United States
Environmental Protection
Agency
Municipal Environmental Research -
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-83-104 Feb. 1984
&EPA Project Summary
Granular Activated Carbon
Adsorption and Fluid-Bed
Reactivation at Manchester, New
Hampshire
David Kittredge, Robert Beaurivage, and David Paris
This study was designed to evaluate
the actual cost and performance of a
fluidized-bed, granular activated car-
bon (GAC) reactivation system, a semi-
automatic GAC transport system, and a
GAC water treatment system at the
Manchester Water Works, Manchester,
New Hampshire.
GAC performance was monitored in
one of the utility's four 38,000-m3/day
(10-mgd) GAC filters to obtain an initial
performance comparison of virgin
carbon and reactivated 5-year-old
service carbon. This filter was divided at
its midpoint and then operated and
monitored until a steady-state condition
was achieved in both filter media
studied. Two additional reactivation
runs were conducted on this same
GAC, providing performance data over
three full reactivation-exhaustion cy-
cles. For a portion of the study, the GAC
filter medium was educted through a
semiautomatic transport system retro-
fitted to the existing filters. Operation
of this semiautomatic system proved to
be unreliable, however, and was subse-
quently abandoned and replaced by a
handheld eductor system. GAC from
the three remaining plant filters was
also reactivated to obtain additional
performance data and to restore the
adsorptive capacity of the spent service
carbon.
Treatment performances of the virgin
and reactivated GAC were evaluated
during each cycle by measuring total
organic carbon (TOC), trihalomethanes
(THM), and trihalomethane formation
potential (THMFP). GAC adsorptive
capacity was also measured using
traditional test parameters including
iodine number, molasses decolorizing
index, Brunauer-Emmett-Teller (BET),
and pore-size distribution analyses.
With the cooperation of three regional
water utilities, a short-term program of
regional reactivation was also investi-
gated. The actual costs and feasibility
of transporting and reactivating GAC
from these utilities were determined.
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
In keeping with the research goals of
the Safe Drinking Water Act (Public Law
93-523), the U.S. Environmental Protec-
tion Agency (EPA) and the Manchester
Water Works (MWW) entered into a
cooperative agreement to evaluate the
cost and performance of a fluidized-bed,
GAC reactivation system plus related
facilities at the Manchester Water
Treatment Plant. GAC effectiveness was
assessed before and after reactivation,
and GAC reactivation for other water
utilities in New England was calculated
on a limited basis. All of the work
associated with this project was done
under actual operating conditions using
full-scale water treatment equipment.
On completion of the water treatment
plant in 1974, MWW officials began
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investigating alternatives for reactivation
or replacement of approximately 432,592
kg (500 tons) of GAC used at the
151,000-mVday (40-mgd) water treat-
ment facility. Results of this investigation
demonstrated that onsite reactivation
was the most cost-effective method of
restoring the adsorptive properties of
spent GAC for the conditions studied.
Water treatment at Manchester consists
of flash mixing followed by flocculation,
sedimentation, and series filtration
through individual beds of sand and GAC
filter media Raw water is obtained from a
naturally occurring, highly protected
surface supply (Lake Mussabesic), which
contains no volatile organics but occasion-
ally has high color plus taste and odor as a
result of algae formation
Since the research project spanned a
period of nearly 5 years (July 1977 to
April 1982), the investigation was
divided into three major phases. Phase 1
involved the design, construction, and
startup of the fluid-bed reactivation
system (see Figure 1), semiautomatic
carbon transport system, and laboratory
monitoring facilities. One of the four GAC
filters in the treatment plant called "the
test filter" was half filled with virgin
carbon and half with reactivated service
carbon to compare GAC filter media.
After about 90 days, exhausted GAC (as
Spent GAC
determined by TOC and THMFP) was
removed from the filter, reactivated, and
then reintroduced to the filter for another
90-day period of service and performance
evaluation.
Phase 2 involved two more cycles of
reactivation and repeated evaluation of
the test filter. The three other GAC filters
in the treatment plant were reactivated a
total of five times to determine the
operational performance capabilities of
the reactivator and to develop reactivation
cost data. Losses from both reactivation
and transport of GAC were also studied.
After all the objectives of the first two
phases were achieved, the third phase
was undertaken to study the possibility of
using the Manchester treatment facility
as a regional reactivation center. The
major objective of this program was to
establish the economic feasibility of
providing a future GAC reactivation
service for other water utilities in the New
England region. Approximately 18,144kg
(40,000 Ib) of GAC from each of three
separate utilities was reactivated and
subsequently returned to service during
1982.
Significant Findings
The Manchester research project
demonstrated that onsite GAC reactiva-
tion at a medium-sized water treatment
Westvaco
Fluid Bed
Reactivator
Recycle Gas
Blower
Steam Generator
Eductor
Figure 1. Process flow for GAC reactivation system at Manchester, New Hampshire.
2
facility is feasible with regard to cost and
operation. A fluid-bed reactivation furnace
was shown to be a practical addition to a
water treatment operation, provided that
a properly trained, full-time work force is
available to operate and maintain the
equipment. During the 10 months from
June 1980 to March 1981, more than 1.8
million Ib of GAC was reactivated at a
total cost of less than 22
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Table 1. Manchester Water Works Reactivation Costs. June 1980 Through March 198V
Cost Item
Makeup carbon
Labor for reactivation
Labor for transportation
Labor for laboratory
Labor for administration
Parts and service calls
Fuel oil
Electrical power
Water
Laboratory supplies and outside
analyses
Depreciation
Overhead
Cost/kg
1C)
15.59
4.28
0.62
0.11
291
5.87
4.92
1.10
1.63
0.11
4.70
6.08
Cost/lb
1C)
707
1.94
0.28
0.05
1.32
2.67
2.23
0.50
0.74
0.05
2.13
2.76
TOTAL
47.92
21.74
*Based on reactivation of 842,401 kg (1,857,176 Ib) of GAC.
tion, poor reliability, excessive mainte-
nance, and unacceptable removal of filter
media. A manually operated hose and
eductor system was then substituted and
used successfully to transport GAC
between the filters and reactivation
building.
Because of the success of the research
program, the Manchester facility was
investigated for use as a regional
reactivation center. This final research
effort demonstrated that MWW could
economically provide a GAC reactivation
service for other water utilities in the New
England region. The combined average
reactivation cost was 49.5C/lb.
The full report was submitted in
fulfillment of Cooperative Agreement No.
CR805371 by the Manchester Water
Works under the sponsorship of the U.S.
Environmental Protection Agency.
David Kittredge, Rober Beaurivage. and David Paris are with the Manchester
Water Works, Manchester, NH 03103.
Ben W. Lykins. Jr., is the EPA Project Officer (see below).
The complete report, entitled "Granular Activated Carbon Adsorption and Flu id-
Bed Reactivation at Manchester, New Hampshire. "(Order No. PB 84-110238;
Cost: $25.00, 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
GOVERNMENT PRINTING OFFICE 1984-759-015/7299
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