生物膜内亚硝化过程及反硝化特性研究

【作者】 张小玲；

【导师】 王志盈；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2001， 硕士

【摘要】 针对常规生物脱氮工艺反应历程长、能耗高及不少行业高氨低碳生产废水难以达标排放的特点，探讨了亚硝化－反硝化生物脱氮工艺。实现硝化反应进行到亚硝酸阶段即终止，缩短了硝化和反硝化的历程，达到了节能高效处理的目的。 采用生物紊动床分别在高氨和低溶解氧条件下，探讨了亚硝化选择过程选择的稳定性；研究了有机物存在时，硝化菌和异养菌的竞争及以亚硝酸为基质的反硝化的特点。试验结果表明： 1．由于硝酸菌对游离氨的适应性，通过游离氨选择性抑制硝酸菌所获得的亚硝酸氮积累是不稳定的，在低溶解氧条件下，生物膜内由于动力学选择，系统可实现持久稳定的亚硝酸氮的积累。 2．溶解氧充分条件下（DO≥3mg/l），异养菌的氧化作用和自养菌的硝化作用可同时发生作用；低溶解氧条件下（DO≤1.0mg/l），由于异养菌生长吸收了部分有限的氧使硝化菌生长繁殖受到抑制，最终使硝化系统破坏。 3．得到反硝化试验系统的最大硝态氮负荷为0.08kgNLSS·d，合适的C/N为6～8，适宜pH为7.1～8.1。以NO₂^-为基质的反硝化比以NO₃^-为基质的反硝化历程短，因而反硝化速率快，试验得出： r_[NO2^-]=0.079kgN/kgMLSS·d r_[NO3^-]=0.053kgN/kgMLSS·d。 4．NO₂^-高到一定程度，水中的HNO₂会对反硝化产生一定的抑制，控制温度为25℃、pH在7左右，当硝态氮浓度小于300mg/l时，以NO₂^-为基质的反硝化速率较快，当硝态氮浓度大于、等于300mg/l时，结果相反。更多还原

【Abstract】 Conventional nitrogen removal process had some questinons, long reaction step,high energy consumption .And high ammonia low carbon wastewater was difficult tocome up to the effluent standard. To solve these questions, this paper studiednitrosofication-denitrosofication process. Which took the nitrite as the terminal productof the nitrification, shorted the reaction step, attained energy conservation and highefficiency.A novel generation of biological biofilm reactor, biological turbulent bed reactor（BTBR）, was used in the tests. The stability of nitrosofication process selection wasdiscussed under high ammonia or low dissolved oxygen, competition betweenheterotrophic and autotrophic bacteria was studied. The paper also dealt with thecharacteristics of denitrification started from nitrite.The experiments results showed:1.The nitrite accumulation was not stable via FA（free ammonia） because of theacclimation of the nitrite oxidizers to FA, while stable via dynamic selection because ofthe limiting substrate（DO） of growth.2.When dissolved oxygen was enough （DO≥3mg/l）,the oxidation ofheterotrophic bacteria and nitrification of nitrifiers can normal occur simultaneously,but at low oxygen（DO≤1.0mg/l） nitrification was destroyed because of heterotrophicbacteria assimilated the limited oxygen,the growth of nitrifiers was influent.3.The maximum NO₃^--N was 0.08kgN/kgMLSS·d, the proper C/N was 6～8,the suitable pH was 7.1～8.1. the step of denitrification started from NO₂^- was shorterthan from NO₃^-,so the rate of the former was faster. The results as follows:r_[NO2^-]=0.079kgN/kgMLSS·d r（[NO₃^-]）=0.053kgN/kgMLSS·d.4.When nitrite concetration was high ,denitrification would be depressed.Temperature: 25℃, pH: around 7, NO_x^-－N concentration: less than 300mg/l, The rateof nitrite denitrification was higher; when NO_x^-－N concentration was more than300mg/l,the result reversed.更多还原