Study On Treatment Of Low Concentration Ammonia Nitrogen By Low Density Zeolite Biological Aerated Filter

Main material is considered as cheap easy natural Zeolite in the text.additive low density grain material and adhesive mix,conglobate and solidify Zeolite powder.Compound fillings of low density zeolite that are grain diameter of 4-6mm succeefully are prepared,which constitutes system of biological aerated filter with compound fillings of low density zeolite.Manual work prepares simulation wastewater of low concentration ammonia nitrogen.Many factors such as ammonia nitrogen concentration,clinoptilolite amounts,temperature,clinoptilolite diameter,time,filtration velocity,water quality regenerative time and regenerative times have the influence of ammonia nitrogen removal were investigated by the static,dynastic and regenerative experiments firstly,The results of static experiment show static absorptive capacity of 1.6mmolNH₄⁺/g in terms of initial ammonia nitrogen concentration of 10mg/Land clinoptilolite diameter of 20～40 item.The results of dynastic experiment show open water capacity of percent gram of 0.62L in terms of filtration velocity of 2m/h,retention period of 30min and ammonia nitrogen concentration of open water of 2m/L below.The results of regeneration experiment show the solution concentration of 500mL NaCl is 5g/L as the regeneration reagent of natural clinoptilolite,and the regenerative time is an hour and recovery rate of once regeneration is better.Manual work prepares simulation wastewater of low concentration ammonia nitrogen.In lab-scale experiment,the removal ammonia nitrogen performance of BAF with compound fillings of low density zeolite is studied.The main objects studied here are the disposal efficiencies of COD and ammonia nitrogen which can influence the efficiency.The experiment reaches a conclusion that:When using 4-6mm grain diameter,1.05-1.5mg/L density and high 50N intensity as the media, the factors that can influence the performance of BAF are:the ratio of gas to liquid,the media height,hydraulic load and organic load.The removal rate of COD and NH₄^*-N respectively is 63%-90.1%,79%-91.6%under the conditions of the ratio of gas to liquid of 1∶1-5∶1,organic load of low 3.2 kgCOD/m³Â·d,hydraulic load of 1-3 m³/m² h and the media height of 20-140cm.The method of backwash using air- water backwashing has many advantages over other methods.After backwashing BAF,goove treatment resumes 5-6h.That is to say COD removal rate is above 70%.