钢企回用水厂外排水双膜法回用处理研究

文章针对钢铁行业综合废水的水质特点,采用超滤+反渗透双膜工艺处理回用水厂外排废水。超滤预处理产水SDI15<3.5满足后续反渗透膜的深度处理进水要求。超滤在反洗周期40 min,反洗时间60 s的情况下运行稳定性良好。采用抗污染反渗透膜对废水电导率的脱除效果较理想,脱盐率大于99%,COD的去除率约65%,对硬度的脱除率达到100%,在连续运行过程中,反渗透的通量和脱盐率表现出良好的稳定性且完全满足设计循环水用水标准。     

发电厂超滤装置反洗水源选择探讨

发电厂化学水处理系统通常采用"超滤+反渗透"模式作为预处理和预脱盐,膜系统运行需要大量的自用水,超滤的自用水率大约为10%,超滤自用水大部分为反洗排水,选择合适的水源作为超滤反洗水有利于节水。     

反渗透非氧化性杀菌剂投加及药性评估方法研究

某电厂反渗透系统在正常运行过程中,膜元件受到微生物污染是影响其运行状态和使用寿命的主要原因,虽然反渗透入口原水经过氧化性杀菌剂(次氯酸钠)处理,但微生物滋生问题依然存在。为保证反渗透系统稳定运行,延长膜元件使用寿命,结合反渗透膜元件不耐氧化的特性,可在反渗透系统入口投加非氧化性杀菌剂。本文主要介绍非氧化性杀菌剂在反渗透系统中的投加方法,包括加药点设置及加药浓度控制,并通过细菌培养和药剂投加试验的方法评价非氧化性杀菌剂杀菌效果。     

关于超滤在运行时不加次氯酸钠的可行性探析

某350 MW超临界机组锅炉补给水处理过滤使用超滤装置,设计之初运行时需要投加次氯酸钠,由于运行过程投加次氯酸钠出水余氯较难控制,且存在氯超标氧化反渗透膜的危险。因此分别使超滤装置在投加次氯酸钠和不投加次氯酸钠工况下长时间运行,通过超滤的流量、压差、迚出口浊度等斱面迚行比对,探析在正常制水情况下不加次氯酸钠的可行性,为超滤装置的安全经济运行提供了依据。     

热电厂水资源的综合利用

分析了热电厂的各种水的品质,根据不同情况回收利用:反渗透浓水用作除铁过滤器反洗用水,超滤浓排和超滤反洗水回收至循环水系统,汽轮机凝结水和蒸汽疏水回收到除盐水箱.实施后,每年可减少新水消耗418 300 m3,降低了水资源消耗,减少了废水外排.     

快滤池改造及其在中水回用项目中的应用

由于池体滤板破损、进出水流向与反洗流向相同,快滤池无法满足中水回用项目的要求。针对快滤池存在的问题,采取了相应的改造措施,消除了超滤及反渗透装置因预处理效果不佳而出现的膜污堵现象,不仅节约了化学清洗超滤和反渗透装置的原材料,而且增大了废水回用率,外排水量也控制在规定的范围内,有效降低了排污费用。     

超滤-反渗透组合工艺处理稀土冶炼废水

采用混凝沉淀-超滤和反渗透膜集成技术处理稀土冶炼废水,考察了各处理单元及集成系统对污染物的去除效率;采用不同的化学试剂对污染膜进行清洗,评价了膜通量的恢复效果。结果表明,膜集成技术能有效处理和降低废水中的污染物,混凝-超滤能去除废水中的大部分有机物、浊度和重金属,反渗透可以进一步去除废水中的氨氮和其它污染物,膜集成系统对废水COD、NH_4~+-N、浊度、Zn、Cu和Pb的整体去除效率分别为95.3%、80.6%、99.2%、98.3%、95.3%和96.0%。处理过程中,会产生严重的膜污染尤其是反渗透膜。膜污染以氯化铵盐等无机污染为主,采用稀盐酸清洗对污染膜的恢复效果优于氢氧化钠、次氯酸钠和EDTA。     

江苏洪港石化PTA中水回用工程双膜法的方案设计及探讨

江苏洪港石化PTA项目中水回用处理系统设计规模为1000 m3/h,采用超滤+反渗透双膜法进行处理,最终产水作为全厂循环冷却水的补充。因PTA废水碱度高,含重金属结构离子,特别是含有微量的催化剂钴元素,且COD含量较高,易造成反渗透膜的氧化及污堵,故方案设计中需充分考虑预处理工艺的选择,能保证重金属的去除及膜的进水COD控制在允许范围内。     

脱盐水超滤膜反渗透膜的运行管理

超滤作为反渗透预处理,截留了大部分的悬浮物、胶体、有机物等,保证了反渗透装置正常运转。但超滤、反渗透存在膜易污染,易阻塞、氧化等问题,日常运行中加强对超滤反渗透的管理,即可延长膜使用寿命,也可减少污水排放。     

