One-year operation of a 20-L submerged anaerobic membrane bioreactor for real domestic wastewater treatment at room temperature: Pursuing the optimal HRT and sustainable flux

Jiayuan Ji; Yujie Chen; Yisong Hu; Akito Ohtsu; Jialing Ni; Yemei Li; Satoshi Sakuma; Toshimasa Hojo; Rong Chen; Yu-You Li

doi:10.1016/j.scitotenv.2021.145799

One-year operation of a 20-L submerged anaerobic membrane bioreactor for real domestic wastewater treatment at room temperature: Pursuing the optimal HRT and sustainable flux

Sci Total Environ. 2021 Jun 25:775:145799. doi: 10.1016/j.scitotenv.2021.145799. Epub 2021 Feb 12.

Authors

Jiayuan Ji¹, Yujie Chen², Yisong Hu³, Akito Ohtsu², Jialing Ni², Yemei Li², Satoshi Sakuma², Toshimasa Hojo⁴, Rong Chen⁵, Yu-You Li⁶

Affiliations

¹ Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan; Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. Electronic address: kikaen@tohoku.ac.jp.
² Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
³ Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan; Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
⁴ Department of Civil Engineering and Management, Tohoku Institute of Technology, 35-1, Yagiyamakasumi-cho, Taihaku-ku, Sendai 982-8577, Japan.
⁵ Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
⁶ Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan; Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan. Electronic address: gyokuyu.ri.a5@tohoku.ac.jp.

PMID: 33621884
DOI: 10.1016/j.scitotenv.2021.145799

Abstract

A 20 L hollow-fiber submerged anaerobic membrane bioreactor (SAnMBR) was used to treat real domestic wastewater at 25 °C with hydraulic retention times (HRTs) ranging from 4 to 12 h. The process performance was evaluated by organic removal efficiency, biogas production, sludge yield, and filtration behaviors during one-year's operation. For HRTs ranging between 6 and 12 h, the AnMBR showed good organic removal efficiency with chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal efficiencies of about 89% and 93%, respectively. The biogas yield was 0.26 L-gas/g-COD_fed, with approximately 80% methane content, and the sludge yield was 0.07-0.11 g-VSS/g-COD_rem. While at an HRT of 4 h, with the higher wastewater treatment capacity and organic loading rate (OLR), the biogas production was lower (0.17 L-gas/g-COD_fed), and the sludge production was higher (0.22 g-VSS/g-COD_rem). The organic removal performance (COD 84% and BOD 89%) at HRT of 4 h was acceptable due to the effective separation effect of the membrane filtration process. According to COD balance analysis, the low biogas yield and high sludge yield at HRT of 4 h were due to insufficient biodegradation under an OLR of 2.05 g-COD/L-reactor/d. Theoretical calculations based on Henry's law indicate that the ideal methane content in the biogas should be 82-85% when the operational temperature was 25 °C. To achieve a high flux and sustainable AnMBR operation, the impact of mixed liquor suspended solid (MLSS) and gas sparging velocity (GSV) on the filtration performance was analyzed. The critical flux increased with increase in the GSV from 24.2 to 174.3 m/h, but decreased with increase in the MLSS concentration from 8.2 to 20.2 g/L. Therefore, decreasing fouling rate to 0.8-1.2 kPa/d by efficiently controlling GSV and MLSS, sustainable operation could be achieved at a flux of 0.34 m/d.

Keywords: Anaerobic membrane bioreactor; Biogas composition; Hydraulic retention times; Mass balance; Real domestic wastewater; Sustainable flux.

MeSH terms

Anaerobiosis
Bioreactors
Membranes, Artificial
Methane
Sewage
Temperature
Waste Disposal, Fluid*
Wastewater
Water Purification*

Substances

Membranes, Artificial
Sewage
Waste Water
Methane