Research On Simultaneously Removal Of Nitrate And Chromium Synchronously Using Biofilm Reactor

In our environment,groundwater as an important resource of drinking water supplies takes lots of people’s attention.The nitrate and chromium salt as concomitant contaminants is very common in groundwater and it brings serious influence to drinking water safety.But the current study focuses on the disposal methods of these two kinds of pollutants existing alone.This study used a anaerobic biofilm reactor with the filler internally installed and water distribution uniformity to remove the two pollutants existing alone and simultaneous.Introduce the electrode biofilm technology with the shape of double ring in order to enhance the effect of biological membrane,decrease the amount of carbon source adding and reduce cost and the secondary pollution.In the reactor with the nitrate as the separate pollutant,the theoretical carbon and nitrogen was 0.71.In this reactor.To achieve the removal rate more than 90%,the lowest carbon nitrogen ratio was 0.8,the smallest hydraulic retention time was 4 h.In the reactor with the chromium as the separate pollutant,the reactor with the hexavalent chromium concentration of 2.0 mg/L inflow could still maintain the removal rate of more than 95%.In order to satisfy the removal rate of more than 90% when the hexavalent chromium concentration of inflow was 1.0 mg/L,the smallest hydraulic retention time was 4 h.The reactor well tolerated within the pH 4-10,compared with biological method usual y tolerance for pH 6-9.In the reactor with the nitrate and chromium as the simultaneous pollutants,in order to meet the two kinds of pollutants removal rate both higher than 90%,the lowest carbon nitrogen ratio was 0.9,the minimum hydraulic retention time was 8 h.Reactor of acid and alkali resistance was still good;the p H within 4-10 basic on the impact was not big.After adding micro electric current,for nitrate pollution as alone matrix of reactor the carbon nitrogen ratio went down to 0.5 to achieve the removal rate of 90%,with chromate matrix to be a separate pollution carbon source in the reactor the carbon source amount reduced to 30 mg/L to achieve the removal rate of 95%.The micro electric current increased the reactor treatment effect and reduced the carbon source in best effect.