PRB处理酸性矿山废水及填料堵塞过程

Clogging of Acid Mine Drainage Treated by Permeable Reactive Barrier

矿产资源的开发过程中会产生大量酸性矿山废水(Acid mine drainage,AMD),会对矿区生态环境造成严重危害。可渗透反应屏障(Permeable reactive barrier,PRB)可以有效中和酸性废水并去除废排水中的有害金属离子。通过进行PRB箱体试验,旨在研究石灰石作为填料介质中和酸性和处理污染物的潜能,以及PRB在运行过程中化学堵塞的发生机理。结果表明:石灰石填料中和酸性和重金属去除能力较好,试验终止时出水的pH维持在6.29,重金属离子去除率最高接近于100%;PRB处理过程中,以铁为主的矿物沉淀是化学堵塞的主要原因,并且堵塞程度表现为进水区域>中间区域>出水区域;PRB装置的堵塞对水力特性的影响明显,进水反应区域的相对渗透率降低了56.1%,出口区降低了27.6%。

The development of mineral resources will produce a large amount of acid mine drainage(AMD),which will cause serious harm to the ecological environment of mining area.Permeable reactive barrier(PRB)can effectively neutralize acidic wastewater and remove harmful metal ions from waste drainage.The experiment of PRB chamber was carried out to study the potential of limestone as a filling medium to neutralize acidity and treat pollutants and the mechanism of chemical blockage in PRB operation.The results show that the limestone filler has good neutralization and heavy metal removal ability.At the end of experiment,pH value of effluent water is maintained at 6.29,and the removal rate of heavy metal ions is close to 100%.In the process of PRB treatment,iron mineral precipitation is the main reason of chemical blockage,and the degree of blockage is shown as the inlet area>the middle area>the outlet area.The blockage of PRB device has an obvious effect on hydraulic characteristics.The relative permeability of influent reaction area is reduced by 56.1%,and that of the outlet is reduced by 27.6%.