산성광산배수(acid mine drainage, AMD)는 가행탄광 또는 폐광지에서 지속적으로 수질 및 토양 환경오염을 일으키는 오염원이다. 산성광산배수를 무해화 하기 위한 많은 공법들이 연구되고 개발되었다. 산성광산배수는 대기 중에 노출된 황철석(FeS2), 백철석(FeS) 등의 황화광물이 산소 및 물과 반응하여 산화되면서 형성되며, pH가 낮아 산성을 띠고 있으며, 황산염을 비롯한 철, 알루미늄, 망간 등 금속함량이 높은 것이 특징이다. 산성광산배수의 처리방법은 크게 적극적 처리법(active treatment)과 소극적 처리법(passive treatment)으로 나누어진다. 적극적 처리법은 중화제를 이용한 pH 조절, 이온교환과 흡착, 응집, 여과 등의 방식을 이용하는 방법으로서, 대표적인 적극적 처리법으로는 역삼투압법, 이온교환법, 전기투석법 등이 있다. 소극적 처리법은 유기물과 석회석 등을 이용하여 동력을 투여하지 않는 방식으로 대표적인 소극적 처리법으로는 SAPS (successive alkalinity-producing systems) 등이 있다. 특히, 소석회(Ca(OH)2)를 이용하여 산성광산배수를 중화시켜 산성광산배수에 포함된 금속들을 슬러지로 침전시켜 시멘트 회사 등으로 운송되어 폐기물로 처리하고 있다. 본 연구에서는 산성광산배수에서 폐기물로 처리되는 산성광산 슬러지를 바이오가스 정제 분야 등에 이용할 수 있는 흡착제를 제조하여 폐기되는 슬러지의 배출량을 절감시키는 기술을 적용하여 바이오가스 산업에 경쟁력을 부여하기 위한 결과를 얻었다.

In this research, equilibrium of adsorption and kinetics of As(V) removal were investigated. The coal mine drainage sludge(CMDS) was used as adsorbent. To find out the physical and chemical properties of CMDS, XRD (X-ray diffraction), XRF (X-ray fluorescence spectrometer) analysis were carried out. The CMDS was consist of 70% of goethite and 30% of calcite. From the results, an adsorption mechanism of As(V) with CMDS was dominated by iron oxides. Langmuir adsorption isotherm model was fitted well more than Freundlich isotherm adsorption model. Adsorption capacities of CMDS 1 was not different with CMDS 2 on aspect of amounts of arsenic adsorbed. The maximum adsorption amount of two CMDS were respectively 40.816, 39.682 mg/g. However, the kinetic of two CMDS was different. The kinetic was followed pseudo second order model than pseudo first order model. Concentrations of arsenic in all segments of the polymer in CMDS 2 does not have a constant value, but the rate was greater than the value of CMDS 1. Therefore, CMDS 2, which is containing polymer, is more effective for adsorbent to remove As(V).

In this study, to stabilize the heavy metal in the contaminated soils, the column leaching test based on rainfall and pH value was performed by using coal mine drainage sludge(CMDS): which was generated during electrical purification of abandoned coal mine wastewater. Four types of testing column were used in this study. That were the CMDS and the heavy metal contaminated soils well mixed in 0 wt%, 1 wt%, 3 wt% and 3 wt% layered column. According to the investigation, when the influent pH was 5.5∼6.2, there were no heavy metal elution at all conditions, and when the influent pH was 3∼3.3, the order of Cu, Zn, Pb, Cr elution concentration was 3 wt% M(mixed)＜3 wt% S(separation)＜1 wt% M＜0 wt% and the average elution concentration was quite low, the value was 0.005 mg/L. Therefore, CMDS can used as new stabilizer of the heavy metal in the contaminated soils.