酸缓冲容量对污泥屏障重金属再溶出控制研究  

Acid Buffer Capacity of Sewage Sludge Barrier for Immobilization of Heavy Metals

作　　者：张虎元[1] 鞠圆圆[2] 范志明[2] 王宝[2] 

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,兰州730000 [2]兰州大学资源环境学院,兰州730000

出　　处：《环境科学》2010年第12期2956-2964,共9页Environmental Science

基　　金：国家自然科学基金项目(50678075)

摘　　要：借助污泥中的厌氧微生物活动,污泥屏障可用来固定尾矿堆场的重金属.针对尾矿风化淋滤形成的酸性采矿废水(acidmine drainage,AMD)与污泥屏障相互作用,可能会引起已固定重金属再次溶出问题,通过酸滴定实验,研究了不同厌氧培养时间的污泥悬液的酸缓冲容量及其对重金属再溶出的影响.结果表明,污泥悬液酸缓冲容量与悬液固液比成正比,并随着厌氧还原程度的加深而增加.碳酸盐缓冲体系和有机质缓冲体系对污泥悬液酸缓冲有重要意义.酸滴定实验发现,随着pH降至6.2以下,重金属Zn、Pb和Cu开始快速溶解释放,且释放量符合Zn>Cu>Pb.基于实验结果,建立了污泥屏障在AMD渗透条件下酸缓冲容量消耗的数学模型.模拟计算结果表明,对于厚度2.0 m的污泥屏障,即使在10.0 m水头的AMD渗透酸化条件下,有效酸缓冲容量经历666 a之后才能被耗尽,在此时间内污泥屏障具备对重金属的生物化学固定能力.Employing the anaerobic activities of microorganisms,sewage sludge can be used as a barrier to immobilize the heavy metals leached from tailings.Due to the interactions between sewage sludge barrier and acid mine drainage（AMD）,it is possible that the heavy metals that have been immobilized previously might be released out.The acid buffering capacity（ABC） of sewage sludge suspensions with various anaerobic incubation time and the effect of ABC on the mobility of heavy metals were investigated by acid titration tests.Test results showed that ABC of sewage sludge suspensions was increased with the solid-liquid ratio of the suspensions and the anaerobic incubation time,and that carbonate and organics play an important role in acid buffer of sewage sludge suspensions.During the acid titration test,Zn,Pb and Cu were released out obviously following the order of Zn〉Cu 〉Pb as pH was decreased less than 6.2.A mathematical model was established to predict the ABC consumption of the sewage sludge barrier under AMD penetration condition.The simulation results showed that a sewage sludge barrier with 2.0 m thickness,even undergoing 666-years acidification by AMD under 10.0 m water head,can maintain a condition of pH≥6.2 and,therefore,keep immobilize the heavy metals of AMD in the barrier.

关 键 词：酸性采矿废水 污泥屏障 酸缓冲容量 重金属 

分 类 号：X705[环境科学与工程—环境工程]