Peat soil for synthetic acid mine drainage treatment: Characteristic study

Abstract

Acid Mine Drainage (AMD) is an untreated outflow of acidic water from metal or coal mines. Improper treatment of the harmful effluent causes major environmental concern and remains as an unsolved problem for mining operators worldwide. The untreated AMD contains high concentration of several heavy metals despite low pH level. Iron (Fe) is most dominant element of heavy metal spotted in the AMD water and must be filtered and treated before being released to open water bodies. Current practises by the industries adopted two categories of AMD treatment methods, namely active and passive treatments. Passive treatment method was adopted into this study by using successive alkalinity producing system (SAPS) to reduce Fe concentration in the AMD. Strict regulations by mine operators to acquire on-site AMD, led to use of synthetic AMD. Peat soil was introduced as organic substrate treatment media, as compared to common materials used such as mushroom spent, wood shaving and animal manure. In this research the peat soil was characterized and its effectiveness to filter the Fe content was assessed using laboratory scale studies. Prior to the test, the natural peat soil was analyzed via Scanning Electron Microscopy (SEM) analysis, Energy Dispersive X-Ray (EDX) analysis and carbon-hydrogen-nitrogen-sulphur (CHNS) element analysis. After going through laboratory tests, the peat soil residues were assessed through SEM-EDX analysis to determine the trapped Fe content. The natural peat soil does not contain any Fe substance. However, the analyzed peat soil residues showed that, approximately one to four percent of the Fe were found in the peat soil residues. The use of the peat soil for the AMD treatment in SAPS method is applicable and can be used as alternative organic substrate for treatment media.