United States
Environmental Protection
Agency	
Risk Reduction
Engineering Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-89/026  Mar. 1990
   roject  Summary
Removal  and  Fate of
RCRA and  CERCLA Toxic
Organic Pollutants in
Wastewater  Treatment
Sanjoy K. Bhattacharya, Rao V. R. Angara, Dolloff F. Bishop, Jr.,
Richard A. Dobbs, and Barry M. Austern
  Two separate studies  were  con-
ducted to investigate the removal and
fate of 28 selected Resource Conser-
vation and  Recovery Act (RCRA)
compounds  (0.25 mg/L of each
compound) and 19 selected Compre-
hensive  Environmental  Response,
Compensation, and  Liability Act
(CERCLA) compounds (0.5 mg/L  of
each compound) in conventional
activated sludge treatment In each
study, two pilot-scale (35 gpm) acti-
vated sludge systems (Solids Reten-
tion Time (SRT): 4 days for  RCRA
study and 8 days for CERCLA study)
were operated in parallel  at The U.S.
Environmental Protection Agency's
Test &  Evaluation  Facility  in
Cincinnati, Ohio.  One system was
spiked continuously with either RCRA
or CERCLA toxics to produce an
acclimated biomass; the  other was
spiked intermittently with the same
toxics and sampled  to  determine
performance  under  unacclimated
conditions. The selected RCRA  or
CERCLA  compounds did  not cause
any adverse effects on Chemical
Oxygen  Demand  (COO)  and
Suspended Solids (SS) removals. The
concentrations of organics  (RCRA
study) in the air emissions indicated
that the chlorinated aliphatic solvents
were essentially volatilized into the
plant air emission stream, whereas
the aromatic volatile benzenes were
substantially degraded.  Additional
work is planned to attempt to reduce
the analytical variability encountered
in these studies.
 This Project Summary was devel-
oped by EPA's Risk Reduction engi-
neering Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented In a
separate report of the same title (see
Project Report ordering information at
back).

Introduction
 A survey of  publicly owned treatment
works (POTW)  showed that concentration
of  priority pollutants in  the influent
wastewater to  many of these plants
exceeded the  allowable concentrations
for these chemicals. In a study of the fate
of  22 toxic  organics  in wastewater
treatment plants, researchers reported
that a typical  POTW significantly (up to
90%) reduced the concentrations of most
of these compounds. Certain compounds
were, however, present in the activated
sludge effluent  in  relatively  high  (20-30
ug/L) concentration. In an investigation of
the comparative  removal  of priority
pollutants by six biological and physical-
chemical  treatment processes, research-
ers reported that the activated sludge
process provided best results. A further
review of  the literature indicated that only
limited data  are  available  for  many
priority pollutants.
 In the  study summarized here, the
removal and fate of selected  RCRA and
CERCLA  toxic organic pollutants  were
evaluated with  two pilot-scale activated

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sludge systems fed  municipal  waste-
water. The 28 RCRA (semi-volatile and
volatile) and  19 CERCLA (semi-volatile
only)  chemicals (Table  1) were spiked
into the raw wastewater in two separate
test periods.

Experimental Systems and
Testing Approach
  The two  activated sludge systems
were operated at a flow rate  of 35 gpm
and a hydraulic  retention time (HRT) of
7.5 hr. An operational SRT of 4 days was
used  in the RCRA study period.  In the
CERCLA study period, the SRT was 8
days. Each compound  was  spiked at
0.25 mg/L for the RCRA study and at 0.5
mg/L for  the CERCLA study.  The
operating  conditions and  design  char-
acteristics for the two systems used in
the study are given on the  next page.
Both  RCRA and CERCLA studies were
performed with an  acclimated  (con-
tinuous  addition of  toxicants) and  an
unacclimated (intermittent  spiking of
toxicants) system.  These systems were
operated in parallel.
  To  sample from the air space  above
the primary clarifier, the units  were
covered and vented through a duct to the
Operating Conditions and Design Characteristics of the Pilot Systems
 Design flow = 2.2 Us
            = 191

 Primary clarifiers -Diameter            = 2.9 m
                 Weir diameter        = 2.8 m
                 Surface area         = 6.8 m2
                 Surface overflow rate  = 28.0 m3/m2.d

 Aeration basins - LW:D                 = 5.4 m:3.0 m:3.6 m
                Surface area          = 16.3 m2
                Volume               = 59.7 m3
                Hydraulic residence time = 7.5 hr.

