Development of an assessment methodology to predict the effectiveness of UV disinfection of recycled water by screening Trade Waste streams causing reduction of UV transmittance

One wastewater treatment (WWT) option is disinfection with ultra violet (UV) light to remove pathogens and some contaminants, but substances in treated wastewater, such as particles of solid matter, can absorb the UV radiation and reduce its disinfecting activity. This research identified the sources of substances which are not removed by standard WWT plant processes, and which impair UV disinfection. It was concluded that trade wastes are a major source of organic, non-biodegradable humic-like substances which pose more of a problem to UV disinfection than total suspended solids. A sensor-probe based method for analysing fluorescence (‘EEM-PARAFAC’) was found to be an effective way to evaluate amounts of humic-like substances in effluents, and this information will improve management of UV WWT.