复合菌剂在强化污泥和秸秆的好氧堆肥中应用研究

Research on the Application of Compound Microbial Agent in Aerobic Composting of Sludge and Straw

好氧堆肥是能同时实现污泥减量化、无害化、资源化最有发展潜力的处置方式之一,为强化污泥的好氧堆肥进程和提高堆肥质量,将圆褐固氮菌(Azotobacter chroococcum)、蜡状芽孢杆菌(Bacillus cereus)和解淀粉芽孢杆菌(Bacillus amyloliquefaciens)等比例混合组建为复合菌剂,污泥与玉米秸秆按体积比1∶1.5混合,烘干调节混合物的含水率至60%后接种10%的复合菌剂,装入堆肥装置中,调节空气流量为0.20 L/min进行通气发酵15 d,所得堆体的TN、TC、TP、TK分别为(23.20±0.21)、(230.80±0.56)、(3.13±0.03)、(1.55±0.01)g/kg,发芽指数为(129.95±5.42)%。比较于未加菌剂空白组,营养基质含量均有提高,且重金属含量均大幅度降低,除As外,其他重金属指标均低于有机肥国标的限值。复合菌剂发酵的堆料中总氮减少量降低,总磷含量增高,重金属含量减少,表明该混合菌剂具有固氮、聚磷和钝化重金属的作用,有助于解决市政污泥堆肥中存在的堆肥效率低、营养流失大、重金属超标等瓶颈难题。

Aerobic composting is one of the most potential disposal methods realizing sludge reduction,innocuity and resource utilization simultaneously.To strengthen the aerobic composting process of sludge and improve composting quality,compound bacterial agent were formed by mixing Azotobacter chroococcum,Bacillus cereus and Bacillus amyloliquefaciens with the equal ratio.The sludge was mixed with corn straw according to the volume ratio of 1∶1.5,the moisture content of the mixture was adjusted to 60%by drying,then the mixture was inoculated with 10%compound microbial agent and put into the composting device,and the air flow is adjusted to 0.20 L/min for aeration fermentation for 15 d,the TN,TC,TP and TK of the sludge composting were(23.20±0.21)g/kg,(230.80±0.56)g/kg,(3.13±0.03)g/kg and(1.55±0.01)g/kg,respectively,the germination index was(129.95±5.42)%.Compared with the control group,the contents of nutrient substrate were increased,and the contents of heavy metals were decreased significantly,except As,other heavy metal indexes were lower than the limits of national standard of organic fertilizer.The decrease of total nitrogen,the increase of total phosphorus and the decrease of heavy metals in the compost of the compound microbial agent fermentation indicated that the compound microbial agent had the functions of nitrogen fixation,phosphorus accumulation and passivation of heavy metals,this will help to solve the problems of low composting efficiency,high nutrient loss and excessive heavy metals in municipal sludge composting.