EIS-79-
1363D
c.2
<>EPA
United States
Environmental Protection
Agency
Region V
230 South Dearborn
Chicago, Illinois 60604
Water Division
Environmental
Impact Statement
Supplemental EIS
Metropolitan Sanitary
District of__ ^
GreatefjChicago^
O'Hare Water
Reclamation Plant
SEPTEMBER 1979
Draft
M
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DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT
FOR THE
METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
DES PLAINES - O'HARE WATER RECLAMATION PLANT
Prepared by the
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION V
CHICAGO, ILLINOIS
Valdas
Acting Regional/Administrate
U.S. Environmental Protection Agency
September, 1979
le..
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ERAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT
METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
O'HARE WATER RECLAMATION PLANT
DES PLAINES, ILLINOIS
Prepared by
U.S. ENVIRONMENTAL PROTECTION AGENCY, REGION V
Comments concerning this document are invited and should be received by
November 12, 1979.
For further information, contact
Mr. Gene Wojcik, Chief, EIS Section
USEPA Region V
230 South Dearborn Street
Chicago, Illinois 60604
Abstract
On January 13, 1975, a Notice of Intent to file an Environmental Ijnpact
Statement (EIS) was issued on the Metropolitan Sanitary District of
Greater Chicago's (MSDGC) Des Plaines-O'Hare facilities plan. Two EIS's
were prepared on this facilities plan, one on the proposed O'Hare Water
Reclamation Plant (WRP) and Solids Pipeline, to be constructed in the
City of Des Plaines, Cook County, Illinois, and the other on the proposed
wastewater conveyance system for the Des Plaines-O'Hare service area.
The final EIS's were published in May of 1975.
A primary issue addressed in the WRP EIS was the potential health effects
resulting from respiration of aerosols generated from the WRP's aeration
tanks.
The WRP EIS concluded that funding the project was acceptable to USEPA,
provided the recommended measures were implemented. Since knowledge on
the potential health hazard from aerosol generation at treatment plants
was sparse and inconclusive at that time, the EIS recommended inclusion
of a condition in the grant agreement which required aerosol suppression
at the WRP. To ascertain the effectiveness of potential aerosol suppression
facilities, the EIS recommended that MSDGC demonstrate the level of
aerosol reduction achieved by the suppression facilities.
USEPA1 s original decision to require aerosol suppression facilities at the
O'Hare WRP was based on the lack of scientific evidence regarding the
relationship of wastewater aerosols and human health as well as our
responsibility under NEPA to avoid health risks. Since that time, however,
considerable research ahs been conducted to evaluate the potential dis-
cernible effect on human health from exposure to wastewater aerosols.
The USEPA prepared this document to examine the quality of the recent
research, and to decide whether the grant condition should be retained,
rescinded, or modified.
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TABLE OF CONTENTS
Page
SUMMARY iii
A. Background iii
3. Events Since May, 1975 iv
I. PURPOSE AND NEED FOR FURTHER ACTION 1
II. ALTERNATIVES CONSIDERED AND THEIR COMPARATIVE FJt^RCNMENTAL IMPACTS 1
A. Alternatives Considered 1
B. Comparison of Environmental Impacts 2
III. AFFECTED ENVIRONMENT 2
IV. ENVIRONMENTAL CONSEQUENCES 3
A. Basis of Evaluation 3
B. Evaluation of Alternatives 33
V. PUBLIC PARTICIPATION 37
VI. PREPARER 37
VII. LIST OF AGENCIES, ORGANIZATIONS, AND PERSONS TO WHOM COPIES OF THIS 37
STATEMENT WERE SENT
VIII. SELECTED REFERENCES 39
IX. GLOSSARY OF TERMS 40
X. FIGURES 1 THROUGH 11 44-54
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I. SUMMARY
A. BACKGROUND
On January 13, 1975, a Notice of Intent to file an Environmental Impact
Statement (EIS) was issued on the Metropolitan Sanitary District of
Greater Chicago's (MSDGC) Des Plaines-O'Hare facilites plan. Two EIS's
were prepared on this facilities plan, one on the proposed O'Hare
Water Reclamation Plant (WRP) and Solids Pipeline, to be constructed
in the City of Des Plaines, Cook County, Illinois, and the other on
the proposed wastewater conveyance system for the Des Plaines-O'Hare
service area. The Final EIS's were published in May of 1975.
The O'Hare WRP is an activated sludge plant with a design capacity of
72 million gallons of sewage daily (MGD), and is to serve 277,000
residents located in a 52.8 square mile area of northwestern Cook
County.
A primary issue addressed in the WRP EIS was the potential health effects
resulting from respiration of aerosols generated from the WRP's aeration
tanks.
The MRP EIS concluded that funding the project was acceptable to USEPA,
provided the recommended measures were implemented. Since knowledge of
the potential health hazard from aerosol generation at treatment plants
was sparse and inconclusive at that time, the EIS recommended inclusion
of a condition in the grant agreement which required appropriate aerosol
suppression at the WRP. To ascertain the effectiveness of potential
aerosol suppression facilities, the EIS recommended that MSDGC demonstrate
the level of aerosol reduction achieved by the suppression facilities.
After the Final EIS was published, the City of Des Plaines filed a suit
against the MSDGC and USEPA, alleging that the two Final EIS's issued by
EPA failed to comply with the requirements of the National Environmental
Policy Act (NEPA). The U.S. District Court entered judgment against the
City. The City appealed this judgment, but the U.S. Court of Appeals
upheld the District Court's judgment and ruled, in City of Des Plaines
v. Metropolitan Sanitary District of Greater Chicago, 552 F.2d 736
(7th Cir. 1977), that:
1) "Our review of the adequacy of an EIS and of the merits of a decision
reflected therein, while careful, has real limits. On the merits,
the review should be limited to determining whether the agency's
decision is arbitrary or capricious." (552 F.2d 737.)
2) "We believe the EIS unquestionably contains a fair statement of the
problem and the solutions intended, insofar as was possible, and we
do not believe more was required in this case." (552 F.2d 739.)
"As to the procedure followed, we believe it is clear from the
material of record that EPA took the requisite hard look at this
problem and reacted sensitively to it." (552 F.2d 738.) Because
no definitive answer could be made, "... EPA took a conservative
approach and required MSD to design, construct, and install devices
to suppress aerosol emissions." (552 F.2d 739.)
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3) "The uncertainty regarding the very existence and scope of the
potential health hazard is ignored by the City in its argument
that the failure to specify standards and specific devices renders
the pertinent EIS inadequate and in its insistence that the entire
project be held in abeyance until definitive answers and solutions
can be obtained." (552 F.2d 739.)
B. EVENTS SINCE MAY 1975
Since the court ruling, MSDGC has undertaken studies sponsored by the
USEPA to evaluate the performance and costs of alternatives for
suppression of aerosols.
In addition, other research listed below has been sponsored by the USEPA
to evaluate aerosol emissions and the potential health effects from
exposure to wastewater aerosols emanating from activated sludge treat-
ment processes.
1) Report entitled "Health Effects of Aerosols Emitted from an Acti-
vated Sludge Plant" available as EPA-600/1-79-019.
2) Report entitled "Health Implications of Sewage Treatment Facilities"
available as EPA-600/1-78-032.
3) Report entitled "Health Effects of a Wastewater Treatment System"
available as EPA-600/1-78-062.
4) Report entitled "Assessment of Disease Rates among Sewer Workers
in Copenhagen, Denmark" available as EPA-600/1-78-007.
5) Draft report entitled "Environmental Monitoring of a Wastewater
Treatment Plant" in prepublication review by USEPA.
6) Final Report entitled "The Evaluation of Microbiological Aerosols
Associated With the Application of Wastewater to Land: Pleasonton,
CA." available from the Department of the Army.
7) Draft Report entitled "Health Risk of Human Exposure to Wastewater"
in prepublication review by USEPA.
Also, other research on the potential health effects from aerosol
exposure has been conducted.
Since May 1975, the construction of the interceptors leading to the
O'Hare WRP, and construction of the plant itself, have been virtu-
ally completed. The plant will be available for operation as of
October 1, 1979.
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II. PURPOSE AND NEED FOR FURTHER EPA ACTION
USEPA's original decision to require aerosol suppression facilities at the
O'Hare WRP was based on the lack of scientific evidence regarding the
relationship of wastewater aerosols and human health, as well as our
responsibility under NEPA to avoid health risks. Since that time,
however, considerable research has been conducted to evaluate the
potential discernible effect on human health from exposure to wastewater
aerosols. The USEPA prepared this document to examine the results
of the recent research, and to decide whether the grant condition
should be retained, rescinded, or modified.
III. ALTERNATIVES CONSIDERED AND THEIR COMPARATIVE ENVIRONMENTAL IMPACTS
A. Alternatives Considered
1. Action.
a) Remove the grant condition requiring MSDGC to construct
aerosol suppression facilities at the O'Hare WRP.
b) Modify the grant condition and allow operation of the
O'Hare WRP without aerosol suppression facilities, and
continue ongoing analysis to demonstrate whether or not
the potential transmission of wastewater aerosols is a
significant health concern.
2. No Action. Retain the grant condition requiring MSDGC
to construct appropriate aerosol suppression facilities at
the O'Hare WRP prior to operation of the plant.
B. Comparison of the Environmental Impacts
There is no indication that direct or indirect health effects will
result from operation of the O'Hare WRP without aerosol suppression
facilities.
If aerosol suppression facilities are constructed, there will be a
significant expenditure of monetary, natural, and depletable resources
in their construction and operation. Other adverse impacts include
noise and dust associated with construction.
Based on our analysis of the studies, it is our conclusion that the
grant condition can be rescinded with no significant impacts.
IV. AFFECTED ENVIRONMENT
The environment potentially affected by this action is that nearby the
O'Hare WRP, including the areas's residents. For a thorough description
of the areas land use, population, and environment, see Section III of
this document.
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V. ENVIRONMENTAL CONSEQUENCES
A. Basis of Evaluation
The research projects referenced in this document are used in the
evaluation of the environmental consequences of alternatives.
B. Evaluation of Alternatives
1. Action
a) Rescind the grant condition requiring MSDGC to construct aerosol
suppression facilities at the O'Hare WRP:
No significant direct or indirect effects result from this action,
since testing of a thorough, critical, and sensitive nature,
representing the feasible limit of scientific and economic
capability, have shown that no significant adverse health
effects result from exposure to aerosols.
b) Modify the grant condition and allow operation of the O'Hare WRP
without aerosol suppression facilities, and continue ongoing ana-
lysis of potential health effects:
i) If further study shows need for aerosol suppression:
Monetary, natural and depletable resources would be ex-
pended on further study and in the construction and operation
of aerosol suppression facilities. Other adverse impacts
include noise and dust associated with construction.
ii) Further study shows no need for aerosol suppression:
Beyond the expenditure of monetary resources to further
study the potential effects of aerosol exposure, no direct
or indirect impacts will result from this action. Thorough
research has shown that no significant adverse effects
result from exposure to aerosols emanating from activated
sludge wastewater treatment processes within the envelope
of accepted U.S. design and operational practice.
2. No Action
Retain the grant condition requiring MSDGC to complete construction
of aerosol suppression facilities prior to or concurrently with
commencement of operation:
Monetary, natural, and depletable resources would be expended
on the construction and operation of aerosol suppression
facilities. Other adverse impacts include noise and dust
associated with construction.
If operation of the O'Hare WRP would be delayed to construct
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aerosol suppression facilities, the overloaded system presently
used would cause continued combined sewer overflows and
flooding of basements with combined sanitary and stormwater,
thereby threatening public health.
VI. RJBLIC PARTICIPATION
A Notice of Intent to prepare a Supplemental WRP EIS was issued on July 18,
1979. The distribution of this Draft Supplemental EIS will be followed by
a 45-day comment period. A public hearing will be held as indicated on
the Notice enclosed with this Draft Supplement. Comments on this
Draft Supplemental EIS should be submitted to: Mr. Gene Wojcik,
Chief, EIS Section (5WEE), U.S. Environmental Protection Agency,
230 South Dearborn Street, Chicago, Illinois 60604. A Final Supplemental
EIS will then be published. After a mandatory 30-day waiting period, the
USEPA will issue its final decision.
VII. PREPARER
Richard Beardslee, Environmental Engineer, U.S. EPA, Region V.
VIII. LIST OF AGENCIES, ORGANIZATIONS, AND PERSONS TO WBOM COPIES OF THIS
STATEMENT WERE SENT
The following Federal, State, and local agencies have been requested to
comment on the Draft Supplemental Environmental Impact Statement:
Council on Environmental Quality
Department of Agriculture
Soil Conservation Service
U.S. Army Corps of Engineers
Chicago District
North Central Division
Department of Energy
Argonne National Laboratory
Department of Health, Education and Welfare
Department of Housing and Urban Development
Department of the Interior
Fish and Wildlife Service
Geological Survey
Heritage Conservation and Recreation Service
Department of Transportation
Federal Aviation Administration
Governor of Illinois
Illinois Sanitary District Observer
Illinois Environmental Protection Agency
Illinois Institute for Environmental Quality
Illinois Division of Waterways
Illinois Department of Conservation
Illinois Department of Public Health
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Northeastern Illinois Planning Commission
Cook County Department of Environmental Control
Metropolitan Sanitary District of Greater Chicago
City of Des Plaines
Village of Elk Grove
Village of Arlington Heights
Village of Mount Prospect
Village of Palatine
Village of Wheeling
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DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT
FOR THE
METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
DES PLAINES-O'HARE WATER RECLAMATION PLANT
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I. HJRPOSE AND NEED FOR FURTHER EPA ACTION
USEPA's original decision in May, 1975 to require aerosol suppression
facilities at the O'Hare WRP was based on two considerations. The
first involved the state of scientific knowledge at the time with
respect to the health impacts associated with the respiration of
wastewater aerosols. Our review of the literature at that time
revealed that no conclusive evidence could substantiate either a
health effect existed or that it did not exist. We did find that
aerosols were generated and could be transmitted by winds to the
areas in the vicinity of the O'Hare WRP. There was also some evidence
relating to the viability of bacterial and viral organisms under
differing atmospheric conditions. While this evidence indicated
that organisms were adversely affected by transport on aerosol particles,
we felt there was still a possibility that viable organisms could
reach some residents near the O'Hare WRP.
