Vacuum Dosing Chemical Feeder For Chlorination And Dechlorination Helps Minimize O&M Costs For City Of Nashua, NH CSO Screening And Disinfection Facility

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.