Performance of membrane bioreactor versus activated sludge at a domestic wastewater treatment plant in Oman

The main objective of this study is to evaluate two wastewater treatment methods that are implemented at a sewage treatment plant (STP) in Oman; Conventional Activated Sludge (CAS) and Membrane Bioreactor Technology (MBR). The CAS STP receives its domestic wastewater through tankers while MBR STP receives its wastewater through sewer network. Samples from influent raw sewage, biological aeration tank and treated effluent from both systems were analyzed for physical, chemical and biological properties. The obtained results showed that the raw sewage of the CAS STP can be categorized as high strength concentration compared to medium strength concentration for the MBR STP. The removal efficiency achieved at the CAS plant for TSS, TN and BOD are 97%, 57% and 98% respectively. The accomplished removal efficiency by the MBR plant is 98%, 82% and 98% for TSS, TN and BOD, respectively. However, the removed amounts of the TSS, TN and BOD in the CAS plant were 437, 40 and 442 kg per 1000 m³, respectively, compared to 147, 37 and 206 kg per 1000 m³ respectively, for the MBR plant. Thus, the CAS plant was able to remove higher amounts of pollutants compared to the MBR plant.