 Secondary clarifiers -Diameter          = 3.6 m
                   Surface area       = 10.4 m2
                   Surface overflow rate = 18.4 m3/m2.d
 roof. An  air sweep equivalent to  a 5
 km/hr wind  was maintained  over the
 surface of the  primary  clarifier by ex-
 hausting  air  at 14,000 L/min.   The
 aeration basin was fitted with an air tight
 cover and the off-gas was also vented to
 the roof.  Air flow in the aeration basins
 averaged 5,600 L/min.
   Automated analytical procedures were
 used  for the   conventional   pollutants
Table 1.   RCRA and CERCLA Toxic Organic Pollutants

            RCRA study period
          CERCLA study period
 acetone
 cyclohexanone
 furfural
 2-butanone
 4-methyl-2-pentanone
 tetrahydrofuran
 carbon tetrachloride
 chlorobenzene
 chloroform
 1,2-dichloroethane
 1,2-dichloropropane
 methylene chloride
 tetrachloroethylene
 trichloroethylene
 1,1,1-trichloroethane
 1,1,2-trichloroethane
 ethylbenzene
 toluene
 total xylenes
 bis(2-ethylhexyl) phthalate
 butyl benzyl phthalate
 1,4 -dichlorobenzene
 2,4 -dimethylphenol
 2,4-dinitrophenol
 naphthalene
 nitrobenzene
 4-nitrophenol
 pheno
1,2-dichlorobenzene
1,3-dichlorobenzene
1,4-d/cWorobenzene
1,2,4-trichlorobenzene
nitrobenzene
1,3-dinitrobenzene
2,6-dinitrotoluene
p-cresol
4-chloroaniline
hexachloroethane
hexachlorobutadiene
dimethyl phthalate
diethyl phthalate
dibutyl phthalate
butyl benzyl phthalate
bis(2-ethylhexyl) phthalate
naphthalene
lindane
dieldrin
(COD,  BOD,  IMH4-N,  NO3-N and  TKN]
and  Gas Chromatography/Mass  Spec-
trometry (GC/MS) procedures were used
for the toxic organic compounds.  RCRA
samples  were analyzed  by a  contract
laboratory  (PEI  Associates   Inc.,
Cincinnati, OH). Air samples, collected in
stainless  steel canisters,  were analyzed
by GC/MS. From these data, masses ol
each RCRA compound stripped  during
the sampling event  were  calculated.
Sludge and liquid  samples  were  also
analyzed  by  GC/MS  according  to
approved USEPA methods. Semi-volatile
RCRA  compounds  were  extracted from
the samples with the use of continuous
liquid-liquid extraction. Prepared portions
of the  extracts  were injected  into  the
GC/MS for analysis.  The semi-volatile
CERCLA compounds were analyzed
following  Method 1625.  Analyses were
performed at the EPA's  Risk Reduction
Engineering Laboratory (RREL). Details
of the  analytical  procedures are  in  the
Project Report.
  Three tests (sample collection events)
were performed  during the RCRA study
period. For the  CERCLA  study, 11 tests
were done on  the  continuously  spiked
(acclimated) system and 4 tests on the
intermittently  spiked (unacclimated)
system.