The second consideration came directly from the National Environmental
Policy Act of 1969 (NEPA), which declares that it be National policy
that the Federal Government use all practicable means to assure a
healthful environment and to attain the widest beneficial uses of the
environment without undue risk to health or safety. Therefore, given the
state of scientific knowledge, the possibility of exposure to residents,
and our responsibility _to avoid health risks, we chose to require
the appropriate suppression of aerosols generated at the O'Hare WRP.
In the past four years, considerable research has been undertaken to
explore the relationship between health and the respiration of waste-
water aerosols. The purpose of this document is to examine this
new information regarding the health risks of human exposure to aerosols
and to decide whether the grant conditions should be retained, rescinded,
or modified.
II. ALTERNATIVES CONSIDERED AND THEIR COMPARATIVE ENVIRONMENTAL IMPACTS
A. Alternatives Considered
1. Action
a) Rescind the grant condition requiring MSDGC to construct
aerosol suppression facilities at the O'Hare WRP, since the
conclusions of the studies to date indicate that no significant
adverse health effects result from exposure to aerosols
emanating from activated sludge wastewater treatment processes
within the envelope of accepted U.S. design and operational
practice, either to proximate residents or to plant workers,
and by inference to the general public apart from these
categories.
b) Modify the grant condition and allow commencement of functional
operation of the O'Hare WRP without aerosol suppression
facilities, and continue ongoing analysis to demonstrate
whether the potential emission of wastewater aerosols
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at the O'Hare WRP is a significant health concern.
2) No Action
Retain the grant condition requiring MSDGC to complete construction
of appropriate aerosol suppression facilities at the O'Hare
WRP prior to or concurrently with the commencement of functional
operation, since studies to date do not indicate significant
adverse health effects result from exposure to aerosols emanating
from activated sludge wastewater treatment processes.
B. Comparison of the Environmental Impacts of the Alternatives
There is no indication that direct or indirect health effects will
result from operation of the O'Hare WRP without aerosol suppression
facilities.
While it is always desirable to study an issue in more detail, it is
our conclusion that further study would only have the direct impact
of expending monetary resources, and would not alter the conclusions
that the health risk associated with close proximity to wastewater
aerosols, and hence the O'Hare WRP, is not any greater than that presented
by routine environmental exposure to bacterial and viral organisms.
If aerosol suppression facilities are constructed, there will be a
significant expenditure of monetary, natural, and depletable resources
in their construction and operation. Other adverse impacts include
noise and dust associated with construction.
If operation of the O'Hare WRP would be delayed to construct aerosol
suppression facilities, the overloaded system presently used would
cause continued combined sewer overflows and flooding of basements
with combined sanitary and stormwater, thereby threatening public
health.
Based on our analysis of the studies, it is our conclusion that the
grant condition can be rescinded with no significant impacts.
III. AFFECTED ENVIRONMENT
The environment potentially affected by this action is that close to the
O'Hare WRP, particularly the 1200 residents within 2000 feet of the
plant boundaries, and is shown in Figure 2. Figure 1 delineates the
O'Hare WRP and adjacent service areas. The northern and southern boundaries
of the O'Hare Service Area follow the Cook County boundary lines. The
eastern boundary extends from Lake County south along the Des Plaines
River to the intersection of Rand and River Roads, thence in a southwesterly
direction along the Chicago and Northwestern Railway to the DuPage County
line. The western boundary separates the O'Hare and Salt Creek Service
Areas, and generally follows the ridge line dividing the Salt Creek
and Des Plaines River drainage areas.
The O'Hare Service Area lies in the northwest portion of Cook County. It
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encompasses an area of 37,250 acres of which 26,400 acres are residential,
5,000 acres are industrial and 5,850 acres are rural or otherwise unsewered.
The 1970 census population for the O'Hare Area was 223,000 people.
The area includes the older (but growing) communities of Arlington Heights,
Mount Prospect, Wheeling, and a part of the City of Des Plaines, as well as
newer urban developments such as Elk Grove Village, Rolling Meadows and
Buffalo Grove.
IV. ENVIRCNMENTAL CONSEQUENCES
A. Basis of Evaluation
Since May, 1975, MSDGC has undertaken studies sponsored by the USEPA, to
evaluate the performance and costs of alternatives for suppression of
aerosols. Phase I of the study which is projected to be completed by
March of 1980, is to measure the physical, chemical, and biological
properties of aerosols emanating from the aeration tanks of the J. E.
Egan WRP and relate these to measurements of the wastewater aeration
process parameters of the plant and environmental parameters which may
have an influence on aerosol properties. Using these data, MSDGC
would prepare engineering estimates of the potential efficiency of
alternative aerosol suppression methods identified for consideration,
and select up to five (other than covering or vegetative barrier)_
alternates for detailed testing by pilot plant performance trials.
The performance characteristics of the Egan WRP are presumed to
be representative of the planned operation of the O'Hare WRP.
The proposed Phase II and III portions of the study were designed to
construct a pilot plant, representing a segment of the O'Hare WRP
aeration tanks, emitting aerosols comparable to a demonstrated degree,
in physical, chemical, and biological properties, to those of the
entire Egan WRP, and to construct full-scale short segment prototype
equipment for up to five selected alternative aerosol suppression
systems to be tested on the pilot plant. Aerosol suppression efficiency
of each alternative would then be measured, and the most appropriate
alternative would be recommended, and detailed design criteria presented.
Since virtually nothing was known about the possible health effects of
wastewater aerosols on populations living near activated sludge wastewater
treatment plants, the USEPA sponsored several research efforts to
investigate potentially related health effects. The first study funded
by USEPA was an investigative study conducted at MSDGC's Egan WRP
to determine if a potential problem existed for residents which would
warrant further investigation. Since this study revealed a possible
association of certain symptoms with nearby operation of a wastewater
treatment plant, further investigation was initiated.
The USEPA also sponsored a study at Pleasanton, California which obtained
detailed information on the types and concentrations of microorganisms
in aerosols, and the factors affecting their viability after aerosoliza-
tion in order to estimate exposure of those nearby.
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To further evaluate potential health effects from exposure to wastewater
aerosols, the USEPA sponsored studies conducted by the University of
Michigan and the University of Illinois to investigate potential
health effects of those residents near a wastewater treatment plant.
Meanwhile, a study conducted by Hebrew University was investigating the
incidence of disease on Kibbutzim utilizing wastewater irrigation and
those not using wastewater. This study showed some evidence of
increased incidence of disease associated with wastewater use. However,
there was doubt indicating the possible pathway of infection, so USEPA
is sponsoring further study to clarify this issue.
Another study sponsored by the USEPA to evaluate potential health
effects from aerosol "exposure involved the health experience of students
attending schools adjacent to the wastewater treatment plant in Tigard,
Oregon.
Health reports of sewer maintenance workers in Copenhagen, Denmark
were also reviewed by the USEPA.
To evaluate potential health effects from close occupational exposure
to wastewater and their aerosols, the USEPA then sponsored a study
of sewage treatnent plant workers and sewage maintenance workers, to
be conducted by the University of Cincinnati.
The research studies are discussed in the following pages.
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Health Implications of Sewage Treatment Facilities; Schaumburg, Illinois /3
This study was conducted by the Southwest Research Institute to identify
the health implications of operating a recently constructed activated
sludge sewage treatment plant. The general study design was to make baseline
(preoperational) period versus operational period comparisions at the
Egan Water Reclamation Plant (WRP) in each of two seasons on the same par-
ticipants and sampling areas.
The Egan WRP was chosen since the design of this epidemiological study
required that the sewage treatment plant had to be a new plant being built
on a new site and could neither be an expansion of an existing plant nor
built on the site of an old plant. The design capacity of the plant had
to be one millions gallons per day (MOD) or larger and use the activated
sludge method of treatment. Other constraints also limited the choice of
plant. The plant had to serve a residential area with no heavy industry
contributing to the waste influent, and there could not be another sewage
treatment plant within a six-mile (approximately 10 Km) radius.
The other major factor which influenced the selection or rejection of a
plant was the population living around the plant site. Within a 5.0 kilo-
meter (ftn) (3-mile) radius of the plant, a minimum of 1,000 households
had to be present. Ideally, a uniform population density was needed
throughout the study area.
The Egan WRP was placed in service December 16, 1975, serving
a design population of 160,000 people in an area of 49 square miles.
A generalized flow diagram is presented in Figure 3. The wastewater
treated at the STP is primarily normal to low strength domestic-commercial
waste. The area served has limited light industry. The influent bio-
chemical oxygen demand (BOD) concentration averages approximately 100 to
150 milligrams per liter (mg/1). The total suspended solids (TSS)
concentration is in the same range (100 to 150 mg/1). The waste
flow at plant start-up was in the range of 10-15 MGD.
The daily waste flow presently is in the range of 15 to 20 MOD. The
monthly average daily flow is aproximately 17 MGD. The flow into the plant
is somewhat equalized by a wet well and by allowing the collection system
(sewer lines) to act as a holding device. This is done in an attempt to
distribute the daily flow variations in a more uniform fashion. The
design dry weather daily average flow capacity is 30 MGD.
The plant is presently operated in the conventional mode; that is, the
raw sewage is discharged into the head end of a series of long tanks and
aerated. The flow process of the plant is given in Figure 3.
A map of the study site is provided in Figure 4. The Egan Sewage
Treatment Plant is located at the center of the map, on Salt Creek, a
tributary of the Des Plaines River. The area is located in the northwest
portion of the Chicago Metropolitan area, approximately 35 miles from
the downtown business district. A number of suburban communities
as village, surround the Egan Plant. These are the villages of
Rolling Meadows, Arlington Heights, Elk Grove Village, Itasca,
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Schaurrburg, and Hoffman Estates.
The area occupies a plain, which for the most part, is only some tens of
feet above Lake Michigan (579 feet above mean sea level). Topography
does not significantly alter air flow, except that lesser frictional drag
over Lake Michigan causes winds to frequently be stronger along the lakeshore.
The quandrant from the east to about due north of the Egan treatment plant
is a designated forest preserve. Two four-lane highways (Higgins and
Arlington Heights Roads) pass through portions of this preserve. Esti-
mated traffic patterns for each of these roads would be between 20,000
and 30,000 cars/day.
The remaining three quandrants of the study area can be described as a
mixture of residential, agricultural, and small business tracts. Resi-
dential areas are estimated to comprise about 30-40 percent of these
quandrants. However, rapid growth in the area is taking over the availa-
ble farmland and would appear to substantially increase the residential
percentage within the next few years. The agriculture usage is predominately
for grain crops such as corn, wheat, and oats. An extimated 10 percent
of the study area is presently commercial enterprise such as shopping
malls and business zones along the major thoroughfares.
The study design provided for a self-paired comparison of individual health
observations from the operational period against those from the corresponding
baseline period is a very sensitive procedure for detecting changes
because it eliminates the substantial inherent variability between human
subjects and between locations. For an epidemiological investigation
of microbiological hazards to have the power to identify any health
hazards that are present, newly exposed human subjects were necessary,
because sporadic inhalation of low concentrations of pathogens may confer
a degree of immunity. With a new sewage treatment site, all the potential
perticipants are newly exposed.
The original human subjects selected as participants were not to be replaced
if they dropped out of the study. Each participant was to be his own control,
so very sensitive self-paired comparisons of the corresponding operational
and baseline results could be performed. In the health surveys and for
the soil and water environmental samples, the same locations were to be
used in each sampling period, again to improve the sensitivity of the
comparisons.
Pathogens might come from various sources both within and adjacent to the
study area. Local farmers use a combination of chemical and biological
fertilizers for their grain crops. As manure is spread by machine over
the fields some form of particulate matter would be emitted to the atmos-
phere. No feedlots were observed within the study area.
Environmental monitoring was conducted to characterize the ambient air, surface
soil, and surface water in the vicinity of the WRP aeration basin, outward to
residential distances of 0.3 to 5.0 Km in all four sampling periods. The
researchers' concurrent extensive aerosol and wastewater monitoring study
of spray irrigation at Pleasanton, California helped develop a superior
microbiological aerosol sampling and analytical protocol. Six high volume
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air samplers operating simultaneously were used to perform ten aerosol
sampling runs over a seven-day period, with one upwind and five downwind.
The upwind station was intended to describe the background levels of airborne
microorganisms and trace metals.
For sampling off the plant grounds, 24 sampling sites were preselected to
describe the windrose pattern at 1.6 and 5.0 Km distances from the plant.
Twelve additional sites were preselected in case the wind direction was
different than that predicted by the windrose pattern charts for the
area. The sampling sites were changed each day to follow the wind direction.
