Microbial electrolysis cell (MEC) has excellent CH4 production performance, however, CO2 still remains in the produced biogas at high content. For achieving in-situ CO2 sequestration and thus upgrading biogas, mineral carbonation was integrated into a MEC treating sludge hydrolysate. With 19 g/L wollastonite addition, in-situ mineral CO2 sequestration was achieved by formation of calcite precipitates. CH4 content in the biogas was increased by 5.1 % and reached 95.9 %, with CH4 production improved by 16.9 %. In addition, the removals of polysaccharide, protein, and chemical oxygen demand (COD) of the MEC were increased by 4.4 %, 6.7 %, and 8.4 %, respectively. The generated precipitates rarely accumulated on bio-cathode, and did not significantly affect the morphology of cathode biofilm. However, integrating mineral carbonation resulted in a higher relative abundance of Methanosarcina on anode and slightly decreased the ratio of Methanobacterium to Methanosaeta on cathode, which should be noticed. In conclusion, integrating mineral carbonation is an attractive way to improve the performance of MEC by achieving in-situ CO2 sequestration, accompanied with CH4 production enhancement.

中文翻译：

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在产生甲烷的微生物电解池中处理污泥水解产物的原位矿物CO2隔离。

微生物电解池（MEC）具有出色的CH4生产性能，但是，CO2仍以高含量残留在生产的沼气中。为了实现二氧化碳原位封存，从而提高沼气利用率，将矿物碳酸化技术整合到了MEC处理污泥水解产物中。添加19 g / L硅灰石后，通过方解石沉淀物的形成实现了原位矿物固存二氧化碳的隔离。沼气中的CH4含量增加了5.1％，达到95.9％，CH4产量提高了16.9％。此外，MEC的多糖，蛋白质和化学需氧量（COD）的去除分别增加了4.4％，6.7％和8.4％。产生的沉淀物很少聚集在生物阴极上，并且不会显着影响阴极生物膜的形态。然而，整合矿物碳酸化作用会导致阳极上甲烷菌的相对丰度更高，阴极上甲烷菌与甲烷菌的比例略有下降，这一点应引起注意。总之，整合矿物碳酸化是通过实现原位CO2固存并提高CH4产量来改善MEC性能的一种有吸引力的方法。