The following projects have progressed over the months of August & September:

• Clearwell & Backwash Pump Station - CH Nickerson is nearing completion of this project and worked on final tasks across the project site while waiting for the arrival of delayed MCCs (motor control centers) for the pumps. The MCCs finally arrived in late August and were installed in early September. With the installation of the MCCs, the project is advancing to completion with startup activities scheduled in October. Upon completion in November the project will be officially renamed the "Backwash Facility".

• New Water Treatment Plant - Hazen submitted draft 90% design documents and scheduled a workshop in October to review the documents with Commission staff. They also continue to host regular meetings with Commission staff to closely review each aspect of the design and to receive input on the final design details. Hazen continues to work on permitting and contractor engagement for this project as well and prepared Request for Qualifications documents that are being used to prescreen contractors prior to bidding on the project.

Clearwell & Backwash Pump Station Site

(SWSC drone photo, 08/10/2023)

Over the month of August, the contractor worked to complete final tasks across the project site while they waited for the arrival of the pump Motor Control Centers (MCCs), which were delayed by several weeks. The MCCs finally arrived at the end of the month, allowing the contractor to move forward with the project schedule and continue working towards facility startup and final tie-in connections to the transmission mains. 

Over the month of September, the contractor began startup and testing activities. The contractor disinfected the backwash tanks and completed pump testing. The facility is scheduled to be brought online in mid-October after systems testing. Final tie-ins to the transmission mains to disconnect the existing clearwell and demolition of existing equipment are scheduled for late October into November.    

The new Clearwell and Backwash Pump Station facility ("Backwash Facility") will replace the existing clearwell and backwash, domestic, and process water pumps. The existing clearwell was originally constructed as a slow sand filter in the 1920s and the roof leaked into the clearwell until we installed the temporary tarp cover. Failure of this clearwell would require the Rapid Sand Filter Plant to be shut down entirely. The existing backwash pumps were installed in the 1970s with the construction of the Rapid Sand Filter Plant and need to be replaced. Parts for these pumps are no longer available should they require repair. This new Clearwell and Backwash Pump Station structure will provide the reliability and redundancy needed for the water treatment process and will be utilized with both the existing and new treatment plant.

Construction Progress

Inside the new Backwash Facility, the contractor has continued working on punch list and finish work. Work was completed on the plant domestic water treatment systems (UV system for disinfection and sodium hypochlorite system for chlorine residual). The water storage tanks were pressure washed in preparation for final disinfection. The contractor also made adjustments to the AC system in the electrical room, added additional paint on submerged piping to protect from rust, repaired leaks in the waterproofing system on the backwash tanks, and completed the installation of pipe insulation. The electrician continued to install conduit and wiring and began installing the MCCs immediately after they arrived.

Testing and training activities continued through August and included Bridge Crane training for Water Operations staff and testing of the waterproofing system over the backwash tanks, as well as testing the new caustic piping for relocation of caustic dosing of the backwash water.  In September, the MCC and VFDs were commissioned, the individual pumps were tested, and pump training was provided to Water Operations staff. MassDEP performed a site inspection of the Backwash Facility and the domestic water system and conditionally approved the work for startup. 



On site, the contractor added crushed stone where required, placed loam, and seeded grass.  Work was completed on the chemical injection vaults and chemical injection quills were installed. Routine flushing was performed to keep water in new piping from becoming stagnant.  Existing cathodic protection systems for site piping was repaired. The contractor also worked on general cleanup including restoring the site lighting and fencing that were removed or disconnected for construction activities and adjusting structures and gate boxes to the final grade.   The new Backwash Facility is on-schedule to be completed in November.

Raking/spreading crushed stone

(photo by AECOM)

Grading along the south side of the facility

(photo by AECOM)

Raking/spreading crushed stone

(photo by AECOM)

Pulling cables

(photo by AECOM)

Painting the submerged piping in southern tank

(photo by AECOM)

Pressure washing tank walls and floor

(photo by AECOM)

Performing cleanup in the center vortex channel (photo by AECOM)

Filling up the center vortex channel for disinfection

(photo by AECOM)

Testing residual chlorine

(photo by AECOM)

Pumping from exterior to interior hatches to mix dechlorination chemical

(photo by AECOM)

Insulating mechanical piping

(photo by AECOM)

Vertical turbine pump training

(photo by SWSC, 09/28/23)

Backwash pumps inside facility

(photo by SWSC, 09/26/23)

Setting the next intermediate section of precast concrete chemical injection vault

(photo by AECOM)

Chemical Injection Quills in the southern chemical injection vault

(photo by AECOM)

Installing new chemical injection vaults and future location of tie-ins to existing transmission mains

(SWSC drone photo, 08/10/2023)

Installing chemical injection vault access ladder

(photo by AECOM)

Reinstalling fence and gates around flocculators

(photo by AECOM)

Last August (left) vs this August (right)

(SWSC drone photos, 08/12/2023 and 08/10/2023)

New Water Treatment Plant - Highlights

Hazen completed and submitted 90% design documents in September for the Commission's review. Hazen has scheduled a workshop for October to review the documents with Commission staff.

Hazen continues to host regular meetings with Commission staff to closely review each aspect of the design and to receive input on the final design details. Hazen continues to work on permitting and contractor engagement as well and prepared Request for Qualifications (RFQ) documents that will be used to prescreen contractors prior to bidding on the project. The RFQ was issued in early September.

Bid opening for this project is planned for mid-2024.

New WTP Progress Rendering

(Hazen rendering, May '23)

Why are we building a new plant?

The Commission currently relies on our 1970s era dual media filtration rapid sand filters to treat most of the system's water, and uses the slow sand filters, which date back to the 1920s, to augment production when needed.

In 2012 the U.S. Environmental Protection Agency (EPA) and Massachusetts Department of Environmental Protection (MassDEP) updated its regulations related to disinfection byproducts (DBPs).

DBPs form when chlorine (required for safe disinfection) reacts with dissolved natural organic matter (NOM) found in surface water bodies such as the Commission’s Cobble Mountain Reservoir, the main source of the drinking water supply. Data indicate that the more intense and extreme precipitation patterns observed in recent years can cause increases in the amount of NOM in the reservoir.

The 1970s-era rapid sand filters are not capable of removing the amount of NOM now necessary to consistently meet the new DBP regulations. In addition, many other components of the plant are at or beyond the end of their useful life, increasing the risk of failure. Therefore, in 2015 the Commission initiated a comprehensive planning process to modernize the drinking water treatment plant.

The new plant will include the use of Dissolved Air Flotation (DAF) to treat the water by using rising bubbles to push flocculated particles up into a floating mat. The floating mat is collected at the end of a long tank. This process removes particulates and organics upstream of the filters and will enable the Commission to reduce DBPs in the distribution system to meet regulatory compliance for decades to come.

View this short video about why we are building a new plant:

 https://youtu.be/8J2NK0hqgNs?si=ALguKF_TUsgBwFmU

We would like to invite you to view the Backwash Facility and tour the past, present, and future of West Parish Filters Water Treatment Plant at our Open House!

Thursday, Oct. 19, 3 - 6:30 PM.

More info: waterandsewer.org/open-house

Nature moment...

Morning mist rises over the WPF Sedimentation Basin

(photo by Kevin Zeneski 09/07/23)