If the wind direction changed drastically during any one sampling period
attempts were made to move the samplers. Sampler location distances in
meters (m) from the edge of the aeration basin fell into the following
distance ranges: 15-30; 50-75; 100-150; 200-400; 600-1200. An upwind station
was located directly upwind at a distance of 500-1600 m for each run.
In the event wind direction and physical obstructions prevented placement
of samplers at one of the distance ranges, the sampler in question was
placed at the nearest unobstructed point.
Sampling occurred only if the mean wind direction remained fairly constant
and if no marked changes in meteorological conditions were expected over
the next 30 minutes. The run was continued as long as there was no marked
change in mean wind direction prior to the completion of 15 minutes of
sampling.
Each of the 60 aerosol samples was analyzed for total viable particles (TVP),
total and fecal coliform, coliphage, pathogenic bacteria-salmonella, Shigella,
Pseudomonas, streptococcus, proteus, and viruses: polio, adeno, coxsackie,
and e.cho. Air samples were also analyzed for concentrations of lead, zinc,
copper, cadmium, and mercury. In the operational periods, the mixed liquor
being aerated in the aeration basins was also sampled for trace metals,
viruses, parasitic worms, protozoa, and* enteric and respiratory human
pathogenic bacteria.
A health survey was conducted to obtain personal information on households
and detailed background information on volunteer participants. The household
health survey was also to obtain disease and symptom incidence on the household
members through a door-to-door interview. Half of the households were within
3.5 Km in all directions from the plant site, with the other half residing
between 3.5 and 5 Km in all directions from the plant. Clinical specimens
were obtained from the participating subjects for microbiological and
trace metal analyses. The clinical specimens selected were blood, feces,
hair, throat swabs, sputum, and urine. One hundred of the participants'
baseline and operational blood samples were analyzed using 23 additional
viral serology tests.
The household health survey was conducted only in the baseline and operational
sampling periods, with health information being collected on the members
of 1000 households in each survey. From 200 to 240 participants were
selected from the baseline household volunteers residing within the 3.5
kilometer radius, so at least 140 to 160 would remain to provide clinical
specimens through all four sampling periods. The participants were equally
distributed among four desired age groups: 3 months to 4 years; 6 to 12 years;
21 to 45 years; 60 years or older. The months during which the samples
-7-
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for each sampling period were actually obtained were: September-October
1974; February 1975; September 1975; February 1976; September-October 1976.
The data from the Household Health Survey was in the form of frequency
counts for occurrence of a particular chronic illness, symptom, or disease.
The statistical methodology used was designed to determine if any significant
changes in the frequency of occurrence were detectable between the baseline
(pre-operational) period and the operational (post-operational) period. In
addition, any increase in incidence should be related to the distance of the
household to the Egan plant, if the sewage treatment plant was to be implicated
as a potential health hazard.
In order to determine whether the occurence of pathogens in the clinical
specimens had increased after the plant began operating, the analytical re-
sults of the samples taken from each participant were matched according to
season (February or October) and compared for each of the bacteria, para-
sites, and viruses analyzed in the four sample media (feces, throat swabs,
sputum, and blood).
The study concluded that the Egan plant appears to be a source of indicator
bacteria, coliphage, pathogenic bacteria, enteroviruses, and mercury in the
aerosols emanating from its aeration basins.
However, the levels of microbiological or chemical agents of the air, soil,
and water samples in the neighboring residential areas were not distinguishable
from the background levels monitored before plant operation.
From the patterns observed in the household health survey, the reported incidence
of skin disease, and the symptoms of nausea, vomiting, general weakness, diarrhea,
and pain in chest on deep breathing may be associated with the nearby operation
of the wastewater treatment plant. However, it was considered that this correlation
could be due to people biasing their responses to the questionnaire because they
were aware of the purpose of the study and consciously or unconsciously recalled
a higher incidence than they might have otherwise.
Results for alpha-and gamma-hemolytic streptococci isolations in the throat swabs
for the subjects from the Lexington Green Apartments provide some evidence that
the pattern may relate to exposure to the wastewater treatment plant aerosols.
However, alpha-and gamma-hemolytic streptococcus species are part of man's
normal flora in the intestinal tract, upper respiratory tract and skin, and of
his environment (e.g., vegetation, insects, and animal feces) and do not normally
produce disease. Therefore, their presence in the vicinity of the wastewater
treatment plant or in the throat swabs is of little practical health concern.
Thirty-one viral antibody tests and attempted isolations of many pathogenic
bacteria, parasites, and viruses yielded no evidence of an adverse wastewater
treatment plant effect.
The combined baseline-operational and distance experimental design used in this
study is very sensitive for identifying potential health hazards and inferring
whether or not the wastewater treatment plant may be their source. However, the
findings obtained in this study, when considered overall, did not detect a
public health hazard for persons living beyond 400 m from a well-operated
wastewater treatment plant.
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The Evaluation of Microbiological Aerosols Associated with the Application
of Wastewater to Land; Pleasanton, California72
This research project was conducted by the Southwest Research Institute to
determine to what extent individuals living near sites practicing spray
irrigation are exposed to microorganisms.
A water reclamation plant in the City of Pleasanton, California was
selected as the study site: the City of Pleasanton Sunol Sewage Treatment
Plant (STP). The plant was modified just prior to the study by the addition of
an activated biofiliter process following the trickling filter to enhance
the treatment system's biochemical oxygen demand (BOD) removal efficiency.
The City of Pleasanton STP utilized physical and biological processes in the
treatment of its sewage flow. This STP is unique in that it combines
two biological waste treatment systems, fixed film and fluidized culture.
The fixed film is conveniently termed "trickling filter" and the fluidized
culture is termed "activated sludge". Additionally, the STP has aerated
ponds which serve as polishing and equalization for the land application
phase. Provisions have been made for odor control, such as lime addition,
partial chlorination, and off-gas ozonation. Figure 5 presents the
general plant layout flow scheme for liquid wastes.
A schematic of the study area is shown in Figure 6. A population with
middle-class socioeconomic characteristics is located within one mile-to
the east/southeast of the plant. This population is located in a recently
completed subdivision off Mission Drive. Mission Drive runs east-west,
and the street begins on Sunol Blvd. opposite the treatment plant. The pre-
vailing winds in this area are from the southwest to northwest quandrant;
thus, this inhabited area would be downwind of the spray fields. There is
a population in this subdivision to conduct an epidemiological study, and
there are also suitable control populations in Pleasanton with middle-class
socioeconomic characteristics located more than 2000 m from the spray
fields.
The principal objectives of the first phase of the study were to establish
the relationship in wastewater between pathogen levels and levels of the
traditional indicator organisms (total and fecal coliform and standard bac-
terial plate count), to determine microorganism levels in air within 100
m of the spray source, and to begin the assessment of factors thought
to affect the levels of pathogenic organisms collected in aerosol samples,
including aerosolization efficiency, pathogen survival upon becoming
airborne (impact), and microbiological die off with time (viability decay).
Routine monitoring of the wastewater was accomplished by taking a 20 liter
composite sample from the aeration basin during the hours of spraying.
Analyses included total and free chlorine, pH, total organic carbon, total
solids, and total suspended solids. In addition, one-half of the composite
samples were tested for biochemical oxygen demand, chemical oxygen demand,
total phosphorus, hardness, and the nitrogen series (nitrite, nitrate, ammonia,
and organic nitrogen). Microbiological analyses run on all wastewater samples
included total and fecal coliform, total viable particles (TVP), coliphage,
and assays for selected pathogens (Klebsiella, Pseudomonas, fecal streptococci,
Clostridium perfringens, and enteroviruses).
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The objectives of the second phase of the study were toward the development
and validation of a predictive model of aerosol dispersion and pathogen
survival. To accomplish this goal, 50 successful aerosol runs (each utilizing
a minimum of 8 samplers) were made using large volume electrostatic precipitator
samplers. These samplers were selected because the large volume of air sampled
over a 30-minute period increases the sensitivity for the microbiological assay.
Air sampling was conducted upwind and up to 600 m downwind in configurations
to obtain the information necessary to perform the mathematical modeling. The
samples were analyzed for the same microbiological parameters as the wastewater,
with the exception of one run for which the collecting fluids from all samples
were pooled for conduct of a pathogen screen.
Two special virus aerosol runs were conducted with all available samplers
operating close to the spray line under meterological conditions expected to
result in high virus aerosol concentrations. The sampler collection medium was
changed every 30 minutes and the samplers ran for a total of about three hours,
therefore the results were based upon a total of over 5000 cubic meters (m3) of
air. Additionally, 17 aerosol runs were made after the injection of dye into the'
wastewater to allow estimation of the proportion of the sprayed effluent that
became aerosolized. All glass impingers were used to collect the aerosols from
the dye runs, to determine the aerosolization efficiency of the sprinklers.
An explicit model for predicting downwind concentrations of pathogens was developed
by expanding more general mathematical dispersion models. The model adds factors
for microorganism impact, viability decay, and aerosolization efficiency, to the
standard diffusion model estimate of pathogen concentration based on source strength.
The distributions of aerosolization efficiency and the impact and decay values for
each organism were determined and these were used to allow evaluation of the model
using monitoring data from the Egan WRP study and the Tigard, Oregon, study.
The dispersion model developed in this study was then validated. It was shown
to produce satisfactory results when used to predict aerosol concentrations
at three sites. Most of the predicted results fell within a factor of five of
the measured concentrations when non-chlorinated effluent was being sprayed.
Through wastewater monitoring it was found the wastewater effluent applied
was of relatively consistent day-to day quality (BOD-18.7 mg/1; Chemical Oxygen
Demand (COD) 99.5 mg/1; Total Organic Carbon (TOG) 33.0 mg/1; pH 8.4; hardness
235.2 mg/1; TSS-33.0 mg/1; total phosporus-5.6 mg/1; and nitrite, nitrate, ammonia,
and organic nitrogen-0.15 mg/1; .06 mg/1; 23.9 mg/1; and 5.6 mg/1, respectively).
Pathogenic bacteria and viruses were found consistently in the pre-application
effluent samples, and coliphage was found in all pre-application effluent samples.
A wide range of levels of these microbial components was found. Concentration
levels routinely varied by one order of magnitude and variation often approached
two orders of magnitude.
A special study of respiratory viruses in wastewater found confirmed viruses in
five of forty cultures. Typing disclosed that four of the five tubes contained
echovirus 6, while the other viral isolate could not be identified. Echovirus
6 may occur as either a respiratory-tract virus or as an enteric virus. The
failure to isolate respiratory viruses in the Pleasanton wastewater confirmed
the researchers' suspicion that the likelihood of finding respiratory viruses
in wastewater is very small.
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There was no significant difference in the coliform or coliphage concentration
in corresponding effluent samples taken from a spray head during the aerosol runs
and from the effluent composite samples at the pond pimp. The standard bacterial
plate count, however, was significantly higher in the spray-head wastewater
samples. The correlations of the spray-head and pond composite microorganism
concentrations were generally significant, but not adequate for prediction.
The median aerosolization efficiency obtained for the sprayers over 17 dye
runs at Pleasanton was 0.33 percent. There was over an order of magnitude
of variation in aerosolization efficiency estimates. Eighty percent of
this variation in aerosolization efficiency at Pleasanton appears to have
resulted from changes in metercological conditions (air temperature, wind
velocity, and solar radiation) that affect the evaporate capability of the air.
The median impact factor estimates for the micro-organism groups studied
were 0.13 for fecal coliform (13% survive aerosol impact), 0.16 for total
coliform, 0.21 for standard bacterial plate count, 0.34 for coliphage, 0.89
for mycobacteria, 1.2 for Clostridiunv perfringens, 1.7 for fecal streptococci,
14 for Pseudoroonas, about 10 for three-day enteroviruses (mostly polioviruses),
and about 40 for all (3-day and 5-day) enteroviruses. Most individual impact,
factor estimates were quite imprecise, reflecting the imprecision of the
microbiological aerosol concentration measurements. Since the middle range
of impact factor values (fortieth to sixtieth percentiles) for each microorganism
group were quite consistent, they were considered to be characteristic of
the microorganism groups' typical survival through aerosol impact.
As indicated by impact factors exceeding 1.0, the enteroviruses and some hardy
bacterial pathogens were frequently found in wastewater aerosols at higher con-
centrations than could be expected based on their wastewater concentrations.
Mechanical splitting of colony forming units (CFM) may account for this phenomenon.
The range of impact factor estimates for each microorganism group was broad,
generally covering two orders of magnitude from the tenth percentile to the
ninetieth percentile. The detectable viability decay rates of each micro-
organism group also covered a wide range. Limited data suggest ambient condi-
tions such as low relative humidity, high wind velocity, and a large temperature
differential between wastewater and air all may reduce the initial survival.
Viability decay may be more rapid with high solar radiation, high tem-
peratures, and middle or low relative humidity.
The viability decay rates for total coliform and fecal coliform were more rapid,
more reliable, and more frequently detectable than those of the other micro-
organism groups. Viability decay was less rapid for coliphage, Clostridium
perfringens, and standard bacterial plate count and its effect could only be
ascertained within 100 m on about half the runs. Viability decay could
seldom be ascertained for fecal streptococci, mycobacteria, and Pseudomonas.
No attempt was made to determine the viability decay of enteroviruses due to
insufficient data.
