【作者】 卢徐节；

【导师】 陈季华；

【作者基本信息】 东华大学 ， 环境工程， 2009， 博士

【摘要】 作为国民经济重要支柱产业的纺织行业,是用水和产生有机污染废水的大户。染整废水不仅组分复杂、难降解物质多,难以用常规方法进行完全处理;而且该类废水的回用率极低,因此开发染整废水深度处理装置及其工艺,研究其相关基础理论,不但解决染整废水排放对环境造成的污染,缓解水资源的短缺,而且具有重要的学术意义与应用价值。本文首先以针织染整废水二级出水为研究对象,分别以两段式复合滤料曝气生物滤池和预涂动态膜技术进行深度处理,系统研究了深度净化染整废水的影响因素、工艺条件、运行特性及其反应动力学和净化机理;得到如下结论:1.系统研究了曝气生物滤池工艺参数,如气水比、水力负荷、HRT、温度、进水浓度、pH等对有机物去除效果的影响。结果表明:当气水比为2、水力负荷在0.39m³/（m²·h）左右、HRT为1 h、温度在25℃～30℃、pH值控制在7.0～8.5之间,曝气生物滤池对污染物的去除效率达到最佳。其中NH₄⁺-N、COD_Cr、SS、浊度、色度的去除率分别达到89%、55%、87%、83%、75%以上,出水分别低于1.5 mg/L、50 mg/L、10 mg/L、5 NTU、20倍,满足生活杂用水回用水质标准,该工艺参数可为实际工程的设计和运行提供了有力的理论依据。2.探讨了曝气生物滤池净化机理及反应动力学。根据曝气生物滤池沿程对有机污染物质的去除,建立了一套进出水浓度随反应器高度变化的经验模型S=S₀exp{-3.8562HS₀^0.1697（Q/A）^-0.1804},通过一系列实验验证该模型的实用性,可为实际提供设计和运行依据。3.通过涂膜试验的结果显示,从处理二级出水水质的通量及其污染情况比较,6000目的高岭土作为涂膜材料,涂膜条件为错流速度0.5m/s的,跨膜压力0.2MPa和涂膜液浓度0.3g/L,涂膜15min时形成的动态膜较为稳定,可以作为最佳的涂膜条件。在此条件下进行涂膜,在操作压力0.1MPa,错流速度1m/s条件下运行,对染整废水二级出水进行深度处理后COD去除率在50%左右,浊度去除率接近100%,色度去除几乎不影响。通过涂膜与未涂膜比较研究,涂膜后对延缓通量衰减有明显作用;通过比较COD去除率可以看出,涂膜后的出水要优于末涂膜,这是由于在基膜上形成一层过滤层对污水起进一步过滤。4.从陶瓷支撑体的酸液浸出液的污染物元素分析,Ca、Mg元素是膜管内部无机污染物的主要部分,Fe和P为其次。而从从碱液浸出液的总有机碳的分析比较看,动态膜的支撑体内部污染程度远远没有微滤无机膜直接过滤严重,说明动态膜对膜管抗内部污染的性能较好。5.化学浸洗过程:碱洗(0.2/mg·L^-1NaOH)1小时—酸洗(0.1/mg·L^-1HCl)1小时的效果要好于酸洗(0.1/mg·L^-1HCl)1小时一碱洗(0.2/mg·L^-1NaOH)1小时。经过反复清洗,涂膜过滤经化学清洗后的膜管通量恢复稳定在90%左右,而未涂膜的膜管只能恢复到原来的60%左右,说明涂膜有效的阻止了膜内部的不可逆污染。从水力清洗的比较发现,涂膜后的膜管通量恢复率明显高于微滤无机膜的,而且每次都能恢复到原来的45～55%,说明预涂膜能提高了膜管再利用率,工程应用中可省略了化学清洗过程。最后以宁波海达针织染整厂排放的实际废水,提出“清污分流、分质供水”的方案,采用BAF和膜组合技术,以300t/d中试规模进行深度处理并回用。中试结果表明:（1）进水在一定范围波动时,出水水质稳定,出水CODcr＜50mg/L,色度＜2倍,浊度＜1NTU,水质指标优于建设部生活杂用水水质标准（GB/T 18920-2002）,其中CODcr、色度、浊度的平均去除率分别为91%、95%、96%以上。通过五个多月的生产实验表明,本套工艺对针织染整废水深度处理后出水满足该企业染整工艺对水质的要求。（3）由于目前国内没有染整废水回用水水质标准,企业应根据自身的情况筛选出影响染整工艺的水质指标:pH值和盐度。回用水生产实验表明,回用水pH值一般为6.5～8.5时,对织物的影响较小;采用合理的分流方案,回用系统的盐度控制在0.924g/L以下,回用水对织物的染色质量影响较小。（3）本工艺得到的回用水,适用于针织染整工艺中的煮练、漂白、染色、洗涤等工序,而对一些要求较高的产品,煮练和洗涤工序可考虑使用回用水,染色和最后一道洗涤工序使用自来水,这样可保证产品质量。该研究为发展完善纺织废水再生水回用的集成化技术奠定了理论基础,为提高纺织行业水的回用率提供了技术储备,并为其工业规模应用提供实际运行及设计参数。更多还原

