FIELD STUDY FOR THE ALTERNATIVE ORGANIC SUBSTRATES FOR SULFATE REMOVAL IN ACID MINE DRAINAGE

Successive Alkalinity Producing System (SAPS) is the most common unit using in acid mine drainage (AMD) passive treatment systems. All of SAPS in South Korea has been constructed with using the mushroom compost as the organic substrate. However, despite of cheap price of mushroom compost and high capacity as a substrate material, it has the limitation for usage due to the lack of production site, high transport cost and the difficulty of purchase in required timing. So, several organic mixtures were considered as the alternative organic substrate – CS (Cow manure + Sawdust), CO (Cow manure + Spent Oak), CRE (Cow manure + Reed), CRS (Cow manure + Rice Straw), CG (Cow manure + Gingko leaves), and CF (Cow manure + Fallen leaves). Field study was performed to identify the alternative organic substrates for the SAPS in AMD passive treatment system. Seven columns (2.4m high and 0.3m diameter) were installed to installed to monitor the treatment efficiencies of each candidate organic mixture at the Seong-bong coal mine (pH 3.6, iron 102.9mg/l, sulfate 1206mg/l), Mun-gyeong, Gyeong-buk, Korea.

From the 125days observation, the acidity neutral capacity was only a few different values – average pH was from 6.33 (CRS) to 7.42 (M). And the development of the reduced condition was in the order of CS = CRE < CRS = CF < CO = CG = M. Sulfate removal ratio and iron removal ratio was the order of CS = CRE < CRS < M < CG = CF < CO and CRE < CS < CRS < CO < CF = M = CG respectively. From the field study, CO and CG may be suggested as the alternative organic substrates for the SAPS in AMD passive treatment system for reduce of sulfate and iron in the AMD.