Vermi Sludge Treatment Wetland

Three pilot-scales Vermi Sludge Treatment Wetland (VSTWs) have been constructed and operated treating sewage sludge from Wastewater Treatment Plant (WWTP), Ichalkarnji, and Dist-Kolhapur. Quantification of the dewatering mechanisms in these systems (i.e., evapotranspiration and draining) is attempted here, and the effects of different parameters, i.e., the level of sludge loading, the presence of plants, the substrate materials used etc., on these mechanisms are presented. Results reveal that evapo-transpiration is the major dewatering process that takes place in STW systems, accounting for 58–84% of total water losses, depending on unit characteristics, sludge loading, season and other parameters. Draining follows in significance, with respective values varying from 13% to 47% of total water losses, while 1% to 4% of water remains in the sludge layer. The presence of wetland plants was found necessary, since it improved the dewatering efficiency. Precipitation and temperature were also found to affect the dewatering process under climatic conditions. Since Earthworms are used change in solid concentration is observed. Also as they survived in sludge, the final bioproduct has a good fertile quality.