不同蓬松剂对城市污泥强制通风堆肥的影响

Effects of various bulking agents on the sewage sludge composting by using forced aerating in still pile system

采用药渣和木花作为蓬松剂按体积比1∶3混合,在强制通风不足的情况下,结合每周的人工翻堆,污泥高温堆肥也可实现,高温阶段(>55℃)可维持4d。堆肥的高温使大肠杆菌数量降低4个数量级,达到国家高温堆肥卫生标准。在污泥堆制过程中,pH、VSS、有机质含量下降;但全N、P、K含量的变化与堆肥的系统条件有关。药渣堆肥在堆制35d后,种子发芽指数(GI)达50%以上,木花堆肥在堆制50d后GI达到51%。堆肥结束时,Cu、Zn、Cd在药渣堆肥中含量增加,在木花堆肥中含量减少;但其中Cu的化学有效性降低,而Zn、Cd的化学有效性提高。

Municipal sewage sludge was composted for 52 days with Chinese medical herb residues and wood chips as bulking agents in forced aerating still pile model. The temperature quickly rising above 55℃in about 4 m3 pile can be observed on second day after composting and reach the highest62℃on 6th day. The cress seed germination index (GI), used as indicator of phytotoxicity and maturation of compost, exhibited that the sludge compost was almost stabilized and mature near the 50thday of composting, when 80% and 50% of GI were obtained. The content of volatile solid, organic matter, and pH decreased as the composting time elapsed, while total N, P,K,Cu, Zn and Cd in compost were more related with the composting conditions. E. Coli,as a common indicator of pathogens in sludge, reduced greatly from the order of 105to the 101 in the final examination of the compost.