfected and the previous  study1
showed that these waters had very low plate counts.


COD PROCEDURE

     The COD procedure used was the low-level or dilute sample procedure
outlined in Standard Methods for-the Examination of Water and Wastewater,
14th edition (1976).Duplicate 50-ml samples were tested for their COD
values.  All glassware used was rendered COD free by placing it in a
muffle furnace at 550°C for one hour.
TOC PROCEDURE

     The TOC procedure used Oceanography International (O.I.) equipment

                                     3

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and methods.  The procedure consists of two parts, ampule preparation
and ampule testing which are described as follows:  A 5.0-ml  sample is
volumetrically pipetted into a precombusted ampule covered with aluminum
foil.  The ampule with sample is placed in a holder attached to the O.I.
ampule sealing unit.  The ampule sealing unit consists  of a purging unit
in which purified oxygen is bubbled through the sample and an oxygen-
propane microburner which seals the ampules.  Then 0.25 ml of 6% phosphoric
acid is added to the ampule with sample just before purging.   The sample is
purged with purified 02 for 4 minutes.  After 3 minutes  of purging,  1  ml  of
saturated persulfate solution is added to the ampule.  The ampule is sealed
by the oxygen-propane microburner.  A purified oxygen atmosphere is main-
tained inside the ampule during the sealing process.  After all the ampules
have been sealed, they are placed in a holding rack.  The rack fits into a
metal pressure vessel.  Approximately 1 liter of distilled water is added
to the pressure vessel.  The vessel is sealed by a metal top that bolts on.
The pressure vessel is placed in an oven at 170°C for 24 hours.  The pressure
vessel is allowed to cool to room temperature before the ampules are removed.
The ampules are stored at room temperature; until analyzed.  The samples are
analyzed on an O.I. ampule analyzing unit.  Standard TOC samples (10.0 ppm,
7.5 ppm, 5.0 ppm, and 2.5 ppm) are run prior to the GAC samples.  A linear
curve is established relating an integrated machine number with the
respective TOC standard.  Boiled distilled water is used as dilution water
for the TOC standards.  The dilution water is analyzed on the ampule
analyzing unit and the integrated machine number is subtracted from each
of the TOC standards before the linear curve is plotted.  A minimum of five
samples are analyzed to obtain an average value.  Once an average inte-
grated machine number is found for a GAC sample, the respective TOC value
is taken from the standard TOC curve.

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                                SECTION 4

                          EXPERIMENTAL RESULTS
     An average of four samples were obtained from each of the nine water
treatment plants that participated.
ORGANIC REMOVAL VERSUS TEMPERATURE

     Table 1 summarizes the COD and TOC removal  for each sample pair, one
sample being taken before and the other sample after granular activated
carbon (GAC) adsorption.  The average COD and TOC removal  for all the data
was 21 percent and 18 percent, respectively.  Plots of the percent COD and
TOC removal versus temperature did not show any pattern, thus, it is
believed that any sloughing of microbial  growths during the spring warm-up
was negligible.

     The chemical oxygen demand (COD) test measures the amount of oxygen
needed to oxidize most organic and some inorganic compounds to carbon
dioxide and water.  The total organic carbon measures the organic carbon
in a water.  Since COD is an oxygen-demanding parameter, the COD/TOC ratio
can represent the pounds of oxygen required to oxidize one pound of carbon.
Thus the COD/TOC ratio is an indication of the oxidation state of the
carbon.2  A calculation of the COD/TOC ratios by linear regression using
all the before and after GAC values suggests a higher oxidation state after
GAC since the COD/TOC ratios were 3.43 before and 2.76 after.  The rationale
is that less oxygen is required for oxidation of the residual carbon after
GAC treatment than before.  See the Appendix  for  the  specific  statistical
analysis.
     Looking at the <10°C before  and after GAC curves, Figures 1 and 2,
the slope before is steeper than  after.  This means that more oxygen
would be required per pound of carbon (TOC) before treatment with GAC
than after (3.82 ys_. 2.84).  At higher temperatures (>14°C), Figures 3
and 4, the difference in slope is less (2.87 vs. 2.31) but the direction
is the same (a lesser slope after GAC).  Hence, the GAC treatment does
satisfy some of the oxidation requirements.

