Autotrophic-heterotrophic Mutiple Denitrification Combing Process For Nitrate Removal From Groundwater

Deal with the dissolved organic carbon lack on groundwater,Firstly, Usingself-made electrode of biofilm reactor for autotrophic denitrification. Select titaniumplate as the anode material in the reactor, carbon felt for cathode, the three carbonfelt with cotton thread suture and sandwich filled with activated carbon particles.The effect of electric current, temperature, influent nitrate nitrogen concentration,influent pH and hydraulic retention time and nitrite nitrogen accumulation of thereactor were investigated.Secondly: With straw and corn starch as the releasing carbon fractions, PVA asskeleton materials, using the gel molding process, Produced with straw (type A) andstraw starch mixture (type B) as the main component of two kinds of releasing carbonmaterials. Through the two reactor and4groups of denitrification experiments cometo a conclusion: The group join with the releasing carbon materials have a higherefficiency of nitrate removal than the group without releasing carbon materials. Thenitrate nitrogen concentrations reduced from50mg/L to6.72mg/L in the reactorwhich add the B type releasing carbon materials, At the same time the reactor have astable COD concentration in300mg/L.Through the static biological nitrogen removalexperiment, achieved good biological nitrogen removal using the material. Thebiological nitrogen removal rate of type A and type B material is1.414gN/(m3·d) and1.792gN/(m3·d).Finally, Add the type B material as an organic carbon source into the self-madeelectrode biofilm reactor to form a complex system. The combing process have ahigher removal nitrate than electrochemical hydrogen autotrophic denitrification,shorter HRT and smaller electric current in the complex system.Results showed that:(1) The complex system with the electric current as60mA and the HRT as5h,the nitrate nitrogen concentrations reduced from70mg/L to less than10mg/L,and no nitrite.(2) The pH of the system was stable between7.0and8.1, the reactor hasgood pH self-regulation(3) Releasing carbon materials are cheap and simple, as electron donor isgood enough to improve the denitrification efficiency of the reactor, at the same time, effectively avoid the COD pollution.