The Simultaneous Treatment Process Of Landfill Leachate And Acid Mine Drainage

The output of domestic waste in our country is increasing with the process of urbanization.At present,sanitary landfill still is widely used on middle-sized and small cities,landfill leachate is a kind of high concentration organic wastewater containing a large number of polymeric and refractory compounds and their specific characters are as follows: high concentration of organic matter,ammonia nitrogen and metal-ion,the quality and quantity of it changes largely and the imbalance of microbial nutrient elements.In addition,many mines are located on middle-sized and small cities in China.The mine wastewater produced by mining and mineral processing is industrial waste water containing high concentration sulfate and metal ions.Currently,the treatment of these two kinds of high concentration wastewater is a difficult problem in the industry,so we need to seek technical breakthrough and innovation.According to the characteristics of small and medium sized resource mining cities,in view of the present situation of landfill and acid reservoir on the top of the Xiangshan tailings reservoir in Ma'anshan city.This paper presents the mixed treatment of acid mine drainage and landfill leachate to realize the effective and simultaneous removal of COD,sulfate and metal ions.In this paper,the treatment processes of anaerobic anoxic / aerobic combined process?A²/O?and the up-flow anaerobic sludge bed?UASB?were studied,respectively.The results are as follows:?1?Leachate and acid mine drainage were mixed with m?COD?/m(SO₄^2-)as the ratio of 3,and they entered the A²/O system for treatment,A²/O system ran for 450 days.It can effectively remove pollutants such as COD,sulfate,ammonia nitrogen and metal ions.The removal efficiency of COD was above 98%,the removal efficiency of sulfate was about 91%,the removal efficiency of ammonia nitrogen was up to 99.6%.Change of influent load had some influence on the initial stage of the system,the removal efficiency of COD,sulfate and ammonia nitrogen can be stable at 98%,90% and 99% in the steady operation stage,respectively.?2?In the stable A²/O system,The main bacteria in anaerobic reactor are hydrolytic bacteria?18.2%?,acid producing bacteria?40.91%?and sulfate reducing bacteria?26.33%?.Acetotrophic methanogens were dominant in archaea.Thauera and Thiobacillus are the main functional bacteria of nitrogen removal in anoxic/aerobic system.In the whole system,different microorganisms are mutually beneficial,pollutants can be removed by synergistic reaction and formed a relatively stable microbial community structure.?3?The UASB reactor can reduce the start-up time by using stable and mature anaerobic granular sludge.The ratio of m?COD?/m(SO₄^2-)in the mixed wastewater was still 3 in the start-up stage,COD and sulfate removal efficiency can reach 72% and 69% in the stable stage,respectively.COD and sulfate load were increased to 1680 g·m^-3·d^-1 and 560 g·m^-3·d^-1,the removal efficiency of COD and sulfate were 75% and 72%,respectively.The influent sulfate load was further increased to 840 g·m^-3·d^-1 and the removal efficiency of COD and sulfate could reach 81% and 76.5% in UASB reactor,respectively.