Results
  The  presence of  the spiked  toxic
organics  in the wastewater produced no
major adverse effects on the treatment of
conventional pollutants. Average  re-
movals of conventional pollutants in the
pilot systems during  the two studies
were between 94%  and 97% for SS and
between  81% and 88% for COD. In the
RCRA  study period,  nitrification  in  the
activated  sludge processes  produced

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average NH4-N reductions between 76%
and 81% percent. In the CERCLA study,
the NH4-N removal was  between 88%
and 98%. The CERCLA toxics (0.5 mg/L)
did interfere with nitrification in the
acclimated system.
  Substantial variability occurred in the
reported results  with some toxic  com-
pounds, especially in  the  RCRA study
period. Table 2  lists  average measured
concentrations of  the  selected RCRA
organics in wastewater and sludges for
the acclimated system.  The difference
between the concentration of most toxics
in the  spiked   wastewater feed  and
primary effluent  was  very small.  The
primary sludge  showed  enhanced con-
centrations  of the two phthalates  and
naphthalene along with  reduced concen-
trations in  primary effluent; this indicated
adsorption onto  sludge  solids.  Four
compounds (tetrahydrofuran, 1,2 dichlo-
roethane, methylene chloride, and 1,1,2-
trichloroethane)  were  present in the
secondary effluent stream in  high con-
centrations  (between  95 and 140 ug/L);
this indicated these organics were poorly
removed. Five other compounds (cyclo-
hexanone, furfural, 2,4-dimethyl phenol,
2,4-dinitrophenol  and 4-nitrophenol) were
not evaluated because of  inconsistent
results. The average  removals of the
toxic compounds in the RCRA study are
summarized (Table 3). The  removal  of
RCRA  organics   with  primary  treatment
was  between 3% and  44%.  The total
removals were between 37%  and  99%.
The  calculated percent stripped for the
individual volatile  compounds varied from
1%  to  139%. No  air  analyses  were
performed for  the semivolatiles.. Biode-
gradation of  a  compound was estimated
by subtracting the measured removals by
adsorption and  stripping of the compound
from the total  removal.  The estimated
biodegradation  was  between -42% and
97%. A negative biodegradation indicated
inconsistent mass balance and the  prob-
lems of estimating  biodegradation  with
this approach.  Biodegradation appeared
to be the predominant removal  mecha-
nism for the  polar  solvents and the
aromatic  volatiles (e.g.,  toluene:  72%,
xylenes:  66%, chlorobenzenes:  60%).
The  unacclimated system (e.g.,  biodeg-
radation of toluene: 56%) showed similar
results, and  no significant advantage  of
acclimation was observed.
  Table 4 lists the  average concentra-
tions of  the CERCLA  organics.  Five
compounds showed  high concentrations
in the secondary effluents:  1,2,4-trichlo-
robenzene;  89 ug/L; 2,6-dinitrotoluene;
125 ug/L; p-cresol; 156 ug/L; lindane; 198
ug/L; and dieldrin; 99 ug/L. The average
removals of  the toxic compounds in the
CERCLA study are summarized in Table
5. The  removals of CERCLA organics  in
primary  treatment with  the acclimated
system was  between 4% and 79%. The
total  removal varied between  56% and
98%. Biodegradation was estimated by
subtracting  the removal by  adsorption
from the total  removal  of a  particular
compound. The extent of biodegradation
varied  between  28%  and  100%.  The
unacclimated  system  also exhibited
similar  removals. Biodegradation values
were  similar for  both acclimated and
unacclimated systems (e.g., naphthalene:
79% and dimethyl phthalate: 85%). As in
the RCRA study, no significant advantage
of acclimation  was  observed  for  the
CERCLA compounds.  In  the  CERCLA
study period, the amounts of organics
found in the complex primary  sludge
samples were substantially  lower than the
measured removals across the primary
process.  Because of  the analytical
variability  encountered  in these studies,
additional work has been planned.

