Chemical Feed Control and Efficiency May 2016
Chemical Feed Control and Efficiency™
Vol. 1, No. 1 Reported independently by Catalytic Objective Synthesis™* May, 2016
Vacuum Dosing Chemical Feeder for Chlorination and Dechlorination Helps Minimize O&M Costs for City’s CSO Screening and Disinfection Facility
As part of its Long Term Control Plan to reduce combined sewer overflows (CSOs) to the Merrimack River, the City of Nashua, NH constructed a new Screening and Disinfection facility (SDF), to reduce untreated discharges of CSOs to the Merrimack River.
Sewer system modeling was performed by the engineering firm Hazen and Sawyer, to evaluate baseline condition performance and develop alternatives to mitigate untreated CSOs. Various CSO disinfection strategies were evaluated, and Computational Fluid Dynamics (CFD) analysis was also performed to confirm flow routing/mixing and disinfection contact times.
The results of the modeling indicated that the recommended CSO control technologies would satisfy the requirements to screen and disinfect flows up to a 2-year “actual” design storm event, without any untreated discharges at either locations CSO 005 or CSO 006.