污水厂自然渗滤消化污泥的蚯蚓堆肥研究

Study on Vermicomposting of Digested Sludge from WWTP

堆肥是实现污泥资源化的有效途径。城市污水厂的剩余污泥经自然渗滤消化后，与芦苇、蚯蚓混合进行堆肥，考察了污泥中氮元素形态的变化特征。堆肥周期为60d，包括自然腐熟（0～30d）和好氧腐熟（31～60d，投加蚯蚓）两个阶段。结果表明，在自然状态下堆肥，堆体高温期持续时间短，氮素损失较少，三个堆体TN含量的降低幅度分别为17．4％、16．0％和16．8％；当堆体温度〈32℃后，NH4^＋—N开始转化为硝态氮，转化率分别为44．4％、41．9％和35．9％。至堆肥结束时，种子发芽指数为（90±3）％，达到了相关堆肥标准的要求。

Sludge eomposting is an effective way to achieve resource reuse. The transformation of nitrogen forms was investigated during co-composting of reed, earthworm and the digested sludge from WWTP. Composting period is 60 days, including the natural decomposition （0 to 30 d） and aerobic de- composition （31 to 60 d, adding earthworms）. During the composting tests in the natural state, the dura- tion of high temperature of composting piles is short, the nitrogen loss is less, and the rates of TN loss in three composting piles are 17.4% , 16.0% and 16.8% respectively. When the pile temperature is less than 32 ℃, ammonia nitrogen is converted to nitrate nitrogen, and the conversion rates are 44.4% , 41.9% and 35.9% respectively. Seed germination indexes at the end of composting are （90 ± 3） % , which meets the relevant standards for composting.