采用分段进水生物脱氮工艺处理小区生活污水,考察了在碳氮比约为7、污泥回流比为60%的情况下,进水流量分配比(λ)对系统硝化效果、反硝化效果以及去除TN的影响。结果表明,当λ为0.2∶0.3∶0.3∶0.2时,系统的硝化容量能够满足去除进水中氨氮的要求,硝化效果最好。反硝化效果受λ的影响较大,当λ为0.2∶0.3∶0.3∶0.2时,进水中的碳源能够满足前段产生的硝态氮(NOx^--N)进行反硝化的需求,反硝化效果较好。对TN的去除率受硝化和反硝化的综合影响,当λ为0.4∶0.3∶0.2∶0.1及0.1∶0.2∶0.3∶0.4时硝化不完全,对TN的去除率较低;当λ为0.1∶0.4∶0.4∶0.1时中间两段的硝化容量不足,最后一段缺乏足够的碳源,导致出水NH4^+-N和NOx^--N浓度都很高,对TN的去除效果最差;当λ为0.2∶0.3∶0.3∶0.2时,充分利用了系统的硝化和反硝化容量,对TN的去除效果最好。
The lab-scale step-feed biological nitrogen removal process was used to treat domestic wastewater from residential area.The effect of 5 influent flow rate distribution ratios(λ) on nitrification and denitrification efficiencies and removal efficiency of total nitrogen under the conditions of C/N ratio of 7 and sludge reflux rate of 60% was investigated.The experimental results show that when λ is 0.2 ∶0.3 ∶0.3 ∶0.2,the nitrification capacity of the system can meet the demand of removal of ammonia nitrogen in the influent,and the nitrification efficiency is best.The denitrification efficiency is considerably affected by λ.When λ is 0.2 ∶0.3 ∶0.3 ∶0.2,the carbon source in the influent can meet the demand of nitrite nitrogen produced in the preceding stage for denitrification,and the denitrification efficiency is better.The removal efficiency of total nitrogen is affected by both nitrification and denitrification.When λ is 0.4 ∶0.3 ∶0.2 ∶0.1 and 0.1 ∶0.2 ∶0.3 ∶0.4,the nitrification is incomplete,and the removal efficiency of total nitrogen is lower.When λ is 0.1 ∶0.4 ∶0.4 ∶0.1,the nitrification capacity in the middle two stages is insufficient.The last stage can not provide sufficient carbon source for denitrification in preceding stage,which results in higher concentrations of ammonia nitrogen and nitrate nitrogen in the effluent and the poorest removal efficiency of total nitrogen.Whenλ is 0.2 ∶0.3 ∶0.3 ∶0.2,the nitrification and denitrification capacities are fully utilized,and the removal efficiency of total nitrogen is the best.