East Bank Wastewater Treatment Plant Bleach Disinfection System

Due to excellent past performance on other wastewater treatment plant projects, the S&WB’s private operations contractor for the East Bank Wastewater Treatment Plant (EBWWTP) requested that Trigon serve as the prime engineer for a new disinfection system at the 200 MGD EBWWTP.

The existing disinfection system utilized gaseous chlorine delivered via railway and stored on-site in the delivered rail car(s). Changes in the ability of the S&WB to utilize the railway for gaseous chlorine delivery created the need for another disinfection method to be available at the plant. The new disinfection system was based on utilizing sodium hypochlorite/liquid bleach. In general, the new bleach system includes:

• New storage tanks within a pile-supported structure, including containment area;
• New metering pumps elevated above grade to minimize the potential for flooding,
housed within a weatherproof structure;
• New chemical piping from the tanks to metering pumps to multiple injection points;
• New electrical service from a recycled activated sludge (RAS) pump house MCC/service panel to the new metering pumps;
• New instrumentation and controls to allow for flow-paced sodium hypochlorite dosing with fine adjustment of dosing based on chlorine residual;
• New controls to display and control the new metering pumps’ run status on existing SCADA system;
• Replacement of total chlorine analyzers;
• New potable water lines to new eye wash stations; and
• Other miscellaneous improvements.

Services provided by Trigon include:

• Task 1: Data Collection and Evaluation
• Task 2: 90% Design Phase Services
• Task 3: 100% Design Phase Services
• Task 4: Bid and Award Phase Services
• Task 5: Construction Phase Services