蚯蚓直接处理城市剩余污泥的研究

Study on Municipal Excess Sludge Treatment by Earthworms

以城市剩余污泥为饲料,根据蚯蚓的繁殖、生长时间,定时引出成蚓换料连续饲养,并改变留在原泥中蚓卵的生存环境来控制卵的发育之蚯蚓养殖方法,并对城市剩余污泥直接饲养蚯蚓的可行性及其重金属转移规律进行研究。结果表明,城市剩余污泥直接饲养蚯蚓是可行的;饲养过程中蚯蚓体内的重金属浓度随着饲养时间而上升,至4个月左右,蚯蚓体内重金属浓度达到极限,且该养殖法具有蚯蚓产量低,对蚯蚓具有易于处理和处置的优点。

Beneficial roles of earthworms on soil fertility, nutrient cycling and plant growth has been commonly observed. Earthworms could influence metal mobility in soil through burrowing and casting activity. The question arised whether earthworm could feed directly on no- -pretreated excess sludge,or whether multiplication rate of earthworms could be controlled . The objective of this study was to investigate the feasibility of earthworm feed directly on excess sludge and the effect of earthworm on metal accumulating under low multiplication rate. Excess sludge from Ningbo municipal sewage plant was used in the pot experiment. The results showed that new excess sludge was eatable to earthworms. Earthworms could accumulate heavy metals in sewage sludge , and with culturing time increasing , the concentrations of heavy metals in earthworms increased. According to the culturing methods, the concentrations of heavy metals in earthworms increased high - point after about four months, and multiplication rate of earthworms was lower than that by using conventional culturing methods.