蚯蚓处理污水污泥制取土壤改良剂

将污水污泥和秸秆按不同比例混合后进行30 d预堆肥处理,然后在实验室条件下接种爱胜蚓(Eisenia fetida)开展60 d蚯蚓处理实验,研究污水污泥理化性质变化规律及其影响因素,并分析最终产品(蚯蚓粪)质量。结果表明,蚯蚓处理使污水污泥pH、有机碳(TOC)、C/N和病原菌含量显著降低,电导率(EC)升高,TN、TP、TK(总钾)、碱解氮、速效磷、速效钾分别升高26.8%～40.8%、26.7%～52.4%、25.9%～44.8%、43.0%～120.0%、88.6%～406.8%、38.2%～113.2%,发芽指数(GI)达到80%以上。由于基质分解矿化引起质量损失,使蚯蚓粪中重金属相对含量增加,但仍在土地改良允许范围内。蚯蚓放养密度和物料含水率及其交互作用对蚯蚓处理效果存在显著影响,处理污水污泥的最优工况为:放养密度2.5 kg/m2、含水率60%。堆肥-蚯蚓处理组合工艺可将污水污泥转化为无害的、有价值的土壤改良剂。

Vermicomposting for conversion of sewage sludge to soil amendment

Sewage sludge was mixed with straw at different ratios to keep for pre-treatment for 30 days,and subsequently,vermicomposting was used for 60 days’ trials by inoculating earthworm(Eisenia fetida) under laboratory conditions.Variations of physical and chemical properties of sewage sludge and its influencing factors were then studied,and the quality of final products(vermicomposts) was also analyzed.Results showed that vermicomposting may significantly decrease pH,TOC,C/N ratio and content of pathogens;and also increase electrical conductivity(EC) and contents of TN(26.8%~40.8%),TP(26.7%~52.4%),TK(25.9%~44.8%),available nitrogen(43.0%~120.0%),available P(88.6%~406.8%) and available K(38.2%~113.2%);in addition,GI of vermicomposts could reach more than 80%.Relative contents of some heavy metals in vermicomposts were higher than initial mixtures due to mass loss with decomposition and mineralization of substrate,while it was still within the allowable limit for land improvement.Earthworm stocking density,moisture content of materials and their interaction significantly affected vermicomposting efficiency,optimal processing conditions for vermicomposting of sewage sludge were earthworm stocking density of 2.5 kg/m2,moisture content of 60%.In a word,the integrated composting-vermicomposting process can be an effective technology for conversion of sewage sludge into harmless and valuable soil amendment.