混凝剂后絮凝对超滤反渗透膜系统影响的研究

采用PAC作为地表水预处理的混凝剂时,过量地使用混凝剂常常导致双膜系统的混凝剂污染。研究发现,当pH低于6.5,PAC投加量为15 mg/L时,铝离子水解不彻底,原水中残留的铝离子质量浓度可达到0.3 mg/L。而在超滤反渗透处理系统中,总体水力停留时间（HRT）大于2 h时常出现后絮凝现象。同时,铝盐絮体与反渗透阻垢剂发生交联反应,沉积到反渗透膜面,直接影响双膜系统的正常运行。因此合理地控制混凝剂投加量、调节pH、控制系统HRT等可有效抑制混凝的后絮凝现象,防止超滤反渗透膜的污染。     

基于海水淡化中试的超滤膜清洗工艺及机理

为了对海水淡化过程中的超滤膜进行清洗,利用超滤中试设备研究了反洗水和清洗药剂对超滤膜清洗的效果。分别研究了不同的反洗用水对于跨膜压差的影响,结果表明,清洗效果：淡水（自来水）>超滤产水>反渗透浓水。另选用不同的酸性清洗剂与碱性清洗剂进行清洗,结果表明,清洗效果：柠檬酸>草酸>盐酸>次氯酸钠>氢氧化钠,柠檬酸清洗效果最好,纯水透过速率可从283.24 L/(m²·h)恢复至571.56 L/(m²·h)。此外,实验证明碱洗+酸洗效果优于单独清洗效果,先用氢氧化钠清洗,再用柠檬酸清洗,纯水透过速率可从283.24 L/(m²·h)恢复至818.81 L/(m²·h)。本研究成果对于海水淡化过程中超滤膜的维护具有较好的应用前景。     

Ultrafiltration membrane cleaning technology and mechanism based on seawater desalination pilot equipment

In order to clean the ultrafiltration membrane in the process of seawater desalination, this paper studied the cleaning effects of backwash water and chemical agents on the ultrafiltration membrane by using the ultrafiltration pilot equipment. Effects of different backwash water on the transmembrane pressure difference were studied. The results showed that the cleaning effect was in the order of fresh water (tap water) > ultrafiltration water > reverse osmosis concentrated water. In addition, cleaning effect was as follows: citric acid > oxalate > hydrochloric acid > sodium hypochlorite > sodium hydroxide. Citric acid had the best cleaning effect, and the pure water penetration rate could be restored from 283.24 L/(m²·h) to 571.56 L/(m²·h). Moreover, the effect of alkali washing and acid washing together is better than that of cleaning alone. After cleaning with sodium hydroxide and then citric acid, the pure water transmission rate can recover from 283.24 L/(m²·h) to 818.81 L/(m²·h). The results of this study have a good application prospect for the maintenance of ultrafiltration membrane in seawater desalination.     

Influence of Ca and Na ions in backwash water on ultrafiltration fouling control

The effect of calcium and sodium in backwash water on the fouling control of ultrafiltration is investigated on a bench scale. Besides permeate of ultrafiltration and demineralized water, solutions with different calcium or sodium concentrations were used for backwash. The results show that backwashing with demineralized water is better than with permeate of ultrafiltration. The backwash efficiency decreases when calcium and sodium are added in demineralized water for backwash. That is probably because the presence of calcium and sodium in backwash water increases the Ca-bridging effect between the negatively charged membrane and the negatively charged NOM, and compresses the double layer of the membrane and the NOM, leading to a strong adhesion force on the membrane.     

Grey water treatment and simultaneous surfactant recovery using UF and RO process

The membrane-based grey water treatment for grey water reuse and surfactant recovery is presented in this research paper. Grey water from washing machine discharges having turbidity and used surfactant was processed through the polymeric ultrafiltration (UF) membrane to remove the turbidity. The UF treated grey water is further purified by reverse osmosis (RO) membrane for surfactant recovery and water reuse. The surfactant trapped inside the RO spiral wound membrane module is recovered through various membrane physical regeneration techniques such as backwashing, simultaneous backwash–back-flush and ozone back-flush. Among this, backwash–back-flush is found to be effective process for surfactant recovery. The methodology for optimising surfactant recovery is captured by studying effect of various operating parameters such as feed detergent concentration, backwash pressure, backwash temperature and back-flush flow rate. By implementing optimal process conditions, the integrated UF and RO membrane process is able to produce 300 L of reusable pure water and 80 L of concentrated detergent solution and 20 L of turbid water while treating 400 L of grey water discharges. Maximum surfactant recovery of 82% is obtained while treating grey water which consists of 720 ppm of total dissolved solids (detergent) and 45 ppm of surfactant. The extent of UF and RO membrane fouling is determined by measuring the pure water flux before and after the grey water treatment. The membrane performance is found to be stable when membrane is regenerated by backwash–back-flush technique for RO and gravity backwash for UF membrane.     

