Concentration And Clemical Fractions Of Heavy Metals In Sewage Sludge

In recent years, the production of municipal sludge has been sharply increasing with more and more municipal sludge treatment plants and sewage treatment plants.The disposal and the environmental impact of municipal sludge have been paid more and more attention. Land application of sewage sludge is one of the important disposal alternatives. For the comprehensive utilization of the city sewage treatment plant sludge, not only the content of heavy metals in sludge but also the speciation of heavy metals were paid attention, which will be beneficial to the heavy metal forms according to the suitable processing method and the reasonable technology.In this work selects 29 sewage sludges from different wastewater treatment plants all over the Sichuan province was selected for the research.For the 55 city’s sewage treatment plants around Sichuan Province, sludge heavy metal contents and distributions of different sewage treatment plant and sewage treatment process were researched.The results are as follows:1. The contents of Zn, Cu, Cr, Ni, Pb, As, Cd, Hg in sewage treatment plant of Sichuan Province sludge samples varied significantly,the range of heavy metal content was large.2. Sichuan Province treatment plant sludge in As, Cd, Cr, Hg, Pb, Ni, Cu, Zn and other eight kinds of heavy metals content is not high, the contents of Cu and Zn were the highest of individual sludge.3. The results showed Hg, Cr, As and Pb in sludges mainly existed in residue state, Cd were principally distributed in the residual fraction strong organic matter fraction and Fe-Mn oxides fraction, Ni were principally distributed in the residual fraction and water soluble fraction, Zn were principally distributed in the Water soluble fraction and Ion exchange state,Cu were principally distributed in the residual fraction strong organic matter fraction and Fe-Mn oxides fraction.4. Sludge was rich in organic matters and nutrients, such as nitrogen and phosphorus and so on, nitrogen and phosphorus in sludges mainly existed in available state, Sichuan Province suggesting an ecological risk of using sewage sludge for agriculture in these areas in the lower level,can be agricultural utilization.5. The results showed that Sichuan Province suggesting an ecological risk of using sewage sludge for agriculture in these areas in the lower level,can be agricultural utilization.In order to research the speciation of heavy metals in municipal sludge, this article determination of As、Cd、Cr、Hg、Pb、Ni、Cu、Zn elements in the form of heavy metals in sludge samples were investigated using selective sequential extraction procedure,as well as the and related to sludge nutrients N, P, K and organic matter content were determined.In addition, this article also research the method of practical disposal of Sichuan province sludge, provides some new ideas for practical disposal of sludge.Therefore,through the research of this article to explore the amount and species distribution of heavy metals in sludge and the accumulation of basic physicochemical data of sludge, to provide theoretical data on the basis of the proposed Sludge harmless and resource utilization technology technical solutions.