The Experiment Research On Using Lignite As The Solid-phase Organic Carbon-source To Remove The Nitrate From The Groundwater

Groundwater is the precious freshwater resources for humans. It plays an extremely important role in the development of national economy. But in recent years, with the development of industry and agriculture, nitrate pollution in the groundwater becomes more and more seriously. It is a threat to human health. Therefore, to developing an efficient and feasible groundwater bioremediation technology of nitrate pollution is imminent. Solid organic carbon source biological denitrification technology has the application prospect in remediation of nitrate polluted groundwater.In the simulation of shallow groundwater temperature, velocity and pH condition, the Sanjitun, Faku, Zhangdang, Pingzhuang, Akesu, Lingshi, Zhangjiakou, Wangniutan, Longkou, Ruzhou, Yima and Zhaotong lignite are as research objects to explore the feasibility of remediation of nitrate polluted groundwater by using batch experiments and column reactor simulation. The Results show that Wangniutan, Zhangjiakou, Akesu and Faku lignite have good denitrifying performance. After the domestication of denitrifying bacteria, their nitrate nitrogen removal rates are increased by 10% or more. Small molecular organic compounds, such as alcohols and alkane, are primarily used by denitrifying bacteria. The denitrifying process of the lignite columns are all accord with zero-order kinetics model. The nitrate nitrogen removal rates of the Wangniutan, Zhangjiakou, Akesu and Faku lignite columns are increased with the extension of HRT and decreased with the increase of influent nitrate nitrogen concentration.This work use the microbial dissolve coal technology and ultrasonic technology to enhance the denitrifying effect of Wangniutan, Zhangjiakou, Akesu and Faku lignite columns. The Results show that the two methods can effectively enhance the nitrate removal. Each column reactor's nitrate nitrogen removal rate is increased by 20%. Dissolve coal bacteria and ultrasonic cavitation can degrade the macromolecular organic compounds of the lignite and make the C/N of the reaction system increase. Hydraulic retention time and influent nitrate nitrogen concentration are still the main influence factors of the reactor operation.When the inflow concentration of nitrate nitrogen is 30mg/L and the HRT is 24h, Wangniutan, Zhangjiakou, Akesu and Faku lignites have good performances for treatment of nitrate polluted groundwater. After the vaccination of dissolve coal bacteria or ultrasonic cavitation, their nitrate nitrogen removal rates are increased to 50%. There is no secondary pollution problem during the study. Therefor, domestic lignite as the solid-phase organic carbon sources for remediation of nitrate polluted groundwater is feasible.