【作者】 庄严；

【导师】 周立祥； 陈立伟；

【作者基本信息】 南京农业大学 ， 环境工程， 2008， 硕士

【摘要】 本试验对医药化工废水的同步硝化反硝化（SND）生物脱氮脱碳进行了系统研究。采用实验室序批式反应器（SBR）小试试验和工程化应用试验,分别研究了溶解氧（DO）、pH对SND碳氮去除的影响和SND在实际工程运行中COD、氨氮、总氮去除效果;同时对污泥各项指标变化进行研究,为SND工程化应用提供了数据参考和拓展方向。最后提出了今后SND的研究方向,如SND反应机理和动力学研究、好氧反硝化菌的筛选和驯化、同步硝化反硝化和短程硝化反硝化及反硝化除磷技术相结合等。本文主要研究结果如下:（1）实验室小试阶段利用SBR反应器,SND最佳DO浓度应控制在1～2 mg/L,最佳曝气时间控制在8h。在此条件下,COD去除率达76%～78%、氨氮去除率达78%、总氮去除率高达74%～77%。不同DO条件下污泥氨氧化菌的数量有所差异,DO:0.5mg/L条件下的氨氧化菌数量仅为9.533×10²个,而DO:1,2,4 mg/L条件下都达到10⁴,这和氨氮去除率情况吻合。（2）控制DO:1 mg/L下SND最佳进水pH为7～7.5,此时的COD去除率达80%以上,氨氮去除率高达80%～82%,总氮去除率高达74%～78%。pH过低或过高都会影响碳氮的去除。在单个反应周期中,pH变化范围在7.49～7.15,没有明显的pH先下降后上升现象;NO₃^--N、NO₂^--N浓度在反应中没有明显积累过程,最终出水浓度分别为2.21 mg/L和1.87 mg/L。DGGE图谱表明,pH对污泥氨氧化菌群落结构和丰富度有较大影响,pH 7.5时的种群多样性最高,而pH 6.5最低。氨氧化菌种类差异是造成高pH下维持较高氨氮去除率的原因,而非氨氮吹脱去除。pH对SND过程反硝化菌的影响是今后值得研究的方向之一。（3）在实际工程应用中,控制曝气强度DO:1～2 mg/L,进水pH7～7.5时,水温在28～32℃下的COD、氨氮、总氮去除率分别高达78.8%、78.4%和74.5%,工程应用中的SND碳、氮去除效果比较理想。同时SND脱氮脱碳过程所需曝气量和酸碱投加量较传统生物脱氮有明显减少,降低了处理成本,其工程应用有广阔的前景。（4）研究结果表明水温和盐离子浓度过高对SND的碳氮去除有负面影响。在试验后期水温高达40～42℃,SO₄^2-浓度:8512 mg/L、Cl^-浓度:8031 mg/L下的COD、NH₄⁺-N、TN平均去除率分别只有66.9%、56.8%、44.9%。DGGE图谱表明:在多种影响因素的作用下,虽然出现适应环境变化的氨氧化菌菌种,但总体上氨氧化菌种类和数量都有减少。氨氧化菌种群多样性降低导致SND的氨氮、总氮去除率变差。更多还原

【Abstract】 In this work,the carbon and nitrogen removal efficiency of simultaneous nitrification and denitrification（SND） process in medicine chemical industry waste water was investigated.Sequencing batch reactor（SBR） was used for lab experiment and project application experiment respectively.The influences of dissolved oxygen（DO） and pH to carbon and nitrogen remove in SND process were researched,and the effects of COD、NH₄⁺-N、TN removal rate in project application were studied as well.Meanwhile,the changs of indexes of sludge were tested.This work provides data reference and developing direcation of SND project application,and proposes the direcations and emphasis of SND research in the future,such as the reaction mechanism and dynamics model of SND, screening and traning of aerobic denitrifiers,combination of simultaneous nitrification-denitrification,shortcut nitrification-denitrification and denitrifying dephosphorization.The major results are summarized as follows:（1） The sequencing batch reactor was used in lab experiment and the best condition of carbon and nitrogen removal efficiency of SND was DO:1～2 mg/L and 8h aeration time. In this condition,COD removal rate was 76%～78%;NH₄⁺-N removal rate was 78%;TN removal rate was 74%～77%.Ammonia-oxidizing bacteria（AOB） abundances of sludge in various DO conditions were different.AOB abundance of sludge was only 9.533×10² in DO:0.5 mg/L,but 10⁴ in DO:1,2,4 mg/L conditions.This was consistent with NH₄⁺-N removal rate.（2） Under the condition of DO:1 mg/L,the best influent water pH of SND should be controlled between 7 and 7.5.In this condition,COD removal rate was above 80%, NH₄⁺-N removal rate was 80%～82%and TN removal rate was 74%～78%.Excessive high or low pH would influence carbon and nitrogen removal efficiency.In single reaction cycle, pH fluctuated just between 7.49 and 7.15,and didn’t show partition-change phenomenon; the concentrations of NO₂^--N and NO₃^--N didn’t accumulatie massively,only 2.87 mg/L and 1.21 mg/L in effluent water.Denaturing gradient gel electrophoresis（DGGE） profile showed that influence of pH on sludge AOB microbial community structure and richness index was obvious.Microbial diversity of AOB was the highest under pH 7.5 and the lowest under pH 6.5.The reason of high NH₄⁺-N removal rate in high pH condition was various of AOB population,but not ammonia-nitrogen desorption.The influence of pH on denitrifying bacteria in SND process is a valuable research direction in the future.（3） The carbon and nitrogen removal efficiency of SND in project application was excellent.Under condition of DO:1～2 mg/L,influent water pH:7～7.5 and water temperature:28～32℃,the average COD、NH₄⁺-N and TN removal rate was 78.8%,78.4% and 74.5%respectively.Meanwhile,the aeration intensity,acid-base dosing quantity and treatment cost of SND process was much less than that in traditional biological nitrogen removal technology.SND denitrification technology has bright future in project application.（4） Excessive high water temperature and salt ion concentration could decrease COD, NH₄⁺-N and TN removal rate in simultaneous nitrification and denitrification process.In the late experiment period,water temperature rose up to 40～42℃,the concentrations of SO₄^2- and Cl^- reached 8512 mg/L and 8031 mg/L respectively,and the average COD、NH₄⁺-N and TN removal rate was just 66.9%,56.8%and 44.9%respectively.DGGE profile showed that,although new AOB strain appeared in different environment conditions, species and abundance of sludge ammonia-oxidizing bacteria decreased under the effect of influence factors.The decrese of AOB microbial diversity caused NH₄⁺-N,TN removal rate of SND process fall down.更多还原