Conclusions
  The following conclusions were drawn
from this study:
1.  The polar solvents and  aromatic vola-
   tiles were  biodegraded to  a great
   extent. For example,  toluene  ex-
   hibited 72% and total xylene showed
   66% biodegradation.
2.  A significant amount of chlorinated
   aliphatic  solvents may  be  volatilized
   from  an activated sludge system.
   The percent stripped varied between
   1% and 139%.
3.  Pesticides (lindane and  dieldrin) were
   removed both by  adsorption onto
   sludge and by biodegradation in  the
   secondary tank.
  The full  report was submitted in partial
fulfillment of Contract No. 68-03-4038 by
the University  of  Cincinnati under  the
sponsorship  of  the  U.S. Environmental
Protection Agency.
                                      U.S.  Environmental
                                       Great  Lakes Rational Program
                                                     GLNPO Library

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Table 5.   Average Percent Removals of CERCLA Organics for the Acclimated System (Average of Eleven Test Runs)

                                   Primary                Total*           Removed in Sludge+       Biodegradation
Compounds
Dichlorobenzene, Probably 1,2
Dichlorobenzene, Probably 1,3
Dichlorobenzene, Probably 1,4
1 ,2,4-Trichlorobenzene
Nitrobenzene
1 ,3-Dinitrobenzene
2,6-Dinitritoluene
p-Cresol
4-Chloroaniline
Hexachloroethane
Hexachlorobutadiene
Dimethyl phthalate
Diethyl phthalate
Dibutyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl)phthalate
Naphthalene
LJndane
Dieldrin
Removal
15.1
15.0
11.3
27.2
6.9
79.0
23.3

21.4
34.3
39.8
3.5
3.6
36.5
43.6

9.9
18.7
54.0
Standard
Deviation
11.7
9.9
11.6
15.0
12.8
9.8
18.5

35.2
16.2
13.6
6.2
7.8
10.7
11.3

9.6
8.0
15.2
Removal
93.4
88.9
95.3
85.1
92.8
96.7
68.2
73.9
87.6
97.1
96.2
98.1
97.6
96.1
96.9

97.9
55.9
81.4
Standard
Deviation
4.3
5.1
5.2
7.8
2.6
3.7
15.3
21.9
23.1
2.5
4.5
1.5
1.6
3.7
3.9

7.3
39.2
9.1
Removal
20
16
17
37
1

12
2
2
0
50
1
1
42
49

14
27
48
Standard
Deviation
9
10
9
12
1

15
1
1
tt
16
0
1
10
12

9
10
19
Removal
73
72
79
48
91

57
69
78
100
47
97
96
54
47

84
28
36
Standard
Deviation
10
11
10
14
3

38
21
28
•*
17
1
2
10
12

8
38
24
  Total   : Primary * Secondary
 'Sludge :  Primary * Waste Activated Sludge
 "       :  Only one data point available
Sanjoy K. Bhattacharya and Rao V. R. Angara are with the University of Cincinnati,
  Cincinnati, OH 45221; the EPA authors Dolloff F. Bishop, Jr., Richard A. Dobbs,
  and Barry M. Austern  are with  the Risk Reduction Engineering  Laboratory,
  Cincinnati, OH 45268
Sidney A. Hannah  is the EPA Project Monitor (see below).
The complete report, entitled "Removal and Fate  of RCRA and CERCLA Toxic
  Organic  Pollutants in  Wastewater Treatment," (Order No. PB  89-195 2001 AS;
  Cost: $21.95, subject to change) will be available only from:
        National TechnicaJ Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone: 703-487-4650
The EPA Project Monitor can be contacted at:
        Risk Reduction Engineering Laboratory
        U.S. Environmental Protection Agency
        Cincinnati,  OH 45268
                                         U.S.  Environmental Protection  Agency
                                         Great Lakes National Program Office
                                                       GLNPO Library

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Environmental Protection         Information                                                   POSTAGE & FEES PAIC
Agency                        Cincinnati OH 45268                                                    EPA
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EPA/600/S2-89/026

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