Abstract: Coal mines and various sulfide ore deposits are widely distributed in Southern China. Acid mine drainage associated with coal and metal sulfide deposits affects water quality in some mined areas of Southern China. Mining operations accelerate this natural deterioration of water quality by exposing greater surface areas of reactive minerals to the weathering effects of the atmosphere, hydrosphere, and biosphere. Some approaches to reduce the effects of acid mine drainage on water quality are adopted, and they can be divided into two aspects: (a) Man-made control technology based on long-term monitoring of acid mine drainage; and, (b) Neutralization of acidity through the addition of lime. It is important that metals in the waste water are removed in the process of neutralization. A new method for calculating neutralization dosage is applied. It is demonstrated that the calculated value is approximately equal to the actual required value.

Abstract: Constructed wetland treatment system effectiveness has been limited by the alkalinity-producing, or acidity-neutralizing, capabilities of systems. Anoxic limestone drains (ALD's) have allowed for the treatment of approximately 300 mg/L net acidic mine drainage, but current design guidance precludes using successive ALD's to generate alkalinity in excess of 300 mg/L because of concerns with dissolved oxygen. “Compost” wetlands designed to promote bacterially mediated sulfate reduction are suggested as a means of generating alkalinity required in excess of that produced by ALD's. Compost wetlands create two basic needs of sulfate reducing bacteria; anoxic conditions resulting from the inherent oxygen demand of the organic substrate, and quasi-circumneutral pH values resulting from the dissolution of the carbonate fraction of the compost. However, sulfate reduction treatment area needs are generally in excess of area availability and/or cost effectiveness. Second generation alkalinity-producing systems demonstrate that a combination of existing treatment mechanisms has the potential to overcome current design concerns and effectively treat acidic waters ad infinitum. Successive alkalinity-producing systems (SAPS) combine ALD technology with sulfate reduction mechanisms. SAPS promote vertical flow through rich organic wetland substrates into limestone beds beneath the organic compost, discharging the pore waters. SAPS allow for conservative wetland treatment sizing calculations to be made as a rate function based on pH and alkalinity values and associated contaminant loadings. SAPS potentially decrease treatment area requirements and have the further potential to generate alkalinity in excess of acidity regardless od acidity concentrations.