Vermiremediation of microelements and soluble salts in sewage sludge by earthworms

Municipal sewage sludge is the by-product of wastewater treatment plants, generated in huge quantity, causing health hazards for plants, animals and human beings. It shows presence of trace elements and their salts along with heavy metals at toxic level. The goal of present study was to reduce the high concentrations of phytotoxic trace elements and harmful soluble salts from sewage sludge, making it suitable for agricultural use as fertilizer and protection of the environment by vermiremediation technology. The experimental setup was factorial arrangement with randomized complete block design having three replications. The experiment was conducted during 2012-13 at Department of Environmental Science, University of Pune, India. For vermiremediation, Eisenia foetida and Eudrilus eugeniae were procured from regional research institutes, Pune and bulking materials (Cow Dung-CD, Sheep Manure-SM and Garden Soil-GS) were obtained from authentic local sources. The findings indicated that the high concentrations of Mg+2 and Na+ as well as NO3-2, PO4-2 and SO4-2 were brought to the minimum level at final stage of vermiremediation in all the treatments. Significant reduction (50-80 %) in trace elements and soluble salts was observed in the treatments SM and SG in presences of E. eugeniae. It can be concluded that for safe disposal of sewage sludge and its eco-friendly management bioremediation using above mentioned best treatments can be recommended.