膜分离技术在环境工程中的应用探讨论文
摘要:随着科学技术水平的提升,膜分离技术发展的越来越成熟,且应用范围也不断的拓宽,这其中,以环境工程中的应用最为广泛,环境工程中通过应用膜分离技术,可有效地提升环境污染治理及预防的效果,在本文中,论述了各种膜分离技术在环境工程中的具体应用。
关键词:膜分离技术;环境工程;应用
以分离过程为划分依据,膜分离技术中包含多种类型,比如微滤、超滤、纳滤等。通过膜分离技术,可有效地处理环境中的固体、气体污染物,避免这些污染物污染环境,提升环境中的清洁度。环境工程开展的目的在于缓解环境污染的现状,防止环境污染加重,提升环境质量,应用膜分离技术后,可有效地提升工程开展的效果,实现环境质量提升的目的。
一、微滤技术在环境工程中的应用
颗粒、细菌等物质的大小位于 lOLm时,过滤时适合采用微滤技术,此项技术属于筛网过滤,操作过程中,具备比较低的压力,而且能够较好的适应液体,在饮水处理工程中有着比较广泛的应用。传统的过滤技术中,过滤池中需要设置澄清过滤和二沉池,占地面积比较大,但在应用微滤技术后,澄清过滤及二沉池可以直接取消,使得过滤池的占地面积有效缩小,而且如果水质出现比较大的波动时,过滤处理的效果依然比较好。此外,通过膜分离技术,可以良好的处理废水,循环实现闭路,经过处理的'污染水可以再次回收利用,实现废水再利用的同时,节约水资源,并提升资源的利用效率,同时,还可以将环保意识有效地提升。
二、超滤技术在环境工程中的应用
超滤膜的过滤孔直径非常小,最小,最大Inm。环境工程中,应用超滤技术后,物质中含有的固体颗粒、悬浮物可以被有效的过滤清除,同时,大分子物质、胶体的过滤中也可以应用超滤技术,具备比较好的过滤效果。在电泳涂漆废水的处理工程中,广泛的采用超滤技术,通过此种膜分离技术,有效地清除废水中的金属离子杂质,实现废水的回收再利用,提升了废水的再利用效率,并且其再生的可生化性显著增强。需要注意的是,在环境工程在应用超滤技术时,使用的超滤膜及相应的组件通量要比较大,而且所具备的耐高温、抗氧化性能要非常好,当前的超滤技术水平还无法有效地满足这一要求,需要进一步加大研发的力度,实现这一目标。
三、反渗透技术在环境工程中的应用
无论是何种类型的溶质,反渗透膜虽具备的脱除率都非常高,且具备非常高的出水水质,通常,除盐处理工程中经常采用反渗透技术。现阶段,环保领域已经大规模的应用了反渗透技术,主要体现在四个方面,一是改善城市饮用水的水质,二是处理城市污水,三是处理工业废水,四是处理垃圾渗滤液。在垃圾渗滤液中,含有的氨氮、碱度及重金属的浓度非常高,而当氨氮的浓度非常高时,会产生比较大的毒副作用,利用活性污泥法处理垃圾渗滤液时,处理的效果非常差,而应用反渗透技术进行处理时,可以显著的提升处理的效果。现阶段,环境工程应用反渗透技术时,还存在的一定的问题,主要表现在两个方面,一个是膜污染,一个是浓差极化,在今后的研究中,重点在于研究出耐污染、价格低的膜材料,并使新研制的膜材料具备耐高温、抗氧化、超低压的性能。
四、纳滤技术在环境工程中的应用
上世纪八十年代,典型反渗透复合膜出现,随后,经过进一步的研究与开发之后,研制出新型的膜分离技术——纳滤技术,该项技术为分子级技术,位于超滤技术与反渗透技术之间。纳滤技术的过滤过程属于压力驱动型,操作过程中,设置压力时,通常最小设置为,最大时设置为。离子选择性是纳滤膜的一个突出特点,去除二价离子时,去除率可超过95%,但去除一价离子时没去除率仅在40%~ 800/0之间,基于纳滤技术的特点及去除率,在河水有害物质去除、地下水有害物质去除、废水脱色等工程有着比较广泛的应用。在低压状态下,纳滤膜的通量比较高,与反渗透膜相比,仅需比较少的投资成本及操作成本,但利用纳滤技术过滤过程中,纳滤膜较易受到污染,预处理时,需要进水水质比较高,且处理过程比较复杂,使得纳滤技术的应用受到一定的限制。
五、液膜技术在环境工程中的应用
