Enhanced two-phase anaerobic digestion of waste activated sludge by combined free nitrous acid and manganese dioxide
Enhanced two-phase anaerobic digestion of waste activated sludge by combined free nitrous acid and manganese dioxide
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DOI：
10.1016/j.jclepro.2022.134777
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发表时间：
2022-10-24
影响因子：
11.1
通讯作者：
Wang, Qilin
中科院分区：
文献类型：
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作者：
Liu, Gang;Liu, Lei;Wang, Qilin
厌氧消化（AD）是一种成熟可靠的污泥处理技术，但仍面临水解速率慢、产甲烷量低等技术难题。游离亚硝酸（FNA）预处理在厌氧消化中被证实能增强污泥的水解和胞外聚合物（EPS）的破坏。推测在产甲烷阶段添加二氧化锰（MnO2）后，直接种间电子传递（DIET）促进了生物活性，从而促进了经FNA预处理的两相AD模型中甲烷的产生。结果表明，与单独投加MnO2或FNA预处理的反应器相比，FNA预处理和MnO2预处理相结合的反应器甲烷产量分别提高了18.64%和22.23%。通过测定辅酶F420和电子传递系统（ETS）来评价微生物代谢活性的变化。在双相AD模型中，辅酶F420和ETS活性分别增加了156.26%和134.71%。同时，微生物群落演替明显，甲烷八叠球菌属和甲烷杆菌属等产甲烷菌富集。FNA预处理与MnO2投加相结合，避免了FNA预处理对产甲烷前期的抑制作用，对产甲烷表现出正协同效应。在两阶段AD模型中，微生物代谢的增强是促进甲烷产生的原因。本研究为提高污泥厌氧消化的效率和产甲烷提供了一种新的途径。
Anaerobic digestion (AD) is a mature and reliable technology for sludge treatment, but it still faces many technical problems including slow hydrolysis rate and low methane yield. Free nitrous acid (FNA) pretreatment was previously confirmed in enhancing sludge hydrolysis and extracellular polymeric substances (EPS) disruption in anaerobic digestion. It was hypothesized that, due to the manganese dioxide (MnO2) addition during methanogenic stage, direct interspecies electron transfer (DIET) facilitated the biological activities, thus boosting the methane production in FNA-pretreated two-phase AD model. The results showed that the methane production of the combination of FNA pretreatment and MnO2 addition was improved by 18.64% and 22.23%, compared with reactors that solely treated by either MnO2 addition or FNA pretreatment. The changes of microbial metabolism activity were evaluated by measuring the coenzyme F420 and electron transfer system (ETS). The activities of coenzyme F420 and ETS were increased to 156.26% and 134.71% in two-phase AD model, respectively. Meanwhile, the obvious microbial community succession was found with the enrichment of methanogens such as Methanosarcina and Methanobacterium. Overall, the combination of FNA pretreatment and MnO2 addition avoided the inhibition of FNA pretreatment on methanogenesis in the early stage, and showed positively synergistic effect on methane production. The enhancement of microbial metabolism was responsible for, promoting methane production in the two-stage AD model. This research provides an alternative strategy for efficiency improvement of anaerobic sludge digestion as well as methane production.