The geometric mean aerosol concentrations obtained at 50 m downwind of
the wetted spray area were:
1) standard bacterial plate count 460.0 /m3
2) total coliform 2.4 MPC/m3
3) fecal coliform 0.37 MFC/m3
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4) ooliphage 0.38 PFU/m3
5) fecal streptococci 0.61 CFU/rn3
6) Pseudomonas 34.0 CFU/m3
7) Klebsiella 5.0 CFU/m3
8) Clostridium perfringens 0.9 CFU/m3
9) mycobacteria 0.8 CFU/m3
10) enteroviruses (3 and 5 day) 0.014 PFU/m3
PFU = Plaque Forming Units
CFU = Colony Forming Units
MFC = membrane filter count
m3 = cubic meters
Individual aerosol measurements frequently differed by more than an order of
magnitude from these mean values.
Limited particle size data obtained with two-stage Andersen samplers showed a
substantial portion in the respirable range. The median percent respirable
particle values downwind of the spray line were 44 percent for total count and
74 percent for total coliform. In general, there was a higher percentage of
respirable particles at close downwind distances (5 to 25 m), than at back-
ground and farther downwind distances. This meager data is in general
agreement with more thorough particle size studies performed at the Egan WRP.
Particle size was not considered in the mathematical modeling.
Wastewater quality as measured by chemical and physical parameters was
unrelated to the generation or transport of microbiological aerosols from
spray irrigation. In addition, little correlation was found in the wastewater
between levels of the traditional indicator organisms; total coliform, fecal
coliform, standard bacterial plate count, and coliphage, with the levels
of the pathogens which they are intended to indicate.
Aerosol studies indicated that use of the traditional indicator organisms
to predict human population exposure results in extreme underestimation
of pathogen levels. The pathogens studied survived the wastewater aerosol-
ization process much better than did the indicator organisms. Based upon
the results of this study, fecal streptococci may be an appropriate indicator
due to ease of assay, levels routinely seen in wastewater, and the similarity
of their hardiness upon impact and viability decay rate to those of the
pathogenic organisms of interest. However, an apparent problem was the
occasional presence of fecal streptococci in aerosols due to non-wastewater
sources.
Although Klebsiella was relatively prevalent in the wastewater, it was far less
prevalent in the wastewater aerosol. It appears that Klebsiella die off
repidly during the aerosolization process. This finding was in contrast to
data seen in the literature which consistently report Klebsiella as the pre-
dominant pathogen found in the air near spray irrigation sites and near sewage
plants. More analytical confirmation steps were used in this study than
in earlier studies. If the confirmation steps had been stopped at the
point used by other investigators more values would have been reported
as Klebsiella when, in fact, they were primarily other organisms of the
mucoid type.
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The study was supported by an extensive quality assurance program. Chemical,
physical, and microbiological methods used were subjected to accuracy and pre-
cision studies, and alternative laboratories were used, where feasible, to verify
the results.
Studies conducted on the aerosol collection media, the temperature at which the
samples are shipped, and the total time from collection to analysis were examined
in detail in the laboratory. The results led to the design of adequate methods
for sampling and analysis so that pathogenic organisms were found consistently.
Some difficulties were encountered in contamination of the high-volume aerosol
samplers between aerosol runs. This problem appeared primarily in the standard
bacterial plate count and Pseudomonas assays. Special care must be taken to
adequately decontaminate high-volume aerosol samplers between aerosol runs.
The microbiological aerosol data varied substantially in quality and statisti-
cally usable information content. Accordingly, a suitable aerosol data
weighting procedure was employed, according to consistent rules, in con-
ducting the aerosol factor analyses. In the quality assurance aerosol runs
for systematic sampler differences, it was concluded that after correcting
for the air flow rates, there was no systematic bias in microbiological
collection efficiency among the high-volume samplers evaluated.
There was substantial imprecision using the methods employed in this study
for measuring microbiological concentrations in aerosol samples. The aerosol
measurement coefficients of variation were 17 percent for dye, 50 percent
for total coliform and standard bacterial plate count, 58 percent for
fecal coliform and Pseudomonas, 60 percent for Clostridiura perfringens,
73 percent for coliphage, 74 percent for Klebsiella, 77 percent for fecal
streptococci, and 81 percent for mycobacteria. While the microbiological
aerosol variation due to field sampling sources was considerable, even
more variation was caused by analytical sources such as sample processing,
shipping, and laboratory procedures. Relatively little of the analytical
variability was reflected in replicated analyses, which is the usual manner
of reporting analytical variation.
The accuracy and precision of microbiological dispersion model predictions have,
in general, been validated to 100 m downwind of spray sources of unchlorinated
wastewater aerosols. Most model predictions (e.g., 77 percent for standard bac-
terial plate count, 71 percent for total coliform, and 80 percent for coliphage)
were within a factor of five of the net measured aerosol concentrations evaluated.
Considering the imprecision and cost of measuring micro-organism aerosol con-
centrations from spray irrigation by field sampling, using predictions of the
micorbiological dispersion model supplemented with minimal field sampling does
appear to be a preferable alternative to extensive field sampling when the sprayed
wastewater does not contain residual chlorine.
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Health Effects of a Wasbewater Treatment System /6
The University of Michigan and the IIT Research Institute utilized data obtained
as part of a comprehensive community health study conducted during 1965-71 to
examine the incidence of acute illness in a population surrounding an activated
sludge wastewater treatment plant and a control location in Tecumseh, Michigan.
The Tecukmseh wastewater treatment plant (WWTP) is located in the southeast
quandrant of the city (Figure 7). The plant is at a lower elevation than
most of the populated study area and is surrounded by deciduous trees on the
east, west, and south. This plant processes approximately 1 million gallons
of wastewater per day (MGD) by activated sludge secondary treatment. Acti-
vated sludge has been in use since 1956, when the plant was redesigned
from a trickling filtration facility. Data that might be used to estimate
the fecal contribution to the wastewater, such as total or fecal coliform
concentrations, are not available for the study period. Wastewater flow
rates for the study period were not available from the Tecumseh VWTP, but
available data were obtained from the Michigan Department of Natural
Resources.
Average monthly flow rates at the Tecukmseh wastewater treatment plant
ranged between 0.64 and 1.18 MGD from 1965 to 1971. Data, however, were
not available for 1966 and some data for 1965, 1968, and 1969 are missing.
The study population was defined as those participants in the University
of Michigan Tecumseh Community Health Study from 1965 to 1972 who resided
in dwelling units at specific distance ranges from the Tecumseh wastewater
treatment plant (Figure 7). Dwelling units located within each of five
concentric rings and beyond, radiating from the plant in approximate multiples
of 600m, were identified. Dwelling units were likewise identified with
a second set of concentric rings constructed around a nonemitting location.
This site was located in the northwest quandrant of the city in an undeveloped
area approximately 180 m west of Seminole and 275 m south of Brown Roads.
This control location was selected because it is upwind from the wastewater
treatment plant and had a surrounding population density comparable to
that of the study groups. The dwelling units within the study area were
primarily single family houses, although multiple family units occured
at various locations within the area. Confirmation of dwelling unit locations
near concentric ring boundaries was made by site visitation. All dwelling
units studied were assigned to concentric rings surrounding both the wastewater
treatment plant and control location. Data with reference to each index
point were analyzed separately.
The population used in nonseasonal-related analyses included those in-
dividuals who were contacted at least 50 weeks in a row with no absences
during four or more weeks. The illinesses included are those whose
onset occurred within this 50-week period. The entire population on
report from 1965 to 1971 was used for determination of true illness
incidence rates.
As used in this study, colder months included November through April
whereas warmer months included May through October. In each case, the
study population was defined as those persons on report for the entire
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26-week period, with no long periods (two weeks or more) off report. The
illnesses included are those whose onset occurred during the 26-week period.
Data were obtained from the participating families regarding health history,
socioecononic factors, employment locations, and schools attended by all children.
After recruitment, each family was contacted weekly by telephone or personally,
and a single respondent was questioned regarding the occurrence of short
term illness within the family during the past week. When illness was
reported, the details of the specific event were recorded using a question-
a'ire. The respondent was contacted during the weeks following the initial
report and asked whether the illness persisted and to describe the symptoms.
The date of illness termination, was obtained and the respondent was
questioned regarding other illness development within the family. An
illness occurring at least two days after a termination date was regarded
as a new event.
Acute illnesses were grouped into three general categories: total, respira-
tory, and gastrointestinal. Data are reported as incidence rates and as
individual illness rates. Age-sex-distance-specific true incidence rates
were determined by dividing the number of each kind of illness by the number
of person-years observed within each group. Age-sex-distance-specific indi-
vidual illness rates were calculated by number of illnesses during report
period/nunber of weeks on report.
Study participants were classified into concentric rings of approximately 600m
each by dwelling unit distance from both the study and control site. School
children were classified by school attended in a similiar manner.
The objective of the statistical analyses was to determine whether the inci-
dence of illness varied with distance of the dwelling unit from the waste-
water treatment plant, and, in children, also whether incidence depended upon
distance of the school attended from the wastewater treatment plant. Dwell-
ing units and schools were also classified with respect to distance from a
control location.
Differences in illness incidence occurred during the May through October season
at varying distances from the wastewater treatment plant, but persons within
600m appeared to have a greater risk of respiratory and gastrointestinal
illness than the control group. The data do not, however, demonstrate a
causal effect and factors other than the wastewater treatment plant, such as
higher rates of illness transmission in areas of higher densities of lower
socioeconomic families, could have contributed to these findings. Persons
dwelling within 600m of the plant had respiratory illnesses that exceeded
those of the control group by 20% and 27%, and gastrointestinal illnesses
that exceeded those of the control group by 78% and 50% when specified
for income and education, respectively. When specifying socioeconomic
factors, education and income exerted an unequal influence on the significance
of illness incidence variation and, in general, such variations between
geographiic locations were found to be greatest in groups having the lowest
income and education. Therefore, the data suggest the higher illness
rates are related to higher densities of lower socioeconomic families
rather than the wastewater treatment plant.
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The group within the 1800 to 2400m concentric rings from the wastewater treat-
ment plant had a greater than expected incidence of respiratory illnesses
during both warm and cold seasons. Significant differences were not
found in the control location related groups at this distance. However,
the higher than expected illness cannot be related to the wastewater treat-
ment plant itself, since they appear to be related to socioeconomic status.
Differences in total illness were observed in the school children with regard
to distance of school attended from both the wastewater treatment plant and
control location. But "these results are inconclusive since the schools
were very unevenly distributed with reference to distance from
these locations.
These observations should be tempered with the recognition that the Tecumseh
wastewater treatment plant is located at a lower elevation than most of the
populated study area and is surrounded by deciduous trees on the east, west,
and south. Depending upon wind direction, velocity, and atmospheric stability,
surrounding trees may act as a partial barrier for persons dwelling nearest
the plant while lofting the airflow, resulting in further downwind dispersion.
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Ifealth Effects of Aerosols Emitted From an Activated Sludge Plant /4
This research project investigated the potential health effects of aero-
sols emitted from an activated sludge plant. The University of Illinois
Medical Center conducted an 8-month environmental health study using a
stratified sample of persons residing near the North Side sewage treatment
plant (NSSTP) in Chicago.
The NSSTP was chosen for the study since the plant is nearly surrounded
by a substantial number of residences. Census information (1970) indi-
cated the population to be of homogeneous socio-economic status and to
consist of appropriate numbers of individuals in the desired high-risk
age groups. Tne sewage is not heavily industrial, and the prevailing
wind patterns and topography appeared to be conducive to exposure
of population groups.
Built in 1929, the IESTP is one of the three main plants of the Metro-
politan Sanitary District of Greater Chicago (MSEGC). The plant is
located on Howard Street between Hamlin Avenue and McCormick Boulevard
in Skokie, Illinois (Figure 8), which is a northwest suburb of Chicago.
The NSSTP is an activated sludge plant employing diffused aeration with
tapered aeration. Chlorination occurs after the final settling process.
No sludge processing occurs at the plant. A schematic of the plant
is shown in Figure 9. The maximum capacity of the plant is 399 million
gallons of raw sewage per day. During the study period (April-November,
1977) the plant had an average daily flow rate of 292 million gallons
of sewage and a median air rate of 4.6 x 10 m3/day. The estimated
surface area of sewage in the aeration tanks is about 55,000 m3 in
settling tanks, concentration tanks, etc., exposed to the atmosphere.
The total retention volume of one battery of aeration tanks is 7.45 x 10 m3.
The tank levels are maintained at approximately 4.6 m. Residence
time of sewage in the aeration tanks is generally 5-1/2 hours.
The area within a 1.6 Km radius of the treatment plant as shown in
Figure 8 was designated as the study area. Previous studies at other
locations have found that the dispersion of viable particles does
not exceed 0.8 Km from the source. Therefore, the 1.6 Km radius study
area permitted analysis of exposed and unexposed populations. The
study area included portions of four communities: Skokie, Lincolnwood,
Evanston, and Chicago. As can be seen in Figure 8, the plant is located
in a small industrial area. Light industries are situated north, east,
and south of the plant, occupying most of the land within the first
0.4 Km (1/4 mile) radius of the plant. Residences are located about
152 meters west of the aeration basins, and about 0.8 Km (1/2 mile)
directly east of the tanks. Housing also exists within 0.8 Km north
and south of the plant. The major residential section begins at
the 0.4 Km radius line and extends uniformly through the 1.6 Km radius
area.
The population of the study area was estimated to be 15,850 persons, or
5,600 households, based on the 1970 census. Considering property value,
age, and race, the population appeared to be relatively homogeneous.
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Although there were differences in several characteristics between
sane of the tracts, these 1970 figures were used for preliminary evaluation
of the population and not for subsequent demographic analysis.
