Biological nutrient removal in a UCT-MBR pilot

Abstract

In the last years, there has been an increasing awareness about the environment pollution protection. As a consequence, the Environmental Regulation has increased the emission limits imposing, for instance, lower concentrations at the wastewater treatment plant (WWTP) outlets. As a consequence of this fact, several WWTPs are not able to respect the emission limits and need to be upgraded. In view of such needs new technology are emerging and new WWTP solution schemes are being realized. With respects to the nutrient removal enhancing, a possible solution can be the UCT-MBR which couples the University of Cape Town scheme with a Membrane Bioreactor. In the light of such considerations, the study presents a survey about the performance of a UCT-MBR pilot plant, which may offer high performance in terms of carbon and nutrient removals. Specifically, a UCT-MBR pilot plant has been designed, realized and monitored with the aim of investigating the efficiency in treating real municipal wastewater. The pilot plant has been operated for a period of 165 days during which an extensive data gathering campaign has been carried out. The pilot-plant showed good performances in terms of effluent pollutant concentrations. Further, although the pilot plant showed an overall good efficiency in terms of both carbon and nutrients removal, nitrogen and phosphorus removal efficiencies showed sometimes negative efficiencies fluctuations likely due to sporadic discharges of industrial wastewater and landfill leachate. Such a fact was justified by assuming a sensitivity of the heterotrophic biomass during the biological phosphorus and denitrification removal processes.