Study On The Bioavailability Of Heavy Metal In The Sewage Sludge Stabilization Process

With the fast development of China's urban sewage treatment industry,the sludge production from sewage treatment has surged,therefore effective sludge treatment methods are faced with great challenges.Currently sludge-to-landfill is the most widely used method in sludge treatment,so it is of high importance to achieve sustainable development landfill,extend the useful life of the landfill and promote recycling landfill.At present,the main usage of sludge landfill after stabilization is in agriculture,with green and soil improvement,so the heavy metal content of sludge landfill after stabilization should be consistent with national standards to control pollutants in sludge.The researches on effect of heavy metals,the migration and transformation of different additives on heavy metal bioavailability in the landfill are of great significance for landfill exploitation and sustainable development.This study will take the second sewage treatment factory in Tai'an City as the research subject,and will focus on three different aspects that are heavy metals distribution change and the biological effectiveness of the process of filling in the form,35 ? constant temperature influence on the effectiveness of the biological changes,and the influence of different additives on the biological effectiveness.Studies have shown that:pure sludge landfill with time difference,the total amount of heavy metals vary.After the pure sludge landfill at room temperature,if used in agricultural,landscaping and soil improvement,the total amount of heavy metals in the sludge are exceeded.After heated at 35 ? landfill disposal,only the total amount of heavy metals in sludge than the standard muddy farm,and when used in landscaping and soil improvement may be applied to neutral,alkaline soil,when sewage sludge is applied to acidic soil,the heavy metal Cd,Ni,Cu element exceeded.The last four additives mixed with pure sludge landfill,the total amount of heavy metals are below the farm,when landscaping and soil improvement with the pollution control standard limits,construction waste and fly ash which was the best,relatively safe.Use mud and mineralized refuse the introduction of heavy metals Cr,Cu,Ni.Modified sludge,heavy metal influence different elements by the time in different forms,the additive increases the sludge and residual state Sulfided Cd content of waste and soil mineralization Cr passivation of the more obvious elements.Most additives are accelerated passivation of Cu and Pb in,but inactivation of Ni element was less affected.Different additives are state Zn sulfide content increased.Compared with pure sludge content in the form of additive reduces the content of heavy metals in varying degrees of active state,increasing the vulcanization state and residual state in the content,so the nature of heavy metal is more stable,effectively reducing the heavy metal bio effectiveness,which better soil.