Overcoming the Challenges of a Minimum Continuous UV Dose Requirement for Disinfection of Secondary Effluent

Abstract

Overcoming the Challenges of a Minimum Continuous UV Dose Requirement for Disinfection of Secondary EffluentAbstractFacing a number of drivers related to disinfection performance and redundancy, the Stamford Water Pollution Control Authority (SWPCA) retained Hazen and Sawyer (Hazen) to evaluate alternatives for upgrading and expanding the existing ultraviolet (UV) disinfection system at the Stamford Water Pollution Control Facility (WPCF). This technical paper will review the following: National Pollutant Discharge Elimination System (NPDES) permit limits at the Stamford WPCF; Field sampling conducted to understand bacteriological reductions required of the plant’s disinfection process; Bench-scale collimated beam testing for two indicators to inform UV disinfection design dose requirements; Design considerations to ensure compliance with bacteriological limits for fecal coliform and Enterococcus and with a continuous minimum UV dose requirement; and An approach to construction that allowed the plant to maintain continuous operation of the UV disinfection process during replacement of the existing UV system.The Stamford WPCA evaluated alternatives for upgrading and expanding its UV disinfection system at the Stamford Water Pollution Control Facility (WPCF) in Stamford, CT. Primary drivers for this evaluation included planning for compliance with more stringent permit limits for Enterococcus, the need to add standby UV disinfection equipment at the plant's peak design flow, and measures needed to comply with the plant's NPDES permit requirement for the UV dose to always be a minimum 30 mJ/cm2.SpeakerHross, MattPresentation time08:30:0009:00:00Session time08:30:0010:00:00SessionUV Disinfection: Where are we? Where are we going?Session locationRoom S404c - Level 4TopicDisinfection and Public Health, Intermediate Level, Municipal Wastewater Treatment Design, Research and InnovationTopicDisinfection and Public Health, Intermediate Level, Municipal Wastewater Treatment Design, Research and InnovationAuthor(s)Hross, MatthewAuthor(s)M. Hross ¹; B. Levin ² ; M. Hross ¹; M. Mann ³; W. Brink ²; R. Pudelka ⁴;Author affiliation(s)Hazen and Sawyer ¹; Hazen and Sawyer ² ; Hazen and Sawyer, Wethersfield, CT ¹; Hazen and Sawyer, Raleigh, NC ³; Stamford Water Pollution Control Authority ²; Stamford Water Pollution Control Authority ⁴;SourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct 2023DOI10.2175/193864718825159161Volume / Issue Content sourceWEFTECCopyright2023Word count16