【摘要】 采用改良分段进水工艺处理低C/N值城市生活污水,通过小试及物料衡算研究不同曝气量对系统除污效果、SND率以及污泥沉降性能的影响。系统设置0.20、0.16、0.10、0.06m~3/h等4组不同曝气量,结果表明:对COD的去除率基本不受曝气量的影响,好氧区曝气量低至0.06 m~3/h时,相应好氧3区平均DO为1.38 mg/L,系统出水COD仍低于50 mg/L;而硝化效果受曝气量的影响较大,随曝气量降低,硝化效果明显恶化;较高的曝气量和较低的曝气量对厌氧释磷均有不利影响,进而降低除磷效率;此外,高DO水平和低DO水平对污泥沉降性能均产生了不利影响;经物料衡算,因硝化效率降低导致反硝化效率也明显下降;此外,SND率及微生物同化作用对系统去除TN具有重要影响。综合考虑处理效率及能耗问题,较为优化的曝气量为0.10 m~3/h(相应好氧3区平均DO为2.32 mg/L)。更多还原

【Abstract】 The modified step feed process was used to treat the municipal sewage with low C / N,and the effect of different aeration rates on pollutants removal efficiency,SND rate and settleability of sludge were analyzed through small-scale tests and material balance calculation. The aeration rates of four groups were set as 0. 20 m~3/ h,0. 16 m~3/ h,0. 10 m~3/ h and 0. 06 m~3/ h respectively. The results showed that the COD removal efficiency was little affected by aeration rate. When the aeration rate in aerobic zone was as low as 0. 06 m~3/ h,the average concentration of DO in relevant aerobic zone 3 was 1. 38 mg /L,and the effluent COD concentration was below 50 mg / L. Nitrification was greatly affected by aeration rate,and it was obviously deteriorated with the decrease of aeration rate. The removal efficiency of phosphorus reduced whether at high or low aeration rates because anaerobic phosphorus release effect was weakened. No matter at high or low DO concentration,the settleability of sludge was negatively affected.Through the material balance calculation,it was found that the reduction of nitrification efficiency led to an obvious decrease in denitrification efficiency. Moreover,SND rate and microbe assimilation had important effect on TN removal. With a comprehensive consideration of treatment efficiency and energy consumption,the optimized aeration rate is 0. 10 m~3/ h,and the average DO concentration in aerobic zone 3 is 2. 32 mg / L.更多还原