     The oxidation state is higher (slope is less) at warmer temperatures
than at the cooler temperatures for the before GAC curves  (2.87 vs.  3.82).
This is as expected if biological processes in the water bodies are slowed
in cooler weather.  The same observation  is true in comparing the after
GAC curves at the two temperatures - a lesser slope at the warmer tempera-
tures.

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TABLE 1.  RESULTS OF WATER TREATMENT PLANT SAMPLING

Plant
No.
1





2



3



4





6



Water Temp.
at time
of Sampling
2.2°
6.7°
7.2°
10.0°
12.2°
14.4°
8.9°
10.0°
15.0°
17.8°
10.0°
15.6°
16.7°
19.4°
4.4°
4.4°
11.1°
14.4°
15.6°
22.2°
2.8°
3.9°
8.3°
20.0°
TOO
Before
GAC
mg/1
4.2
4.2
4.5
4.0
4.6
3.3
4.3
3.5
3.8
3.7
4.5
4.2
5.7
5.1
3.6
2.8
3.2
3.2
3.2
3.3
7.3
7.7
4.8
5.8
COD
Before
GAC
mg/1
8.2
10.8
10.6
7.4
10.7
9.8
11.7
8.5
6.4
7.5
8.9
7.7
14.4
12.0
4.5
6.5
4.6
6.5
6.6
14.7
21.2
24.9
17.0
18.6
TOC
After
GAC
mg/1
3.7
3.8
4.2
3.6
4.1
3.1
3.3
3.2
2.6
2.4
2.6
3.0
3.3
3.1
3.0
1.9
2.2
2.8
2.6
*
6.5
6.7
4.7
5.3
COD
After
GAC
mg/1
7.2
9.0
8.5
5.4
8.8
8.8
8.6
6.0
4.2
4.8
2.4
4.3
7.2
5.3
4.1
5.9
4.0
5.2
6.4
*
14.1
20.2
13.9
13.1

Percent
COD
Removed
12.2
16.7
19.8
27.0
17.8
10.2
26.5
29.4
34.4
36.0
73.0
44.2
50.0
55.8
8.9
9.2
13.0
20.0
3.0

33.5
18.9
18.2
29.6
                   (continued)

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   TABLE 1.  RESULTS OF WATER TREATMENT PLANT SAMPLING (continued)

Plant
No.
8



10




11


12



Water Temp.
at time
of Sampling
7.0°
17.0°
17.0°
23.3°
10.0°
13.9°
20.0°
20.0°
24.4°
4.6°
7.4°
24.0°
6.0°
11.0°
12.0°
14.0°
TOC
Before
GAC
mg/1
2.5
2.0
2.8
2.6
3.4
4.5
3.3
3.0
3.4
3.2
2.8
2.8
broken
3.7
3.5
3.6
COD
Before
GAC
mg/1
4.7
5.0
5.9
6.2
10.3
12.5
8.4
9.1
5.3
7.2
5.7
5.4
broken
7.7
8.0
7.5
TOC
After
GAC
mg/1
1.9
2.0
2.4
2.3
broken
3.3
2.6
2.2
*
2.9
2.5
2.3
broken
3.4
•3.3
3.3
COD
After
GAC
mg/1
3.1
5.0
5.4
5.1
broken
10.1
7.7
6.4
*
7.7
5.6
5.1
broken
7.2
7.2
5.9

Percent
COD
Removed
34.0
0.0
8.5
17.7
.
19.2
8.3
29.7

+ 6.9
1.8
5.6

6.5
10.0
21.3
* Inconclusive result

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 25
  IS


                                                                     t
                                                                         X
                                                                     x   •


                               •   r
                          /     •
                                            *J

                                            (mg/l)
FIGURE-  ):
                                                          TE-MR <<• >O°O
                             coo
                                             Toe -
Q

8
                                                      TE-MR
                            coo * 2.8H TOC -».«>&

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\
 I*
                                    TOC.
                          3.
                             =2.87 Toc.-l.fc2.
  JLO
   \5
 Q

