Simulated Leaching Research On The Use Of Sewage Sludge On Sand Soil

This thesis is based on the sludge of Northern Shenyang Wastewater TreatmentPlant as research object, and select the Zhang Gutai forest land desertification chaptersand soil as a research materials. In order to provide theoretical basis for the city inthe use of forest land desertification sludge, through the leaching analog to the0-20cm、20-40cm、40-60cm sand soil which are from the sampling area to study theexchange trend of the soil nutrient and the heavy metal before and after used thesludge.Research shows that: the sludge of the Northern Shenyang WastewaterTreatment Plant is rich of organic matter, especially N and P. Cu、Zn and Pb’s contentare above80%of the totally rates and they are existed in a stable way, and Cb’scontent is7.91mg kg-1，its more than58.2%of national standards, because of thecontent is lower, this kind of sludge has good availability.Sand soil after leaching analog, the contents of organic matter、total nitrogen、available nitrogen、total phosphorus and available phosphorus are increasing45.7%、51.4%each more. And0-20cm is more obvious than20-40cm、40-60cm. It showsthat city life sludge to greatly improve surface soil nutrient content and increase thesoil fertility, and the rate of increase and decrease with depth.Sand soil after leaching analog, the amount and exchange trend of every heavymetals are all different. The total amount and content of Cu are focus on soil0-20cmsurface, Residual State content in the0-60cm are occupied more than80%, only alittle unstable forms in the surface. Because of the influence of the organic matter, theCd Exchange State in20-40cm increased91%. Along with the increase of depth, theOrganic and Sulfide Bounded State and Residual State are increased. The CarbonateState and Organic and Sulfide Bounded State of Pb are increased obvious in0-20cmsoil, respectively for44.8%and40.7%, but these two kinds form are leaching in the20-40cm soil, the increase rate is obvious decreased than that in0-20cm soil. Afterusing sludge, the stable form of Pb’s content in every soil are all keep at about70%. Before and after using the sludge, the stable form of Zn’s content is about75%. Afterleaching analog, Cu、Cd、Pb、Zn’s metal content and forms’ exchange are focus on thesand soil0-20cm surface, along with the increase of depth, the content of ResidualState increases stably, and on the other side, the activity of the heavy metal becomeslower. Every metal activity’s serial is: Cu> Zn>Pb> Cd.The using of the sludge makes the contents of heavy metal in the soil increasingobviously, but they were not more than the state soil environment quality level3standards. Through the Nemrow Index analysis, sand soil after leaching which is stillless than the national safety standards, but it belongs to the level of security, so citysludge used in the forest land desertification in short-time has good feasibility.