【作者】 毛永灏；

【导师】 张胜；

【作者基本信息】 河北工程大学 ， 环境工程， 2007， 硕士

【摘要】 钢铁厂每天会排放出大量的循环冷却排污水,用膜分离技术将该废水处理并补给循环冷却水系统,意义重大。膜污染是反渗透技术应用中所面临的重要问题,它不仅直接影响膜的高效连续运行,还会增加运行费用,缩短膜的使用寿命。要使膜组件能够长期稳定的运行,就必须根据废水的水质情况,制定出合理的预处理方案;针对废水中污染物质的种类与特性,通过试验得出最佳工艺参数。基于此,本文开展了钢厂废水再生的反渗透膜污染控制策略的研究。首先进行水质分析,结果表明废水有结垢倾向;悬浮物含量严重超标;油、总铁也超过了允许值;此外,废水中有机物会引起反渗透膜的微生物污染。最后确定了以多介质过滤-活性炭过滤-微滤-反渗透为主的技术路线来处理该废水。从降低废水中悬浮物和胶体的角度出发确定混凝剂、盐酸、杀菌剂的最佳用量。结果表明,经过加药获得理想混凝过滤效果后,出水浊度值平均为0.2NTU,SDI<3,满足反渗透膜对悬浮物和胶体的进水要求,pH值在7左右时的加药量:混凝剂PAC为15mg/L;杀菌剂NaClO为6mg/L。继续投加PAM,出水的浊度和SDI值又分别升高了,原因是水中产生了胶体再稳现象,建议在该系统中停止使用PAM。通过臭氧投加量和CODMn的去除率之间的关系,确定了臭氧投加量为1.5mg/L。全面考察臭氧活性炭工艺去除色度、有机物、油、铁、锰的效果。结果表明,臭氧活性炭工艺对上述污染物质均有很高的去除率,对色度的去除率为70%;对CODMn的去除率为67%;对油的去除率为87.5%;对Fe2+的去除率为85.7%;对Mn2+的去除率为62.5%。臭氧的强氧化作用可使有机物不饱和键断开,苯环开环,将大分子有机物转化为小分子有机物,再通过活性炭对有机物的吸附,达到控制的目的。通过对阻垢剂的中试试验,考察阻垢剂是否能够有效防止膜表面结垢。结果表明,在使用该阻垢剂后,系统在后期产生碳酸钙结垢,证明该阻垢剂不能有效的起到阻垢作用,建议更换,并提出膜清洗的专项策略。采用0.5%(w) HCl清洗液清洗后,系统各项指标恢复到原始状态,达到了预期目的。更多还原

【Abstract】 Iron and steel works let off much circulate cooling wastewater everyday,it is worth to treat and reuse it as circulate cooling make-up water.Membrane fouling is one of big problem in the application of membrane technology. In order to keep the long-term and stable run effect of membrane parts, it’s necessary to analyse the quality of wastewater, to make acceptable pretreatment technology, to find the best parameter.The control of RO membrane fouling for regenerate wastewater from iron and steel works were systematically studied in the paper.In this paper, the quality of wastewater was analyzed.Based on the results of water quality analysis, the wastewater has scaling tendency;suspended substance、oil、Fe、Mn were overproof;and organic matter in the water can cause microorganism pollute.The SF(sand filter)-GAC(granular activates carbon)-MF (microfiltration)-RO(reverse osmosis)system was adopted to treat the wastewater.The optimum dosing amount of PAC、HCl、NaClO were determined from the angle of decreasing suspended substance and colloid. The result showed that the optimum dosing amount of medicament which made the perfect coagulate, the average turbidity is 0.2NTU,silt density index (SDI) is less than 3, which could meet the requirements of RO feed. The dosage of PAC is 15mg/L;the dosage of NaClO is 6 mg/L.If continued dosing PAM, turbidness and SDI of the wasterwater were increasing,the reason of the phenomenon is colloid stabilization.So stopping dosing PAM was suggested.Through the variation of CODMn with the dosage of O3,the dosage of O3 was defined as 1.5mg/L.The writer made an overall observation on the effectiveness of O3-GAC process of removing colourity、CODMn、UV254、oil、Fe、Mn. The result showed that O3-GAC filters have high removal efficiency of such contaminant which could meet the requirements of RO feed. The remove rate of colourity is 70%; the remove rate of CODMn is 67%; the remove rate of oil is 87.5%; the remove rate of Fe2+ is 85.7%; the remove rate of Mn2+ is 62.5%. The strong oxidizing action of the O3 can broke the unsaturated bond, open benzene ring, transform macromolecule to micromolecule, then through the adsorption of the GAC to remove the pollutant.To test the dependability of adding scale inhibitor technology, the experiment of scale inhibitor was conducted.The result showed that RO membrane was scaling fast. It is proved that the scale inhibitor can not inhibit scale effectively.So it is necessary to change scale inhibitor. In the end,the special membrane cleaning method is presented.更多还原