 0
 U
   10
                                    TOC.



             F-IC^URE- 4: AF-Tfe-R
                       5



                     TE-MR
= 2.31
                                        - 0.3

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     The amount of organic removal for all samples averaged 18 percent
for TOC and 21 percent for COD.  Thus, it is clear that a small  amount
of organic removal is accomplished by these GAC beds operating in a
non-adsorptive mode since some of the beds were exhausted.
COMPARISON OF COD WITH TOC VALUES

     The percent removal of COD and TOC yielded a correlation of 0.615.
In the water treatment plants studied, the percent removals of COD and
TOC did not show any trend as the water temperature increased.

     It is recommended that the dilute or low-level COD procedure be
used at each water treatment plant that employs GAC beds and which does
not have TOC capability.  Since TOC is recommended by EPA for the control
of GAC adsorption beds, it is apparent that in the absence of costly TOC
equipment, the dilute or low-level COD procedure can be used.
                                   10

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                               REFERENCES
1.   Wolf, H.W.,  Camp,  B.J.,  Hawkins,  S.J.,  and Jorgensen, J.H., Pyrogenic
    Activity of  Carbon-Filtered  Waters,  EPA-600/1-79-009, U.S.  Environ-
    mental Protection  Agency, Cincinnati,  Ohio,  February  1979.

2.   McCarthy, J.J.,  "The Influence  of Particle Size on Oxidation of Total.
    Soluble and  Particulate  Municipal  Wastewaters", Ph.D. dissertation,
    Southern Methodist University,  Dec.  5,  1974.
                                   11

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                                 APPENDIX
                     STATISTICAL  ANALYSES  CALCULATIONS
                              All  Data Before
                                  n = 39

  iy       ly2       sxy       ix       ix2     (x-x)2      3i        So
368.60   4304.88   1618.29   151.60   643.44   54.14359   3.4256   -3.8647
                              4304.88-(-3.8647)(368.60)-3.4256(1618.29)
                           ~                     39-2
MSE  =  5.021
SS    .  0,2 .         .  643.44  -
  xx              n
SSXX  =  54.144
S:   =  MSE/SS    =  5.021/54.144  =  0.0927
 31           XX
           S?   =  v/0.0927  =  0.
            Pl     V
3040
Confidence Interval on ^ using 95/i C.I., a = .05

Si  ±  (ta/2« dfn-2} ^
3.4256  ±  (1.960)(0.3040)
3.4256  ±  0.5958


                                     12

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                              All Data After
                                  n = 36
  zy        zy2       zxy       zx       zx2    (x-x)2     3i        30
258.90    2298.43    957.73   116.10   418.87  44.4475   2.7623   -1.7168
            A    /S
        Zy2-30zy-g1(zxy)  _  2298.43-(-l.7168)(258.90)-(2.7623)(957.73)
               n-2        "                     36-2
MSE  =  2.864
                                             2
SS Y  =  zx2 -  (zx)2  =  418.87  -  (116.10)
  XX              n                     36
SSxx  =  44.447
  l  =  MSE/SS    =  2.864/44.447  =  0.0644
              XX
     =  0.2540
  I
Confidence Interval  on 3i using 95% C.I.,  a = .05

**  +~  (ta/2' dfn-2) (*lj
2.7623  ±  (1.960)(0.2540)
2.7623  ±  0.4978
                                    13

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                            Data Before @ <10°C
                                   n = 12
                                                             ^          ^
  zy        zy2       zxy        EX      zx2    (x-x~)2       BI         BO
133.00    1960.50    691.05    51.90   254.77   30.3025    3.8223    -5.4481
            /\    /\
        Zy2-B0zy-Bi(i:xy)   _  1960.50-(-5.4481) (133.00)-(3.8223) (691.05)
     ~         n-2         "                     12-2
MSE  =  4.370
                        =  254.77  -
      -  30.303
S;   •=  MSE/SS    =  4.370/30.303  =  0.1442
 PI           xx
S:    =  0.3798
 PI
Confidence Interval on 3x using 95% C.I., a = .05
3.8223  ±  (2.228)(0.3798)
3.8223  ±  0.8462
                                     14