In order to characterize the nature and degree of exposure of the study
population to pollutants emitted during treatment plant operation,
environmental air quality, measurements of total viable particles
(bacteria containing particles), total coliform bacteria, total suspended
particulates (TSP), and 19 metals and gases were made at regular intervals
at different distances from the plant in ambient air. Concentrations
of total viable particles (TVP) were measured on a regular basis
(approximately every other day) at the plant and in the community
for eight months (April-November, 1977) using Anderson 2000 six-stage
(ASS) viable samplers. Initial attempts to monitor for total"and
fecal coliform were made using an All-Glass-Impinger on six days during
April and May. Ihese samplers were found to be below the sensitivity
required for detection of the concentrations present. Beginning in
September, airborne total coliform samples were taken with Andersen sam-
plers on days of total viable particle sampling and with a Litton Large
Volume Air Sampler (LVAS) one day per week. Airborne coliphage measure-
ments were originally scheduled to be taken once every other week. How-
ever, many equipment problems were encountered with the LVAS, and only
eight coliphage in air measurements were obtained. Animal virus in air
samples were obtained for two days using LVAS's (one upwind and one down-
wind each day). Monitoring of nonviable constituents was conducted every
five days from April through November on the plant and in the community.
The Andersen 2000 six-stage (A6S) viable samplers used are a multi-orifice
cascade impactor consisting of six aluminum stages accompanied by six
glass petri dishes and a pump. Each stage collects particles of pre-deter-
mined size range with stage six collecting particles of 0.65 to 1.1/tm
diameter and stage one collecting particles of 7.7jU,m and above. These
samplers were calibrated to sample air at 28.3 liters/minute.
The LVAS's use a liquid collection media to filter the air samplers which
are initially collected at approximately 1.0 m3/minute. The fluid con-
taining the air sample is then filtered through a membrane filter in a
Millipore filtration apparatus.
Grab samples of sewage were collected from the aeration tanks concurrently
with the air measurements and were analyzed for total viable particles,
total coliform bacteria, trace metals, sulfates, and nitrates. A limited
number of measurements were also made of viruses and coliphage in
sewage.
The environmental measurements were used to develop study period exposure
indices for each household for total viable particles, TSP, and eight
metals and gases, a similiar 2.5-month exposure index was developed for
total coliform bacteria. Virus and coliphage measurements in sewage and
air were inadequate in number to determine their concentrations with any
confidence.
In an attempt to determine whether or not the sewage treatment plant was
hazardous to the health of the community exposed to the plant aerosols,
several measurements of health were made.
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An important requirement for this study was that the sample of households
be equally distributed throughout the study area. Therefore, three con-
centric sampling zones were designated around the sewage treatment plant
as follows: I) 0-.8 Km; 2) .8-1.2 Km, 3) 1.2-1.6 Km (from center of plant).
A random sample was chosen from each zone in order to obtain a more uni-
form geographic distribution of households throughout the study area.
The sample size for each zone was determined by the number of households
in the smallest zone (nearest the plant, 394 households). Thus, nearly
every family in this zone was included in the sample.
A history of the baseline health status of each participant was tabulated
in a health questionnaire developed in collaboration with the Survey Research
Laboratory (University of Illinois, Circle Campus). Specific questions
were asked regarding any acute illnesses the participant had experienced
in the past year. Additional questions concerned such factors as
chronic disease, smoking habits, demographic characteristics (i.e., age,
sex, race, income, occupation), length of residence in the study area,
travel, and vaccination history.
In order to obtain ongoing, prospective information about health in the
"study population, a subsample of the persons interviewed in the Health
Questionnaire Survey was solicited into the Health Watch. Participants,
as family units, were asked first to maintain a health diary to self-report
any and all illnesses they encountered for an 8-month period. Secondly,
they were requested to provide blood samples at the beginning and again
at the end of the 8-month period, and finally, families with young chil-
dren were asked to provide clinical specimens, i.e., throat and/or stool
specimens, for biweekly microbiological surveillance.
The cross-sectional demographic and health survey carried out in the
area surrounding the activated sludge plant (which processes 292 million
gallons of sewage daily) revealed a relatively homogeneous, predominately
white, upper middle class group, with no remarkable prevalence of health
problems. Seven hundred and twenty four people (246 families) volunteered
to record self-reported illnesses at biweekly intervals. Throat and stool
specimens were collected from a selected subsample of about 161 persons.
In addition, 318 persons submitted paired blood samples at the beginning
and at the end of the study period to determine prevalence and incidence
of infections to five coxsackievirus and four Echovirus types potentially
associated with aerosol exposure.
In relating illness rates to total viable particle exposure, it was necessary
to limit the illnesses to those which potentially have a casual association
with viable particle exposure—respiratory, gastrointestinal, eye and ear,
skin, and total illness.
A dose-response approach was taken in the analysis of exposure and health
effects. Conceptually, if the sewage treatment plant was the source of
infections, trace metals and gases, or other hazardous materials, then the
level of exposure may be directly related to the number of infections
and/or diseases occurring in the exposed population. Standard techniques
such as regression analyses were performed to determine if health effects
increased with exposure, or if the two variables varied independently.
Scatter diagrams were prepared to further examine the relationship between
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exposure and health effects.
Results of the health survey and the specimen and serological analyses of
residents as close as 152 meters were compared with the household exposure
indices. No significant correlations were found between the exposure
indices and the rate of self-reported illnesses or of bacterial or
viral infection rates (antibody levels) determined by laboratory analysis.
This lack of correlation between 8-month total viable particle exposure
and illness rates may be the result of an inadequate sample size (in
terms of number of households), an unequal frequency distribution
of household exposure indices in terms of not having enough households
exposed at "low" or "high" levels of TVP concentrations, the inaccuracies
in self-reported illness rates, the existence of more complex functional
relationships between health and exposure variables, or no'relationship
at all.
The relationship between temporal illness and exposure was also evaluated on a
2-week averaging period basis. No linear relationships were found when analyzed
separately or together for all types of illnesses evaluated or for respiratory
illnesses alone.
In order to examine a possible lag effect between exposure and illness, a 2-
week lag period analysis was carried out. Again, no linear relationship was
detected. A 2-week period was the smallest lag period possible to
analyze, since the health survey was conducted biweekly. In addition
to the possible reasons for lack of correlation provided above, it was
possible that the 2-week lag period was too long in terms of incubation
period for most bacterial and viral agents possibly associated with these
illnesses. It was also important to note that the 2-week exposure indices
were much less reliable than those based on the total study period.
An attempt was made to examine the relationship between illness and exposure
for various sub-populations potentially at high risk to the effects of TVP
exposure. Age (0-12, 13-18, 19-59, greater than 59 years), chronic respiratory
disease (chronic bronchitis, emphysema, or asthma), chronic gastrointestinal
problems, smoking, family composition (families with one or two adult mem-
bers, youngest children aged: 0-5; 5-14; and greater than 13 years), and length
of residence (less than 1 yr., 1-5 yrs., 6-10 yrs., 11-20 yrs., and greater
than 20 yrs.) in the study area were considered potential risk factors. The
analysis did not reveal any linear relationships except for skin illnesses
for families with the youngest child between 5 and 14 years, and for skin
conditions in the over 20 years of residence sub-population. However it was
reported by the researchers that these linear relationships are of
questionable importance since the mean illness rates were so low.
No linear relationship was found for respiratory illnesses or for all illnesses
combined when compared to total coliform bacteria exposure. Exposure to metals,
gases, and TSP did not exhibit a linear relationship when compared with household
illness rates for all illnesses combined, as well as for the separate illness
categories.
Throat bacterial infection rates were compared to TVP exposure and no dose-
response relationship was found. Analysis of virus infections was possible
through serosurvey. The differences observed were not statistically significant.
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Environmental Monitoring of A Wastewater Treatment Plant /I
This draft research report was compiled by the Southwest Research Institute
to evaluate aerosol emissions from the Durham activated sludge treat-
ment plant (DASTP, Tigard, Oregon) and their possible health effects.
The DASTP is situated next to Fanno Creek, a tributary of the Tualatin River,
in an area which has recently (Fall 1978) been annexed by the City of
Tigard. The DASTP services the entire Fanno Creek drainage basin and
nearby areas. Figure 10 shows the location of the plant and the area
served. The DASTP commenced operation on July 6, 1976, with an initial
design capacity of 75,000 cubic meters per day (20 MGD) that can be expanded
to 227,000 cubic meters per day (60 MOD) by the year 2000 to meet the needs
of this rapidly growing area.
Designed as a modern activated sludge plant incorporating some advanced
processes for wastewater treatment, the DASTP is comprised of two parallel
plants which can be operated separately from primary clarification to the
point of effluent discharge. Alternatively, flows can be combined from
the separate plants after various stages of treatment. All plant influent
first passes through barminutors to screen out and reduce the size of
large objects. The flow is then divided to two primary clarifiers in
parallel where settleable solids and grit are removed. Secondary treat-
ment begins with the classical activated sludge process in four aeration
tanks.
After secondary clarification, the wastewater is subjected to advanced
wastewater treatment processes for reduction of phosphorus and solids.
Plant effluent is then filtered and chlorinated prior to discharge in the
Tualatin River. Organic sludge from the primary and secondary clarifiers
is processed in a series of gravity sludge thickeners, cyclone-type
grit separators, disc centrifuges and continuous bowl centrifuges. After
heat treatment and incineration, the resulting ash is landfilled.
A schematic flow diagram of plant processes is shown in Figure 11.
To accommodate plant flow during periods of extensive rainfall, two large
surge basins were built adjacent to the plant. The largest surge basin
has a capacity of 38,000 m3 (10 million gallons), while the others
have capacities of 19,000 m3 (5 million gallons). A small basin of
7,600 m3 (2 million gallons) capacity is situated adjacent to the
surge basins and has no surface aeration. Its purpose is to catch
backwash from the filters. Flow from any of the plant processes can
be diverted to the surge basins, but typically, primary clarifier
effluent is diverted to these basins in sufficient quantity to maintain
a relatively constant flow through the activated sludge process. Three
surface aerators in the second largest surge basin (No. 1 surge basin)
prevent the primary treated wastewater from becoming anaerobic. During
periods of low influent flow, wastewater from the surge basin can
be reintroduced into the secondary treatment process to equalize flow
through the secondary and tertiary treatment sections of the plant.
It was determined that there were three potential sources of aerosol
formation within the DASTP: the aeration basins, the surge basins, and
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the secondary recarbonation basin.
No chemical treatment (including recarbonation) was performed during
either of the sample periods. This eliminated the secondary recarbona-
tion basin as a source of aerosol.
Also, plant personnel determined that use of a single aeration basin
resulted in optimal operation of the activated sludge process. In this
mode of operation, all wastewater is mixed with activated sludge in a
3,800 cubic meter (1 million gallon) capacity aeration basin with a
detention timne of 1.5 to 2 hours. Air at a pressure of 0.39 to 0.53
kg/cm (5.5-7.5 psi) is introduced through a 10-cm (four-inch) diameter
nozzle located 1.5 m (5 feet) from the bottom of the basin.
Each nozzle is oriented vertically upward underneath a variable speed
turbine aerator that agitates the aeration basin liquor and disperses
the air stream from the nozzle. There are two nozzle mixer systems in
each 21 x 30 x 6 m deep (69 x 100 x 20 feet) aeration basin. Based on
the surface area of the aeration basins, perhaps one-fourth of the poten-
tial aerosol was being generated, since only one of the four aeration basins
was being utilized for secondary treatment during the monitoring period.
The third source of aerosol generation, surface aerators on the No. 1
surge basin, was functional during both sampling periods. When the waste-
water characterization samples were collected in November 1977, the No. 1
surge basin was being used to return surge to the aeration basin. A
total of 12,200 m3 (3.22 million gallons) were returned to the aeration
basins during 19 hours of the 24-hour operating day commencing at
midnight November 9. During the aerosol study in Mary 1978, the depth
of the only aerated surge basin (No. 1) remained constant at 4 m (13 feet)
since no wastewater was diverted to or removed from it.
One objective of this study was to measure the types and quantities of viable
microorganisms present in the ambient air 0-100 m downwind of the DASTP.
A second objective was to determine whether the absentee rate at Durham
Elementary school (next to the DASTP) was significantly different
from the absentee rates at control schools located in the same area
but not near a wastewater treatment facility. This would provide some
preliminary indication of possible health effects which might be associated
with the treatment facility.
To address the first objective, large wastewater samples were collected from
each potential source of aerosols, to characterize the type and approximate
concentration of viruses and enteric bacteria available for aerosolization.
These results were used to select the types of organisms and methods to be used
during routine monitoring of wastewater and aerosols.
Six aerosol runs were conducted to simultaneously measure levels of micro-
organisms in wastewater and air. This was achieved using a sampler array of
eight high-volume air samplers (Litton Model M). Two samplers were paired upwind,
while the six downwind samplers were deployed as three pairs, at planned distances
of 30 m and 100 m downwind of the aeration basin and 50 m downwind of the surge
basin. During the six high volume aerosol runs, temperature, relative humidity,
wind direction, wind speed, and solar radiation intensity were monitored. The
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aerosol runs were taken over a wide range of solar radiation conditions, from
darkness during run 3 to noon during run 6.
Based on experience in detecting microorganisms in the aerosols monitored at
the Egan WRP and at Pleasanton, California, the following microorganisms groups
were selected for routine monitoring: total coliform; fecal streptococci;
Pseudomonas, mycobacteria, and coliphage. A special enterovirus aerosol run
was also conducted to measure enterovirus levels at the aeration basin.
