Design and operation of 800,000 gpd reverse osmosis seawater system

The paper will review the design and operation of the 800,000 gpd reverse osmosis seawater system installed at the Punta Moron Station, of the C.A. de Administration y Fomento Electrico (CADAFE) of Venezuela. The plant will produce potable and boiler feed water for the utility. The specific areas discussed will be as follows: $\text{Pretreatment}$The design and operation of the Permutit Seawater Pretreatment system producing an influent to the membrane system with an SDI less than 3, will be described. $\text{Membrane System}$The B-10 Seawater Membrane system will be reviewed as to design and operation, with particular emphasis on the process and control features necessary to provide low maintenance operation. $\text{Brackish Water System}$ p]The secondary brackish water B-9 system treating the influent from the seawater unit will be reviewed as to design and operation with particular emphasis on its ability to produce low TDS water for the demineralizers providing boiler feed water for the utility.The paper will outline data and the general experience with the operation of a large Reverse Osmosis Seawater plant. In addition, the integration of the brackish and seawater units into a single system will be reviewed.Operating costs will be outlined and the general question of Reverse Osmosis Seawater plant operation will be discuessed. The impact of the successful operation of this first single pass Reverse Osmosis Seawater System on the future of desalting technology will be evaluated.     

Non-conventional treatment of treated municipal wastewater for reverse osmosis

High-quality potable water can be produced at a reasonable cost if reverse osmosis (RO) technology is applied to renovate secondary/tertiary urban wastewater effluent. Such implementation would yield many advantages to Kuwait, namely: satisfying the increasing agricultural, industrial and domestic demands for good quality water that is free from viruses and bacteria and other microbials present preserving the natural strategic water resources; reducing the environmental pollution resulting from the direct discharge of secondary/tertiary municipal effluents to the sea; and meeting unexpected emergency cases of shortages in freshwater produced from the desalination of seawater for certain domestic applications. The main aims of this work are to assess the technical viability and the economic feasibility of implementing RO technology to renovate Kuwaiti wastewater treated effluent. The paper describes the design of pretreatment, experimental set-up, results, and data analysis of desalinating municipal wastewater by RO. The results indicate that wastewater can be treated to produce an excellent permeate quality almost devoid from salts and pollutants.     

反渗透运行情况小结

介绍了反渗透系统的流程及特点，通过反渗透运行参数的变化，分析了反渗透膜遭到污染的机理并提出了防治污染的措施。     

Deformed reverse osmosis membrane and low pressure operation

The phenomena of hysteresis described elsewhere in cellulose acetate RO membranes are discussed, in order to show that the pressure normally required by the desalting process produces two effects: one deforming the membrane and the other maintaining the flux through the deformed membrane. This paper shows that the use of independently deformed membranes can permit a lower operating pressure while maintaining the rejection factor and flux in the effluent water.     

反渗透装置的运行要求及保护措施

对20万t/a离子膜法烧碱项目中纯水生产装置——反渗透装置的运行要求进行了分析,并提出了相关的保护措施。     

Design and operation of a 5000 m/d reverse osmosis dual product plant

A dual product quality plant was designed and commissioned to supply 3000 m³/d of very high quality product plus 2000 m³/d of medium quality product from a single RO process train. In this plant, the high purity product from the first bank may be diverted directly to the end use without further treatment, while the lower purity water from the second and third banks is polished in an existing D.I. plant to supply required ultrapure water. By processing only a portion of the RO product in a D.I. train, a large savings in operating and capital costs were realized.A present-worth analysis showed the ratio of present value to cost to be 3.1 with a payout time of 1.1 year based on comparison with D.I. alone.Original design values for the plant were:

Feedwater Quality	1940 ppm as CaCO3
1st Bank Product	20–25 ppm as CaCO3
2nd & 3rd Bank Product	30–45 ppm as CaCO3
Hydraulic Recovery Rate	82%
Installed Electric Power	320 Kw

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反渗透系统的设计与应用

反渗透作为一种重要的水处理技术,越来越广泛地应用到各个领域,其处理水源也变得复杂多样化,因此要求在反渗透系统和反渗透预处理设计时予以高度关注.作者主要讨论了现代水处理应用中反渗透系统的设计方法和应用技术.     

反渗透膜的污染原因及处理方法

介绍了反渗透膜的污染原因,并进行了有针对性的分析,提出了相应的预防措施。     

影响反渗透制备脱离子水的运行因素

介绍了影响反渗透装置制备脱离子水的运行因素并进行了有针对性的分析,提出了相应的预防措施。     

Design and performance of two-stage reverse osmosis plant

Simple explicit equations are derived for the design of permeate-staged and reject-staged reverse osmosis plants. