Expanding the wet weather treatment capacity by enlarging existing plant facilities has been a cornerstone in ALCOSAN’s strategy for reducing sewer overflows. This strategy dates to the 1996 Act 537 Plan which envisioned phased plant expansion and upgrades to reduce overflows.
As a result of expanding, the current capacity of 250 million gallons per day (mgd) will be increased to 480 mgd by the end of 2025 and to 600 mgd by the end of 2027. This additional capacity will help reduce the number of overflows caused by excess stormwater entering the system.
The expansion of ALCOSAN’s treatment plant was designed in two major phases. Phase 1 was completed in 2005 and ALCOSAN has begun phase 2 which is expected to be completed in 2027.
Phase 1 included the construction of new operation and maintenance facilities and the upgrading and expansion of the main pump station. This station lifts the wastewater from ALCOSAN’s deep tunnel conveyance, or transport system to the surface for treatment.
Phase 2 of the treatment plant expansion focuses on wet weather treatment capacity to allow more sewage to be captured and treated, thereby reducing overflows during periods of rain and snowmelt.
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