Innovative sponge-based moving bed–osmotic membrane bioreactor hybrid system using a new class of draw solution for municipal wastewater treatment

• Published in: Water research (Oxford) 2016-03, Vol.91, p.305-313
• Main Authors: Nguyen, Nguyen Cong, Chen, Shiao-Shing, Nguyen, Hau Thi, Ray, Saikat Sinha, Ngo, Huu Hao, Guo, Wenshan, Lin, Po-Hsun
• Format: Article
• Language: English
• Subjects: Bioreactors; Carrier; Draw solution; Flux; Forward osmosis; Hybrid systems; Joining; Magnesium Chloride - chemistry; Membranes; Membranes, Artificial; Moving bed; Osmotic membrane bioreactor; Polyethylene Glycols - chemistry; Sponge; Sponges; Surface-Active Agents - chemistry; Triton; Waste Disposal, Fluid - methods; Waste Water - analysis; Wastewater treatment; Water Pollutants, Chemical - chemistry
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2016.01.024

For the first time, an innovative concept of combining sponge-based moving bed (SMB) and an osmotic membrane bioreactor (OsMBR), known as the SMB-OsMBR hybrid system, were investigated using Triton X-114 surfactant coupled with MgCl2 salt as the draw solution. Compared to traditional activated sludge OsMBR, the SMB-OsMBR system was able to remove more nutrients due to the thick-biofilm layer on sponge carriers. Subsequently less membrane fouling was observed during the wastewater treatment process. A water flux of 11.38 L/(m2 h) and a negligible reverse salt flux were documented when deionized water served as the feed solution and a mixture of 1.5 M MgCl2 and 1.5 mM Triton X-114 was used as the draw solution. The SMB-OsMBR hybrid system indicated that a stable water flux of 10.5 L/(m2 h) and low salt accumulation were achieved in a 90-day operation. Moreover, the nutrient removal efficiency of the proposed system was close to 100%, confirming the effectiveness of simultaneous nitrification and denitrification in the biofilm layer on sponge carriers. The overall performance of the SMB-OsMBR hybrid system using MgCl2 coupled with Triton X-114 as the draw solution demonstrates its potential application in wastewater treatment. [Display omitted] •A mixture of MgCl2 and Triton X-114 can serve as a novel draw solution.•The reverse flux of novel draw solution was 4.5 times lower than that of only MgCl2.•Low salt accumulation was achieved during 90-day SMB-OsMBR operation.•Approximately 100% NH4–N and 98% PO4–P were removed by the SMB-OsMBR hybrid system.•Moving free sponge carriers in the bioreactor continuously cleaned the FO membrane.