【作者】 姚晓莉；

【导师】 李彦锋；

【作者基本信息】 兰州大学 ， 应用化学， 2008， 硕士

【摘要】 近年来随着工业的发展,工矿企业的快速增加,苯系物苯、甲苯、乙苯及二甲苯(简称BTEX)对环境的污染已成为突出的问题之一。苯系物为挥发性有机污染物,其在环境中通过迁移转化而造成的污染已引起国内外的广泛关注。然而,目前对工业废水处理过程中苯系物的迁移转化规律的现场考察及实验的还比较少见。本文以某涂料废水为研究对象,对废水中BTEX在物化预处理+生物处理过程中的迁移转化规律进行了现场考察和模拟试验,研究氧化沟技术主要运行条件对BTEX去除率的影响。研究结果表明:1、BTEX去除率较高,苯的去除率为89.6%,其它污染物去除率在99.0%以上,外排废水能够达到GB8978-1996一级标准。研究发现BTEX的去除主要集中在氧化沟和气浮池系统;隔油池除油效率降低,且苯、甲苯、间二甲苯不易被悬浮物吸附,BTEX在隔油池的去除不明显。2、氧化沟系统中,苯、甲苯、乙苯、邻二甲苯及间、对二甲苯的去除率分别为82.59%、97.48%、96.37%、95.83%、95.10%。生物降解是BTEX在氧化沟中的主要去除方式,其次是表面曝气挥发,剩余污泥吸附量很少。3、BTEX的挥发主要集中在氧化沟系统的表面机械曝气过程及气浮池微气泡的吹脱过程中,各构筑物表面挥发都较少。据估算,BTEX中排空量最高的为甲苯。4、在氧化沟系统中,溶解氧浓度由2～3mg/l提高到4～6mg/l时,曝气挥发量、生物降解量增加,BTEX去除率提高;MLSS值由8.0g/l降低到4.5g/l时,BTEX生物降解率下降,总去除率降低;温度对氧化沟中微生物有一定影响,BTEX降解率在冬季有所下降。更多还原

【Abstract】 In recent years, with the development of the industry and rapid increase of industrial and mining enterprises, environmental pollution of benzene homologue compounds has been one of the extrusive problems. Benzene homologue compounds are volatile organic pollutants. They can transfer and transform in the environment, and will lead to environmental pollution. It has aroused extensive attention inside and overseas. At present, spot review experiment about transfer and transformation law of benzene homologue compounds during the process of industrial wastewater treatment is seldom relatively.In this paper transfer and transformation law of BTEX of paint-producing wastewater during the process of biological treatment, physical and chemical pretreatment was investigated. Simultaneously, simulant experiment went along. It was analysed that Several main running conditiones of oxidation ditch process exerted an influence on removal rate of BTEX. The research showed that:1. The removal rate of BTEX was high fairly .And the removal rate of benzene was 89.6%, the rest exceeded 99.0%. The quality of effluent could meet the first class of the national discharging standard(GB8978-1996). BTEX were removed mostly in floatation and oxidation ditch process. The removal of BTEX was unconspicuous in oil separation system, because oil separation was ineffective, and benzene, toluene, m-xylene were not adsorbed easily by suspend substance.2. The removal rate of BTEX was high in oxidation ditch process. The removal rate of benzene, toluene, ethylbenzene, o-xylene, m,p-xylene was 82.59%, 97.48%, 96.37%, 95.83%, 95.10% separately. In oxidation ditch process biodegradation was the most important removal manner of BTEX, to the exclusion of benzene, volatilization by surface aeration was the second, and surplus sludge sorption was little.3. Volatilization of BTEX was concentrated in the process of mechanical surface aeration of oxidation ditch and bubble stripping in floatation vessels. Surface volatilization in all vessels was less. According to compution, the emission of toluene to the ambient air was the largest.4. In oxidation ditch system biodegradation and volatilization by surface aeration heightened, and the removal rate of BTEX enhanced when DO concentration increased from 2～3mg/l to 4～6mg/l; The overall removal rate declined, as well as biodegradation rate, when MLSS decreased from 8.0g/l to 4.5g/l; Temperature influenced on microorganism of oxidation ditch on a certain extent,the biodegradation rate of BTEX declined in winter to the degree.This study provided scientific, applied and credible parameters for the design and running of correlative wastewater treatment process, and contributed to improvement of oxidation ditch process. It was significant to environmental protection and development of pollution prevention technique.更多还原