Optimization of membrane filtration and cleaning strategy in a high solid thermophilic AnMBR treating food waste

• Published in: Chemosphere (Oxford) 2023-11, Vol.342, p.140151-140151, Article 140151
• Main Authors: Jiang, Mengmeng, Huang, Jiu, Li, Peng, Ataa, Bridget, Gu, Jinheng, Wu, Zhiyue, Qiao, Wei
• Format: Article
• Language: English
• Subjects: Anaerobic membrane bioreactor; High solids; Membrane cleaning; Membrane operation; Thermophilic
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.140151

Anaerobic membrane bioreactor is advantageous over traditional processes for food waste treatment, i.e. short retention time, high loading rate, and particulate clean permeate. However, establishing a sustainable membrane filtration is a long-standing challenge because of its high viscosity and solids concentration characteristics. Therefore, this study investigated the changes in the membrane permeability before and after the cleaning during a 130-day thermophilic anaerobic experiment. Results show that the AnMBR system could maintain high stability even under a short HRT of 10 days and OLR of 9.0 kg-COD/(m3·d) with low volatile fatty acid of 50 mg/L. The membrane filtration deteriorates with the concurrence of a sharp increase of viscosity when the volatile solids reached 23 g/L. A critical flux was achieved at 5.5 L/(m2·h) under optimized operation conditions, membrane filtration/relaxing ratio with less than 4:1 at a hydraulic retention time of 15 d. Membrane fouling can be removed by soaking the membrane in NaClO (1 g/L, 15 h) and citric acid (2 g/L, 2 h). Conclusively, this work provides insight to establish the operation strategy for a thermophilic AnMBR treating food waste. [Display omitted] •Sustainable filtration of AnMBR correlated with TS concentration and viscosity in the reactor.•Critical flux and optimized membrane filtration mode were established.•Sludge viscosity increased obviously when TS concentration reached 23 g/L.•1 g/L NaClO and 2 g/L citric acid soaking for 15 h and 2 h respectively effectively relieve membrane fouling.