BIOASSAY FOR FULL-SCALE UV DISINFECTION SYSTEMS

A new bioassay technique for ultraviolet (UV) disinfection is presente d which permits application to full-scale systems. The technique invol ves comparison of batch dose-response behavior and full-scale, continu ous-flow disinfection efficacy using indigenous indicator organisms pr esent in secondary or tertiary wastewater effluent. This approach allo ws the bioassay to be applied to UV systems of all sizes, thereby elim inating the need for extrapolation of pilot-scale bioassays to full-sc ale systems. By comparing the results of the bioassay with dose estima tes from numerical modelling, a semi-quantitative assessment of full-s cale system hydrodynamic efficiency is developed relative to two ideal ized reactor models. This approach has merit in terms of evaluating fu ll-scale disinfection system design and identification of hydrodynamic shortcomings.