Metals are of particular importance in relation to water quality, and concern regarding the impact of these contaminants on biodiversity is being encapsulated within the latest water related legislation such as the Water Framework Directive in Europe and criteria revisions to the Clean Water Act in the USA. This review undertakes an evaluation of the potential of two stage wastewater treatment consisting of primary sedimentation and biological treatment in the form of activated sludge processes, to meet more stringent discharge consents which are likely to be introduced as a consequence. The legislation, sources of metals and mechanisms responsible for their removal are discussed, to elucidate possible pathways by which the performance of conventional processes may be optimized or enhanced. Improvements in effluent quality, achievable, by reducing concentrations of suspended solids or biochemical oxygen demand may also reduce metal concentrations although meeting possible requirements for the removal of copper my be challenging. Running head:The removal of metals in wastewater treatment.

Eight different sewage treatment works were sampled in the North West of England.