TY - JOUR
T1 - Anaerobic submerged membrane bioreactor (AnSMBR) treating low-strength wastewater under psychrophilic temperature conditions
AU - Martinez-Sosa, David
AU - Helmreich, Brigitte
AU - Horn, Harald
N1 - Funding Information:
This research was supported by the German Ministry for Education and Research (BMBF) , project contract no. 02WA0854/55. Authors thank the Mexican National Council for Science and Technology (CONACYT) and the German Academic Exchange Service (DAAD) for the grant to David Martinez.
PY - 2012/5
Y1 - 2012/5
N2 - An anaerobic submerged membrane bioreactor (AnSMBR) treating low-strength wastewater was operated for 90 days under psychrophilic temperature conditions (20 °C). Besides biogas sparging, additional shear was created by circulating sludge to control membrane fouling. The critical flux concept was used to evaluate the effectiveness of this configuration. Biogas sparging with a gas velocity (U G) of 62 m/h together with sludge circulation (94 m/h) led to a critical flux of 7 L/(m 2 h). Nevertheless, a further increase in the U G only minimally enhanced the critical flux. A low fouling rate was observed under critical flux conditions. The cake layer represented the main fouling resistance after 85 days of operation. Distinctly different volatile fatty acid (VFA) concentrations in the reactor and in the permeate were always observed. This fact suggests that a biologically active part of the cake layer contributes to degrade a part of the daily organic load. Hence, chemical oxygen demand (COD) removal efficiencies of up to 94% were observed. Nevertheless, the biogas balance indicates that even considering the dissolved methane, the methane yield were always lower than the theoretical value, which indicates that the organic compounds were not completely degraded but physically retained by the membrane in the reactor.
AB - An anaerobic submerged membrane bioreactor (AnSMBR) treating low-strength wastewater was operated for 90 days under psychrophilic temperature conditions (20 °C). Besides biogas sparging, additional shear was created by circulating sludge to control membrane fouling. The critical flux concept was used to evaluate the effectiveness of this configuration. Biogas sparging with a gas velocity (U G) of 62 m/h together with sludge circulation (94 m/h) led to a critical flux of 7 L/(m 2 h). Nevertheless, a further increase in the U G only minimally enhanced the critical flux. A low fouling rate was observed under critical flux conditions. The cake layer represented the main fouling resistance after 85 days of operation. Distinctly different volatile fatty acid (VFA) concentrations in the reactor and in the permeate were always observed. This fact suggests that a biologically active part of the cake layer contributes to degrade a part of the daily organic load. Hence, chemical oxygen demand (COD) removal efficiencies of up to 94% were observed. Nevertheless, the biogas balance indicates that even considering the dissolved methane, the methane yield were always lower than the theoretical value, which indicates that the organic compounds were not completely degraded but physically retained by the membrane in the reactor.
KW - Anaerobic submerged membrane bioreactor
KW - Critical flux
KW - Low-strength wastewater treatment
KW - Membrane fouling
KW - Psychrophilic treatment
UR - http://www.scopus.com/inward/record.url?scp=84859430076&partnerID=8YFLogxK
U2 - 10.1016/j.procbio.2012.02.011
DO - 10.1016/j.procbio.2012.02.011
M3 - Article
AN - SCOPUS:84859430076
SN - 1359-5113
VL - 47
SP - 792
EP - 798
JO - Process Biochemistry
JF - Process Biochemistry
IS - 5
ER -