【Abstract】 The textile industry as a pillar industry of national economy not only demands a great deal of water but also generates large amount of organic wastewater.Dyeing and finishing wastewater characterized by complicated composition,a great number of nondegradable substances,is generally difficult to be effectively disposed using conventional methods, and such wastewater recovery rate is quite low.Therefore,it is very important to develop a technology of recovery and recycling of water coming from textile wastewater in order to reduce the pressure of water scarcity and impact on environment from discharged textile wastewater.Knitting dyeing and finishing wastewater was studied in this paper by two-stage biological aerated filter（BAF） and pre-coating dynamic membrane technology for advanced treatment,respectively.The influential factors such as operational conditions, reaction kinetics and purification mechanism were systematically explored,and the experimental results obtained are as follows:1.The effect of operational parameters of BAF on removal efficiency of organic matter, including gas water ratio,hydraulic load,hydraulic retention time,temperature,inlet concentration,pH value was studied in detail.The results showed that:air/water=2, hydraulic load=0.39 m³/（m²·h）,HRT=1 h,temperatures=25℃～30℃,pH value= 7.0～8.5,the removal efficiency of NH₄⁺-N,COD_cr,SS,turbidity,color were above 89%, 55%,87%,83%and 75%,respectively.The effluent concentration under the above operational conditions are below 1.5 mg/L,50 mg/L,10 mg/L,5 NTU and 20 times, respectively,which can meet quality standards of municipal reuse water,and such parameters can be referenced for industrial scale application for textile wastewater advanced treatment and reclamation.2.The purification mechanism and reaction kinetics of BAF were analyzed.According the removal of organic pollutants along the way in BAF,a experiential model has been set up to correlate the effluent concentration of treated wastewater with height of reactor,as S=S₀exp{-3.8562HS₀^-0.1697（Q/A）^-0.1804},which were verified by a series of experiments.3.Based on the flux of secondary effluent treatment and membrane pollution,the pre-coating experiments showed that the more stable dynamic membrane was formed under the conditions of kaolin with 6000 mesh used as film materials,the crossflow velocity=0.5m/s,transmembrane pressure=0.2MPa,kaolin concentration=0.3g/L, time=15 min.Under the above conditions of pre-coated membrane,the operating pressure =0.1 MPa,cross-flow velocity=1m/s,removal efficiency of COD_cr and turbidity of secondary effluent treatment using dynamic membrane were 50%and nearly 100%, respectively,however,without the effect on color removal rate.By comparison of secondary effluent treatment between direct filtration and dynamic membrane filtration,it was found that pre-coating membrane played a significant role in reduction of flux,which also chieved better COD_cr removal than that of direct filtration,which can be explained that the film formed on base membrane acted as a additional filter to enhance the filtering for wastewater treatment.4.According to SEM and ICP element analysis of acid leachate from ceramics supporter, it was found that Ca,Mg were detected as the main composition of inorganic pollutants of the internal membrane,Fe and P were in the second abundance.While comparing the TOC contained in basic leachate,it indicated the pollution within supporter with dynamic membrane was not as serious as that without the micro-filtration inorganic membrane, which mean that dynamic membrane played better performance of anti-pollution inside ceramics dynamic membrane.5.Comparing the effect of different order of chemical washing method on membrane fouling it was indicated that alkaline washing(0.2/mg·L^-1NaOH) 1 h-acidic washing (0.1/mg·L^-1HCl) 1 h better than that of acidic washing(0.1/mg·L^-1HC1) 1 h-caustic washing(0.2/mg·L^-1NaOH) 1h.After repeated chemical washing experiments,the results showed that flux of pre-coating membrane restored with the capacity of 90%by chemical cleaning,however,it only restored into 60%of the original capacity for the filtration,which means pre-coating membrane can effectively prevent the non-reversible contamination inside membrane.It was indicated that recovery rate of MF for pre-coating membrane via tap water washing significantly higher than that of inorganic micro-membrane,namely,it was generally restored to the original capacity of 45～55%.It can be explained that the pre-coating film can increase the utilization efficiency of membrane,and that the chemical washing step was basically omitted in engineering application.Finally,the actual wastewater from Haida knitting& weaving company in Ningbo city was targeted in this study.The plan of technical process was proposed as:separate the clean flow from contaminated flow and supply the water in corresponding to the quality requirement of the manufacturing.In this case,the combined technology of BAF and membrane was applied into wastewater advanced treatment with a pilot scale of 300t/d, and the treated water was recycled and reused.The conclusions of the test were shown as follows:（1）The results showed that the average concentration of CODer,color and turbidity in the effluent were less than 50 mg/L,10 times,1NTU,respectively when influent-quality index fluctuated.Each quota of the treated water has the superiority over the gray water standards（GB/T 18920-2002）.The average CODer,color,turbidity removal efficiencies were 91%,95%and 96%,respectively.The treated effluent quality satisfied the requirement of water quality for printing and dyeing process.（2）At present,there is no standard of water quality for reuse and reclamation of dyeing and finishing wastewater applied into production process in China.Therefore,the essential parameters of water quality affecting dyeing and finishing process should be selected in according to the native situations such as pH and salinity.The experimental results of dyeing and finishing process using reclaimed water showed that reused water,pH value of 6.5～8.5 and salinity within 0.924g/L,can satisfy the product quality requirement.（3）The reclaimed water obtained from combined technology of BAF and membrane treatment suits for the process of scouring,bleaching,dyeing,washing and etc.in dyeing and finishing process,what’s more,the reclaimed water also can be applied into scouring and washing process.While for some products with higher requirement,tap water is only necessary for the final step of washing and dyeing to guarantee the product quality.The conclusions of this study have further not only improved the fundamental theory for integrated technology of reclaimed and recycled water from knitting dyeing and finishing wastewater,but also provide the technical support to upgrade the recovery rate for manufacturing water in such industry as well as the parameters for operation and design in industrial scale application.更多还原