分质供水模式的发展研究

文章详细介绍了国内外的分质供水概念,对日本、美国及国内的分质供水模式发展进行了调研分析,指出国内外的分质供水系统在概念上有着较大差别。发达国家城市供水是以利用优良水源,全面提高供水水质为主导思想。在上世纪九十年代的国内供水,由于水源水质受到严重污染,在大城市出现了利用自来水深加工形成小区直饮水供水形式,形成了"饮"用水分质供水系统。随着国内城市饮用水水源水质及制水工艺提高,供水水质改善,小区直饮水将慢慢退出市场,城市供水模式以全面提高主供水系统水质为主导发展方向。     

管道分质供水TCCA消毒方法

对三氯异氰尿酸(TCCA)消毒法在管道分质供水中的应用进行了研究。结果表明,利用TCCA消毒管道分质供水,只要控制管网水中余氯质量分数>3.0×10-8,就能起到良好的消毒效果,并能有效的控制消毒副产物,使管道分质供水具有较好的口感。采用的TCCA消毒法在管道分质供水工程具有广泛应用前景。     

浅谈住宅（办公楼）分质供水管道纯净水设计

本文担子同住宅（办公楼）分质供水管道纯净水设计水量,分质标准,重点阐述了住宅（办公楼）分质供水管道纯净水水厂设置及供水设备与管道选择,并简要地作了住宅（办公楼）管道纯净水经济分析。     

分质供水的模式与应用

为解决城市供水资源短缺问题、优化水资源的利用,分质供水逐渐成为城市供水系统的重要组成部分。该文以供水范围和供水目的等为划分依据,把分质供水分为小分质供水-直饮水系统、小分质供水-中水系统、大分质供水-直饮水系统和大分质供水-优水优用系统,并对这四种供水模式的特点、目的、应用情况及存在问题进行分析。通过比较分析这四种模式的优缺点,最后指出我国未来改善饮水水质的大方向是城市集中提供优质水,但需根据我国国情,因地制宜地分阶段、分步骤逐步加以实现。     

域市分质供水浅析

分析了我国城市供水的水质现状,国内外分质供水的区别,介绍了分质供水的处理技术,指出了分质供水存在的问题及解决方法。     

城市分质供水浅析

分析了我国城市供水的水质现状,国内外分质供水的区别,介绍了分质供水的处理技术,指出了分质供水存在的问题及解决方法。     

阳离型聚丙烯酰胺(CPAM)在处理黄磷生产废水中的技术应用

在黄磷废水处理中用石灰乳作中和剂及沉淀剂,并控制污水的pH在5.5～7之间,其后再加入阳离型聚丙烯酰胺(CPAM)作为絮凝吸附剂,吸附污水中的悬浮物颗粒,悬浮物聚沉,降低浑浊度使水质澄清,经过处理的废水在管道内壁面上不结垢,堵塞管道,处理后的水质大为改善,满足黄磷生产用水质的需要。     

从技术经济角度分析直饮水在我国的推广前景

本文从目前我国实施分质供水的背景及其现状出发，通过某一住宅小区的管道直饮水工程，就管道直饮水系统采用的水处理工艺，设备投入及运行成本与其两种供水方式进行了技术分析与比较，并结合国际上分质供水的概念，分析直饮水在我国的推广前景。     

供水系统二次污染的原因与控制方法

该文主要从出厂水水质、管道的腐蚀和结垢、二次供水设施及加氯消毒等方面分析了造成供水管网水质二次污染的原因,并有针对性地提出了改善供水管网水质的多项措施和方法,列举了一些国内外的相关例子。     

上海市某小区饮用水水质污染事件调研

针对某小区水质投诉事件展开调研,检测水质,查找水质污染原因,确定供水水泵泵芯锈蚀污染供水管道以及管网内水力停留时间过长为此次事件的主要原因,采取多种管道清洗方式对管道进行清洗,寻找解决方案。     

Feed Water Treatment for Industrial Boilers & Power Plants

In steam generation systems, ensuring the quality of the boiler feed water is essential for successful unit operation. Power plants traditionally employ a multi-step process to remove impurities from the influent water. Belwo, New Logic Research Inc, USA, explains why its VSEP technology, fitted with NF or RO membrane modules, is a commercially viable alternative to exisitng boiler feed water treatment processes.     

