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The
Wells Sanitary District
provides
treatment for up to 2.0 million gallons per day of sanitary
wastewater for the Town of Wells, Maine. The original
wastewater treatment facility was constructed in the late
1970's. Over the years, the plant had suffered significant
corrosion, and had areas that were not in compliance with the
latest safety codes. In addition, a number of original
equipment systems were worn out and the facility had
faced some difficulties in consistently meeting a number of
requirements contained in its wastewater discharge permits
from the US Environmental Protection Agency and the Maine
Department of Environmental Protection. As a result, by the
end of the 1990's, the facility was in need of upgrade work.
To
address these issues, the District selected Wright-Pierce to
recommend short-term measures that could be undertaken to
improve facility operations and compliance, while concurrently
performing a comprehensive evaluation of the entire facility
focusing on longer-term solutions.
Based on
the results of the evaluation, Wright-Pierce completed the
design of a major plant upgrade in early 1999. Construction of
the upgrade was completed in January of 2002.
The upgrades to the facility feature:
New Preliminary Treatment
-New two-story Headworks Building including state-ofthe-art
fine
screening unit.
-New HEADWORKS BUILDING vortex grit removal chamber.
water
regenerated granular activated carbon odor
control unit.
Enhanced Biological Treatment
-New fine bubble aeration system with new
multiple sized blower units.
-Advanced design allows for SO percent increase
in BOD. removal with
same horsepower requirements as
previous system.
-With enhanced system, overall plant power usage
has been markedly
reduced.
Solids Handling Improvements
-New facilities for receiving, storing. and
handling ferric chloride and lime.
-New sludge press feed system. controls, and
high-tech sludge pumps.
-New innovative acid wash system to facilitate
cleaning of dewatering
equipment.
Disinfection
-Retrofitted previously abandoned secondary
clarifiers for use as chlorine
contact tanks and effluent pump
wetwell.
-Use of existing infrastructure dramatically
lowered construction costs
Process Control and Instrumentation
System
-New SCADA system allows all equipment to be
monitored and controlled.
-SCADA system allows for trending screens, DO
levels and adjustment of
automatic control loops to improve
operations.
New
Aeration Blowers
-Electrical
Facilities Improvements
-New
transformer and upgrade to emergency generation system.
-New separate electrical rooms to minimize
corrosion
In summary. the upgrade was successful in improving process
systems and overall facility operations. addressing worker
health and safety needs. and increasing energy efficiency. The
upgrade will allow the District to continue to provide
reliable and environmentally sound wastewater treatment for
the next twenty years.
Wells Sanitary District
P.O. Box 428
Wells, Maine 04090
(207) 646-5906
FAX (207) 646-4020
Website:
www.wellssanitarydistrict.com
E-mail:
wsd@wellssanitarydistrict.com
The District's normal business hours are
8:00 a.m. to 4:30 p.m. Monday through Friday. Other
hours are available by appointments made through the
Superintendent's office.
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