Biological treatment of mustard tuber wastewater and urban sewage by cyclic activated sludge system

Abstract

Treatment of high salt,high nitrogen and high phosphorous organic wastewater has been proved to be a difficult task due to the toxic effects of high salinity on microorganisms. In order to find an effective, economical and environmentally friendly approach, a cyclic activated sludge system (CASS) was used at the pilot scale for the treatment of nitrogen, phosphorus, COD and suspended solid in mixed wastewater of mustard factory effluent and urban sewage. The treatment performance of CASS pool under the several conditions of mustard wastewater mixing ratios were investigated. Effectiveness was measured periodically in terms of influent and effluent COD, total nitrogem, total phosphorus and suspended solid. The oxido-reduction potential (ORP) in anoxic phase in the reactor was also considered. Results showed that the highest mixing ratio that met the discharge standard was obtained, thus the highest salinity, COD, total nitrogem, total phosphorus and suspended solid of influent wastewater were determined. Therefore, an alternative for high salinity wastewater treatment via CASS is provided.