好氧区DO对水解酸化-缺氧-好氧工艺处理石化废水的影响

Effect of Aerobic DO on the Performance of HydrolysisAcidification-Anoxic-Oxic Process of Treating Petro-chemical Wastewater

采用水解酸化-缺氧-好氧工艺处理某石化废水，研究了不同好氧区P（DO）下，系统中的有机物、NH4＋-N和TN的去除效果，SMP（solublemicrobialproducts，溶解性微生物产物）的产生情况，以及污泥沉降性能的变化．结果表明：在总水力停留时间为40h、污泥回流比为100％的情况下，好氧区P（DO）平均值从6—7mg／L降至1～2mg／L左右时，系统仍可维持较为稳定的有机物、NH4＋-N和TN去除效果；随着好氧区ρ（DO）的降低，出水中ρ（SMP）对ρ（CODcr）的贡献有所降低，SMP中ρ（蛋白质）与P（多糖）之比由4．6：1降至0．8：1；随着好氧区ρ（DO）的降低，污泥的沉降性能逐渐变差，SVI（污泥指数）由62．7mL／g升至136．9mL／g，但并未导致污泥流失．综合污染物去除效果和运行能耗来看，该研究中较为适合的好氧区ρ（DO）为2～3mg／L．

Petrochemical wastewater was treated by a hydrolytic/acidification-anoxic-oxic process. The effect of the dissolved oxygen （DO） in oxic reactor on the performance of the process was investigated by detecting the organics, ammonia nitrogen （ NH4 ＋ -N） and total nitrogen （TN） removal, soluble microbial products （SMP） production and settling property of activated sludge. The hydraulic retention time （HRT） of the process lasted 40 hours, and the sludge recycle ratio was 100% during the process. The results showed that the removal of TOC, NH4＋-N and TN remained stable when average p（DO） in the oxic reactor decreased from 6-7 mg/L to 1-2 mg/L. SMP was an important component of the residual CODcr of the effluent. The contribution of SMP on the residual CODcr of the effluent decreased with the decrease of aerobic p（DO） from 6-7 mg/L to 1-2 mg/L in the oxic reactor. Meanwhile, the ratio of protein to polysaccharide in the SMP decreased from 4.6：1 to 0.8： 1. The settling properties of activated sludge became worse with the decrease of/9（DO） , and the sludge volume index （SVI） increased from 62.7 mL/g to 136. 9 mL/g. Fortunately, the water quality of the effluent was not deteriorated with this limited filamentous sludge bulking and there was no sludge loss under this condition. Generally, considering the performance and energy consumption, the recommended aerobic p（DO） for the hydrolytic/aeidification-anoxic-oxic process was about 2-3 mg/L.