Nanofiltration and reverse osmosis of model process waters fromthe dairy industry to produce water for reuse

In dairy plants the process waters generated during the starting, equilibrating, interrupting and rinsing steps contribute to the production of effluents. They correspond to milk products (milk, whey, cream) diluted with water without chemicals. The treatment of these dairy process waters by nanofiltration (NF) or reverse osmosis (RO) operations was proposed to concentrate dairy matter and to produce purified water for reuse in the dairy plant. The study reports one-stage and two-stage (NF + RO and RO + RO) spiral-wound membrane treatments with five model process waters representative of the main composition variations observed in dairies. Performances (permeate flux, milk components rejection, purified water characteristics) of the different operations were compared. Discussion was focused on the comparison between quality of produced waters and vapour condensates (from product drying and evaporation processes) reused in dairy plants. Accordingly, both total organic carbon (TOC) and conductivity of water treated by a single RO or NF + RO operations were convenient for reuse as heating, cooling, cleaning and boiler feed water. With the two-stage RO + RO process, a more purified water complying with the TOC drinking water limit was achieved.     

纳滤和反渗透膜形貌结构与膜性能关系探索

纳滤和反渗透膜表面形貌结构、亲疏水性的性质与膜脱盐率、水通量等性能存在一定关系。对几款商用纳滤、反渗透膜进行表面形貌结构、表面粗糙度、亲水性表征。结果表明,纳滤膜表面平整粗糙度低、亲水性强、脱盐率较低,但水通量高。反渗透膜表面存在大量疏松的峰谷结构,比纳滤膜粗糙度更大、亲水性强。对比两款海水反渗透膜,推测调整反渗透膜"叶片"大小和数量可调节反渗透膜的脱盐率和水通量性能。     

Optimal design of nanofiltration system for surface water treatment☆

Both reverse osmosis (RO) and nanofiltration (NF) membranes have been increasingly used for water purification and desalination. However, the salt rejection of NF membranes is quite different from that of RO membranes, which makes a significant distinction in their process designs. This work started from the performance investigation of a single NF membrane element and then focused on the process design of the NF system for surface water treat-ment. In experimental tests, it was found that the observed rejection of the NF element becomes nearly constant when the concentrate flow is large enough, while the membrane flux of the NF element is quite stable regardless of the water flow across the membrane surface. These findings can be used to instruct the process design of the NF system for surface water treatment. In process design, a two-stage arrangement is sufficient for the NF system to reach the highest water recovery, while the RO system requires a three-stage arrangement.     

水源切换过程中对给水管网水质的影响研究

在水源切换过程中,由于水源水质不同造成的管网水质化学不稳定,引起水质恶化,发生＂红水＂现象。本文通过实验室模拟实际管网,观察切换水源过程对给水管网水质指标的影响,监测到浊度明显升高从0.32NTU上升到6.38NTU,pH从7.97上升到8.30,电导率从825s·m^-1降到779s·m^-1,总溶解性固体从403mg·L^-1下降到380mg·L^-1,余氯迅速下降从2mg·L^-1下降到0.02mg·L^-1。感官上色度增加,水浑浊有沉淀生成,管网水中铁的含量增加,最大到1.15mg·L^-1严重超标。经分析提高pH、增加碱度、投加缓蚀剂及严格保证出厂水指标等可控制管网水质稳定性。     

Discussion on calculation of maximum water recovery in nanofiltration system

In desalination process, the effect of concentration factor (CF) and concentration polarization degree (CP degree) on water recovery in nanofiltration (NF) system displays a significant difference from that in reverse osmosis (RO) system due to their different salt rejections. In this work, the relationship between CF, salt rejection and water recovery was firstly discussed in a single NF element. In order to keep a stable performance, a spiral NF2 membrane was taken as an example, and water recovery for the single NF2 element should be about 25% instead of 15%, which is generally considered suitable for the single RO element. Then, the CP degree was calculated according to the theoretical model and experimental test, and the ultimate value was pointed out to be below 1.2. Thus, when calculating the scaling tendency of the sparingly soluble salts, the salt concentration near the membrane surface was recommended to be 1.15 times as high as that in bulk solution. Finally, a calculation method for maximum recovery was proposed for NF system. Because of the varied rejection with different NF membranes for the same feed water, which is significantly different from that in RO system, the pre-test is very necessary for NF system design.     

