Research on agricultrual utilization of sewage sludge in China began in the early fo 80's and criteria has been set for agricultrual application of sewage sludge. usually sludge is composted, it is used as ferilizer in China. During composting, straw, wood chips, bark and tree leaves are added as amending and/or bulking agent to improve fertility fo composted sludge. Sometime potassium fertilizer and lime are also added to increase the K content and to reduce the bio-activity of heavy metals. COmpared to developed countries, the percentage of treated wastewater, especially domestic wastewater, is still very low in china. Howvver, as environmental protection laws are implemented and domestic wastewater treatment becomes more usual. the total amount of sludge will increase dramatic ally. Therefor research on proper use of sludge should be given high priority.
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