The City of San Mateo rehabilitated the 42nd Avenue Pump Station as part of the CWP and as a compliment to the City’s biennial pump station rehabilitation program. The project was not intended to increase the capacity of the system rather, it ensures the existing collection system components continue to function optimally.
The project consisted of three elements: (1) the rehabilitation of an underground pump station; (2) the replacement of underground electrical conduit; and (3) the installation of a new, above-ground, standby generator. This project required the demolition and removal of existing electrical equipment, pumps, valves, piping, and access hatches.
To provide a complete and functional pump station rehabilitation, this work included:
1. Underground Pump Station Rehabilitation
Pump stations are a necessary component of the wastewater collection infrastructure. These pumps support the upward movement of wastewater from underground gravity pipelines. When the wastewater levels rise, the pump starts and lifts the wastewater upward through a pressurized pipe system, and ultimately to the wastewater treatment plant.
Over time, underground pump stations corrode and break down. Rehabilitation helps to extend their useful life. Failure of the pump station to move the wastewater can lead to sewer overflows.
The rehabilitate work included repairing pipes and valves, as well as recoating the existing wet well and underground vaults. The project also included replacing electrical and instrumentation controls, constructing a remote motor control center and transfer switch, and installing new valve access hatches.
2. Underground Electrical Conduit
All wiring to the pump station must be run in a conduit and be routed below-grade, inside walls, or within slabs to the extent possible. The existing conduit was in need of replacement due to age and deterioration.
The electrical conduit was installed in El Camino Real from 42nd Avenue to 43rd Avenue for the new backup generator across 43rd Avenue, which included excavation of existing material, installation of conduit, backfilling, and final paving. Electrical conduit was also installed along El Camino Real from the pump station and across 43rd Avenue to the new above-ground generator across 43rd Avenue.
3. New Above-Ground Standby Generator
The purpose of a standby generator is to automatically come online in the event of an outage to keep the pumps running and wastewater flowing through the collection system. The existing standby generator had reached the end of its expected useful life and could no longer be maintained with available parts. In lieu of repair and upgrades to the existing unit, a full replacement was determined to be more cost-efficient, more reliable, and provide faster response time when utility power is out.
A more compact, diesel-powered engine generator and fuel tank was installed as part of this project. The work included a new generator pad area, as well as a remote motor control center and transfer switch. The new system includes new switch gear, batteries, and battery chargers.