Summer is on its way to New England (or so they tell us), which most of us are looking forward to for the long days and great weather. But it also can mean trouble for water utilities, as the higher temperature can lead to increased water age and degraded quality issues. The plant manager at Woodard & Curran’s contract-operated Howe Street Water Treatment Facility in Ashland, MA—Jeff Fournier—published an article in this month’s issue of Treatment Plant Operator on their creative and cost effective approach to system-wide water management that addresses both these challenges.
Historically, the Ashland Water Department invested substantial resources (as do most systems nationwide) throughout the year treating water to strict compliance standards, but the distribution system the water was being pumped to was preventing the utility from seeing a return on this investment due to its total volume (MG) and hydraulic design. Without the necessary pump strategies to maintain a high level of water quality or reduced water age, the operations staff had to frequently shock one of the system’s water tanks with chlorine to maintain a minimum disinfectant residual within that service area. While this was technically working, it was a major task that required the assistance of the local fire department and safety officials, was reactive and not proactive, and the staff was working too hard to see these kinds of results once the water reached this point in the system. While shocking the tank provided short term results, the real issue of extended water age was not being addressed.
To address this problem, staff at the treatment plant implemented a “Strategic Pump Operations” procedure that would restore the hydraulic integrity of the system for effective water age management and monochloramine disinfectant residuals in the water tanks and entire distribution system. The central components of this new approach are using real time water modeling and treating the whole distribution system as a separate water tank to accomplish effective water turnover. Using the passive mixing system in one of the tanks that the Town of Ashland had installed years prior, which was intended to stabilize the degradation of chlorine with improved hydraulic mixing, and operational changes of the remotely operated altitude valves that alter the directional flow from the plant based on water demand, the plant has seen a major turnaround without having to acquire new assets, invest capital, or disrupt service. These changes at the plant have increased water turnover, improved water quality, and allowed for chlorine residuals to be maintained above the MassDEP recommended standards for total chlorine without shocking the storage tanks; a trend that has proven successful for the past four years.
To learn more about how Ashland accomplished these goals without making large capital investments, you can read the full article here.
