Chemical conditioning and cost analysis for advanced dewaterability and deodorization of primary dewatered sludge

Water content of sludge from urban wastewater treatment plant was about 80% after primary dewatering. To meet Chinese national landfilling standard, advanced dewaterability was required. A laboratory test including chemical conditioning and filter pressing was carried on. Reagent mixture ratio demanded for advanced dewaterability and cost analysis was concluded. Results showed that adding FeCl₃ solution, quicklime powder, H₂O₂, surface active agent, fly ash to wet sludge with water content of 80% for conditioning and then filtering pressing, water content could be decreased from 80% to less than 60% and to less than 45% It could reduce sludge odor, and heavy metal concentrations in sludge cake leachate could meet "Chinese Standard for Pollution Control on Landfill Site of Municipal Solid Waste"(GB16889-2008). After advanced dewaterability, water content of sludge could meet sludge landfilling requirement in "Chinese Disposal of sludge from municipal wastawater treatment plant-Quality of sludge for co landfilling" (GBT 23485-2009). Reagent cost for sludge advanced dewaterability was about 30-80 Yuan / ton wet sludge.