High-Rate Contact Stabilization Process-Coupled Membrane Bioreactor for Maximal Recovery of Organics from Municipal Wastewater

• Main Authors: Wenchen Dai, Xiaochen Xu, Fenglin Yang
• Format: Article
• Language: English
• Published: MDPI AG 2018-07-01
• Series: Water
• Subjects: bioflocculation; membrane bioreactor (MBR); high-rate contact stabilization process; organics recovery; energy recovery
• Online Access: http://www.mdpi.com/2073-4441/10/7/878

The high-rate activated sludge (HRAS) process is being studied for the removal and recovery of organics with short solids retention time (SRT) from wastewater, facilitating energy recovery by the subsequent anaerobic digestion process. In the present study, the feasibility of a novel high-rate contact stabilization (HRCS) process coupled with a membrane bioreactor (MBR) was investigated as a HRAS technique to harvest organics compared to a high-loaded MBR (HL-MBR) process treating the same sewage. Results showed that higher chemical oxygen demand (COD) removal efficiency and better bioflocculation performance were obtained using HRCS-MBR compared with HL-MBR with SRTs from 0.5 to 1.8 days. The increased bound extracellular polymeric substances content in the contactor was responsible for the improved biosorption and bioflocculation performance in the HRCS-MBR configuration. At an optimal SRT of 1.2 days, incoming organics of 47.5% and 40.5% were harvested in concentrate for HRCS-MBR and HL-MBR. These harvested organics from the concentrate per liter from HRCS-MBR and HL-MBR produced 4.28 × 10−3 and 3.72 × 10−3 kWh of electricity, respectively. The clear advantage of fouling control for HRCS-MBR was determined because of significantly lower concentrations of colloidal materials and soluble microbial products in the concentrate compared with HL-MBR. Therefore, HRCS-MBR holds promise for organics recovery and sustainable wastewater treatment.