The Deer Island Wastewater Treatment Plant secondary treatment facilities were designed (and partially constructed) utilizing flow and loading projections from the 1980’s. Since that time, the MWRA has substantially increased its database with respect to operating data and influent flows and loads, and started pilot plant operations.

The original design provided full secondary treatment of flows (up to 1,080-MGD peak capacity) in our “Batteries” designated A through D. Construction had begun on Batteries A and B. Given the improved database and pilot plant operation, the Authority believed that a conceptual design reassessment of the remaining Secondary Treatment and Sludge Processing Facilities was warranted.

Savin Engineers (under a subcontract to CDM) assisted in evaluating the impact of reduced flows and loads on the original design of the Secondary Treatment System. Oversized secondary treatment facilities were identified and resized. Alternative approaches were evaluated for applicability, ability to meet permit conditions, and cost-effectiveness. Savin also assisted in the evaluation of the Pilot Plant performance and provided recommendations for the use of the pilot plant in the determination of the appropriate sizing of the facilities.