大中型湿垃圾半干法全混式厌氧反应器的运行性能、微生物特性及经济性评价

Operation efficiency,microbial characteristics and economic evaluation of large-scale and medium-scale semi-dry CSTR for kitchen wet waste treatment

随着湿垃圾产生量的持续增加,大中型高效湿垃圾厌氧发酵工程发展迅速。以上海某生态园有机质固废处理项目为研究对象,对项目中有效容积分别为7160、4150 m^(3)的大型、中型半干法全混式厌氧反应器(CSTR)的运行性能及微生物群落结构特征等进行了系统研究。结果表明,稳定运行期间,大型、中型半干法CSTR平均有机负荷总体接近,平均值分别为2.02、2.04 kg/(m^(3)·d);大型半干法CSTR平均产沼率为914 Nm^(3)/t(以进料中单位质量挥发性固体(VS)产生的标况下沼气体积计,下同),显著高于中型半干法CSTR的696 Nm^(3)/t(P<0.01)。两种规模CSTR中的污泥浓度、上清液溶解性化学需氧量(SCOD)和挥发性脂肪酸等均无显著差异,SCOD去除率均可达90%以上。两种规模的CSTR中,微生物在门水平上的多样性分布无显著差异(P>0.05),均以厚壁菌门、盐杆菌门、拟杆菌门为主。大型、中型半干法CSTR进料收益分别为91.3、62.8元/m^(3),随着反应器规模的扩大,经济效益明显提升。

With the continuous increase of kitchen wet waste production,large-scale and medium-scale high-efficiency anaerobic digestion projects are developed rapidly.An organic solid waste treatment project of a Shanghai ecological park was selected as research object,the large-scale and medium-scale semi-dry continuous stirred anaerobic tank reactor(CSTR),with effective volume of 7160 and 4150 m^(3)respectively,were systematically studied from the view of operation efficiency and microbial community structure.The results showed that during long time stably operation,the average organic loading rates of large-scale and medium-scale semi-dry CSTR were similar,which were 2.02,2.04 kg/(m^(3)·d)respectively.The average biogas yield of large-scale semi-dry CSTR was 914 Nm^(3)/t(counted by biogas volume under standard conditions generated from the per unit volatile solid(VS)in feed,similarly hereinafter),which was significantly higher than that of medium-scale CSTR 696 Nm^(3)/t(P<0.01).The sludge concentration,effluent soluble chemical oxygen demand(SCOD)and volatile fatty acid of two scales of CSTR had no significant different(P>0.05).In the two scales of CSTR,the diversity distribution of microorganisms in phylum level had no significant difference(P>0.05).Firmicutes,Halobacterota and Bacteroidota were the dominant bacteria in both CSTR.Economic evaluation results showed that the feed income of large-scale and medium-scale semi-dry CSTR were 91.3,62.8 yuan/m^(3),and the economy benefits improved with the CSTR volume increasing.