Pilot plan protocol for optimization of UV dose required to obtain an appropriate municipal wastewater disinfection

In this work a simple but comprehensive protocol for ultraviolet (UV) pilot plant studies was developed in order to meet the microbiological guidelines established by the Andalusian Regional Government (ARG) and Aguas de Jerez, Empresa Municipal, S.A. (AJEMSA). For this purpose, two pilot UV disinfection systems were tested at the municipal wastewater treatment plant in Jerez de la Frontera (Spain) over a period of thirteen months. Both pilot units were operated using unfiltered secondary wastewater. The results obtained from the pilot plant experiments suggest that an average UV dose of 50 mW s/cm² is sufficient to meet required microbiological quality standards. The quality of the unfiltered wastewater shows that turbidity and total suspended solids could serve as good indicators for UV transmittance variations. The key parameters for an optimum protocol definition are temporal wastewater characterization, the planning and executing of UV disinfection experiments, determining the hydraulic behaviour of the UV channel, calculating the UV dose applied and, finally, evaluating experimental data.