The level of microbial aerosols reaching the school were then estimated. Since
previous experience had shown aerosol monitoring beyond 400 m downwind
of the aerosol source was infeasible, the only means to obtain exposure dose
information was by calculation involving a mathematical model, monitoring data,
and wind direction data. Since the calculation required data extrapolations
and assumptions whose validity is uncertain, the estimated peak exposure doses
do contain considerable uncertainty. However, the researchers have verified
the predictions of the model from extensive monitoring data at the Egan WRP
and at Pleasanton, California.
The frequency with which children at Durham Elementary were exposed to
aerosols from the DASTP was investigated. Two exposure locations at the
school (classroom and playground area) were considered. Wind direction
observations made at Portland International Airport (24 Km northeast
of the DASTP) by the Portland Weather Service office at 7 a.m., 10 a.m.,
1 p.m., and 4 p.m. on each of the school days were used in estimating
the frequency of student exposure.
A daily exposure index was computed for each exposure location-aerosol
sources combination, based on the four wind direction observations for the
day. Wind direction observations within 30 degrees of the schools direction
were considered to represent an occasional exposure, and the exposure index
was adjusted using a weighting factor.
Quarterly attendance for Durham Elementary and eight control schools were
obtained for the seven school years prior to DASTP operation and for the
first two school years of DASTP operation. If the DASTP had an adverse
health effect, one would expect higher absenteeism at Durham Elementary
(relative to the control schools) in the two operational years. Such absentee-
ism might take the form of a uniformly higher absence rate throughout the
two operational years, or because of acquired immunity, it might only be
evident during the first several months of aerosol exposure.
Wastewater monitoring detected the concentration levels for mycobacteria and
Klebsiella were fairly high relative to the microbiological indicators at the
DASTP. Also Pseudomonas were found at relatively high concentration levels.
However, Salmonella and Shigella, generally regarded as the most common bacterial
pathogens, were not prevalent in the wastewater samples. Microorganism con-
centration levels tended to be higher in the aeration basins than in the surge
basin, recarbonation basin or effluent pond. Consequently, the aeration basin
was selected as the most suitable source for monitoring the aerosols.
The geometric mean aerosol concentration at 30-50 meters downwind of the aeration
basin were 5.8 cfu/m3 of total coliforms, 2.0 cfu/m3 of fecal streptococci,
9.1 cfu/m3 of mycobacteria, 7 cfu/m3 of Pseudomonas, and 0.7 pfu/m3 of coliphage.
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Enteroviruses were not detected in the air 30 meters downwind of the aeration
basin. This resulted from their low concentration in the wastewater
and from the association of 98 percent of the wastewater enteroviruses
with solid matter which is not readily aerosolized. Mycobacteria were
observed to be more prevalent at the DASTP than at the Egan WRP and
Pleasonton, California wastewater aerosol monitoring sites.
The microorganism aerosol concentration levels tended to decrease with
increasing downwind distance from the wastewater aerosol source, and
also tended to vary from one aerosol run to another due to variations
of microorganism levels in the wastewater. However, high and extremely
variable aerosol concentration levels were probably due to contamination
of the high-volume aerosol samplers.
Aerosol runs indicated that levels of fecal streptococi, Pseudomonas,
and mycobacteria were generally as high or higher at 70-100 m downwind
than the levels of such indicator organisms as total coliform and coliphage.
Thus, the use of indicator microorganisms such as total coliform or
coliphage in wastewater aerosol monitoring appeared to be inadequate
to characterize the pathogenicity of the aerosols.
The calculated daily exposure index over the 355 school days the DASTP was
operational showed that on the majority of school days the classroom area had
no exposure to aerosols. Cn ten days the classroom area was steadily exposed
to aeration basin aerosols and on five days to surge basins aerosols. The
playground area had steady exposure to DASTP aerosols more frequently, but
the number of days was still low. These calculations were based on four
wind direction measurements per day, and since wind direction is variable,
exposure was greater than indicated here.
The weather on the days of steady aerosol exposure in the classroom area was
reviewed, and revealed conditions conducive to survival of aerosolized
microorganisms. However periods of rainfall experienced on the days of
steady aerosol exposure would reduce the duration of exposure. The weather
on days of steady aerosol exposure in the playground area was similiar.
Based on precipitation during and proceeding the school day, the playground
was considered usable for student play on 13 of the 31 school days with
steady aerosol exposure.
Assuming a breathing rate of 0.25/m3/hr, the estimated peak microorganism
dose received by Durham Elementary students on a single school day was as
high as 9 cfu of mycobacteria and 3.5 cfu of fecal streptococci during seven
hours while in the classroom area. Substantially lower doses were calculated
for one hour of playground exposure. However, since the bacteriological
strength of the surge basin wastewater may vary substantially, the peak play-
ground exposure may be considerably underestimated. In making this calculation
it was assumed that the wastewater and aerosols sampled during the one-week
monitoring period were representative of the levels and variability occurring
throughout the two-year DASTP operational period.
From comparison with usual outdoor background exposure, measured upwind of
the aerosol source, the peak exposure dose during a school day may exceed
the usual seven-hour outdoor background dose by two orders of magnitude
for fecal streptococci, and perhaps three or more orders of magnitude
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for mycobacteria.
In the two school years after the DASTP began operating, annual school attend-
ance at neighboring Durham Elementary School improved. The improvement at
Durham was evident in comparison both to prior school attendance at Durham and
to school attendance in the surrounding control schools. Hence/ there was no
evidence that operation of the DASTP had any sustained adverse effect on school
attendance at Durham Elementary. Analysis of the school attendance data on a
quarterly basis also yielded no evidence of adverse effects having a shorter
duration. However, very occasional transitory effects could not have been
identified from the quarterly attendance data available for this study.
The analysis of class attendance data showed some extended periods of elevated
absenteeism among first and second grade students at Durham Elementary (compared
to the control school class attendance) after operations at the DASTP commenced.
However, periods of even higher absenteeism among first and second grade students
at Durham Elementary also characterized many of the baseline years. Thus, it
was indeterminate whether the absenteeism among the younger students at Durham
Elementary had any relationship to DASTP operation.
This study illustrates both the advantages and disadvantages of using ele-
mentary school attendance data for an epidemiologic investigation of a
localized potential health hazard. The advantages are the uniformity,
availability, and copious volumes of school attendance data, which permit
the detection of many significant differences. The primary disadvantage is
the existence of many potentially confounding factors affecting school
attendance which are unrelated to student health and which can obscure the
potential hazard being investigated. School attendance is affected by school
factors under the principal's and teachers' control (e.g., policies regarding
student progress, nature of curricular and extracurricular activities), as well
as student factors (e.g., personal stress, sickness in family, work at home,
poverty, inclement weather, parental difference, travel distance in rural
schools) /6. While personal illness is one of the leading causes of absence, other
factors may also have sizable effect. Hence, school attendance is quite an
insensitive measure of adverse health effects. The lack of an effect on school
absenteeism does not necessarily imply the absence of any health hazard.
There were three principals at Durham Elementary during the school attendance
study period. The third principal served only during the two DASTP opera-
tional years, so the effects of his policies on school attendance are confounded
with those of the DASTP. This change in principal may have been responsible
for much of the improvement in attendance at Durham Elementary in the DASTP
operational years.
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Assessment of Disease Rates Among Sewer Workers in Copenhagen, Denmark /7
This report attempts to provide an assessment and discussion of pertinent
data as it applies to the health of sewer workers from a series of documents
published over the period of 1975-1977. The report was based on four
separate sources: 1) responses to a questionaire to sewer workers about
health and working conditions; 2) a study of sick leave records from
January 1957-December 1973 for sewer workers and a control group of all
city office workers; 3) a study of death records compared with national
mortality statistics; and 4) assessment of reports of analyses of sewer
atmospheres for toxic substances.
The municipality of Copenhagen serves 600,000 permanent residents, approxi-
mately 200,000 transients and commuters and has an industrial load equivalent,
on a BODS basis, to 1,600,000 additional persons for a total equivalent load
of 2.4 milion. The sewage is strong with a BODS concentration of 750 mg/1.
Over the entire period covered by the reports, sewer work involved primarily
cleaning and maintenance of sewers, manholes, screens, and pump stations.
About eighty permanently employed workers were classified as sewer workers
in 1976.
Mortality statistics show that sewer workers die earlier than Copenhagen males
of comparable age, many of them within the year that employment terminates.
Attempts to correlate the statistics with sick leave records or chemicals in
the environment were not successful. Sewer workers experience a high
rate of gastrointestinal tract disorders which the workers associate with
chemical odors and infectious agents. Workers have elevated levels of gamma
globulins. Analytical work has not identified any agents that might
be responsible for the observed death rates or gastrointestinal problems.
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Health Risks of Human Exposure to Wastewater /5
This draft research report was compiled by the Department of Environmental
Health and Medicine at the University of Cincinnati (U of C) Medical Center
to determine the health effects, if any, associated with occupational
exposure to biological agents present in municipal wastewater. An additional
objective was to determine the sensitivity of the methodology used for de-
tecting potential health irtpacts of other wastewater exposures, such as
recreational contact with surface water receiving wastewater effluents.
About one year after this research began, its goals were expanded to include
a determination of the health effects, if any, associated with the dispersion
of airborne bacteria and viruses generated by the activated sludge wastewater
treatment process.
In order to evaluate potential health effects, a sero-epidemiologic study
was conducted with municipal wastewater workers and controls in three
metropolitan areas: Cincinnati, Ohio; Chicago, Illinois; and Memphis,
Tennessee. The study consisted of four aspects: epidemiological,
environmental monitoring, clinical aspects, and a serological survey. The
epidemiological phase involved selection of study population, recruitment
of volunteers, collection of biological specimens for the serological and
clinical survey, collection of illness information, collection of demographic
and medical history information, and worker activity observations.
The environmental monitoring portion of the study consisted of determination
of airborne bacterial levels at worksite locations, and assay of wastewater
for viruses and bacteria.
The clinical aspects consisted of yearly multiphasic and physical examina-
tion of study volunteers, and analyses of throat and fecal specimens for
bacteria, viruses, and parasites. Parasitic examinations were performed only
during the early period of the study in Cincinnati. The multiphasic and
physical examinations served three purposes: (1) to evaluate whether waste-
water exposure affected certain tests of liver function, (2) to assess the
overall comparability of study populations, and (3) to provide motivation
for volunteers to participate in the study.
The core of the study involved an extensive serological survey to determine
levels of antibodies to a group of viruses and bacteria and to assess overall
inmunoglobulin levels. Of concern in the serologic survey was whether overall
concentration of antibody concentration was different among the various study
groups.
Possible correlations among results from the epidemiological, environmental,
clinical, and serological phases of the study were investigated to evaluate
potential health effects.
As initially conceived, the study was to include four groups of workers in
Cincinnati, Ohio. Each group was to be a minimum of 30 in number. Two of
the groups were to be routinely exposed to municipal wastewater: one group
for a minimum of two years, and the other just beginning such exposure. The
other two groups were to be engaged in an occupation not involving wastewater
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contact, and, again, one was to have been on the job for at least two years and
the other just employed. In Cincinnati, the occupational group thought to be
most exposed to wastewater was sewer maintenance workers, who were thus chosen
as the exposed population. These workers maintained the combined sanitary and
storm sewer system. Highway maintenance workers of the Cincinnati Public Works
Department were selected as the control group, since they were similar in age
and race to the sewer maintenance workers, and the types of jobs they had
were similar.
Because of a moratorium on hiring new employees in the Cincinnati Public
Works Department, prospects for establishing a newly employed highway mainte-
nance study group could not be obtained, and the group of 30 inexperienced
sewage-exposed workers was expanded to include newly-hired wastewater treat-
ment plant workers as well as the newly-hired sewer maintenance workers. The
study design was then expanded to include two additional exposed population
groups: fifty (50) men at the Cincinnati Mill Creek Sewage Treatment Plant,
which was in the process of being expanded from primary wastewater treatment
to include the activated sludge process; and a total of one hundred (100) men
employed at activated sludge treatment plants. The purpose of including this
group was to differentiate between aerosol exposure and exposure to wastewater
and sludge through those operations associated with primary wastewater treatment.
In all cities the waste water-exposed workers recruited were generally outdoor
workers engaged in various operational aspects of wastewater treatment. In
Chicago the- inexperienced wastewater treatment plant worker groups that were
recruited were laborers and security guards. Laborers and selected operating
personnel at the two Chicago water filtration plants were chosen for control
groups because they were more similar in age and race than Chicago street
maintenance workers. (The choice of a control group in Chicago was also
based in part on an interest in using a different occupational group than in
Cincinnati, where during the first year of the study the highway maintenance
group repeatedly had higher immunoglogulin levels than the sewer maintenance
group.) In Memphis neither highway maintenance nor water treatment plant
workers were similar in age and race to the newly hired wastewater treatment
plant workers. A suitable control group were located at the Gas Service
Center of the Memphis Light Gas and Water Division (MLG<f).
In each city, meetings were held with appropriate management and employee
representatives to explain the study and what was expected of participants.
The study was identified as the Public Works Employees Health Study. It
was stated that participation was voluntary and that all results would be
treated in a confidential manner.
At the time of joining the study, a family history questionnaire was
administered by a member of the research team. Questions included ones
relating to chronic health conditions and previous major health problems
of household members. In addition, at the time of the annual health
evaluation, a more detailed medical history questionnaire was given.
Permission to share study results with the participant's personal physi-
cian was obtained at the time of recruitment.
Demographic information collected on each worker included age, race, years
of school, job classification, salary, total household income, number of
persons dependent on family income, household size, and household composition
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broken -down as to adults, school-age children, and other children.
