Simulasi Pengolahan Air Asam Tambang Menggunakan Open Limestone Channel Skala Laboratorium

Abstract

Acid Mine Drainage (AMD) is characterized as water with high acidity value and elevated metal contents, as a result of oxidation of pyrite in presence of oxygen and water. To ensure that effluent water quality comply with effluent standard, treatment on AMD need to be conducted. One of method on AMD Passive Treatment is open limestone channel (OLC). An OLC is designed and constructed to neutralize AMD by using limestone. To evaluate the neutralizing performance of an OLD, a laboratory-scaled simulation is made. This simulation is also conducted to study physical variables that affecting performance of an OLC to neutralize and enhance the quality of AMD. The study is made by using three different size of limestone (namely coarsegrained, medium-grained and fine-grained). The study shows that with increasing water-flow rate (Q1<Q2<Q3), pH values at the outlet of model with coarsegrained limestone (C50 = 11 mm) are 3,40, 2,93 and 3,22 respectively. pH values at the outlet of model with coarse-grained limestone (C50 = 7,12 mm) are 6,53, 5,72 and 5,99 respectively. pH values at the outlet of model with fine-grained limestone (C50 = 4,05 mm) are 6,51, 6,25 and 6,26 respectively. The results are indicating variables that affecting performance of OLC, i.e. surface area of limestone and retention time. As surface area of limestone increasing, pH value of water at outlet is higher; the longer retention time, the higher pH value of water at the outlet, as a result of increasing reaction between water and limestone.