生物炭对污泥高温厌氧消化连续运行系统的影响

Effect of Biochar on Continuous Operation of Sludge Thermophilic Anaerobic Digestion System

为了研究添加生物炭对城市污水处理厂剩余污泥高温厌氧消化(TAD)连续运行系统的影响,考察了TAD系统的产甲烷特性及挥发性脂肪酸(VFAs)的历时变化,并对微生物群落结构和沼渣沼液性质进行了分析。结果表明,添加生物炭可促进污泥中VS和VFAs的降解,提高沼气中甲烷含量、产气量及产气稳定性。在有机负荷率(以VS计)为2.87 g/(L·d)的条件下,添加生物炭的污泥TAD平均产甲烷速率为96.89 mL/(gVS·d),比对照组提高了11.96%,同时其日产气量的均值偏差减小了5.54%,产气相对稳定。此外,添加生物炭也会显著影响微生物群落结构,促进产甲烷菌和细菌的种间直接电子转移以及互营代谢,显著提高TAD中氢营养型产甲烷菌的相对丰度。添加生物炭使污泥TAD沼液的TP和PO_(4)^(3-)-P含量降低了24.42%和34.46%,同时提高了沼渣中的氮、磷、钾含量及植物次生常量营养元素和微量营养元素含量。因此,添加生物炭有利于提高污泥TAD连续运行系统的稳定性,能够提高甲烷产率并改善消化残余物的性质。

This paper investigated the methanogenic characteristics and the changes of volatile fatty acids(VFAs)with time in a thermophilic anaerobic digestion(TAD)system,and analyzed the microbial community composition and digestate properties,so as to explore the effects of biochar addition on continuous operation of TAD of excess sludge from municipal wastewater treatment plant.The addition of biochar promoted the degradation of VS and VFAs in sludge,improved the methane content,biogas production and stability of biogas production.When the organic load rate was 2.87 g/(L·d)(calculated as VS),the average methane production rate of TAD system with biochar addition was 96.89 mL/(gVS·d),which was 11.96%higher than that of the control group,and the mean deviation of daily biogas production was reduced by 5.54%,indicating that the biogas production was relatively stable.In addition,the addition of biochar also significantly affected the microbial community composition,promoted the interspecific direct electron transfer and syntrophic metabolism of methanogens and bacteria,and significantly increased the relative abundance of hydrotrophic methanogens in TAD.The addition of biochar reduced the TP and PO_(4)^(3-)-P in biogas slurry by 24.42%and 34.46%,and increased the contents of nitrogen,phosphorus and potassium as well as the contents of plant secondary macronutrients and micronutrients in digestate.Therefore,the addition of biochar was beneficial to the stability of sludge TAD system in continuous operation,increased the methane yield and improved the properties of digestate.