Cascade degradation of organic matters in brewery wastewater using a continuous stirred microbial electrochemical reactor and analysis of microbial communities

Abstract

Abstract A continuous stirred microbial electrochemical reactor (CSMER), comprising of a complete mixing zone (CMZ) and microbial electrochemical zone (MEZ), was used for brewery wastewater treatment. The system realized 75.4 ± 5.7% of TCOD and 64.9 ± 4.9% of TSS when fed with brewery wastewater concomitantly achieving an average maximum power density of 304 ± 31 m W m −2 . Cascade utilization of organic matters made the CSMER remove a wider range of substrates compared with a continuous stirred tank reactor (CSTR), in which process 79.1 ± 5.6% of soluble protein and 86.6 ± 2.2% of soluble carbohydrates were degraded by anaerobic digestion in the CMZ and short-chain volatile fatty acids were further decomposed and generated current in the MEZ. Co-existence of fermentative bacteria ( Clostridium and Bacteroides , 19.7% and 5.0%), acetogenic bacteria ( Syntrophobacter , 20.8%), methanogenic archaea ( Methanosaeta and Methanobacterium , 40.3% and 38.4%) and exoelectrogens ( Geobacter , 12.4%) as well as a clear spatial distribution and syntrophic interaction among them contributed to the cascade degradation process in CSMER. The CSMER shows great promise for practical wastewater treatment application due to high pre-hydrolysis and acidification rate, high energy recovery and low capital cost.

Key findings

• ▸7% of TCOD and 64.
• ▸9% of TSS when fed with brewery wastewater concomitantly achieving an average maximum power density of 304 ± 31 m W m⁻².
• ▸6% of soluble protein and 86.
• ▸2% of soluble carbohydrates were degraded by anaerobic digestion in the CMZ and short-chain volatile fatty acids were further decomposed and generated current in the MEZ.
• ▸7% and 5.

Keywords

Identifiers

DOI

10.1038/srep27023

Journal

Scientific Reports

Year

2016