低溶解氧污泥微膨胀节能方法在A/O中的试验验证

Energy Saving Achieved by Limited Filamentous Bulking Under Low Dissolved Oxygen: Experimental Validation in(A/O) Process

采用实际的生活污水,在A/O系统中验证了低溶解氧污泥微膨胀节能理论与方法.结果表明,A/O系统在微膨胀运行期间SVI值能稳定维持在150--230 mL/g之间,单纯低溶解氧不会造成污泥沉降性能的严重恶化.相对于高溶解氧、污泥沉降性能良好时的运行情况,微膨胀期间COD和总氮去除率略有升高,分别为86%和63%,氨氮去除率略有下降,平均为70%,且约有10%--25%的氮可通过同步硝化反硝化去除.丝状菌的网捕作用使出水的SS浓度明显减低,出水浊度低于3 NTU.维持DO=0.5 mg/L所需的理论供气量相对DO=2.0 mg/L时可节约17%,对实际的小试结果比较发现可节约57%的曝气量.

Preliminary studies had been conducted to determine the correctness of the theory and technique of energy saving achieved by limited filamentous bulking under low DO using a lab-scale A/O reactor with real domestic wastewater as the influent. The results showed that SVI could be maintained 150-230 mL/g and sludge setfleability would not become very poor under the condition of low DO. During the period of limited filamentous bulking, COD and total nitrogen removal efficiencies were improved, and distinct simultaneous nitrification and denitrification （SND） was achieved, while ammonia removal efficiency would slightly decline with decreasing of DO, compared with the period of good settleability sludge under high DO. COD, ammonia and total nitrogen removal effieiencies were 86% , 70% and 63 % , respectively. It was found that about 10%-25 % nitrogen would be removed by SND based on the mass balance of nitrogen. Besides, SS in the effluent was almost negligible and the effluent turbidity was lower than 3 NTU. Significantly, aeration consumptions would be decreased by 17 % under the condition with DO of 0.5 mg/L compared with 2.0 mg/L according to theoretical calculation of air requirements to keep different DO levels, which was about 57 % in lab-scale reactor correspondingly.