STUDI PENGELOLAAN AIR ASAM TAMBANG MENGGUNAKAN KAPUR TOHOR DI TAMBANG BATUBARA KECAMATAN PERANAP KABUPATEN INDRAGIRI HULU PROVINSI RIAU

Abstract

Acid mine drainage (AMD) is one of the major environmental impacts of coal mining activities, formed by the oxidation of sulfide minerals such as pyrite (FeS₂) when exposed to air and water. AMD is highly acidic and contains heavy metals like iron (Fe) and manganese (Mn), which can pollute surrounding water bodies. This study was conducted at the Settling Pond (Kolam Pengendapan Lumpur - KPL) of Pit 1, PT. Samantaka Batubara, located in Peranap Subdistrict, Indragiri Hulu Regency, Riau Province. The objective was to evaluate the effectiveness of quicklime (CaO) in neutralizing pH, reducing Total Suspended Solids (TSS), and decreasing concentrations of Fe and Mn in AMD. A quantitative approach was used, with samples taken from three points (inlet, middle, and outlet) and quicklime applied at a dosage of 1.0 gram/liter. The results showed that pH increased from 3.81–4.25 to 7.12–7.42; TSS decreased from 300–302 mg/L to 100–102 mg/L; and Fe concentration dropped from 8–9 mg/L to approximately 0.81 mg/L. However, Mn levels only declined from 6–7 mg/L to around 5.97 mg/L. According to the Indonesian Minister of Environment Regulation (Permen LHK No. 5 of 2022), the pH, TSS, and Fe levels met the environmental quality standards, while Mn levels remained above the permissible limit. Therefore, the use of quicklime is effective for AMD treatment, although additional treatment or a higher pH is required for optimal Mn removal.