所谓液膜,就是乳液颗粒悬浮在液体中,乳液颗粒层非常薄,膜分离过程中,渗透具有一定的选择性,通过化学反应,萃取和吸附其中的污染物,实现净化。与固膜相比,液膜具有更为快速的传质速度,且具备非常高的选择性和分离效率。在溶液中,如果定分离离子和有机物,适合采用此种技术进行膜分离。当前,医药化工、湿法冶金、废水处理中已经良好的应用液膜分离技术,通过资源化处理的方式,促使废水实现再利用。
六、结论
环境工程中,通过膜分离技术的应用,可有效的减少废水、废气、固体颗粒等对环境的污染,并实现废水的再生利用,有效的增强了环境保护的效果。
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Coal mine waste water treatment and reuse technology Comparative StudyDigest:Introduced the sewage and wastewater processing resources of the latest technologies and processes, analysis and comparison of the three kinds of process options to deal with coal mine waste water system investment and operating costs, and to explore the reverse osmosis water treatment technology in the coal mine waste water treatment application The technical and economic mine waste water treatment and reuse of the consolidated operating costs for the : .465 yuan / ton. One membrane of the processing costs as low as: yuan / ton. Such prices on drought and water shortage in the Northwest region is very attractive. 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Membrane water treatment technology and engineering examples 【M】. Beijing: Chemical Industry Press, ~ I, Binchois music. The water and use the net again. Beijing: China Building a Board Association, 1985. 【3】 Bella G. Liputaike. Environmental engineer with the book. Beijing: China Building Industry Society out of plates, 1987.【4】 High from Kai. Membrane separation technology and water reuse 【m】 .2003 Beijing Water Forum papers ..【5】 Feng Zhang, Xu Ping. Reverse osmosis, nanofiltration membrane and its application in wastewater treatment 【M】. Membrane Science and Technology ,2003,23:234-236.【6】 Mayao Guang, Ma Bolin. Wastewater utilization of agricultural resources. Beijing: Chemical Industry Press, ~ 78.【7】 Yao Zhichun. Wastewater treatment and reuse. Gansu Water Conservancy and Hydropower 1999.: 56 ~ 60.