Efficient Treatment of Wood Vinegar via Microbial Electrolysis Cell With the Anode of Different Pyrolysis Biochars

Abstract

Microbial electrolysis cell (MEC) has emerged as the promising technology for COD removal as well as bioenergy recovery during the treatment of bio-refractory wastewaters. This study mainly focused on wood vinegar (the by-product from biomass pyrolysis) treatment via MEC technology with two typical biochars (coconut shell biochar and shrub biochar) as the carriers of microorganisms in anode chamber. Results indicated that MECs with coconut shell biochar had an obvious beneficial effect for treating wood vinegar, with COD removal reached up to 71.4%. GC-MS analysis showed that furfurals present in the wood vinegar were thoroughly degraded after MEC treatment. One interesting finding is that hydrocarbons accounted for a large portion of the compounds in the effluent, which may be the comprehensive result of complex organic reactions, including decarboxylation reactions, dehydration reaction, etc. The dominant microbial populations in MEC with biochar anode mainly included Geobacter, Macellibacteroides, Oscillibacter, Sedimentibacter, Comamonas, and Lachnoclostridium. This study demonstrated that pyrolysis biochar could be incorporated as a high-efficiency MEC anode material, and MECs with the inclusion of biochar could provide a feasible way for the treatment of recalcitrant wood vinegar.