Effect of COD/SO₄^2- Supply Ratio Variations of Sulfate-Reducing Bacteria of Sulphood Raise in Acid Mine Drainage

¹ Department of Environmental Engineering, Faculty of Engineering, Diponegoro University, Semarang - Indonesia
² Magister Program of Environmental Science, School of Postgraduate Studies, Diponegoro University, Semarang - Indonesia

^* Corresponding author: nurandani@gmail.com

Abstract

Sulphur dioxide gas is one of most contaminating gas in the air. Sulphur gas can be produced by mining activities. Sulphur gas will be harmful if bond with CO₂ to form as Sulphur Dioxide. To reduce the Sulphur Dioxide gas concentration we must inhibite the sulphur gas formation from mining activities. The inhibition of sulphur gas could be done by reduce the sulphate concentration in acid mine drainage. One of important factor that influencing the reduce of sulphate is COD/SO₄^2- ratio. The effect of COD/SO₄^2- ratio on bacterial growth and sulfate removal process can be investigated with anaerobic batch reactor. The laundry septic tank sediments were inoculated on an anaerobic batch reactor which were contacted with artificial coal acid mine water wastes with 1000 sulfate concentrations and 2000 mg SO₄^2- /L. In an anaerobic batch reactor there are five reactors with variations of COD / SO₄^2-1.0, 1.5, 2.0, 4.0, and 8.0 ratios. Efficiency ratio and the best sulfate removal rate is in reactor ratio 2.0 with value efficiency of 46.58% and a reduction rate of 29.128 mg / L.day in an anaerobic batch reactor. The efficiency of the removal rate decreased when the COD / SO₄^2->2.0 ratio decreased. The fastest pH decline was in the COD/SO₄^2-8.0 ratio variation in the anaerobic batch reactor and. The COD / SO₄^2-ratio can help the sulfate reduction process in the optimum value by affecting the sulfate-reducing bacterial metabolism in the balance of the acceptor and the electron donor.