Behaviour of Water Framework Directive Priority Substances in Stormwater and Greywater Treatment Systems

To meet the challenges of the European Water Framework Directive (WFD) the potential for water treatment technologies to limit the release of key pollutants to receiving waters must be assessed. This paper investigates the potential for stormwater best management practices (BMPs) to remove priority substances (PS) and also examines the PS emission control impact of household greywater treatment systems. In both cases, there is a limited availability of treatment efficiency data. Therefore, a systematic unit operating approach has been developed for assessing the comparative pollutant removal potentials of different types of BMPs, and fugacity modelling applications have been used as a surrogate to investigate the likely fate of PS during greywater treatment. The results indicate that infiltration basins and sub surface flow constructed wetlands may be particularly useful for preventing stormwater PS from reaching surface waters. By comparison, technical greywater treatment (not involving land disposal) is unlikely to be of major benefit as a PS emission barrier.