| 分段进水A/O工艺外碳源投加控制策略的比较研究 |
| 摘要点击 1114 全文点击 909 投稿时间：2008-04-25 修订日期：2008-06-30 |
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| 中文关键词 分段进水 A/O 生活污水 低C/N 外碳源投加 控制策略 |
| 英文关键词 step-feed A/O domestic wastewater low C/N ratio external carbon addition control strategy |
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| 中文摘要 |
| 采用连续流分段进水A/O中试试验系统处理低COD/N生活污水,为获得高品质出水,投加外碳源(乙醇)强化反硝化效果.为合理、有效控制外碳源投量,针对不同控制参数(ORP和在线硝酸盐氮)及外碳源投加位置(D3和D4),提出5个外碳源投加控制策略,并从基建投资、处理效果、运行费用及维护等方面对控制策略进行比较.结果表明,控制策略Ⅰ和Ⅱ只选取D4为碳源投加控制点,控制结构最为简单,传感器数量最少,造价低,但由于缺氧停留时间过短,在高负荷、低COD/N时,控制参数无法达到预先设定值,而使得碳源投加持续过量,缺氧区D4平均COD浓度高达192.8 mg/L和158.9 mg/L,平均出水TN浓度高达17.42 mg/L和19.04 mg/L,碳源消耗量分别为92 mL/(m3·d)和84 mL/(m3·d).而控制策略Ⅲ～Ⅴ,同时在D3和D4投加外碳源,并采用不同的控制参数.结果表明,3个控制策略能充分利用D3和D4反硝化容量,较好地抵抗冲击负荷,保持出水TN浓度稳定,平均为7.30、 8.2和7.49 mg/L,碳源消耗量分别为29、 45和27 mL/(m3·d).最后,从传感器数量、运行效果稳定性及运行费用等方面对5个控制策略进行综合评价,结果表明,控制策略Ⅲ具有良好的动态品质,抗冲击负荷能力较强,出水效果较好,碳源投加量较低且在线仪器的投资较省,是较为优化的外碳源投加控制策略. |
| 英文摘要 |
| To obtain high quality drainage, external carbon source (ethanol) was used to enhance denitrification when low COD/N sewage was fed to a pilot-scale step-feed A/O system. To use carbon source sufficiently, five different external carbon addition control strategies were proposed based on different control parameters, ORP and on-line nitrate, and dosing positions, D3 and D4. Control strategies were evaluated on investment, treatment efficiency and operation cost basis. The results showed that for the short hydraulic retention time in anoxic zone, the control parameter could not reach the set-point when control strategyⅠand Ⅱ were applied. As a result, excessive feeding of external carbon source was occurred and the average COD concentrations in D4 were 192.8 mg/L and 158.9 mg/L for the insufficient usage of carbon. In this condition, effluent TN concentrations were 17.42 mg/L and 19.04 mg/L and the external carbon dosage rates were 92 mL/(m3·d) and 84 mL/(m3·d), respectively. Control strategies Ⅲ, Ⅳ and Ⅴcontrolled the external carbon dosage in D3 and D4 simultaneously. The results indicated that the strategies had strong resistance to peak loadings and reduced the effluent TN concentration effectively. The average effluent TN concentrations, 7.30 mg/L, 8.2 mg/L and 7.49 mg/L and the external carbon dosage rates, 29 mL/(m3·d), 45 mL/(m3·d) and 27 mL/(m3·d), were achieved respectively. Finally, based on the amount of on-line sensors, reliability of treatment efficiency and cost of operation, the control strategies proposed in this paper were evaluated together. Compared to the other control strategies, the suggested external carbon addition strategy Ⅲ was testified to be an optimal control strategy, which was characterized by good dynamic qualities, strong resistance to peak loadings, quick responding to loadings, and the lower external carbon addition amount. |
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