A bioelectrochemical-system-based trickling filter reactor for wastewater treatment

• DOI: 10.1016/j.biortech.2020.123798
• Publication Date: 2020-07-09T23:17:05Z
• Authors: Qiaochu Liang; Takahiro Yamashita; Kazuyoshi Koike; Norihisa Matsuura; Ryo Honda; Hiroe Hara-Yamamura; Hiroshi Yokoyama; Ryoko Yamamoto-Ik...
• Keywords: Trickling filter; Geobacter; Hydraulic retention time; Nitrifying Bacteria

A bioelectrochemical system (BES)-based trickling filter (TF) reactor was utilized for wastewater treatment. At a COD load of 1.0 g-COD/L/day, effluent chemical oxygen demand (COD) and total nitrogen (TN) were 115 and 108 mg/L, respectively, which were allowed for discharge. Superior performance was achieved at 0.5 g-COD/L/day with a circulation rate of 8 L/h, and both COD and TN removal were >98%. Coulombic efficiency was 11% at 1.0 g-COD/L/day and at most 16% at 0.5 g-COD/L/day. COD removal decreased when the BES was removed, demonstrating that BES improved COD removal capability. In anodic biofilms, exoelectrogenic, facultative, nitrifying, and sulfate-reducing bacteria could coexist. Geobacter for current generation grew inside the biofilm, and bacteria in the middle and outer layers consumed oxygen and degraded organic matter and nitrogen. This BES-based TF reactor may be used for efficient and cost-effective COD and TN removal at high loads without excess sludge removal.