曝气方式及排水比对CASS稳定化运行的影响

针对南京某污水处理厂受冲击的循环活性污泥工艺(CASS),采取了稳定化运行措施,考察曝气量、曝气时间、进水曝气方式及排水比对工艺稳定化运行效率影响。结果表明,工艺历经非限制性、半限制性和限制性进水曝气方式后趋于稳定化运行,二级处理出水COD和TP、NH4^+-N、TN的质量浓度平均分别为33.9 mg/L和0.335、1.85、12.41 mg/L,平均去除率分别为81%和80%、83%、31%,主要出水水质达到GB 18918-2002一级A标准。较低排水比运行处理效率较低,较高排水比运行利于TN去除,但出水COD、NH4^+-N、TP有所增长,出水水质波动;排水体积比在26%~31%运行,处理效率较高,出水水质稳定。稳定运行下平均处理直接费用约0.47元/t。

Effect of Aeration Mode and Drainage Ratio on Stabilized Operation of CASS

Aimed at cyclic activated sludge system(CASS) of a certain sewage treatment plant in Nanjing was impacted, stabilized operation measure was adopted. The effect of aeration rates, aeration time, influent aeration mode and drainage ratio on the stabilized operation efficiency of the process were investigated. The results showed that the process after non-restrictive, semi-restrictive and restrictive influent aeration mode could be stabilized, the COD and mass concentration of TP, NH4^+-N, TN in the effluent of secondary bio-chemical treatment process were 33.9 mg/L and 0.335 mg/L, 1.85 mg/L, 12.41 mg/L respectively, the average removing rates were 81% and 80%, 83%, 31% respectively. The main effluent quality could meet the first level A standard of GB 18918-2002. Sewage treatment efficiency had a certain loss under low drainage ratio operating, high drainage ratio operating was beneficial to TN removal, but COD, NH4^+-N and TP in effluent increased, the quality of effluent was unstable. The optimum drainage ratio was 26%~31%, the treatment efficiency was high and effluent quality was stable. The direct cost of water treatment was 0.47 yuan/t under stable running conditions.