Optimizing mass flow and extracellular electron transfer to promote energy recovery during treating municipal wastewater in a biochar enhanced anaerobic membrane bioreactor (AnMBR)
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引用次数: 0
Abstract
The anaerobic membrane bioreactor (AnMBR) is an alternative technology with energy neutrality potential when treating municipal wastewater (MWW). However, the poor bio-reaction kinetic conditions caused by low COD concentrations in MWW greatly limits the CH yield. In this study, the average methanogenesis rate was significantly increased from 164.8 to 275.5 mL/g COD with the two times biochar addition of 5 g/L. And following the second time addition of 5 g/L biochar, the CH component significantly increased to a high level of 89.0 ± 6.3 %. In addition, the rate for acetate converted into CH increased from 3.3 to 10.5 mmol/(g ·d) with biochar addition of 10 g/L, indicating that acetotrophic methanogenesis route was significantly promoted by biochar. Bio-electrochemistry analysis showed that biochar accelerated 0.74 mol e/g /min of electron transfer velocity in AD system. The addition of biochar enriched organic metabolism bacteria such as , and , and upregulated the expression of functional genes related to organics degradation such as , and facilitates the direct transfer of electrons and acetates produced by and r to convert CO into CH through microbial mediation. Thus, the COD flow shifted significantly towards more CH production. The COD mass flow showed that biochar facilitated more bio-catabolism (up about 52.7 %) and less bio-anabolism (down about 92 %), and more COD in wastewater was converted to CH, resulting a significant promoting of energy production. The energy balance analysis indicated that the net energy consumption was reduced by 15 % after two times addition of 5 g/L biochar, and the key to achieve the net energy output during treating MWW is the efficient operation of AnMBR at ambient temperature.
期刊介绍:
The Chemical Engineering Journal is an international research journal that invites contributions of original and novel fundamental research. It aims to provide an international platform for presenting original fundamental research, interpretative reviews, and discussions on new developments in chemical engineering. The journal welcomes papers that describe novel theory and its practical application, as well as those that demonstrate the transfer of techniques from other disciplines. It also welcomes reports on carefully conducted experimental work that is soundly interpreted. The main focus of the journal is on original and rigorous research results that have broad significance. The Catalysis section within the Chemical Engineering Journal focuses specifically on Experimental and Theoretical studies in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. These studies have industrial impact on various sectors such as chemicals, energy, materials, foods, healthcare, and environmental protection.