| At present,with the rapid development of China,various kinds of wastewater have emerged,and wastewater treatment has also received more and more attention.Biological aerated filter(BAF)is widely used in the advanced treatment of sewage as a kind of feature with small floor area,strong impact load resistance,low operating cost,easy management and good effluent quality.In thesis paper,the effect of different operating conditions and parameters on the treatment efficiency of biological aerated filter was investigated by simulating wastewater with glucose as carbon source;Finally,the treatment effect of biological aerated filter on actual campus domestic sewage was investigated.The following conclusions are drawn:(1)The biological aerated filter(BAF)adopts a combination of inoculation and natural biofilm,using PET resin as the filter material,with an inlet flow rate of 8L/h,first with an air-water ratio of 4:1,and then with an air-water ratio of 11:1.Under this condition,after 17 days of continuous operation,the COD removal rates of the effluent from the four BAFs with different filler heights were stabilized at 38.72%,41.62%,46.59%,and 54.70%,respectively.In addition,indicative microorganisms were detected through microscopic examination,and the biofilm was successfully started.(2)The effect of different operating conditions on the treatment efficiency of biological aerated filter(BAF)was investigated using glucose as a carbon source for simulated wastewater.When analyzing the impact of different influent organic loads on the biological aerated filter,it was concluded that when the influent load was 25-70kg/m3 ยท d,BAF had the best removal effect on COD and ammonia nitrogen,while continued increase in organic load would inhibit the treatment efficiency of the system;When analyzing the impact of different air water ratios on biological aerated filter,it is concluded that when the air water ratio is 6:1,the system has the best removal effect.The average removal rates of COD by four BAFs with different filler layer heights are 58.24%,75.58%,74.34%,and 84.67%,respectively,and the average removal rates of ammonia nitrogen are 47.91%,53.95%,56.05%,and 53.85%,respectively;When analyzing the impact of flow rate on biological aerated filter,the optimal flow rates for BAF1,BAF2,BAF3,and BAF4 are 1m/h,3m/h,2m/h,and5m/h,respectively,due to the different effects of different flow rates on different bed heights;When analyzing the impact of bed height on biological aerated filter,it was concluded that the treatment effect was best when the bed height was 20 cm,but the effect was not significant if the bed height continued to increase;Finally,a parallel experiment was set up to verify the treatment effect of the biological aerated filter under this optimal condition.It was concluded that the curve fitting degree was good and BAF had good carbon and nitrogen removal performance.(3)To investigate the treatment effect of biological aerated filter(BAF)on actual campus domestic sewage,parallel test and comparative test were conducted respectively.The parallel test went through 28 cycles,and the final effluent COD concentrations of the four BAFs were 36.36mg/L,31.82mg/L,31.17mg/L and35.84mg/L respectively,while the ammonia nitrogen concentration was close to zero,and endogenous respiration occurred in about 15 cycles;Two groups were set up for the comparative test.The first group examined the effect of different filler heights on the effluent effect of the biological aerated filter.After 12 cycles,although the final effluent quality was not different,the nodes of endogenous respiration were different.The second group examined the effect of different inlet flow rates on the effluent effect of the biological aerated filter.After 5 cycles,it finally showed that at the flow rate of 3 m/h,COD effluent effect was the best,while ammonia nitrogen was due to the low inlet concentration,Influenced by objective factors,the outlet water is less affected by flow velocity. |
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