Heavy Metals And Nutrients In Sewage Sludge From Different Areas In China And Its Potential Argucultural Landuse

Sewage sludge which mainly comes from the primary settling tank and discharge of surplus sludge is the deposit produced in each operating unit in municipal wastewater treatment plant. Sewage sludge abounds many microelements and organic matters such as nitrogen, phosphor and potassium while it contains pathogen, parasite, heavy metals as well as toxic and hazardous organic pollutants which has caused a tremendous stress on ecologic environment. Research on secure and proper disposal and diposition of sludge has been carried on enthusiasticly by scholars at home and abroad. There were fire, filling and landing use. In due to Environment pression and expensive charge, the formmer disposal were reduced and forbided. Landing use was regarded as the potential disposal. However, heavy metals in sewadge sludge were the restrict factors in landing use because of easy enrichment and harmful characters.Content of nutrient, organic matters and heavy metals in different sewage sludge from 98 sewage treatment plant in 51 cities and potential of sewage in landing using were studied. The standards of controlling using sewage sludge were discussed.1. The distribution of the nitrogen content in sewage sludge was normal, The range and the arithmetic mean and standard divert of which was 8.4-50.3%, 29.5g/kg and 10.1g/kg, respectively; The distribution of the phosphor of content in sewage sludge was normal, The range and the arithmetic mean and standard divert of which was 6.0-37.5g/kg, 22.2g/kg and 6.6g/kg, respectively. The distribution of the kalium of content in sewage sludge was normal; The range and the arithmetic mean and standard divert of which was 1.4-12.1g/kg, 5.8g/kg and 2.4g/kg, respectively; The distribution of the organic of content in sewage sludge was normal, The range and the arithmetic mean and standard divert of which was 112-450g/kg, 281g/kg and 77.5g/kg, respectively. The contents of nutrients and organic contents were different in different area. And there are significant correlation between the content of organic matters and nitrogen in sewage sludge and person GDP.2. Compared with paper making sludge, chicken manure, cow manure and pig mature, the content of nitrogen in sewage sludge was significant higher(p=0.00), and there was no significant differents between sewage sludge and garbage; The content of phosphor in sewge sludge higher than that in other soid castoff and there was no significant different between that in sewage (p>0.05).The kalium content in sewage sludge was higher than that of paper making plant(p=0.00), and kalium content in sewage sludge lower than livestock manure(p<0.01).3. The average mean of heavy metals such as Zn, Cu, Cr, Ni, Pb, As, Hg and Cd in sewage sludge were 1061mg/kg, 220mg/kg, 81.2mg/kg, 49.94mg/kg, 79.31mg/kg, 20.71mg/kg, 0.34mg/kg and 2.02mg/kg, respectivly. Compared with studies in 2001,the content of other 7 kind of heavy metals were significant lower, the range of decline was 36.6%-758%.4. There were 93.8% and 10.2% of Zn which overran than limite of heavy metals in China sewage sludge GB4284-84 and GB18918-2002, and there was 8.0% and 6.12% of Zn which overran than limite of heavy metals in Europe sewage sludge and American.5. There were 17.3% and 6.12% of Cu which overran than the limite of heavy metals in China sewage sludge GB4284-84 and GB18918-2002, and there was 5.1% and 2.04% of Cu which overran than limite of heavy metals in Europe sewage sludge and American most highest sewage sludge.6. There were 7.14% of Ni, 4.12% of Cr, 5.12% of Pb and 1.03% of Cd in sample which overran the limite of heavy metals in China sewage sludge GB4284-84 and GB18918-2002, except to As and Hg.There were 2.04% of Ni, 4.12% of Cr 3.06% of Cd which overran the limite of heavy metals in Europe sewage sludge,except to Pb and Hg. There were 2.04% of Ni, 6.1% of Cr, 1.01% of Pb 1.02% of Cd which overran the limite of heavy metals in American sewage sludge, except to Pb and Hg.