A Water Model for Water and Environmental Management at Mae Moh Mine Area in Thailand

Abstract

It is revealed that the water quality in Mae Moh Reservoir, Thailand, has been deteriorated by lignite mine drainage and power station effluent. This study aims to manipulate water quantity and quality to reduce environmental impacts in Mae Moh area through a model for water management. The model was constructed on the basis of materials balance to predict water flow, which includes concentrations of TDS and SO2–4. Data collected during 1996–2000 were used. Model validation showed that the mean of predicted and actual values of TDS and SO2–4 load were significantly similar at 95% confidence limit. The test result is acceptable and the water model can be used as a tool for water system management in the area. In 2006, Mae Moh mine excess water will be discharged at 10.76 Mm3, with a pH of 7.3, TDS and SO2–4 concentrations of 2,547 and 1,803 mg/l, respectively. Mae Moh power station effluent will be 14.59 Mm3, with pH of 7.1, TDS and SO2–4 concentrations of 610 and 358 mg/l, respectively. Predicted results showed that the outflow of Mae Moh Reservoir will be 83.67 Mm3 and the concentrations of TDS and SO2–4 will be as high as 1,501 and 822 mg/l, respectively. Mine excess water management measures are recommended according to the following strategy. All mine excess water should be stored during dry season. During wet season, 50% of the excess water should be stored and the remaining treated at 90% of TDS removal before being discharged. The end result would be a significant improvement in water quality in the Mae Moh Reservoir over the 4-year period to 2010. Pollutants in terms of TDS would be reduced by 35% from 1,501 mg/l in the beginning of 2006 to 975 mg/l at the end of 2009.