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Donohue is providing design and program
management services for a new 7.5 mgd average-day wastewater
treatment facility (27 mgd peak) and associated collection
system improvements. The service area covers approximately
5,500 acres and serves a resident population of nearly
20,000. The existing collection system includes 93 miles
of pipe, 1,700 manholes, and 25 lift stations. Major portions
of the sewers and numerous lift stations are approaching
their capacity limits.
The design of the new conveyance system includes approximately
6.5 miles of 48- and 54-inch diameter interceptor sewer
and associated manholes and junction structures, 6 miles
of 8- and 16-inch diameter force main, and two new pump
stations. Existing collector sewers along the route will
be connected to the new interceptor sewer.
The project involves multiple stream and railroad crossings.
Trenchless construction methods will be used for sewer
construction in within congested utility corridors, such
as street right-of-ways, under railroad crossings, and
at several road crossings. The interceptor sewer depth
ranges from 20 to 45 feet below the ground surface. Subsurface
conditions include high ground water, sand seams, and soils
comprised of fine sand and silt.
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