Disinfection Alternative Analysis: How Flow Rates, Hydraulics, and Operational History Affect Outcomes and Decisions

Disinfection alternative analysis has been an important consideration with respect to the recent Risk Management Plan activity. Although new regulations often spur activity and influence process change, the RMP legislation caused widespread re-thinking of disinfection alternatives available to the wastewater and water treatment industry. This paper is a case study of one such disinfection alternative analysis that considered the implications of three major wastewater disinfection processes:Chlorine gas disinfection with Sulfur dioxide gas for dechlorinationLiquid Sodium hypochlorite with liquid Sodium bisulfite for dechlorinationUltraviolet light disinfection withLow pressure, low intensity lamps,Low pressure, high intensity lamps, andMedium pressure, high intensity lamps.The study was unique in the fact that four wastewater treatment plants (WWTPs) with very different flow rates and operational history were evaluated for the best-fit alternative, independent of the alternative chosen for neighboring WWTPs.