The breakdown of household composition was primarily for the purpose of
examining the number of school-age children, as they are likely to be
a source of infection.
Each worker was generally visited on his job several times during the
study to determine type of job, frequency of wastewater contact and aerosol
exposure contact, and other related work conditions. Results of these
observations were used to categorize the worker on a relative exposure
scale for direct wastewater contact and one for aerosol exposure.
The environmental monitoring program consisted of viral and bacterial
analyses of wastewater samples and bacterial analyses of aerosols. The
purpose of the aerosol sampling procedure was to provide data for the esti-
mation of the worker exposure to airborne microorganisms. The viral analyses
of wastewater were used in deciding what viruses to test for in the house-
hold member serologic survey.
Six stage Andersen samplers were used to collect the aerosols at about ten
sites at each treatment plant studied. The Andersen samplers were fastened
to tripods about 4 feet high. For all aerosol samples, calibrated pumps
pulling 1 cfm were utilized. Each sampler was specially equipped with
six molded Andersen glass petri dishes containing 27 ml of plate count agar.
In order to process the aerosol samples as soon as possible, preparation
and analyses of the plates for bacterial aerosol sampling was performed
in Chicago by the MSDGC, in Memphis by the Memphis State University, and
by the bacteriologist on the study staff in Cincinnati. At least
once during the study, duplicate samples were collected in Memphis and
Chicago for analyses by University of Cincinnati personnel.
A portable weather station was used during periods of airborne bacterial
sampling. This station consisted of instruments for wind directions and
speed, temperature, relative humidity, and barometric pressure readings.
During the quarterly specimen collection periods, 45 ml of blood were col-
lected from each worker, in three 15 ml portions. After clotting at room
temperature, the tubes were centrifuged, and the serum placed in
labeled vials.
Viral isolation specimens were obtained from a throat swab collected
by a medical technician or nurse, and a rectal swab collected by
the participant. Bacterial isolation specimens were obtained by
a second rectal swab, collected by the participant at the same time
as the first.
During the early portion of the study, before the aerosol-exposed worker
expansion, stool samples rather than rectal swabs were collected and were
analyzed for parasites in addition to viruses and bacteria. At the same
time rectal swabs were substituted for stool specimens for virus isolation,
stool specimen collection was continued for new sewage-exposed workers in
Cincinnati. Urine specimens were also collected during the early portion of
the study and were used for isolation of cytomegalovirus. These collections
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were discontinued because no such virus was isolated during the first
study year, probably because this virus does not survive long in
the environment.
Single blood specimens were obtained from the household members of study
volunteers during late summer of 1978. These specimens were obtained at
various locations in the study cities, including in homes of the volunteers.
These specimens were collected for use in a limited serologic survey to
look for differences among study groups in household-member antibody
levels.
Illness information was obtained through monthly family health diaries,
telephone contacts, and on-the-job contacts. The objective was to contact
each worker at least once a month. At the time of worker absence, tele-
phone contact was made by a study nurse to determine if an infectious
disease existed. If appropriate, a home visit was attempted for specimen
collection. In order to facilitate a worker in contacting a member of
the research staff in the event of illness, or to ask a question about the
study, telephone answering systems consisting of tapes with remote re-
trieval capabilities were installed in all three cities. Illness symptom
information from all sources was categorized as "respiratory," "gastro-
intestinal," "other," and combinations of these.
Daring periods of illness, attempts were made to collect a throat or
rectal swab from the study volunteer. These specimens were generally ob-
tained in the worker's home, but on occasion were obtained at the office
of his physician or at work.
Annual health evaluations of study participants and viral and bacterial
isolations from biological specimens were the primary sources of clinical
data. Stool samples from some Cincinnati workers were examined in the
early portion of the study for the presence of ova and cysts of parasites.
Results of the serological survey of sera collected quarterly provides the
basic core of data for the study. The sera were analyzed for antibodies
to 33 viruses or groups of viruses, 10 bacteria, and 3 classes of irrmuno-
globulins. Their purpose was to determine: (a) whether there were differ-
ences in antibody levels between groups, and (b) whether there were
significant increases in antibody levels within a group of workers over
a period of time, indicating infection. The researchers also investi-
gated the relationships between an increased antibody level in a volunteer
and'"the presence of illness symptoms.
In an effort to determine if there were any relationships among various
types of data, several comparisons have been made among the many possible
ones:
I. Worker Exposure - Virus Serology Comparisons
Every study participant was ranked into one of two categories for
wastewater/sludge and airborne bacteria exposure: (1) above average,
or (2) average or below average. These rankings are in all cases
relative to fellow workers in the same worker group (i.e., experienced
sewer maintenance). Job observations and environmental monitoring
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data even made it possible to separate the control group into
"clean" and "less clean" working environmental groups. Hone of the
comparisons had a significant correlation.
1) Control Group Comparisons—
Using data from January 1978 and October 1978 from the final virus
serology survey, the control group in all three cities were com-
pared by exposure. One exposure category referred to airborne
exposure and the others to solids and dirty water.
2) Exposed Group Comparisons—
The inexperienced sewage-exposed group in each city were ranked
according to their direct contact with wastewater and sludge
regarding the airborne bacterial levels of their workplace air.
Prevalence levels and seroconversion rates were compared between
combined-city groups with above average exposure to these
conditions with those having average or below average exposure.
Results indicate that for only one comparison is the correlation
significant. For sera collected in January 1978, the workers
with average or below average wastewater/sludge contact had
more titre levels less than the detection limit for the test
than above average exposure workers.
3. Comparison of Above-Average Sewage Exposed Group with Control Workers
in Cleaner-Than-Average Working Environments
The inexperienced sewage-exposed workers ranked above average in
wastewater/sludge or airborne bacteria exposure were compared with
control workers ranked average or below average in either liquid/
solids or contaminated air exposure. January 1978 and October 1978
virus serology data were used in making the comparisons. No statisti-
cally significant differences were detected.
II. Illness Rate - Antibody Level Change Comparison—
Four-fold or greater increases in titer level to a virus antibody is
generally regarded as a medically significant increase. Such occurrences
signify an infection which may be either clinical or subclinical.
The study did not reveal statistically significant increases in viral
infections that might be related to occupational exposure to wastewater,
as indicated by virus isolations, distribution of antibody titers
(comparative antibody levels), or increases in antibody titer levels,
either in individuals or among work groups in Chicago, Illinois,
or Memphis, Tennessee. In Cincinnati, Ohio experienced sewer maintenance
workers had higher antibody levels to Poliovirus Type 2 in January
1977. This same group had statistically significant increases in
Echovirus Type 6 antibody levels fron January-September 1977.
Based on the testing to date, there is no indication that occupational
exposure to sewage increased the risk of Hepatitis A or 3 infection
in study participants.
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Analyses of single blood specimens from family members of study partici-
pants for antibody to six viruses did not reveal higher infection rates
among families of exposed workers than controls.
No evidence was found to suggest that occupational exposure to waste-
water by the study participants produced any increase in bacterial
infection by Salmonella, Leptospira, and Legionella pneumophila.
Examination of biological specimens from workers for bacteria and
parasites did not reveal any increase in isolation rates among sewage-
exposed workers.
Iirmunoglobulin (IgA, IgG, IgM) levels were not found to be consistently
higher in the sewage-exposed workers in any of the cities studied.
Testing of liver function did not reveal any consistent abnormalities
in either the sewage-exposed groups or control groups.
Airborne bacterial levels, TVP's, inside buildings where wastewater
sludge was being processed, were higher than those at aeration basins.
TVP levels at some highway maintenance work areas are on occasion as
high as those at aeration basins of activated sludge sewage treatment
plants.
From preliminary analyses of illness rates, inexperienced workers
exposed to sewage had a higher rate of gastro-intestinal illnesses than
experienced sewage treatment plant workers.
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B. Evaluation of Alternatives
The aerosol monitoring procedure, used in 4 of the other 5 studies,
represents the state of the art, since the LVAS's used offer increased
sensitivity over other available methods. These instruments sample
at 1000 1/min, and to increase sensitivity for the viral runs, the Tigard,
Oregon, and Pleasanton, California, studies pooled samples from LVAS's
running simultaneously, resulting in sample volumes of 1,980,000 1
and 5,000,000 1, respectively. The less sensitive Andersen samplers
used in the University of Cincinnati study were considered adequate,
since the microorganism aerosol concentrations at the treatment plant
site itself are of the magnitude where these samplers' sensitivity are
adequate to characterize the exposure levels present.
Since experience in monitoring wastewater aerosols at Pleasanton,
California, showed that statistically usable biological analysis
results could be obtained only up to 200 m away from the aerosol
source during the day, and 400 m during the night, models were used
to predict concentration levels beyond these distances in Pleasanton,
California; Tigard, Oregon; and at the Egan NRP. Although the model
used required assumptions whose validity is uncertain, the predictions
of the model have been verified to 100 m for all three sites and
were considered satisfactory by the researchers. This model represents
the feasible limit of scientific capability for estimation of microorganism
aerosol concentration levels.
To detect possible health effects, all but the Tigard, Oregon study
utilized health surveys to record infectious diseases, symptoms,
and frequency. In addition to using clinical samples (collectively:
blood, feces, urine, sputum, throat swabs) analyzed for bacteria,
viruses, and parasites, the Egan WRP, the University of Illinois,
and the-University of Cincinnati studies utilized a sensitive measure
of antibody titer to detect infection. Antibody titer can detect
subclinical infection which might not be detected through a health
survey or other clinical specimens.
The Egan WKP and University of Cincinnati studies were designed to
make pre- and post-exposure measures of health on the same partici-
pants and sampling area. This self-paired comparison of the results
is a very sensitive procedure for detecting changes because it elimi-
nates the inherent variability between human subjects and between
locations. This study design also eliminates the possibility of
acquired immunity masking potential health effects, since some
participants are newly exposed.
The Tigard, Oregon study utilized a variation of the very sensitive
pre- and post-exposure study design to evaluate health effects of
a potential high risk group with exposure as close as 40 m from
the aerated surge basin. Even though not all of the same students
were investigated in the pre/post-exposure phases of the study, the
potential variability created by this should be minimized through com-
parisons with data from the control schools.
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To evaluate possible relationships between wastewater aerosol exposure
and health effects, rigid statistical procedures were used to analyze
the data. The epidemeologic study design used in the Egan WRP, University
of Illinois, and the University of Cincinnati studies was the most sensi-
tive that could be devised at the time for determining if any relationship
between wastewater aerosol exposure and health effects exists.
The Tigard, Oregon and the University of Michigan studies also utilized
health related data; however, these studies' measure of health and
exposure, respectively, were not as sensitive as those mentioned above.
Nonetheless, these studies should have detected any statistically significant
relationship between exposure to wastewater aerosols and significant
adverse health effects, if present.
The researchers concluded that several pathogens (Klebsiella, Mycobacteria,
and Staphylococcus) in wastewater are usually higher in concentration
than, and appear to have no relationship to, the concentration of indicator
organisms such as T.C. and F.C. Viable enterovirus were found in low
concentration in the primary effluent because they are primarily associated
with the solids fraction of the wastewater.
The University of Illinois study concluded that activated sludge wastewater
treatment plants are a source of low concentrations of bacteria, coliphage,
pathogenic bacteria, and enteroviruses, but are not a source of trace
metals, particulates and gasses.
The study conducted in Tigard, Oregon concluded aerosol concentration
levels tended to vary from one run to another due to variations of micro-
organisms levels in the wastewater. However, high and extremely variable
aerosol concentration levels were probably due to contamination of the
LWS's. The University of Illinois study found no correlation
between the concentration of TVP or T.C. in aerosols and sewage character-
istics. However, the Tigard, Oregon and Pleasanton, California studies
concluded that the use of such indicator organisms as T.C. and coliphage
appear to be inadequate to characterize the pathogenicity of aerosols.
Microorganism aerosol concentration levels 70-100 m downwind of the
aeration basin at Tigard, Oregon were generally as high or higher than
levels of such indicator organisms as T.C. or coliphage. The Pleasanton,
California, study suggested some microorganisms (Coliphage, Clostridium
perfringens, TVP) have a lower decay rate than T.C. and F.C.
The higher concentrations of substances detected close to the aeration
basins have been found to rapidly decrease in concentration with
distance away from the aeration basins. For example, the very sensi-
tive enterovirus monitoring conducted at Tigard, Oregon (referenced
above) detected no enterovirus at 30 m downwind of the aeration basins,
indicating a concentration less than 0.0009 pfu/m3. The study conducted
at the Egan WRP concluded that the levels of microbiological or chemical
agents of the air, soil, and water samples in the neighboring residential
areas were not distinguishable from background levels monitored.
It has been suggested that other factors also affect the microorganism
concentration levels detected. The Pleasanton, California study
suggested ambient conditions, such as low relative humidity, high wind
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velocity, and large temperature differentials between wastewater and
air, may reduce initial microorganism survival, and die-off may be more
rapid with high solar radiation and high termperature. In contrast,
the University of Illinois study found no relationship between TVP
or T.C. bacteria concentrations and aitfoient conditions. However,
as stated above, the use of such indicator organisms as T.C. appears
inadequate to characterize microorganism aerosol concentration, and
since the Pleasantcn, California study used more sensitive sampling
techniques, it appears a relationship does exist between ambient
conditions and microorganisms survival in aerosols.
