Separation Characteristics of Inorganic Particles from Rainfalls in Dissolved Air Flotation: A Korean Perspective

Abstract

Many reservoirs have been constructed in Korea to store water resources utilizing the terrain of the land. In general, dam source waters contain algae species that have densities close to that of water. Consequently algae are difficult to remove by conventional gravity sedimentation (CGS), while dissolved air flotation (DAF) is known to be an effective process for the purpose. The same source waters usually also have high turbidities due to mineral soil particles in the wet summer season. Systematic studies on the effect of high turbidity on the DAF process are very limited. In this work, DAF and CGS experiments were carried out to investigate water treatment characteristics and removal efficiencies under various COD/SS and chlorophyll‐a/SS ratios. A kinetic DAF process model was employed to describe bubble‐floc collision and agglomeration, as well as the rising velocity of bubble‐floc agglomerate. Our results showed that the initial collision‐attachment efficiency for the clay floc size range of 100?400 µm was a relatively low value of 0.3. The removal efficiency by DAF was greater than by CGS when chlorophyll‐a/SS ratio was high. It was also found that sedimentation prior to flotation is required for the effective separation of large clay flocs caused by runoff. Our experimental and theoretical results also suggest that the DAF process requires carefully operation in Korea, especially, in the rainy summer season.     

The Impact of Intermittent Aeration on the Operation of Air‐Lift Tubular Membrane Bioreactors under Sub‐Critical Conditions

Abstract

An air‐lift sidestream polymeric multi‐tube membrane module has been investigated to compare the hydraulic performance of an MBR challenged with municipal wastewater and landfill leachate. In both cases the MBRs were operated under the same conditions of membrane aeration rate and sludge retention time, but with hydraulic retention time for the leachate set by scoping trials based on porous pots to 48 hours. Operation under conventional continuous aeration conditions yielded critical flux values, based on classical flux step experiments, of 36–42 l m^?2 hr^?1 for the sewage‐fed trial compared with ～24 l m^?2 hr^?1 for the leachate‐fed trial. Substantial improvements in operating flux, between 20 and 100%, were obtained when operating with air pulsing (1s on/s off). Intermittent operation under more conventional conditions (5s on/5s off) yielded no improvement.     

秩和比法（RSR法）在环境污染健康损害中的应用

用秩和比法对人群环境污染健康损害进行综合评价。正确运用秩和比法,合理编写秩次。最后得出结论：秩和比法计算简单,易于理解、掌握和操作,对指标的选择无特殊要求。是适合于环境污染健康损害评价的综合评估方法。     

广州市工业VOCs污染控制管理对策研究

VOCs污染对人体健康和区域生态环境危害性的正逐渐受到重视,但我国在这方面的管控工作才刚刚开始,缺乏足够的经验。以珠三角中心城市广州作为研究对象,分析了工业VOCs污染现状和监管工作中遇到的问题,给出了综合防治管理对策,为区域环境治理工作提供了一定的参考依据。     

城市雨水径流污染及防治

城市雨水径流带来的面源污染问题正日渐突出,严重制约了水环境质量的改善。介绍了城市雨水径流污染的特点、污染物的来源及种类,着重论述了城市雨水径流污染控制技术及防治措施。     

面向“化工污染控制”方向的环境工程专业办学特色的研究与实践

融合我校化工优势资源,我校本科专业环境工程在课程体系、课堂教学、毕业论文和毕业设计、学生科研等方面具有鲜明的面向＂化工污染控制＂特色。     

浅谈环境应急监测的质量管理

文章作者通过对突发性环境污染事故应急监测质量管理工作的关键环节进行论述,并提出相应的建议和措施,以提高环境应急监测数据的及时性、准确性和可靠性,确保为环境突发性应急事故处理部门提供科学、有效的决策依据。     

重金属污染土壤的植物修复研究进展

土壤污染是全球面临的一个亟待解决的环境问题。近年来,植物修复技术迅速发展为主要用于清除土壤重金属污染的生态技术。文章介绍了土壤重金属污染的特性、危害及其治理方法。重点介绍了植物修复技术,并探讨了今后植物修复技术的发展前景。     

毛细管网辐射空调系统特点及发展趋势

毛细管辐射空调系统是温湿度独立控制的新型空调技术,是对传统空调技术的挑战和创新。主要介绍了毛细管辐射空调系统的工作原理、系统组成及末端特点,分析了其节能、舒适、环保的优势,并对其今后的发展趋势与市场前景提出了一些看法,毛细管辐射技术在我国一定会有很好的发展前景。     

广州市白云区2010年-2011年农村生活饮用水水质安全分析

目的：了解白云区农村生活饮用水水质卫生状况以及存在问题,为改善农村生活饮用水水质提供科学依据。方法：对白云区2010~2011年农村水厂的水质监测资料进行分析。结果：农村水厂水质总体较好,达标率为82%。2010年全年达标率为100%,不达标水样主要集中在2011年枯水期;不达标项目主要是pH、浑浊度、臭和味、肉眼可见物、锰。结论：白云区农村水厂水源存在人、畜粪便和有机物污染的问题;村民的卫生与安全意识较低,对水源的保护意识不强。政府应加大建设投入和宣传力度,增加监测频率,确保农村用水安全。