折流式内循环生物膜反应器实现同时双加氧和反硝化

发布时间：2018-09-01 16:53

【摘要】：邻苯二甲酸(phthalic acid,PA)作为生产邻苯二甲酸酯类(PAEs)的一种前驱体,被广泛地运用于生产燃料,聚酯树脂,药物和增塑剂等方面,由于人类社会的大量生产和广泛使用,邻苯二甲酸酯类已成为地球上最广泛存在的环境污染物之一。PAEs不仅具有致畸、致癌和致突变特性,而且是一种内分泌干扰素,严重危害人类的健康。一般PAEs较易水解生成PA,作为邻苯二甲酸酯类的最主要中间产物,且该中间产物的积累会严重影响邻苯二甲酸酯类的降解进程,所以对PA的降解机理的研究已显得尤为重要。同时,近年来,由于农业上氮肥的过量使用、居民生活和工业污水的排放,导致我国地表水含氮物质(硝酸盐和亚硝酸盐等)污染日益严重。目前,对于含有PA的污水,一般的生物处理方法是好氧生物降解法,而对于硝酸盐和亚硝酸盐的污水,一般是在缺氧环境下利用反硝化反应来进行去除。本研究通过将折流式内循环生物膜反应器进行改进,提供了一种将好氧区域和缺氧区域在一个反应器内实现的环境,在折流式内循环反应器内实现了PA的双加氧反应和反硝化反应。探究了外源电子供体和紫外辐射产生的内源电子供体是如何通过加速PA的双加氧反应,进而加速了反硝化反应,通过对硝酸盐和亚硝酸盐这两种主要反硝化反应的反应物的研究,发现以亚硝酸盐为氮源时的反硝化反应更易进行。主要结果如下:(1)通过对折流式内循环生物膜反应器的改进,控制反应器的表面溶解氧约2mg/L,由于反应器前段溶解氧的消耗,为反应器后段提供了缺氧环境,经过对生物膜的驯化,在折流式内循环反应器实现了需氧的双加氧反应和缺氧的反硝化反应。(2)外源电子供体丁二酸的投入,促进了PA的初始双加氧反应,生成的下游产物更易被反硝化反应利用,从而加快了反硝化反应的反应速率。(3)当只有以丁二酸提供碳源时,少量的丁二酸投加,反硝化反应基本不进行,当丁二酸的投加量达到1.27m M/L时,反硝化速率明显加快,与PA+丁二酸组的反硝化反应速率相近,通过两组电子平衡的计算,进一步论证了少量的丁二酸作为电子供体优先提供给PA的双加氧反应,从而为反硝化反应提供了充足且易被利用的小分子有机酸。(4)PA经过UV/H2O2的预处理后释放出的诸如丁二酸、乙酸类的小分子有机酸作为内源电子供体和由外部提供的电子供体对双加氧反应和反硝化反应的加速效果相同。(5)在反硝化反应中,由于亚硝态氮所需的电子供体比硝态氮所需的电子供体少,根据相同条件下,亚硝酸盐和硝酸盐的两组实验结果对比,当氮源是亚硝酸盐时,PA的降解速率是以硝酸盐为氮源时的2~3倍,反硝化速率也达到将近3倍。这为短程硝化反硝化提供了实验论据,如果在硝化反应中能控制氨盐直接转化为亚硝酸盐,不仅节约了资源,而且加快了反硝化的速率。
[Abstract]:Phthalic acid (PA), as a precursor for the production of phthalic esters (PAEs), is widely used in the production of fuels, polyester resins, drugs and plasticizers. Due to the extensive production and use of human society, phthalic acid esters have become one of the most widespread environmental pollutants on the earth. It is not only teratogenic, carcinogenic and mutagenic, but also an endocrine interferon, which seriously endangers human health. PAEs are easily hydrolyzed to form PA, which is the main intermediate of phthalate esters. The accumulation of this intermediate will seriously affect the degradation process of phthalate esters, so the degradation mechanism of PA is very important. At the same time, in recent years, due to the excessive use of nitrogen fertilizer in agriculture and the discharge of domestic and industrial sewage, the pollution of nitrogen-containing substances (nitrate and nitrite etc.) in surface water is becoming more and more serious. At present, for the sewage containing PA, the general biological treatment method is aerobic biodegradation method, while for nitric acid. Salt and nitrite wastewater is usually removed by denitrification under anoxic conditions. In this study, the baffled internal circulation biofilm reactor was improved to provide an environment in which the aerobic and anoxic areas are realized in one reactor, and PA double oxygen addition was realized in the baffled internal circulation reactor. Reactions and denitrification reactions. How exogenous electron donors and endogenous electron donors produced by ultraviolet radiation accelerated the denitrification reaction by accelerating the double-oxygenation of PA was investigated. Through the study of nitrate and nitrite, two main denitrification reactants, denitrification was found when nitrite was used as nitrogen source. The main results are as follows: (1) By improving the baffled internal circulation biofilm reactor, the dissolved oxygen on the surface of the reactor was controlled to be about 2 mg/L. Oxygen consumption in the front of the reactor provided an anoxic environment for the rear of the reactor. After domestication of the biofilm, the aerobic hydrogen was achieved in the baffled internal circulation reactor. Oxygenation and anoxic denitrification. (2) Input of exogenous electron donor succinic acid promotes the initial hydrogen peroxide reaction of PA, and the resulting downstream products are more easily used by denitrification, thus speeding up the denitrification reaction rate. (3) When only succinic acid is used as carbon source, a small amount of succinic acid is added to denitrify the reaction group. When the dosage of succinic acid reached 1.27m/L, the denitrification rate was obviously accelerated, which was similar to that of PA+succinic acid group. Through the calculation of two groups of electron balance, it was further demonstrated that a small amount of succinic acid as an electron donor preferentially provided PA with hydrogen peroxide reaction, thus providing sufficient and sufficient for denitrification reaction. Small molecule organic acids that are easy to be used. (4) Small molecule organic acids such as succinic acid and acetic acid released from PA after UV/H2O2 pretreatment as endogenous electron donors and electron donors provided by the outside have the same accelerating effect on the hydrogen peroxide reaction and denitrification reaction. (5) In denitrification reaction, the electrons needed for nitrite nitrogen are the same. According to the experimental results of nitrite and nitrate under the same conditions, when the nitrogen source is nitrite, the degradation rate of PA is 2-3 times that of nitrate and the denitrification rate is nearly 3 times that of nitrate. This provides experimental evidence for short-cut nitrification and denitrification. The direct conversion of ammonia into nitrite can be controlled in the reaction, which not only saves resources, but also speeds up the denitrification rate.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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