Several studies investigated microbiological aerosol particle size
distributions to determine if certain microorganisms contained in
the aerosols could be inhaled. Ihe Egan WRP study and University of
Illinois study found the majority of the T.C. and TVP were in the
respirable range, but no clear trend for change of particle size
distribution with sampler distance could be detected. The Pleasanton,
California, study of aerosols from spray irrigation equipment did
detect a relationship between some microorganisms particle sizes and
distance; however, this relationship would not be expected to apply
to aerosols generated from aeration tanks.
The studies conclude that residential populations as close as 152 m
from the aeration basins at activated sludge wastewater treatment
plants have no significant adverse health effects from aerosols
emitted during plant operation. In addition, elementary school
children—a potential high risk group, appeared to have no adverse
health effects from aerosol exposure as close as 40 m from the aerosol
source at an activated sludge wastewater treatment plant.
Some preliminary analysis of illness rates indicates that inexperienced
sewage plant workers had a higher rate of gastro-intestinal illness
than experienced workers. Since these workers have exposure both
from direct contact and aerosols, the appropriateness of extrapolating
these findings to a population residing near a sewage treatment plant
remains to be determined.
The isolated instances associating wastewater exposure to health effects
could be due to chance, or a result of biased responses to health
questionnaires, and ara not considered significant when weighed
against the preponderance of evidence indicating no adverse health
effects from exposure to aerosols emanating from activated sludge
wastewater treatment plants. This is especially true if considering
nearby populations rather than intensely exposed workers.
Despite the fact it could be argued that weaknesses in individual
studies may lower their sensitivity, if any significant adverse
health effects result from exposure to activated sludge wastewater
treatment plant aerosols some substantial indications of health
effects should have been discovered.
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Since the studies' conclusions result from the investigation of:
1) activated sludge plants receiving up to 292 million gallons of
primarily residential sewage daily,
2) potential health effects of:
a) residential populations exposed to wastewater aerosols as close
as 152 m from the aerosol source,
b) elementary school children, a potential high risk group,
exposed to aerosols emanating from sources as close as
40 m, and
c) workers who directly contact sewage and are exposed to nuch
higher aerosol concentrations than those residing near an
activated sludge treatment plant,
and since the O'Hare activated sludge WRP will initially receive up
to 35 million gallons of residential wastewater daily, and will
potentially transmit aerosols to residents not closer than 117 m
to the aerosol source, the conclusions of these studies are considered
applicable to those residing near the O'Hare WRP.
1. ACTION
a) Rescind the grant condition requiring MSDGC to construct
aerosol suppression facilities at the O'Hare WRP:
No significant direct or indirect effects result from this action,
since testing of a thorough, critical, and sensitive nature,
representing the feasible limit of scientific and economic
capability, have shown that no significant adverse health
effects result from exposure to aerosols.
b) Modify the grant condition and allow operation of the O'Hare
WRP without aerosol suppression facilities, and continue
ongoing analysis of potential health effects.
i) If further study shows need for aerosol suppression:
Monetary* natural and depletable resources would be expended
on further study and in the construction and opeeration of
aerosol suppression facilities. Other adverse impacts include
noise and dust associated with construction.
ii) Further study shows no need for aerosol suppression:
Beyond the expenditure of monetary resources to further study
the potential effects of aerosol exposure, no direct or in-
direct impacts will result from this action. Thorough research
has shown that no significant adverse effects result from
exposure to aerosols emanating from activated sludge wastewater
-36-
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treatment processes within the envelope of accepted
U.S. design and operationsal practice.
2. ND ACTION
Retain the grant condition requiring MSDGC to complete construction of
aerosol suppression facilities at the O'Hare WRP prior to or concur-
rently with the commencement of functional opoeration:
Monetary, natural, and depletable resources would be expended on the
construction and operation of aerosol suppression facilities. Other
adverse impacts include noise and dust associated with construction.
If operation of the O'Hare WRP would be delayed to construct aerosol
suppression facilities, the overloaded system presently used would cause
continued combined sewer overflows and flooding of basements with combined
sanitary and stormwater, thereby threatening public health.
V. PUBLIC PARTICIPATION
A Notice of Intent to prepare a Supplemental WRP EIS was issued on July 18,
1979. Copies of this Draft Supplemental EIS are available to the public
approximately 30 days prior to the scheduled Public Hearing. Depending upon
the response to the Public Hearing, the record may remain open for 15 days
to allow further comment on matters brought up at the Public Hearing.
Comments should be submitted to: Mr. Gene Wojcik, Chief, EIS Section (5WEE),
U.S. Environmental Protection Agency, 230 South Dearborn Street, Chicago,
Illinois 60604. After all comments have been received, a Final Supplemental
EIS will be published.
VI. PREPARER
Richard Beardslee, Environmental Engineer, USEPA, Region V.
VII. LIST OF AGENCIES, ORGAN!ZATIONS, AND PERSONS TO WHOM COPIES OF THIS
STATEMENT WERE SENT
The following Federal, State, and local agencies have been requested to
comment on the Draft Supplement Environmental Impact Statement:
Council on Environmental Quality
Department of Agriculture
Soil Conservation Service
U.S. Army Corps of Engineers
North Central Division
Chicago District
Department of Energy
Argonne National Laboratory
Department of Health, Education and Welfare
Department of Housing and Urban Development
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Department of the Interior
Heritage Conservation and Recreation Service
Fish and Wildlife Service
Geological Survey
Department of Transportation
Federal Aviation Administration
Governor of Illinois
Illinois Sanitary District Observer
Illinois Institute for Environmental Quality
Illinois Environmental Protection Agency
Illinois Division of Waterways
Illinois Department of Conservation
Illinois Department of Public Health
Northeastern Illinois Planning Commission
Cook County Department of Environmental Control
Metropolitan Sanitary District of Greater Chicago
City of Des Plaines
Village of Elk Grove
Village of Arlington Heights
Village of Mount Prospect
Village of Palatine
Village of Wheeling
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VIII. SELECTED REFERENCES
1. Camann, D. E., H. J. Harding, D. E. Johnson, C. A. Sorter, 1979.
Environmental Monitoring of a Wastewater Treatment Plant. Southwest
Research Institute.
2. Camann, D. E., M. N. Guentzel, H. J. Harding, D. E. Johnson, J. W. Register,
C. A. Sorber, J. M. Taylor, R. E. Thomas, 1977. The Evaluation of Micro-
biological Aerosols Associated With the Application of Wastewater to
Land: Pleasonton, California. Southwest Research Institute.
3. Camann, D. E., J. M. Hosenfeld, D. E. Johnson, R. J. Prevost, J. W. Register,
J. M. Taylor, R. E. Thomas, J. B. Tillery, 1978. Health Implications of
Sewage Treatment FAcilities. Southwest Research Institute.
4. Carnow, B., J. Holden, S. Meyer, A. Neal, R. Northrop, S. Rosenberg,
P. Scheff, L. Sheaff, R. Wadden, 1979. Health Effects of Aerosols Emitted
From an Activated Sludge Plant. University of Illinois School of Public
Health.
5. Clark, C. S. Health Risks of Human Exposure to Wastewater. University
of Cincinnati Medical Center.
6. Cochran, K. W., K. F. Fannin*, A. S. Monto, H. Ross, 1978. Health
Effects of a Wastewater Treatment System. University of Michigan and
*IIT Research Institute.
7. Lun Dean Environmental Company, 1978. Assessment of Disease Rates Among
Sewer Workers in Copenhagen, Denmark. Health Effects Research Laboratory,
Office of Research and Development, U.S. Environmental Protection Agency.
8. U.S. Environmental Protection Agency, 1975. Metropolitan Sanitary District
of Greater Chicago O'Hara Water Reclamation Plant and Solids Pipeline
Environmental Impact Statement.
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IX. GLOSSARY OF TERMS
acquired immunity—specific immunity attributable to the presence of antibody
and to a heightened reactivity of antibody-forming (and phagocyte) cells
after exposure to an infective agent or its antigens.
activated sludge sewage treatment plant—a biological wastewater treatment
system in which a mixture of wastewater and biological sludge (microorganisms)
is agitated and aerated. The solids are separated from the treated waste-
water and returned to the aeration process, as needed.
adenovirus—a group of thirty-one viral sero-types that cause diseases of
upper respiratory tract.
aerosol—colloidal-size droplets dispersed in the atmosphere (air).
alpha and gamma hemolytic streptococci—aerobic/ facultative/anaerobic
Streptococcus genus of bacteria; gram positive spheric (or oval) cells
occurring in pairs or chains. Beta hemolytic group include human and animal
pathogenic; alpha hemolytic occur as normal flora in upper respiratory and
intestinal tract.
antibody—an inmunoglobulin molecule of specific amino acid sequence which
interacts only with the antigen that initiates its synthesis in lymphoid
tissues or with antigen closely related to it.
antigen—any substance which is capable, under appropriate conditions, of
inducing formation of antibodies and of reacting specifically, in some
detectable manner, with the antibodies so induced.
bacteria—typically one-celled microorganisms containing no chlorophyll—
some cause diseases and others are necessary, e.g., for nitrogen transforma-
tions, fermentation and organic matter decomposition.
Biochemical Oxygen Demand (BOD)—a standard test, used in assessing waste-
water composition, which measures the oxygen required to oxidize the
organic matter in a sample under standard conditions.
cfu—colony forming units.
cfu/m3—colony forming units per cubic meter.
Chemical Oxygen Demand (COD)—the amount of molecular oxygen required to
oxidize all compounds in water, organic and inorganic.
Clostridium perfrigens—a gas-producing species of bacteria that produce
several toxins and are the principal cause of gas gangrene in humans.
Also known as Clostridium welchii.
coefficient of variation—the statistical ratio of the standard deviation
of a distribution to its arithmetic mean.
-40-
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ooliform—an organism found in the intestinal tract of humans and animals.
Its presence in water indicates pollution and potentially dangerous
bacterial comtaminat ion.
coliphage—any bacteriophage able to infect Escherichia coli.
composite sample—a combination of individual samples taken at selected
intervals that represents the total material (population) being sampled.
coxsackievirus—one of the enteroviruses producing a disease resembling
poliomyelitis but with no paralysis.
echovirus—one of a subgroup of the picornoviruses infecting the gastroin-
testinal tract and discharged in the excreta; includes polioviruses,
coxsackieviruses and echoviruses.
enterovirus—a subgroup of human viruses including the coxsackieviruses
and the echoviruses.
epidemiology—a field of medicine concerned with the determination of
specific causes of local outbreaks of infection, e.g., hepatitis and
toxic disorders such as lead poisoning and other diseases of recognized
etiology.
flora—plant life in a specific location.
free chlorine—the free elemental form of chlorine from a chemical used
for the disinfection or ixidation of drinking water, sewage, or industrial
waste.
gamma globulin—any of the serum proteins with antibody activity. Also
known as inrcune globulin.
gastrointestinal—pertaining to that portion of the digestive system
including the stomach, intestine, and all accessory organs.
intestinal flora—bacteria normally residing in the lumen of the intestine.
Klebsiella—a genus of nonmotile, rod-shaped bacteria in the family of
Enterobacteriaceae; species are human pathogens.
liter—a unit of metric volume or capacity equal to 1000 cubic centimeters.
mfc—membrane filter count.
mixed liquor—a mixture of activated sludge and water containing organic
matter undergoing activated sludge treatment in the aeration tank.
micrometer Qtim)—a unit of metric length equal to one-millionth of a meter.
mucoid type—pertaining to large colonies of bacteria characterized by
being moist and sticky.
-41-
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parasitic worms—worm-like organisms that live in or on another organism
of different species from which it derives nutrients and shelter.
particulates—fine solid particles which remain individually dispersed
in gases and stack emissions.
pathogen—disease-producing organism.
pfu—plaque forming unit.
p_H—a term used to describe the hydrogen ion activity of a system,
or how acid or alkaline a material is presently.
Proteus—a genus of Enterobacteriaceae that occurs in the motile and
non-motile forms.
Protozoa—a diverse phylum of microorganisms; the structure varies from a
simple uninucleate protoplast to colonial forms.
Pseudonpnas—a genus of the Pseudomonadaceae family; most species are
aerobic and include cellulose decomposers and human, animal, and plant
pathogens.
regression analysis—analysis which measures the mean expectation one
variable to another, given two dependent random variables.
Salmonella—a genus of rod-shaped pathogenic bacteria of the family
Enterobacteriaceae that are usually motile by flagella.
scatter diagrams—statistical diagrams involving the plotting of the
pairs of values of two variates in rectangular coordinates.
Shigella—the dysentery bacilli, a genus of the family Enterobacteriaceae.
serological—pertaining to the branch of science dealing with the properties
and reactions of blood sera.
sero survey—a survey involving the properties and reactions of blood sera.
sputum—matter discharged from the surface of the respiratory passages,
mouth, or throat; may contain saliva, microorganisms, blood, or inhaled
particulate matter in any combination.
Streptococcus—a genus of the tribe Streptococceae including many patho-
genic strains; the cells are round and occurring characteristic chains.
titer—the concentration in a solution of a dissolved substance as shown
by titraticn.
total organic carbon (TOG)—a measure of the amount of organic material in
a water sample expressed in milligrams of carbon per liter of solution.
-42-
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total suspended solids (TSS)—the total number of small particles of solid
pollutants in sewage that contribute to turbidity and that resist separa-
tion by conventional means.
viable—capable of living, e.g., a pathogen capable of infecting.
virus—a large group of infectious agents capable of infecting animals,
plants, and bacteria; characterized bo total dependence on living cells
windrose pattern—a diagram in which statistical information concerning
direction and speed of the wind at a location may be suntnarized.
-43-
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