Environmental Engineering and Management Programme, Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India.
Environmental Engineering and Management Programme, Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India.
Ecotoxicol Environ Saf. 2012 May;79:214-224. doi: 10.1016/j.ecoenv.2012.01.004. Epub 2012 Jan 25.
Transformation and availability of nutrients and some heavy metals were assessed during the integrated composting-vermicomposting of both primary sewage sludge (PSS) and waste activated sewage sludge (WAS) using matured vermicompost as indigenous bulking material and employing Eisenia fetida as earthworm species. Vermicomposting resulted in significant increase in total N (TN) (PSS: 41.7-64.6%, F=11.6, P<0.05; WAS: 36.4-58.6%, F=6.4, P<0.05), water soluble N (WSN) (PSS: 37.1-50.5%, F=30.1, P<0.05; WAS: 40.1-53.0%, F=27.6, P<0.05), total P (TP) (PSS: 39.9-69.8%, F=27.1, P<0.05; WAS: 32.2-56.6%, F=21.4, P<0.05) and water soluble P (WSP) (PSS: 25.2-34.3%, F=163.9, P<0.05; WAS: 24.1-34.2%, F=144.3, P<0.05) as compared to the initial compost material depending on different experimental conditions. The study demonstrated that the vermicomposting significantly improved the availability of nutrients in sewage sludges. In addition, vermicomposting considerably reduced the availability of heavy metals except Fe and Mn, presumably by forming organic-bound complexes in spite of several fold increase in their total content. The environmental conditions (i.e., temperature and relative humidity), in general, showed significant effect on the transformation and availability of nutrients and heavy metals. There was no effect of earthworm density on the transformation and availability of heavy metals and nutrients except N and P, possibly due to prior exposure during acclimation period in sewage sludge.
在使用成熟的蚯蚓粪作为本土膨松材料，并采用赤子爱胜蚓作为蚯蚓物种的初级污水污泥 (PSS) 和废活性污水污泥 (WAS) 的综合堆肥-蚯蚓堆肥过程中，评估了营养物质和一些重金属的转化和有效性。蚯蚓堆肥导致总氮 (TN) 显著增加（PSS：41.7-64.6%，F=11.6，P<0.05；WAS：36.4-58.6%，F=6.4，P<0.05）、水溶性氮 (WSN)（PSS：37.1-50.5%，F=30.1，P<0.05；WAS：40.1-53.0%，F=27.6，P<0.05）、总磷 (TP)（PSS：39.9-69.8%，F=27.1，P<0.05；WAS：32.2-56.6%，F=21.4，P<0.05）和水溶性磷 (WSP)（PSS：25.2-34.3%，F=163.9，P<0.05；WAS：24.1-34.2%，F=144.3，P<0.05），具体取决于不同的实验条件。该研究表明，蚯蚓堆肥显著提高了污水污泥中营养物质的有效性。此外，蚯蚓堆肥大大降低了重金属的有效性，除了铁和锰之外，这可能是由于它们的总含量增加了数倍，形成了有机结合的复合物。环境条件（即温度和相对湿度）通常对营养物质和重金属的转化和有效性有显著影响。蚯蚓密度对重金属和营养物质的转化和有效性没有影响，除了氮和磷，这可能是由于在污水污泥的适应期内已经暴露过。
