Ion Exchange Membrane Bioreactor For The Removal Of Nitrate From Groundwater

In recent years,nitrate contamination of the groundwater has become a common issue in many areas.To develop cost-effective groundwater nitrate removal techniques is a very urgent task due to nitrate’s potential adverse health effects.The ion exchange membrane bioreactor (IEMBR) with better nitrogen removal,faster denitrification rate,and no secondary pollution has received much attention. IEMBR is an innovative nitrate removal process,which integrates ion exchange with membrane bioreactor for groundwater denitrification The groundwater and biological denitrification medium was separated by an ion exchange membrane,the nitrate ions in the groundwater was exchanged with the chloride ions in the denitrification medium through the ion exchange memberane,then the nitrate ions would be reduced into nitrogen gas by denitrifying bacteria in the denitrification medium to achieve biological nitrogen removal.Two batch ion exchange membrane bioreactors were designed and made of the AMV anion exchange membrane and plexiglass,and both reactors were used for removing the nitrate from the simulated groundwater.The ion exchange performance of AMV anion exchange membrane,the effects of different concentrations of Cl-and SO42-,different carbon sources,C/N,and sludge concentration on nitrogen removal efficiencies of IEMBR were invesigated.In addation,the feasibility of removing nitrate from the spent regenerant with high concentration NaCl by IEMBR was evaluated.The results showed that the denitrifying medium could be completely separated from the groundwater by AMV anion exchange membrane in the IEMBR,the groundwater was not contaminated by residual denitrification carbon source,denitrifying bacteria and their metabolic products.The ratio of Cl-concentration in denitrification medium to nitrate nitrogen concentration in groundwater should be more than3;the higher concentration of SO42-in groundwater the lower nitrate removal efficiency;ethanol was the most suitable carbon source for denitrification,the nitrate removal rate is proportional to C/N and sludge concentration;The nitrate in spent regenerant with high concentration NaCl could be degradated from550to40mg/L by IEMBR.