厌氧膜生物反应器处理市政污水的产甲烷性能及微生物代谢特征
Study on Process Characteristics and Microorganism of Anaerobic Membrane Bioreactor for Municipal Wastewater Treatment
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摘要: 厌氧膜生物反应器(anaerobic membrane bioreactor, AnMBR)作为一种新型厌氧处理技术,可高效去除污水中的有机物并以甲烷的形式回收再利用,降低污水处理能耗与碳排量,助力实现“双碳”目标。为评估AnMBR处理市政污水时的能源回收潜力,进一步揭示处理系统工艺特性,研究考察了不同水力停留时间(hydraulic retention time, HRT)下AnMBR处理市政污水的污染物去除及产甲烷性能、微生物代谢产物及微生物群落组成特征。结果表明:①在室温条件下,HRT从24 h缩短至3.2 h过程中反应器均可实现高效的化学需氧量(chemical oxygen demand, COD)去除与产甲烷性能,COD去除效率稳定在95%以上,进水77%以上的COD转化为甲烷,出水COD浓度低至(21.2±7.8) mg/L。②反应器中溶解性微生物代谢产物浓度达70~200 mg/L(以COD计),蛋白质/多糖比值为4.3~5.5,远高于胞外聚合物中蛋白质/多糖比值(2.0~4.0),膜污染潜力高。③微生物群落分析发现产甲烷古菌/细菌比值与固体停留时间显著负相关(p<0.05),且不同粒径颗粒中微生物群落组成差异显著,产甲烷古菌在粒径≥10 μm的颗粒中丰度较高,维持混合液挥发性悬浮固体浓度在8.0~11.5 g/L和固体停留时间在60~80 d可避免细菌-产甲烷古菌间菌间失衡。研究显示,AnMBR处理市政污水可实现良好的污染物去除效果与产甲烷性能,但过长的SRT会导致的污泥浓度过高、溶解性微生物代谢产物浓度增大与产甲烷古菌丰度降低,影响系统高效稳定运行。Abstract: As a novel anaerobic treatment technology, anaerobic membrane bioreactor (AnMBR) can efficiently remove organics and recover methane in the treatment of sewage, decreasing energy consumption and cutting carbon emission, hence helps realizing "carbon peak and neutrality".To evaluate the energy recovery potential and disclose process characteristics of AnMBR treating sewage, the organics removal efficiency, methane producing efficiency, microbial metabolites, and characteristics of microbial community AnMBR treating sewage were investigated with different hydraulic retention times (HRT). The results are as follows: (1) the reactor achieved high-efficiency chemical oxygen demand (COD) removal and methane production performance at room temperature when HRT is shortened from 24 h to 3.2 h. The COD removal efficiency was over 95%, and more than 77% influent COD was converted into methane, resulting an low effluent COD concentration of (21.2±7.8) mg/L. (2) Soluable microbial products concentration in the reactor was in the range of 70-200 mg/L (calculated by COD); the protein/polysaccharide ratio of soluable microbial products was 4.3-5.5, it much higher than that of extracellular polymeric substances (2.0-4.0), meaning that soluable microbial products possess a high membrane fouling potential. (3) Microbial community analysis showed that the ratio of methane producing archaea to bacteria is significantly negatively correlated with solids residence time (p<0.05), and microbial community in particles with different sizes show large difference, methane producing archaea reaches higher abundance in particles with size≥10 μm. Maintaining an appropriate volatile suspended solids concentration of 8.0-11.5 g/L and solids retention time of 60-80 d is benefical to avoiding imbalance between bacteria and methane producing archaea. According to the results, AnMBR treating sewage can achieve excellent pollutants removal efficiency andmethane producing performance, while overlong SRT may result in high sludge concentration, increase of soluable microbial products concentration and decreass of methane producing archaea abundance , impacts efficiency and stabilityof the system.
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Key words:
- anaerobic membrane bioreactor /
- sewage /
- methanogenesis /
- microbial metabolites /
- microbial community
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