【8】 LEI Le-cheng, etc., sewage back with new technology and engineering design. Beijing: Chemical Engineering Press, .2002:453 ~ 461.【9】 Zhang Bao cases. Reverse osmosis water treatment application technology 【M】. Beijing: China Electric Power Press, ~ 295.煤矿矿井废水处理回用工艺比较研究摘要:介绍了污水、废水处理资源化的最新技术和工艺,分析比较了三种工艺方案处理煤矿矿井废水的系统投资和运行成本,并探讨了反渗透水处理技术在煤矿矿井废水处理中应用的技术经济可行性.煤矿矿井废水处理回用的综合运行费用为:元/吨。其中膜法的处理费用最低为:元/吨。这样的价格对干旱缺水的西北地区是很有吸引力的。对矿井废水进行回收再利用,不但可以减少废水排放量,又可以使废水资源化,应该说,它是一种水资源再生的希望方法,也是我国实现水资源可持续利用的有效途径之一。关键词:反渗透电镀废水处理回收利用我国人口众多,淡水资源时空分布不均匀,水资源和社会经济发展不均衡;人口的不断增长又使水资源需求量逐年上升,工业的快速发展使水污染愈加严重,因此造成水资源缺短和水环境污染现象日趋严重。目前,我国水资源供需矛盾比较突出,全国有300多个城市缺水,其中有114个城市严重缺水。21世纪我国水资源供需形势非常严重,水资源危机将成为所有资源问题中最为严惩的问题。要解决这一难题,除水资源的科学治理和优化配量之外,充分发挥高新科技手段在水资源利用中的作用也是十分关键的。近年来,我国每年排污水量约400-500亿M3,经处理后排放的仅15-25%,由于污水到处横流,使我国各大水源都产生不同程度的污染,水环境严重恶化【4】。所以,加强污水深度治理,使之不仅达标排放而且还可大量回用,非常必要,这对改善水环境、缓解水资源的不足,节约宝贵的水资源都是十分重要的。城市及工业污水经过深度处理后可用于农业浇灌、工业生产、城市景观、市政绿化、生活杂用、地下水回灌和补充地表水等方面的应用【8】。传统水处理技术能够消除部分污染物,将COD、BOD以及重金融等污染物指标降到安全排放标准或杂用标准,但无法完全消除排水中所含的微量溶解性污染物。采用反渗透膜技术可彻底去除这些污染物,实现严格意义下的污水再生。用传统处理工艺和膜技术集成,可将污水或废水变成不同水质标准的回用水,或使之循环回用,这样即缓解了供求矛盾,又减少了污染,还可促进环保产业的发展【6】。污水废水资源化技术及应用简介水环境质量的严重恶化和经济的高速发展,迫切要求有相应的污水废水资源化的技术。在这一领域中膜分离技术占有重要的位置和作用。膜分离作为一项高新技术在近40年来迅速发展成为产业化的高效节能分离技术过程。40多年,电渗析、反渗透、微滤、超滤、纳滤、渗透汽化,膜接触和膜反应过程相继发展起来,在能源、电子、石化、医药卫生、化工、轻工、食品、饮料行业和日常生活及环保领域等均获得广泛的应用,产生了显著的经济和社会效益。社会的需求使膜技术应允而生,也是社会的需求促使膜技术迅速发展,使膜技术不断创新、技术进步,完善,成为单元操作,成为集成过程中的关键【9】。1.连续膜过滤技术中空纤维膜由于比表面积大,膜组件的装填密度大,所以设备紧凑;这种膜因纺制而成,工艺简单,所以生产成本一般低于其它的膜:由于没有支撑层均可以反向清洗,非凡是一些耐污染性好,对氧化性清洗剂耐受性好的膜的出现,使得在大规模的污水处理工程中,中空纤维膜的应用有独特的优势【7】。CMF技术的核心是高抗污染膜以及与之相配合的膜清洗技术,可以实现对膜的不停机清洗清洗,从而做到对料液不间断连续处理,保证设备的连续高效运行。CMF目前主要用于大型城市污水处理厂二沉池生水的深度处理回用,海水淡化或大型反渗透系统的预处理。地表水地下水净化、饮料澄清除浊等。2.