YAN Xi-peng,XIAO Xiao-lan,QI Jin-peng,et al.Digestion of Excess Sludge in a Pilot Anaerobic Membrane Bioreactor[J].China Water & Wastewater,2020,36(19 19):1-8.
Digestion of Excess Sludge in a Pilot Anaerobic Membrane Bioreactor
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第36卷
Number:
19 19
Page:
1-8
Column:
Date of publication:
2020-10-01
- Keywords:
- anaerobic membrane bioreactor; excess sludge; two-stage anaerobic digestion; membrane fouling
- Abstract:
- Excess sludge without pretreatment was digested in a pilot internal two-stage anaerobic membrane bioreactor (AnMBR), and the digestion efficiency and membrane performance were investigated. The reactor was operated in two phases. During phase Ⅰ (days 1 to 59), the reactor operated without sludge discharge, the organic loading rate (OLR) was 0.58 kgVS/(m3·d), the volatile solid (VS) reduction rate was 51.7%, and the biogas yield was 0.143 m3/kgVS. The total solids (TS) of the sludge in the reactor quickly accumulated to 131.1 g/L, and the soluble microbial products (SMP) continuously increased to 27.0 mg/L. Rapid accumulation of sludge concentration and SMP aggravated membrane fouling, and membrane flux reduced from 1.74 L/(m2·h) to 0.60 L/(m2·h). In order to solve this problem, sludge was discharged during Phase Ⅱ (days 60 to 90), OLR was controlled to 0.50 kgVS/(m3·d), and VS reduction rate and the biogas yield were 48.6% and 0.139 m3/kgVS, respectively. TS decreased to (50±10) g/L by sludge discharge, which was significantly lower than that without sludge discharge. In addition, SMP no longer increased and maintained dynamic balance, and membrane fouling was effectively alleviated and membrane cleaning interval was prolonged. Therefore, the change of sludge properties during anaerobic digestion was the main cause of the increased membrane fouling, and sludge discharge could alleviate membrane fouling.
Last Update:
2020-10-01