The Experimental Study On Treating Domestic Sewage Bythe Automatic Intermittent Feeding And Double Series Aeration Reactor

In recent years, the water pollution phenomenon in small towns and rural areas has been quite serious. And it’s mainly caused by the reason that the sewage was untreated or simply treated, discharging directly. From the investigation, the author found that it’s difficult to treat with the sewage in these areas, because it’s low C/N, changed significantly in quality and quantity, and distributed dispersedly. Besides, the sewage treatment facilities in the above areas were unadvanced by the economic limit. Therefore, it’s urgent and important to find a sewage treatment process which is effective and economic to remove the carbon and nitrogen in high load sewage.Based on the effective, economic and smiple principle, the author chose domestic sewage as the research object and used a reactor of the authomatic intermittent feeding and double series aeration, which was a invention patent(application number: 2015 10432180.5) designed by our team, to look for the optimum operating condition of removing nitrogen and carbon, and to study the performance of sludge reducation. The research lasted 110 days, and the results are as follows.(1)The author looked for the optimum operating conditions of removing carbon and nitrogen in 1.0, 1.5 and 2.0kgCOD/(m3·d). And the result showed that the concentration of COD, ammonia nitrogen and total nitrogen in the final effluent could all meet the discharge requirements of 50, 5 and 15mg/L. Considering the removal efficiency and load of pollutants, the autor think the optimum operating condition in 1.5 kgCOD/(m3·d) is the best. And its operating parameters were as follows. HRT was controlled about 6.9h, sludge recycle ratio was about 30%, the DO in the first and second aeration zone was 1.4 and 0.6mg/L, the periodicity was 10 times per day. And in each recyle, the water filling ratio was about 1/3,the total time was 2.4h, and among that, the feeding time was 30 min, the aeration time in the first and second intermittent aeration zone was 70 and 6min, and the rest was the precipitation time. And its pollutant removal results were as follows, the final effluent concentration of COD, ammonia nitrogen and total nitrogen could all meet the discharge requirements of 50, 5 and 15mg/L, and the tatal removal rate of them was 86%, 94% and 83%.(2)Compared with the trational active sludge process, the sludge reduction rate of the reactor was 73%, 77% and 78%, and its sludge reduction performance was good.(3) Compared with the test running parameters and pollutants removal effect between Sun Aixuan’s and the author’s, the author found that this process had good volume and energy saving performance. Along with its good sludge reduction, they all showed the significant economy. And this process could depend on the promoting function of flow, to drain off water, overcoming the discharge that traditional SBR and CAST process need water decanter to drain off water. So the technical process of this test was more simple. Besides, this research used time controller to control the starting and ending time of inflow and aeration, showing high automatic performance.