The Research On MBR-CANON Process For Treatment Of High Ammonia Nitrogen Wastewater

Water eutrophication has become one of the key issues in the field of water treatment around the world.The increasing nitrogen pollution in water is an important cause of water eutrophication.This study is to investigate the pollution of ammonia nitrogen in wastewater,and to study the process of CANON treatment with little sludge generation,low running cost and good treatment effect.The main contents of the study include the start-up test,orthogonal test,reactor synchronous nitrogen removal and carbon removal effect analysis experiment.This experiment adopted the intermittent operation after the ordinary activated sludge fromdomestic sewage treatment plant was inoculated into the MBR reactor at room temperature,which was aimed at carrying out the laboratory study on the quick start of CANON process by controlling dissolved oxygen.The experimental results showed: under the circumstance of low concentration of dissolved oxygen,the nitrite nitrogen accumulation occurred 7 days later and nitrosation was started partially.Followed by a further decrease in dissolved oxygen concentration,the removal load of total nitrogen(NRR)reached 0.102kg/m3/d after 54 days and the CANON process was launched completely and successfully.Finally,the removal rates of total nitrogen and ammonia nitrogen were up to about 60% and 90% respectively with the NRR of 0.339kg/m3/d.The results showed: CANON process in the MBR reactor can be started quickly and successfully and accomplish the high-efficient nitrogen removal.Start the test conclusion:the four-factor and three-level orthogonal test on the operating reactorwas carried out by regarding dissolved oxygen(DO),temperature,pH and HRT as the regulating factors to determine the optimum values and obtained that the optimal reaction values were DO of 0.35mg/L,temperature of 30?,pH of 7.5 and HRT of 6h by comprehensive balance analysis of the results.It can be seen from the analysis that the most influential factor for the overall operation of the reactor was dissolved oxygen concentration,followed by HRT,again pH,and the temperature was the smallest.Given that the reactor start-up process may be carried out at room temperature and microorganisms had been adapted to normal temperature during the acclimation for more than two months,the temperature changes had little effect on the reactor operation.Based on the optimal conditions from orthogonal test,the finalNRR of the reactor,after 1-month operation,was stabilized at about 0.698kg/m3/d,which was improved by 106.9% compared with the one of 0.339kg/m3/d at the first successful start.Analysis of Synchronous Denitrification and Removal of Carbon in Reactor :Orthogonal test conclusion:the chemical oxygen demand(COD)(C/N=0.5 ? 1 and 2)was increasingly added to the inlet of the reactor to test theability of the MBR-CANON reactor on synchronous decarburization and nitrogen removal.When the C/N was 0.5,1 and 2,the NRR reached 0.68kg/m3/d,0.72kg/m3·d and 0.67kg/m3/d respectively after 30 d culture,which were better than that inorganic high influent ammonia nitrogen and the removal rate of COD was up to more than 80%.It revealed that MBR-CANON process,in the condition of low C/N,can accomplish high-efficient and synchronous decarburization and nitrogen removal.Then keep C/N=1,the removal rate of COD was about 85%,and the lower C/N ratio of NRR was decreased to 0.44kg/m3/d;The effect of COD removal was decreased at 0.49 kg/m3/d,and the final removal rate was stable at 80% under the condition of 50mg/L.Under this condition,it can finish the high efficiency of nitrogen removal and carbon removal.This explained that MBR-CANON process had the development prospect on the organic wastewater treatment of low ammonia nitrogen.The experimental results show that the combination of MBR and CANON process can be achieved by inoculating ordinary activated sludge from sewage treatment plant,It can achieve higher removal load under the optimal conditions determined by orthogonal experiment,And in the treatment of organic wastewater to achieve a better synchronous decarburization nitrogen.