Agronomic Benefits And Environmental Impacts Of Sewage Sludge Application To Soils

With the rapid increase of sewage treatment plants, the disposal and the environmental impact of sewage sludge have been paid more and more attention. Now, land application of sewage sludge has become an important way for sewage sludge disposal duo to its lower cost and higher efficiency. But heavy metals are the key factor that affects the land application of sewage sludge. So we have done some researches on the monitoring of nutrient and heavy metal concentration and the phytoavailability of heavy metal in soil treated of sewage sludge by a pot experiment. Also the impacts of soil environmental and heavy metal contents in wheat by land applications of sewage sludge were evaluated to assess the agronomic benefits and environmental impacts of sewage sludge application to soils. The main results obtained were as the following:1. The content of organic matters, nitrogen, phosphorus and potassium in sewage sludge from Beijing is 35.5%, 2.7%, 3.8% and 0.2%, respectively. Except potassium, those are higher than organic fertilizer as pig manure and chicken manure.2. The mean concentrations of Zn, Cu, Cr, Pb, Ni, As and Hg in sewage sludge from sludge disposal plant are 1665 mg/kg, 238 mg/kg, 98 mg/kg, 79 mg/kg, 46 mg/kg, 20 mg/kg and 13 mg/kg, respectively, and are 821 mg/kg, 149 mg/kg, 31 mg/kg, 35 mg/kg, 40 mg/kg, 21 mg/kg, 14 mg/kg respectively from sewage treatment plant. Compared with the heavy metal limits of sewage sludge for land application in china, Zn, Cu, Cr, Pb, Ni and As concentrations in sewage sludge are lower than the limits value, and Hg concentrations in sewage sludge is overran the limits value for pH...