Mapleton Wastewater Treatment Facility
Mapleton, Maine
Mapleton Sewer District Background
The Mapleton Sewer District
was formed in 1965 and operates about 12,000 linear feet of
collector sewers. The District serves 280 customers which represents
about 700 people. The original facility was constructed as an
activated sludge plant in 1973. Effluent discharge was to the North
Branch of the Presque Isle Stream.
In 1993 the Maine Department of Environmental
Protection notified the Mapleton Sewer District it needed to address
the following issues:
-
Excess Sewer
System Infiltration and Inflow to reduce peak flows
-
Deteriorated
condition of treatment plant and a lack of unit process redundancy
that had contributed to effluent violations.
-
Remove outfall
from stream due to effluent violations in stream and due to the use of
the Presque Isle Stream as a public water supply for Presque Isle.
The District
worked with regulatory and funding agencies from 1993 to 2001 to
define a cost effective solution and to assemble a funding package for
a new treatment facility.
There were
three facility planning studies conducted between 1993 and 1997.
Thirty three different collection, treatment, and discharge options
were evaluated. Of those options the District was asked to consider
only seasonal discharge options or non-discharging options. The
District was also asked to consider options with a $3,000,000 target
budget. Another requirement was that the District only consider those
options that could process seasonal infiltration and inflow to avoid
$1,000,000 in sewer remediation costs.
In 1997 the facilities plan update focused on 2 final
options:
-
Upgrade
existing treatment plant with seasonal storage lagoon for $3,100,000
-
Construct new
facultative lagoon with non-discharging land application effluent
disposal using summer spray irrigation and winter snow storage for
$4,200,000.
The final consensus was to invest in the more costly
non-discharging lagoon option in order to permanently eliminate stream
discharge.
Project's Funding Package
The funding package was assembled between 1997 and
2001. The final project cost in 2001 dollars was $4,600,000. The
40-year Rural Development Loan was recently refinanced with the Maine
Municipal Bond Bank for 20 years with a $40,000 savings in interest
costs. The final cost to Mapleton Sewer District customers was
increase of $75.00 per year for the completely new facility.
Project Funding Sources |
|
|
DEP Grant |
$2,200,000 |
CDBG Grants (3) |
$1,100,000 |
Rural Development Grant |
$1,150,000 |
Rural Development Loan |
$150,000 |
|
|
Total |
$4,600,000 |
Construction began in 2002 and was completed in
2004.
Basis of Design for New Facility
Average Daily Flow |
70,000 GPD |
Normal Peak Hourly Flow |
160,000 GPD |
Spring Peak Hourly Flow |
380,000 GPD |
Peak Wet Weather Hourly Flow |
650,000 GPD |
Biochemical Oxygen Demand |
100 LBS / Day |
Total Suspended Solids |
100 LBS / Day |
Benefits of the Lagoon Facility
The benefits of the Mapleton Wastewater Treatment
Facility included excellent effluent quality obtained in the
facultative lagoon. By using the land application process the facility
met its goal of becoming a non discharging facility. The use of
snowmaking with the spray irrigation process allowed year round
operations with smaller storage lagoon facility.
Lagoon Specifications