| Collection
Systems
The Piqua sewer system is a
separated system consisting of both sanitary wastewater and
stormwater collection piping. The existing sanitary wastewater
collection system has a service area of approximately 5500
acres. The system consists of approximately 120 miles of sewers,
ranging in size between 5" and 42" in diameter pipe.
Six (6) wastewater lift pump stations are located in the City’s
collections system. Additional sanitary wastewater flows come
from outside the City limits, those flows being the Village of
Fletcher, the Piqua Country Club, Monnin
Estates, The Greens at Springcreek, the Villages of Springcreek,
and the I-75 Roadside rest area.
The plant operation is affected by the amount of the wastewater
flow collected by the sewers. Completion of the sewer system
rehabilitation program will eliminate inflow defects, which
currently contribute to higher then normal wastewater flows
during storm events.
The Underground Utilities Department is in charge of maintenance
and repairs in the collections system. If you need service
from this department please contact Todd
Brandenburg, Superintendent at
937-778-2018.
A new three (3) bay Maintenance
Garage plus work area, office/storage loft, and basement for
storage at the Wastewater Plant has been erected and it houses a new VacCon 2-stage
(flush & vacuum) combination sewer maintenance truck,
pipeline televising camera truck, sewer maintenance jet flushing
truck, and utility pickup truck.
Treatment
Plant History
Aerial Photo of Wastewater Plant (1957)
The
existing Piqua Wastewater Treatment Plant was originally
constructed in 1957-1958. It had a nominal design capacity of
4.0 mgd and a peak-pumping rate of 7.0 mgd. The original plant
consisted of barminutors, raw sewage pumps, raw sewage metering,
chemical mix basin for feeding lime and ferric chloride, pre-aeration
basin equipped with grit collector equipment, two
(2) primary settling tanks, four (4) aeration basins, two (2)
secondary settling tanks, one (1) plant effluent pump, two (2)
anaerobic digesters with floating covers, and a sludge
dewatering vacuum filter.
In 1969, additional treatment units
were added in order to upgrade the performance of the plant. The
additional units included one (1) secondary settling tank,
chlorination building with a chlorine contact tank, and an
aerobic digester process.
In
1984, modifications were made to the existing anaerobic
digestion system, gas handling, and flow monitoring systems.
This was needed to meet the increasing and more stringent
discharge regulations. The modifications included replacement of
an existing anaerobic digester cover to a fixed lid
configuration. The gas mixing handling system was modified to
include three (3) gas bubble-mixing guns. Flow metering
equipment and modifications were added to existing primary and
secondary settling tanks.
The 1988-1989 Plant Expansion added many
new tanks and equipment to help meet the Clean Water Act
Regulations of 1972. The Methane Gas created in digestion of
sludge is used to burn in the sludge heat exchanger for the
pathogen treatment of biosolids. During this time period a new
"Caterpillar" methane-burning engine with blower was
added, for the plant’s aeration purposes and to save on
electrical energy costs. Three (3) new screw-type raw sewage
pumps were added along with a new wet well area. A new grit and
grease process removal system with new flow channels and
equipment was also added. A new primary settling tank, two (2)
new aeration basins (2 passes per basin) with all the aeration
receiving four (4) new internal recycling pumps to aid in the
ammonia removal, and two (2) final settling clarifiers (with
piping and electrical for a 5th tank expansion, if
needed). The plant tunnels were expanded, all plant mechanical
HVAC and separate plant electrical power supply feeds with a
main switch – over gear were installed, administrative offices
were added and a new plant computer operating system was
installed at this time. A Centrifuge for dewatering sludge with
all associated piping and pumps were added along with a new
building to house it. Three (3) new river pumps were added at
the Post Aeration Well (pumping allows discharge to river, even
when the river level is higher than the plant’s discharge
line). Along the entire length of the plant on the gravel pit
quarry side, a retention wall was built and the entire plant was
enveloped with 6’ high chain link fence (approx. 6
acres).
View From the
North of the Current Wastewater Plant/Facilities
Since
the 1988-1989 Plant upgrade, numerous modifications include
adding more equipment onto the flushing water system (recycles
the plant effluent discharge water that goes into the river and
reduces the costs of using City of Piqua treated water). A
building was erected for the grit & grease facility along
with installing a new grit classifier and rag press. A
dechlorination system was added due to EPA regulating more
stringent limits on Chlorine.
EQ Basin
In 2009 the city and the OEPA agreed that the city would build a
EQ Basin to capture the smaller SSO's (Sanitary Sewer Overflows)
that would normally happen during small rain events due to I
& I (Inflow & Infiltration) in the collection system,
along with continuing to work toward the elimination of most all
SSO's. This EQ Basin can capture up to a million gallons of
wastewater at this point,that would have gone directly to the
receiving stream. Along with that project OEPA required that we
install a backup generator at the WWTP facility to keep the
treatment process running during a power outage. A 750 KWH Onan
Generator powered by a Cummins Diesel Motor was installed along
with current switchgear being modified to handle the switchover.
Backup Generator
at the Wastewater Facility
Current
Wastewater Treatment
The City of Piqua received its
new NPDES permit that became effective on August 1, 2011.
In this permit the Ohio
Environmental Protection Agency has a compliance
schedule for the SSO. The major item is that by January 31, 2016
the city shall complete all work identified as necessary to
eliminate the West Interceptor Sewer SSO. We are currently in
the planning stages of the Wastewater Plant Master Plan along
with a Sanitary Sewer System Master plan. The information
gathered by these plans will guide us through the improvements
that need made to eliminate this SSO.
The permit also has new schedules of compliance for E-coli and
Ammonia. Under current operations we can meet these effluent
limits imposed, but will look at new technologies in the Master
Plan.
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