聚电解质静电沉积改性制备高性能反渗透膜

利用次氯酸钠溶液对商品反渗透膜表面进行氯化处理,然后将聚阳离子电解质壳聚糖通过静电吸附作用沉积在RO膜的表面,系统地研究了氯化过程的pH、氯化时间、次氯酸钠浓度、壳聚糖浓度及其沉积时间对膜性能的影响,以制备出高通量、高截留率的RO膜。在压力1.55 MPa、原料液温度（298±1）K的条件下,测定RO膜处理2000 μg·g^-1氯化钠溶液的水通量和截留率。结果表明,当pH=9、氯化时间为30 min、次氯酸钠浓度为1000 mg·L^-1时,水通量较原膜提高了约19.89%,截留率略有提高;当壳聚糖浓度为0.1%（质量分数）、沉积时间为30 min时,改性膜的接触角降低到34.88°,亲水性提高,水通量较氯化后的RO膜几乎保持不变,为60.55 L·m^-2·h^-1,截留率达到了99.56%。经过氯化和沉积改性后的RO膜水通量和截留率均得到了提高。     

A novel high‐flux thin film composite reverse osmosis membrane modified by polysaccharide supramolecular assembly

Thin film composite reverse osmosis (TFC RO) membrane is widely used in desalination and water reuse applications. With increasing capacity of Reverse Osmosis desalination all over the world, the increasing green‐house gas emission for the required power is a cause of concern. TFC RO membrane is composed of the top polyamide layer over which, the linear polysaccharide such as chitosan can bind after activating the surface with oxidizing agent. The present paper analyzes the novel protocol of controlled oxidation of TFC RO membrane by exposing the same to potassium per sulfate with varying concentration of chitosan followed by sodium hypochlorite and sodium hypochlorite followed by potassium per sulfate with varying concentration of chitosan. The optimum performance was obtained when TFC RO membrane was exposed to 1% potassium persulfate with 1000 mg/L chitosan solution followed by 1000 mg/L sodium hypochlorite. Reversing order of the treatment resulted in the decline in permeance of the membrane. The reason of improvement in permeance is super‐hydrophilic surface formed by oxidation of chitosan over polyamide surface. Thus, this article demonstrates the novel protocol of significantly improving the flux of TFC RO membrane and thereby reducing the energy consumption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45026.     

反渗透海水淡化膜法预处理技术研究进展

简要论述了反渗透海水淡化的各种新型膜法预处理技术研究进展情况及其在国内外的具体运用情况,内容主要涵括连续微滤技术(CMF)、浸没式帘式膜过滤、超滤技术、纳滤技术以及陶瓷膜过滤.并指出膜法预处理将成为今后反渗透海水淡化预处理的主要发展方向.     

超滤膜在舟山海水淡化预处理中的可行性研究

舟山市是一个资源型和水质型缺水的海岛地区,海水淡化是解决水资源短缺的重要途径。超滤和反渗透工艺组合已成为海水淡化的发展趋势。本文采用中空纤维膜超滤技术对舟山海水进行预处理实验,考察海水对超滤膜的运行情况的影响,结果表明超滤出水SDI1,通过周期性的反冲洗膜性能有较好的恢复,说明超滤膜作为舟山海水反渗透预处理是可行的。     

Study of the structure and transport of asymmetric polyamide membranes for reverse osmosis using the electron spin resonance (ESR) method

The electron spin resonance technique (ESR) was used to study the structure and transport of asymmetric aromatic polyamide membranes. TEMPO (2,2,6,6-tetramethyl-1-piperridinyloxy free radical) was used as a spin probe that was brought into the membrane either by (a) immersion ofthe membranes in aqueous TEMPO solutions, (b) reverse osmosis (RO) experiments with feed solutions involving TEMPO or (c) blending TEMPO in casting solutions. The membranes were further tested for the separation of sodium chloride and TEMPO from water by RO. It was concluded that aromatic polyamide membranes contain water channels in the polymer matrix like cellulose acetate membranes. The presence of such water channels allows aromatic polyamide membranes to be used as RO membranes. The diffusion of organic solutes through the water channels seems much slower in aromatic polyamide membranes than in cellular acetate membranes, which probably causes a higher separation of organic solutes by aromatic polyamide membranes than cellulose acetate membranes. A comparison was made with other RO membranes (cellulose acetate, CA) and ultrafiltration membranes (polyethersulphone, PES). It was observed that the ESR technique can be used to study the structure of OF and RO membranes. The presence of water channels in the polymer matrix seems indispensable for the RO membrane.     

超滤技术在生产水改造中的应用

工厂中使用的反渗透装置,对进水水质有着比较严格的要求。根据生产水改造中的实际情况,针对进水水质对反渗透膜的污染影响,论证了超滤技术作为反渗透预处理的必要性和可行性。作者主要对新建超滤与改造原有多介质过滤器两种改造方案,从工作原理、对原水的预处理效果和经济性等方面做了相应对比。最后还简单介绍了超滤技术在实际生产中的应用情况。