【作者】 孙国新；

【导师】 徐楚韶；

【作者基本信息】 重庆大学 ， 钢铁冶金， 2002， 硕士

【摘要】 焦化废水是典型的有毒难降解废水。我国焦化厂外排废水常因氮含量严重超标而污染环境。而目前普遍认为生物脱氮是从废水中去除氮的经济、有效的方法。本课题根据焦化废水的特点和我国焦化废水的处理现状，采用厌氧-两段SBR-缺氧工艺和亚硝化-反硝化（NH₃→NO₂^-→N₂）过程，对焦化废水的生物脱氮进行了较为深入系统的研究。为高效、经济的去除焦化废水中的COD和NH₃-N开辟了一条新途径。 研究结果表明：①利用游离氨和溶解氧对硝酸菌的选择性抑制，通过高的NH₃-N浓度和低的溶解氧浓度，可培养出亚硝酸菌为优势菌的活性污泥。在两个SBR反应器中接种亚硝酸菌，可实现亚硝化-反硝化脱氮过程；②影响生物硝化作用的因素很多，如游离氨浓度、温度、PH值以及溶解氧，由于生物硝化过程绝对需要氧，因此反应器中溶解氧对硝化作用有重要影响。要长期稳定的实现亚硝化-反硝化过程，实现NO₂^-的积累，关键是控制溶解氧浓度在1.5～2.0mg/L，低的溶解氧不但没有降低NH₃-N的去除率，而且提高了效率；③采用厌氧-两段SBR-缺氧工艺流程处理废水，系统运行周期为24h，各段停留时间分别为6h，SBRⅠ与SBRⅡ采用不同的曝气方式，进水COD、NH₃-N分别为2173.7mg/L和536.3mg/L时，系统出水COD和NH₃-N分别为112.5mg/L和13.4mg/L，均达到了1996年国家环保局颁布的《污水综合排放标准》（GB8978-1996）中规定的国家一级排放标准（其中COD为：新扩改厂≤100mg/L，现有厂≤150mg/L；氨氮为：新扩改厂≤15mg/L，现有厂≤25mg/L）；④亚硝化-反硝化过程具有处理氨氮浓度高，节省反硝化碳源，节约供气量，降低能耗，提高处理效率等优点。 采用厌氧-两段SBR-缺氧工艺流程和亚硝化-反硝化过程能经济有效的处理焦化废水。更多还原

【Abstract】 Coke wastewater is typically toxic difficult degradational pollutant. The enfluent of coke plant pollutes environment in our country because concentration of nitrogen is severely higher than standard. It is generally thought that biological nitrogen removal is economical and effective method to remove nitrogen from wastewater at present. According to the character of coke wastewater and present treatment in our country, anaerobic-two stages SBR-anoxic process with shortened nitriflcation-denitrification (NH3→NO2-→N2) pathway to treat coke wastewater for biological nitrogen removal was studied deeply and systematically in this paper. All of these provide a new way for high-efficiency and economical removal of COD and NHs-N of coke wastewater.Experimental results demonstrate (1)With the selective inhibition of free ammonia and dissolved oxygen on nitrate bacteria, the activated sludge predominated by nitrite bacteria may be obtained when the concentration of NH3-N is high and the concentration of dissolved oxygen is low. By seeding nitrite bacteria in two SBR reactors, the shortened nitrification-denitrification process is feasible. (2)Many factors can influence biological nitrification, such as the concentration of free ammonia, the temperature, the PH value and dissolved oxygen. Because oxygen is absolutely needed in biological nitrification, dissolved oxygen has important influence to nitrification in reactors. In order to realize shortened nitrification-denitrification pathway prolongly and steadily to have the accumulation if NCV, the key is to control the concentration of dissolved oxygen in the range of 1.5mg/L to 2.0mg/L. The low concentration of dissolved oxygen didn’t reduce removal rate at the same time increase removal effect. (3)With total running cycle 24h, 6h for each stage, different airing way between SBR I and SBR II, anaerobic-two stages SBR-anoxic process by shortened nitrification-denitrification is used to treat wastewater. When the influent concentration of COD and NHa-N are 2173.7mg/L and 536.3mg/L respectively, the eufluent concentration of COD andN are 112.5mg/L and 13.4mg/L respectively. Both reach ournational first class standard for existed plants issued in GB-8978-1996 (COD: no more than 100mg/L for newly-built or rebuilt or extended plants, no more than 150mg/L for existed plants; NHa-N: no more than 15mg/L for newly-built or rebuilt or extended plants, no more than 25mg/L for existed plants) .(4)The shortened nitrifi-cation-denitrification process has many advantages, such as treating high ammonia concentration, saving carbon required for denitrification, reducing the amount of air, increasing treatment effect.Using anaerobic-two stages SBR-anoxic process with shortened nitrification-denitrification can treat coke wastewater economically and efficiently.更多还原