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                            Data After @ <10°C

                                   n = 12





  zy        zy2       zxy        zx      zx2    (x-x)2       3i          BO

107.90    1230.99    482.97    45.10   196.77   27.2692    2.8401     -1.6822
     =  Zy -My-M^xy)  _  1230.99-(-1.6822)(107.90)-(2.8401)(482.97)

               n-2                              12-2


MSE  =  4.082
                       .  196.77

SSxx  =  27.269
     =  MSE/SS v  =  4.082/27.269  =  0.1497
              XX
 :   =  0.3869
 PI
Confidence Interval  on Pj using 95% C.I.,  a =  .05



5i  ±  (ta/2' dfn-2)  (S3,)
2.8401   ±  (2.228)(0.3869)


2.8401   ±  0.8620
                                    15

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                            Data Before G> >14°C

                                   n = 17



  zy        zy2       zxy        zx      zx2     (x-x)2        3i         BO

149.50    1560.63    589.14    61.20   238.06    17.7400     2.8715   -1.5432




        Zy2-B0zy-Bi(zxy)      1560.63-(-1.5432)(149.50)-(2.8715)(589.14)

               n-2                                17-2


MSE  =  6.642
SS    =  7x2 -  *  '   =  238 06
*J*J,,..     ij A       ._       L-\J\J • \J\J
  xx     "A       n       "-	        17
SSY¥  =  17.740
  AA
 ^   =  MSE/SSvv  =  6.642/17.740  =  0.3744
 PI           xx
 :   =  0.6119
 PI
Confidence Interval on Bx using 95% C.I.,  a  =  .05
2.8715  ±  (2.131)(0.6119)


2.8715  ±  1.3040
                                     16

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                           Data After @ >14°C
                                  n = 15

 zy       zy2       zxy        zx       zx2     (x-x)2      $l         30
94.00    662.58    283.96    42.00    126.26    8.6600    2.3972    -0.4456

             	  _  662.58-(-.4456)(44.00)-(2.3972)(283.96)
              n-2                            15-2
MSE  =  1.827


SSxx  •  "2   -  ^  •  126'26  -  AafT12
SS    =  8.660
S:   =  MSE/SS    =  1.827/8.660  =  0.2110
 PI          xx
S;   =  0.4593
Confidence  Interval on Bx using 95% C.I., a =  .05
^  +-  (Vz-  dfn-2)  (*;j
2.3972  ±  (2.160)(0.4593)
2.3972  ±  0.9921
                                   17

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                    Equality of the Slopes
          Between All Data Before and All Data After
Ho:  3i - 32 =  °          Using 3i =  before and 32 = after

Ha:  3i - 32 ^  0
TS:
           Pi - 32
     t  -
           SP{[Z (X1V-X!)2]   + [E (X2v-X2)2]  >   df = ni+n2-4

        2   (n1-2)S12 + (n2-2)S22
Where  Sp = —
sP =   v SP
c2  -  (39-2)(0.0927) + (36-2)(0.0644)
bp             (39-2) + (36-2)

Sp  =  0.0791

Sp  =  0.2813



                3.4256 - 2.7623
t  =
      0.2813[(54.1436)"1 + (44.4475)"1]1/2


t  =  11.650       df = 39 + 36 - 4 = 71


Concl.  - the slopes are different @ LOS of p<.005
                               18

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                     Equality of the Slopes
              Between Before <10°C and After <10°C
HQ:  3i - 62 = 0 Using &1 = before <10°C and B2 = after <10°C
     A    /^
Ha:  B! - 62 ^ 0
 2     (12-2)(0.1442) + (12-2)(0.1497)
*(>  ~          (12-2) + (12-2)


Sp  =  0.1470

Sp  0.3833
t  =            3.8223 - 2.8401
      0.3833[(30.3025)~1 + (27.2692)"1]1/2
t  = 9.710        df = 12 + 12 - 4 = 20
Concl. - the slopes are different @ LOS of p<0.005
                              19

