United States
Environmental Protection
Agency
Municipal Environmental Research ^
Laboratory -
Cincinnati OH 45268 "^
Research and Development
EPA-600/S2-84-013 Mar. 1984
&ER& Project Summary
Determination of Dioxin Levels
in Carbon Reactivation Process
Effluent Streams
J. E. Howes, Jr., F. L DeRoos, D. Aichele, D.F. Kohler, M.E. Larson, and B.W.
Lykins, Jr.
A preliminary study was made to
evaluate the potential formation and
persistence of tetrachlorodibenzo-p-
dioxins (TCDDs) and tetrachlorodibenzo
furans (TCDFs) in effluent streams of
the fluidized bed system used at the
Cincinnati, Ohio Waterworks for thermal
reactivation of granular activated
carbon (GAC). The study resulted from
concern about possible releases of
adsorbed organic compounds or their
reaction products into the environment
during reactivation of the GAC used for
treating municipal drinking water.
Four tests were performed to sample
the effluent streams of the reactivator
system and the spent carbon feedstock
during reactivation of a batch of GAC
used to treat Cincinnati municipal
drinking water. During one test, the
natural gas supply to the reactivation
system was sampled for polychlorinated
biphenyls (PCBs). The effluent stream
and spent carbon feed samples were
analyzed to determine (1) 2,3.7,8-
TCDD and 2,3,7,8-TCDF concentra-
tions, (2) total TCDD and TCDF con-
centrations, and (3) the TCDD and
TCDF isomeric composition (i.e., the
number and, when possible, the identity
of isomers in the samples).
This Project Summary was developed
by EPA's Municipal Environmental
Research 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
Activated carbon has been used for
many years to remove taste and odor
components from drinking water. Recent
studies have focused on activated carbon
treatment to remove potentially hazardous
trace organics from municipal drinking
water supplies. In this regard, the
Cincinnati Waterworks conducted a
study of water treatment with granular
activated carbon (GAC). After exhaustion,
this carbon was thermally reactivated in a
fluidized-bed furnace and reused in the
water treatment process. During carbon
reactivation, organic compounds could be
released into effluent streams that enter
the environment. Thus the total evaluation
of the net gains achieved by water
treatment with GAC included an examina-
tion of the potential for causing exposure
to the public from the reactivation
process effluents.
This program was undertaken to
determine whether tetrachlorodibenzo-
p-dioxins (TCDDs) and tetrachlorodibenzo
furans (TCDFs) were in any effluent
streams from the Cincinnati Waterworks
reactivator unit during a carbon reactiva-
tion cycle. The study also evaluated the
possible presence of TCDDs and TCDFs in
the spent carbon feedstock and PCBs in
the natural gas supply used to fire
the carbon reactivator system. The data
generated will be used to evaluate any
possible environmental and health
hazards associated -with effluents from
reactivation of carbon used in municipal
water treatment.
Procedures
Four tests were performed to measure
TCDD and TCDF levels in the effluent
streams and the spent carbon feedstock
of the Cincinnati Waterworks carbon
reactivation system (shown schematically
in Figure 1). The tests were conducted
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Spent Carbon
Storage Tank
Spent
Carbon
Feed
Reactivated
Carbon
Storage Tank
Exhaust
Stack
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(XAD-2) sample from one test. The total
TCDD concentrations found in the stack
emissions (particulate material and gase-
ous emissions) ranged from 0.06 to 0.3
nanograms per dry, standard cubic meter
(ng/dscm), and emission factors ranged
from 0.49 to 1.11 ng total TCDDs/kg of
spent carbon feed. TCDDs were detected
in the dryer off-gas cyclone catch
samples from all four tests and in the
scrubber liquid samples from two of the
four tests. The total TCDD concentrations
found in the cyclone catch ranged from
0.20 to 4.14 ng/g. TCDDs at concentra-
tions of 0.12 and 0.21 ng/L werefound in
the scrubber water from two tests.
Effluent streams in which TCDFs were
detected were the stack emission and the
dryer off-gas cyclone catch. TCDFs were
not detected in any scrubber water,
quench water, or spent carbon feed
samples from the four tests. TCDFs were
detected in stack particulate samples
from three tests and in the vapor phase
(XAD-2) samples from two tests. The total
TCDF concentrations found in the stack
emissions (particulate material and
gaseous emissions) ranged from 0.08 to
0.51 ng/dscm, and emission factors
ranged from 0.28 to 1.88 ng total
TCDFs/kg of spent carbon feed. TCDFs
were detected in the dryer off-gas cyclone
catch from all four tests at concentrations
ranging from 0.48 to 3.33 ng total
TCDFs/g.
The principal TCDD isomers found in
the samples were 1,3,6,8-TCDD, 1,3,7,
8-TCDD, 1,3,7,9-TCDD, and 2,3,7,8-
TCDD. Some samples contained other
unidentified TCDD isomers, but they
were present at very low levels relative to
the isomers listed above. When present,
2,3,7,8-TCDF was identified; but other
TCDF isomers could not be specifically
identified because of lack of suitable
reference standards.
PCBs at a concentration of 2.6 micro-
grams per standard cubic meter (/ug/scm)
were found in the natural gas supply used
to fire the reactivation unit during the
tests. The principal PCBs detected in the
natural gas were tri- and tetrachlorobi-
phenyls.
Reactivated carbon and spent carbon
samples obtained during the test program
and a sample of virgin carbon of the type
being reactivated were analyzed for total
organic halogens (TOX). The TOX levels
found in the samples were as follows:
Virgin carbon None detected
Spent carbon 657 mg/kg
Reactivated carbon 55 mg/kg
The full report was submitted in
fulfillment of Contract No. 68-02-3487 by
Battelle Columbus Laboratories under
the sponsorship of the U.S. Environmental
Protection Agency.
J. E. Howes, Jr.. F. L DeRoos, D. Aichele, D. F. Kohler, and M. E, Larson are with
Battelle-Columbus Laboratories, Columbus, OH 43201.
Ben W. Lykins, Jr. is the EPA Project Officer (see below).
The complete report, entitled "Determination ofDioxin Levels in Carbon Reactiva-
tion Process Effluent Streams," (Order No. PB 84-137 710; Cost: $14.50.
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
U.S. GOVERNMENT PRINTING OFFICE; 1984 — 759-015/7602
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