The Experimental Research On The Disposition Of Acid Coal Mine Drainage By SRB

China is a big coal production country where the water resources are insufficient. The precious underground water is turned into acid waste water through mining and discharged which in turn pollutes clean surface water, underground water and land resources, damages crops, aquatic lives as well as human health. If the acid waste water could be used reasonably and turned to harmless, water and land resources can be protected and waste water can be turned into useful water resources which has significant meaning to our country-especially the western district. Water is of severe shortage in the dry and semi-dry middle and western parts of China, therefore water is a crucial factor for the development of the area. The middle and western parts which are the main coal output districts are abound with coal which are the important components of their economic development. Consequently, it is a significant part for the economy of the districts to protect and raise the utilization of water resources.In recent years, the disposition of high sulfate waste water by sulfate reducing bacteria is carried out mainly passing sewage treatment factory. The main disadvantages of using sewage treatment factory are as follows: the project and equipments need large investment, running fee is high, energy consuming is large, and disposition amount is small, which cause that the enterprises couldn't afford to. It is very necessary to study how to reduce the processing cost of the coal mine drainage.The surface subsidence due to coal mining usually formate accumulating water area. The text research the possibility to dispose the acid coal mine drainage using natural surface subsidence for the reactor and throwing the right amount microorganism as well as carbon source.In this research, we first separated and identificated two strains of sulfate reducing bacteria and studied the condition scope of suitable desulphurization and the strain growth. SRB and carbon source were artificially added to the reactor which simulated the natural condition of the coal mine drainage. The feasibility to dispose acid coal mine drainage by sulfate reducing bacteria under the natural condition is researched through the analysis of the organic acid use, the change of pH, the removal efficiency of SO₄^2- and heavy metal. The experiment of the cheap carbon sources was also attempted. After the neatening and analyzing of the experimental results, the following conclusions can be drawn:(1) Two strains of sulfate reducing bacteria which were isolated from the pond backflow sludge of Taiyuan sewage treatment factory are identified as Desulfovibrio desulfuricans and Desulfotomaculum sp. respectively. It is confirmed that the biological activity of Desulfovibrio desulfuricans is better than that of Desulfotomaculum sp., therefore Desulfovibrio desulfuricans is selected as experimental bacterium.(2) The optimum growth range of the Desulfovibrio desulfuricans is pH 5～8, above 20℃, inoculating ammount above 20%. Desulfovibrio desulfuricans also can grow when pH is 4 and the removal efficiency of SO₄^2- became higher as the increasment of inoculating amount. The effect of original concentration of SO₄^2- on absolute treatment quantity is not significant, but removal efficiency of SO₄^2- became lower as the increasment of the original concentration. Bioreduction ability is decreasing with temperature reducing.(3)It can be concluded that it is practicable to dispose acid coal mine drainage by sulfate reducing bacteria under the natural condition from the simulating experiment on the disposition of acid coal mine drainage when sodium lactate as carbon source of Desulfovibrio desulfuricans. It can be concluded following resultes after disposition: the pH value is over 6.5, the removal efficiency of SO₄^2- is 61.98%, the removal efficiencies of Fe and Mn are 100% and 85% respectively.(4)From the experiment of selecting cheap carbon sources, we can concluded that molasses can be used as carbon source of Desulfovibrio desulfuricans and the results are better after the coal mine drainage is moderated. The removal efficiencies of SO₄^2-, Fe and Mn are 64.75%, 79.5% and 90.46% respectively. Sewage and humic can't be used by Desulfovibrio desulfuricans under the current test conditions.Through the research, it can be concluded that it is feasible in theory and practice treating acid coal mine drainage by sulfate reducing bacteria.