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                    Equality of the Slopes
             Between Before >14°C and After >14°C
Ho:  3i - 62 =  0    Using &l = before >14°C and e2 = after >14°C
     s*    ^
Ha:  &  - 3  ^  0
 2     (17-2)(0.3744) + (15-2)(0.2110)
bp             (17-2) + (15-2)
Sp  =  0.2985
Sp  =  0.5464
t  =              2.8715 - 2.3972
      (0.5464}[(17.7400)"1 + (8.6600)"1]1/2
t  =  2.094        df = 17 + 15 - 4 = 28
Concl. - the slopes are different @ LOS of p<0.023
                               20

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                    Equality of the Slopes

            Between Before @ <10°C and Before >14°C
Ho:  $! -  32 =  0     Using &l = <10°C and B2 >14°C


Ha:  Bi -  B2 /  0
       (12-2)(0.1442) + (17-2)(0.3744)
               (12-2) + (17-2)
Sp  =  0.2823
SP  =  0.5313
.   _  3.8223 - 2.8715
                       1              1
      0.5313[(30.3025)"'  + (17.7400)"' ]
t  =  5.990        df = 12 + 17 - 4 = 25
Concl.  - the slopes are different @ LOS of p<.005
                              21

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                    Equality of the Slopes

              Between After <10°C and After > 14°C
        - B2  =  °     Usin9 ei = <10°c and


        - 82  t  0
c2  _  (12-2)(0.1497) + (15-2)(0.2110)

bp  ~          (12-2) + (15-2)
Sp  =  0.1843
Sp  =  0.4294
      2.8401 - 2.3972
u
      (0.4294)[(27.2692)"1 + (8.66)~V/2




t  =  2.644        df = 12 + 15 - 4 = 23






Concl. - the slopes are different 3 LOS of P<0.0077
                               22

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                                    TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.
 EPA-600/1-80-023
                                                             3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
   Water Treatment Project:
   Observations on Use of  GAC in Practice
              5. REPORT DATE
               May 1980 issuing  date
              6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
   Tom  D.  Reynolds and Scott  J.  Hawkins
                                                            8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
   Texas  A&M University
   College  Station, Texas   77843
                                                             10. PROGRAM ELEMENT NO.
                    C60C1C
              11. CONTRACT/GRANT NO.
                                                                   C  2557-NAEX
12. SPONSORING AGENCY NAME AND ADDRESS
   Health  Effects Research Laboratory
   Office  of  Research and Development
   U.S. Environmental Protection Agency
   Cincinnati,  Ohio 45268
              13. TYPE OF REPORT AND PERIOD COVERED
              Final  02/23/79-08/31/79
              14. SPONSORING AGENCY CODE
                    EPA/600/10
15. SUPPLEMENTARY NOTES
16. ABSTRACT
         The objectives of  this  project were:   (1)  to determine  if granular activated
   carbon  (GAC) adsorption  beds applied  in water treatment practice slough-off
   organic materials during the spring warm-up  and (2) to evaluate the feasibility
   of  the  dilute or low-level COD procedure  for the control of  GAC beds in water
   treatment applications.

         Nine water treatment plants were studied for a period of  five months during
   the  spring of 1979.  An  evaluation of the  COD and TOC removals versus water
   temperature showed that  no temperature related  trend in removal existed.  It was
   found that the COD values determined  by the  low-level or dilute procedure did
   correlate well with the  TOC  values.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS  C.  COSATI Field/Group
   Activated  carbon, water treatment,
   organic  compounds, oxygen  demand
  Chemical oxygen  demand,
  total organic carbon
68D
18. DISTRIBUTION STATEMENT
          Release  to public
                                               19. SECURITY CLASS (ThisReport)

                                                 Unr.lassif ipH
                            21. NO. OF PAGES

                                 31
                                               20. SECURITY CLASS (Thispage)

                                                 Unclassified
                                                                          22. PRICE
EPA Form 2220-1 (Rev. 4-77)    PREVIOUS EDITION is OBSOLETT
                                            23
                                                                  i, U S GOVERNMENT PRINTING OFFICE 1980-657-146/5677

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