The Heavy Metals In Sludge Were Removed By Bioleaching Multiple Times

With the development of the industrialization process,industrial wastewater and domestic sewage will produce a large amount of surplus sludge after treatment.Sewage after sewage treatment plant after the content of heavy metals in the sludge is generally low,so a biological leaching after ordinary will reach the standard,even can be used for farming,such as sludge composting.However,the residual sludge produced by industrial waste water is seriously exceeding the limit of heavy metal production and cannot be used for agricultural use.The main treatment method is landfill.Generate leachate after sludge landfill,leachate would harm of heavy metals in the environment,can cause the pollution of underground water,in particular,the enrichment of heavy metals and easy,refractory characteristics,such as relatively large damage to the environment.Therefore,the removal of heavy metals from sludge becomes an urgent problem.Method at present,the removal of heavy metals in sewage sludge,which mainly divided into physical method,chemical method and biological leaching method,biological leaching remove the heavy metals in the sludge is currently think minimum damage to the environment,the most economic and feasible method.But for sludge containing high concentration of heavy metal,a biological leaching can't meet the requirements,traditional research mostly stay in the optimization of the removal rate of heavy metals in sewage sludge,and there are four kinds of forms in the sludge,its stability is different,also easy to leaching of heavy metals in the sludge,the leach liquor is the true big damage to the environment factors.For heavy metal content,high sludge by processing after generally unable to agricultural soil,mainly in the landfill,and heavy metals in sewage sludge will be after the landfill leaching in the environment of the landfill,the concentration of heavy metals in the leachate is the most important factor is bad for the environment.This thesis mainly through many times of biological leaching,the study of the dissolution rate of heavy metals in the sludge,and each time the sludge after the biological leaching simulation environment of landfill,the determination of the leaching toxicity of heavy metals in the sludge,the concentration of heavy metals in sludge landfill leachate after)according to the state environmental protection department issued on April 2,2008,July 1,2008 implementation of GB-16889-2008 garbage landfill pollution control standard of life,to contain high concentrations of heavy metals of the guidance of sludge disposal provides the rationalization proposal.This thesis mainly through the solid content of 1.0%,1.5%,2.0%,3.0%,4.0%,5.0%,and the sludge leaching,many times by every leaching after heavy metal content in sludge,form of heavy metals in sludge,sludge after leaching toxicity test study of simulated landfill comprehensive all aspects of indicators,and optimize it,it is concluded that the best ratio of material,the number of leaching,leaching time.This thesis mainly to heavy pollution of industrial waste water sludge,under natural conditions by oxidation of the organisms themselves the hard dissolved heavy metal oxide into ion removal by using the method of solid-liquid separation.There are two main important experiment,the first experiment,through the solid content of1.0%,1.5%,2.0%,3.0%,2.0% and 5.0% of biological leaching for many times,analysis of the sludge of solid content of leaching effect,the second is through biological leaching after many times of sludge is analyzed,and the simulation environment of landfill,the leachate were analyzed,and combining with the state environmental protection department issued on April 2,2008,July 1,2008 implementation of GB-16889-2008 garbage landfill pollution control standard of life.This paper mainly through the solid content of 1.0%,1.5%,2.0%,3.0%,4.0%,5.0%,and the sludge leaching,many times by every leaching after heavy metal content in sludge,form of heavy metals in sludge,sludge after leaching toxicity test simulated landfill),experiment it is concluded that the higher the rate of sludge containing solid,biological leaching cycle is longer,the solid content of 1.0%,1.5%,2.0%,3.0% of the sludge in a biological leaching process,Cu,zinc,the dissolution curve of Cr,are all around in the eighth day of the leaching rate of the dissolution of the metal in the sludge has reached the maximum.And solid content of 4.0%,5.0% of sludge in the process of sludge in a biological leaching of Cu,zinc,Cr dissolution curve is almost the same,in the leaching of 22 days or so to reach a maximum amount of solid content of 1.0%,1.5%,2.0%,3.0%,4.0% of sludge by a biological leaching of zinc leaching toxicity in the sludge can reach standard of landfill,and the solid content of 5.0% sludge after two biological leaching,the solid content of 1.0%,1.5%and 2.0% of sludge by a biological leaching of Cu leaching toxicity in the sludge can reach standard of landfill,And solid content of 3.0%,4.0% and 5.0% of sludge need to pass three biological leaching,the solid content of 1.0%,1.5% and 2.0% of sludge by secondary biological leaching the sludge in the Pb leaching toxicity can reach standard of landfill,the solid content of 3.0%,4.0% and 5.0% of sludge need to pass three biological leaching,the solid content of 1.0%,1.5%,2.0%,3.0%,4.0% ofsludge by secondary biological leaching the leaching toxicity of sludge in Cr can reach standard of landfill,and the solid content of 5.0% sludge need biological leaching after three times.