A new Backwash Facility is close to completion as an outcome of the Clearwell and Backwash Pump Station Replacement Project at West Parish Filters Water Treatment Plant. The new Backwash Facility will replace aging infrastructure that is beyond its useful life and add redundancy. Financing for the $25.08 million dollar project comes from a low-interest (2%) loan through the state’s competitive Drinking Water State Revolving Fund (DWSRF) program. In early 2022 the Commission received a $4.96 million grant in the form of loan forgiveness for this project from the DWSRF.
Clearwell Replacement
The West Parish Filters clearwell serves to store filtered water for backwashing (cleaning) the rapid sand filters and for other plant processes. The existing clearwell was constructed in 1925 as a slow sand filter, and then later converted to the clearwell. Its old age makes it prone to structural integrity and infiltration issues, and also offers no redundancy for maintenance.
The new clearwell will be an underground concrete structure of two cells with a total storage capacity of one million gallons. The two cells will provide for redundancy so that maintenance can take place.
Backwash Pump Replacement
Additionally, backwash pumps located at the water treatment plant will be replaced. The two existing backwash pumps are used to backwash (clean) the rapid sand filters. The pumps date from the 1970s and are obsolete, with no availability of replacement parts or service manufacturers.
The new backwash pumps and related systems will provide critical improvements, including increased horsepower, energy-efficient motors and controls, and much-needed redundancy. The project represents Phase 1 of construction of a new West Parish Water Treatment Plant.
New Backwash Facility
The new "clearwell" tanks and backwash pumps will be housed in a singular "Backwash Facility." The 2 tanks are located underground, with the backwash pump station on top. The project is set for final completion in November 2023.
Demolition of slow sand filters built in 1909 commenced in December 2021. These slow sand filters date from the original construction of the plant and have been out of service for some time.
This will be the location of the new backwash facility. Concrete from the old slow sand filters are being used as fill for the new Backwash Facility.
Watch a time-lapse video of the demolition: https://youtu.be/jVKERXYyoYg
The slow sand filters are being demolished to make room for the new Backwash Facility.
Construction of the foundation of the underground tanks of the Backwash Facility, showing the 2 redundant chambers.
The structure of the underground tanks are in place. The backwash pumps will be placed on top.
The walls are pre-fabricated and installed using a crane.
The walls and ceiling of the Backwash Facility are up within a few weeks. Inside the various pumps and valves will be installed.
A new cross-shaped pipe valve was installed near the old clearwell to allow for eventual connection to the new clearwell tanks (while keeping the existing clearwell operational in the meantime).
Construction continues on the interior and exterior components of the new Backwash Facility.
Work throughout the spring and summer mainly focused on the pumps/piping/electrical inside and grading the site outside.
Final electrical components, which were delayed due to supply chain issues, arrived and were installed. West Parish Operations staff worked on inventorying all of the components for our computerized maintenance management system (CMMS), and also received training on the operation and maintenance of the facility. Finishing touches remain ongoing until the Backwash Facility is put into full operation in November 2023.
The new backwash pumps located in the interior of the new Backwash Facility.