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多点强化氧化沟处理混合型城市污水脱氮技术研究

An Experimental Study on Bio-Denitro Process of Mixed Municipal Sewage by Multi-point Strengthen Oxidation Ditch

【作者】 魏锐

【导师】 邢传宏;

【作者基本信息】 郑州大学 , 环境工程, 2012, 硕士

【摘要】 本试验研究内容主要包括以下三个方面:(1)水解酸化调控技术研究,为解决碳源不足或工业废水量比例较大引起COD浓度过高的问题,试验采用折流板式水解酸化反应器,通过厌氧水解酸化反应达到削减COD、提高可生化性同时改善碳氮比的目的,确保后续生化处理单元高效运行,出水稳定达标;(2)溶解氧调控技术及优化研究,在氧化沟单元拟将传统曝气改成“微孔底曝+机械推流”方式,以提高氧的利用率,并大幅加大设计池深。通过调整溶解氧沿沟长空间分布,实现高效硝化反硝化,并达到节能目的。(3)氧化沟调控,研究不同水力停留时间条件下氧化沟的脱氮效率,选择合适的水力停留时间,同时考察温度对氧化沟运行情况的影响。水解酸化池水力停留时间设定1.5h、2h、3h、4h时,对氨氮的平均去除率分别为4.6%、9.9%、13.5%和9.7%,对COD的去除率在-25~60%之间。结果发现水解酸化池HRT=3h时,对COD和氨氮的去除最高。污水经过水解酸化池后,BOD5/COD从反应前的0.33左右提高到了0.45左右。而温度的改变对水解酸化池去除效率的影响甚微,虽然厌氧微生物与好氧微生物相比对温度较敏感,但是低温带来的不利影响通过延长固体停留时间和提高反应器内污泥浓度有效的被弥补了。氧化沟运行过程中,曝气管全开时氧化沟单元出水COD、NH3-N、TN可达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A标准要求。曝气管半开时,沟内缺氧区空间比例过高,使硝化反应受到抑制,氧化沟内不能形成持续稳定的交替好氧缺氧环境。试验进入冬季后,环境温度降低,系统的处理效果不佳。为了提高氧化沟的处理效率以及改善沟内泥水混合效果,试验在氧化沟内每个廊道加放一根曝气管,增加曝气面积后,水深20cm处DO均值为1.93mg/L,水深60cm处DO均值为1.72mg/L,相对沟内之前的缺氧状态有较大改善。氧化沟对COD、氨氮、TN的去除效果均有所提高,氨氮和TN的去除率相对之前增加了一倍,COD去除率增加了10.7%,改善效果明显。在对氧化沟的水力停留时间进行调控时发现,当HRT=10h、8h时,系统的脱氮效率都很高,其中氨氮的去除率可以稳定在90%以上,HRT=8h时对TN的去除效果较好,且与10h时相比更稳定。但是当水力停留时间降到6h和4h后,系统的脱氮效果逐渐变差,对氮的去除非常有限。综合考虑能耗、脱氮效率等因素,氧化沟的水力停留时间取8h最适。监测氧化沟内温度在14~34℃之间系统的脱氮效率时发现,沟内水温在23℃以上时,出水COD、氨氮、TN都可以得到较好的控制;当温度低于20℃时,氨氮和TN的去除效果明显下降,相对之前去除率降低了20%~50%左右。但是,期间温度对COD的去除却没有太大的变化。温度降低对脱氮效果的影响主要原因是硝化细菌的活性受到抑制。而温度降低对系统处理效果的影响可以通过调节水力负荷来改善。

【Abstract】 This pilot study mainly includes the following three aspects:①Research on hydrolysis acidification. To solve the high COD concentration as carbon resource shortage and a larger proportion of quantity of industrial waste water, experiment with a baffle hydrolysis acidification reactor to ensure follow-up biochemical processing unit can be efficient operation and the stability of the effluent water reaches the standard.②Optimum control of dissolved oxygen. We took "the miraco bubble aerate system and mechanical plug flow" instead of conventional aeration in oxidation ditch in order to improve the utilization rate of oxygen. At the same time, we increased the depth of oxidation ditch substantially. By adjusting the spatial distribution of dissolved oxygen along the channel length, achieve high efficiency of nitrification and denitrification, and achieve the purpose of saving energy.③The regulatory of oxidation ditch. This paper investigated the removal effect of nitrogen of oxidation ditch at different HRT. And the effect of temperature on oxidation ditch running effect.When the HRT of hydrolysis acidification was1.5h,2h,3h or4h, the average removal efficiencies of NH3-N was4.6%,9.9%,13.5%and9.7%, and the removal efficiencies of COD was-25~60%. The result showed that HRT=3h achieved the highest COD and ammonia nitrogen removal. And BOD5/COD increased from0.33to0.45. And the temperature had a little effect on hydrolytic acidification tank. Although anaerobic microorganisms is more sensitive to temperature than aerobic, but extended solids retention time and improving sludge concentration can remedy adverse effect of low temperature.In oxidation ditch, the effluent of oxidation ditch COD, NH3-N and TN achieved "Cities Sewage Treatment Plant Pollutant Discharged Standard"(GB18918-2002) the center one levels A to discharge the standard when aeration pipes open full. As aeration pipes open half, in the ditch could not form alternating aerobic-anoxic environment because of the high proportion of anoxic zone space and the nitration is restrained. Treatment effect of the system is poor in winter. In the oxidation ditch put a aeration pipe in each tunnel for improved the treatment efficiency and slurry mixing effect. The DO average value is2.2mg/L underwater20cm, and2.12mg/L underwater60cm after increasing the aeration area of oxidation ditch. The removal of COD, NH3-N and TN was all improved, NH3-N and TN increased doubled, COD increased10.7%.It was found that HRT was1Oh or8h can achieve high removal rate of nitrogen when regulated hydraulic retention time of oxidation ditch. The removal rate of NH3-N could reach more than90%, the removal of TN when HRT was8h was higher than1Oh. But the removal of NH3-N and TN was very poor when HRT drop to6h and4h. In consideration of the removal, energy saving and consumption reducing, HRT=8h was suitable.Control the temperature in14~34℃, effluent of COD, NH3-N and TN could get satisfactory control when the temperature is greater than23℃; the removal of COD, NH3-N and TN was dramatic decline, reduced20%-50%, when the temperature is below20℃. But the removal of COD without any big changes when the temperature below. Temperature influence on nitrogen removal efficiency because of the activity of the nitrifying bacteria was inhibited. But it could improve by adjusting the hydraulic load.

  • 【网络出版投稿人】 郑州大学
  • 【网络出版年期】2012年 09期
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