膜生物反应器膜生物反应器是膜分离技术和生物技术结合的新工艺。用在污水废水处理领域,利用膜件进行固液分离,截留的污泥或杂质回流至在生物反应器中,处理的清水透过膜排水,构成了污水处理的膜生物反应器系统,膜组件的作用相当于传统污水生物处理系统中的二沉池【4】。MBR中使用的膜有平板膜、管式膜和中空纤维膜,目前主要以中空纤维膜为主。生活污水经MBR处理后,生水水源已达到很高的水标准。此方法不仅限于处理生活污水,MBR技术也广泛地用于染色废水,洗毛废水、肉类加工污水等水处理系统。MBR系统的另一个特点是规模可大可小,小装置可用于一个家庭,大型装置日处理量可达数万立方米。3.反渗透技术反渗透技术是20世纪60年代初发展起来的以压力为驱动力的膜分离技术。该技术是从海水、苦咸水淡化而发展起来的,通常称为“淡化技术”。由于反渗透技术具有无相变,组件化、流程简单,操作方便,占面积小、投资少,耗能低等优点,发展十分迅速。RO技术已广泛用于海水、苦咸水淡化,纯水、超纯水制备,化工分离、浓缩、提纯,废水资源化等领域。工程遍布电力、电子、化工、轻工、煤炭、环保、医药、食品等行业。废水资源化是有开发增量淡水资源与保护环境双重目的。无机系列废水处理与海水苦咸水淡化采用同类装并具有较多共性工艺技术。RO可使废液中的铜、铅、汞、镍、锑、铍、砷、铬、硒、铵、锌等离子脱除除90-99%。目前,反渗透技术在城市污水深度处理,一些工业废水深度处理方面的应用受到了高度重视,包括中水回用,污水处理厂二级出水的深度处理,经初级处理后的工业废水深度处理制取优质淡水。中东不少缺水国家,在大量采用反渗透海水淡化技术的同时,引入反渗透技技术处理二级污水,出水水质可达TDS≤80mg/L,扩大了淡水资源。如中东地区、澳大利亚、新加坡等国都有这方面的大型工程实例【9】。4.集成膜过程污水深度处理方法集成膜过程是将超滤/微滤与反渗透结合使用,形成能够满足各咱回用目的的污水深度处理工艺。超滤、微滤可以作为独立的高级三级处理方法,也是反渗透过程理想的预处理工艺,抗污染能力强、性能优越的超滤、微滤单元代替了复杂的传统处理工艺,而且出水品质远高于三级出水指标,不但完全可以去除污水中的细菌和悬浮物,对COD、BOD也有一定的却除效果。在超滤、微滤之后使用的反渗透膜,其清洗周期由采用传统预处理工艺的3-4周增加到半年以上,膜寿命可延长到达-6年。膜集成污水再生工艺具有系统稳定、维护少、占地小、化学品用量少、流程简单和运行费用低等优点。结论煤矿矿井废水处理回用的综合运行费用为:元/吨。其中膜法的处理费用最低为:元/吨。这样的价格对干旱缺水的西北地区是很有吸引力的。用膜法处理煤矿矿井废水并回用在技术上是完全可靠的,国内外都有成功经验。随着工业的快速发展,水资源的污染日益严重,缺水现象会越来越严重,工业废水的回收利用将会提到议事日程。从环境保护方面讲,对矿井废水进行回收再利用具有非常重要的环境意义。对矿井废水进行回收再利用,不但可以减少废水排放量,又可以使废水资源化,应该说,它是一种水资源再生的希望方法,也是我国实现水资源可持续利用的有效途径之一。膜法处理煤矿矿井废水并回用,不但在技术上和经济上都是可行的,经济和环境效益都非常显著。参考文献邵刚.膜法水处理技术及工程实例【M】.北京:化学工业出版社,.希利I,舒瓦乐.水的再净与利用.北京:中国建筑出板社,1985.【3】贝拉G.利普泰克.环境工程师用册.北京:中国建筑工业出板社,1987.【4】高从锴.膜分离技术与水资源再利用【m】.2003北京水务论坛论文..【5】张烽,徐平.反渗透、纳滤膜及其在废水处理中的应用【M】.膜科学与技术,2003,23:234-236.【6】马耀光,马柏林.废水的农业资源化利用.北京:化学工业出版社,.【7】姚志春.污水净化再利用.甘肃水利水电1999.:56~60.【8】雷乐成等,污水回用新技术及工程设计.北京:化学工程出版社.2002:453~461.【9】张葆宗.反渗透水处理应用技术【M】.北京:中国电力出版社,.
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