纤维素乙醇废水物化处理技术的筛选及中试研究

发布时间：2018-08-27 16:02

【摘要】：纤维素乙醇废水一般具有高浓度、高盐度、强酸性、刺鼻气味、高色度、高浊度的特点,且废水中通常含有木质素等难降解类物质,纤维素乙醇废水是一种典型的高浓度工业有机废水。目前,纤维素乙醇废水已成为制约纤维素乙醇生产工业发展的影响因素,如何经济、有效的处理纤维素乙醇废水这一难题亟需解决。采用生物厌氧处理和好氧处理纤维素乙醇废水后,难降解有机污染物质仍然存在于二级生化出水中,未被有效去除,使出水无法达到国家关于纤维素乙醇废水的排放要求。因此,本研究采用物化方法,对纤维素乙醇厌氧生化出水进行强化处理,同时对二级生化出水进行深度处理,从而使出水达标排放。本文以纤维素乙醇废水厌氧出水作为强化处理对象,通过对比混凝法、Fenton氧化法及臭氧氧化法的强化处理效果,筛选出最为合适的强化处理方法,并通过试验考察该方法影响因素对处理效果的影响,确定最佳工艺参数。深度处理对象为二级生化出水,通过试验从臭氧氧化法和Fenton氧化法中筛选出较优方法,并考察其处理效果受不同因素的影响,确定最优反应条件。强化处理部分扩大至中试规模,通过考察反应条件对处理效果的影响确定最优工艺参数,并据此进行经济分析。臭氧氧化法是对纤维素乙醇废水厌氧出水进行强化处理较为合适的方法。反应时间、臭氧投加量、初始p H值和反应温度对强化处理效果均有不同程度的影响。在最优反应条件(臭氧投加量为5 g/h、反应温度为30℃、初始p H值为10、反应时间为80 min)下,COD去除率可达35%,氨氮去除率可达45%,BOD/COD可提高到0.325。在中试臭氧氧化强化处理过程中,当水力停留时间为140 min、臭氧投加量为6 g/h时,出水可生化性显著提高,BOD/COD值提高到约0.26。Fenton氧化法是最为合适的深度处理方法。初始p H值、H2O2/COD值、Fe2+/H2O2值、反应时间和反应温度对Fenton氧化法深度处理效果均有不同程度的影响。深度处理的最佳工艺条件为:初始p H值为3、H2O2/COD值为2.8、Fe2+/H2O2值为0.67、反应时间为3 h、常温或室温下进行反应。在该反应条件下深度处理出水COD稳定低于100 mg/L,氨氮稳定低于4 mg/L,出水中几乎不含有浊度,达到了国家关于纤维素乙醇废水的排放标准。该厂拟建项目高浓度废水产量为2111 t/d,臭氧氧化法强化处理成本较低,其中设备投资约63.0万元,年运行费用约30.9万元。Fenton氧化技术深度处理工艺的设备投资费用为20.0万元,吨水运行成本为69.96元。
[Abstract]:Cellulose ethanol wastewater has the characteristics of high concentration, high salinity, strong acidity, pungent smell, high color and high turbidity. Cellulose ethanol wastewater is a typical high concentration industrial organic wastewater. At present, cellulosic ethanol wastewater has become the influence factor that restricts the development of cellulosic ethanol production industry. How to treat cellulosic ethanol wastewater effectively is an urgent problem to be solved. After biological anaerobic treatment and aerobic treatment of cellulosic ethanol wastewater, the refractory organic pollutants still exist in the secondary biochemical effluent, which are not effectively removed, so that the effluent can not meet the national discharge requirements of cellulose ethanol wastewater. Therefore, the method of physicochemical treatment was used to enhance the treatment of cellulose ethanol anaerobic effluent, and at the same time, advanced treatment was carried out on the secondary biochemical effluent, so that the effluent could be discharged up to standard. In this paper, the anaerobic effluent from cellulosic ethanol wastewater was taken as the object of enhanced treatment. By comparing the effect of Fenton oxidation and ozone oxidation, the most suitable enhanced treatment method was selected. The influence factors of the method on the treatment effect were investigated and the optimum process parameters were determined. The advanced treatment object is secondary biochemical effluent. The optimum reaction conditions are determined by screening the better method from the ozone oxidation and Fenton oxidation methods, and investigating the influence of different factors on the treatment effect. The reinforcement treatment was expanded to the scale of the pilot scale, and the optimal process parameters were determined by investigating the effect of reaction conditions on the treatment effect, and the economic analysis was carried out accordingly. Ozone oxidation is an appropriate method for the enhanced treatment of cellulose ethanol wastewater. The effects of reaction time, ozone dosage, initial pH value and reaction temperature on the strengthening effect were different. Under the optimum reaction conditions (ozone dosage is 5 g / h, reaction temperature is 30 鈩，

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