纳滤膜处理优质饮用水

本试验通过ESNAl-2012纳滤(NF)膜和ESPAl-2012反渗透(RO)膜对东湖自来水进行分离，说明了NF膜和RO膜去除有机物和无机盐的不同效果。根据本研究结果，为获得优质饮用水，除海水和高盐苦咸水外，对其它含盐量不高的水源选择NF膜更为合适，NF膜能满足对饮用水中高毒甚至“三致”作用的有机物去除的要求。     

Treatments of stainless steel wastewater containing a high concentration of nitrate using reverse osmosis and nanomembranes

A nanomembrane (NTR 729HF) and three different types of reverse osmosis (RO) membranes (CPA2, LFC1, and ESPA1) were tested for the treatment of high concentration of nitrate wastewater from stainless steel industry. All the tested RO membranes showed higher rejection rates (90–99% at 1000–60 mg/L of NO₃⁻ -N) than the NF membrane. The rejection rate and flux of RO membranes were not highly affected by pH variation and Ca²⁺ as co-existing ion. However, the rejection rate of NF, which was 67% at 60 mg/L of feed concentration, was decreased as pH decreased and Ca²⁺ concentration increased indicating that charge repulsion is one of the major rejection mechanisms. As nitrate concentration increased from 20 to 1000 mg/L in feed water, the removal rate decreased from 67 to 20% in NF membrane. The flux of RO was relatively high and ESPA1 (a low-pressure RO type) showed more than two times higher flux compared to the NF. ESPA1 was successfully tested for a longterm experiment with real stainless steel wastewater for 30 days of experimental period. Current study implicates that RO membranes could be an alternative for the treatment of stainless steel wastewater.     

Critical risk points of nanofiltration and reverse osmosis processes in water recycling applications

NF/RO membrane filtration processes have been recognized as an important technology to facilitate water recycling. Those processes are well-proven technologies, which can be used to remove a wide range of contaminants including trace contaminants that are of particular concern in water recycling. However, risk implications in association with brine or concentrate and membrane cleaning wastewater disposal have to date not been adequately understood. This study examines the adsorption and release process of several endocrine-disrupting chemicals (EDCs) during NF/RO filtration processes. Results reported here indicate that the membrane can serve as a large reservoir for EDCs and their release may be possible during membrane cleaning or erratic pH variation during operation. Treatment of membrane cleaning solution should be carefully considered when EDCs are amongst the target contaminants in NF/RO membrane filtration.     

Brackish groundwater treatment by reverse osmosis in Jordan

Jordan is characterised by an arid to semi-arid climate and its population is increasing at an annual rate of 3.6%. With such a high population growth rate and fast social-economical development, water demand and wastewater production are steeply increasing, and the gap between water supply and demand is getting wider. Furthermore, the constraints for water resources development are also rising due to high investment costs and water quality degradation due to over-exploitation of aquifers. Desalination of Red Sea water by reverse osmosis (RO) and/or brackish groundwater desalination by nanofiltration or RO might be technically and economically viable to cope with water scarcity and overcome the water deficit in Jordan. The technical-economical feasibility of brackish groundwater treatment by RO for potable water production was investigated in this work. Brackish groundwater samples were collected from the Zarqa basin, Jordan, and characterised in terms of pH, conductivity, total solids, total dissolved solids, total suspended solids, and volatile solids. The water samples were pre-treated through a microfiltration cartridge (5 μm pore diameter) in order to eliminate the suspended matter. A pilot plant equipped with a FilmTec RO membrane (SW30-2521) was operated at 20-30 bar, 40°C, natural pH and up to a water recovery ratio of 77.5%. The results showed that RO is actually efficient since it highly reduced the content of organic and inorganic matters present in raw waters (rejections >98.5%) at a relatively affordable price (0.26 €/m³). This study contributes to the development of efficient technologies to produce affordable potable water in Mediterranean countries where the threat of water shortages is a severe problem.