SCWD WTP Improvements

BAR was selected to be the CMAR (construction manager at risk) for this project, the first time in the company’s history to perform a project in this manner. Work package #1 includes the addition of two prefabricated fiberglass buildings that are used to house dosing equipment along with chemical day tanks. A chemical feed system for chlorine dioxide generation was included along with a 500-gallon bulk tank for sodium chlorite. The chlorine dioxide generation along with a coagulant feed system make up the pretreatment area of the plant. The coagulant feed system contains a dosing pump set up along with a 3,000-gallon bulk tank for ferric chloride. These two pretreatment chemicals are injected into the 24” raw water supply line in an underground concrete vault as built by BAR. The injection points are made into a rapid mixer that allows the chemicals to be mixed with raw water before entering the existing MF filter skid. A third prefabricated fiberglass building houses a gas chlorine feed system that utilizes carrier water to dose finish water with chlorine as needed before it heads out to distribution. This improvement project also includes the addition of air strippers that were installed in the two existing clear wells. The disinfection byproduct (DBP) internal stripping systems consists of two blowers and two sprayers in each clear well (4 each in total). Extensions are being added to the two existing PALL MF filter skids to take them from 60 filters to 88 filters each. Also, a new PALL AP8 skid will be installed to help increase the plant’s capacity to filter the raw water supply. These improvements will increase the plant’s production capacity from 2.5 MGD to a max capacity of 5.6 MGD.