Analysis On The Effects Of Municipal Sludge Utilization On Soil And Plant Growth

China, as the world’s largest developing country, socio-economic growth year after year, is rapidly advancing industrialization, urbanization China is also being accompanied by increased every year. Treatment and disposal problems caused urban sewage treatment plant sludge has become the focus of attention. Urban sewage sludge is rich in nitrogen, phosphorus, organic matter and other nutrients, but at the same time one of the contaminants may also be harmful to the environment and human. So how would the sludge "turning waste into treasure" to ensure that municipal sewage sludge land utilization efficiency of products, while the content of crops to control pollutants to within a safe range, has been a focus of research.In this paper, lime-drying sludge products from Xiaohongmen lime-drying factory and thermal drying sludge products from Qinghe thermal drying factory to provide an example, study the sludge drying products nutrients and heavy metal content and analyze its agricultural potential and safety impacts; Sludge drying products and topsoil(0 ~ 20cm) mixed set application rate was 0kg / m2, 1kg / m2, 2kg / m2, 3kg / m2 four treatments, the use of pot experiment showed that after administration of the soil vegetable growing conditions and the laws on heavy metal accumulation of heavy metal content in soil and vegetable safety analyzes evaluate proposed land use of sludge suitable parameters affect the environment and land use of sludge drying product. The results showed as follows:(1)thermal drying sludge products in total nutrient(N + P2O5 + K2O) and high organic matter content, far exceeding the national standard of organic fertilizer, it has large agricultural value and it’s stronger to improve the soil nutrient, lime-drying sludge products of a low organic matter content, it’s total nutrient content of sludge in agriculture can only meet the standards; Thermal drying sludge product of heavy metals content is higher than lime-drying sludge products, including 2x thermal drying products Pb, Cd, Hg, As and Ni content of approximately lime drying products, Cu and Zn contents lime product is dry several times more. It is found that the threat to the surface soil of the thermal drying sludge product is much greater, and the contents of the heavy metals in the two sludge drying products are much lower than the national standard limits.(2) After administration of lime-drying sludge products and thermal drying sludge products in the surface soil total N, total P, total K, organic matter content and produce different degrees of increase. Application thermal drying sludge products content ratio increase soil organic matter, total N and lime-drying sludge products after administration is much greater with higher land-use value. Due to high soil N element content, pakchoi absorption level of phosphorus, potassium improved, so the thermal drying sludge products function after total P, total K content not increase.(3) The administration of the two sludge drying product after a significant increase in both soil heavy metals content(P <0.05), but the rate of increase of heavy metals is different. The test is administered when the two types of dry sludge content of each product in the processing of heavy metals in topsoil did not exceed(GB 15618-2008) limits. Description The test of sludge drying product was within safety limits volume, but still should pay attention to the agricultural process dynamics of soil concentration of heavy metals.(4) Lime sludge drying in the test group, lime sludge drying products increased role of pakchoi production is not significant, only if 3kg / m2 treatment a certain third harvest pakchoi total output growth compared with the control group. Sludge thermal drying products on Chinese cabbage increase more significant effect. Sludge thermal drying test group administered 2kg / m2, 3kg / m2 thermal drying sludge products, pakchoi yield was increased by 73.20% and 77.20%. Both sludge drying product on growth could show some inhibition, but fertilizer can make Yield increases up to a certain amount.(5) After application of lime sludge drying product Pb, Cd, Cr, As, Cu, Zn content compared to controls showed a significant growth trend, at 3kg / m2 treatment growth rates of more than 100%, of which the most abundant growth of As, an increase of 408.33%, the content of Cd and Cr which is beyond pakchoi(NY 5003-2008) standard limits. Content of heavy metals in varying degrees of increase when applying sewage sludge thermal drying products, but the content of heavy metals did not exceed(GB 18406.1-2001) standard limits.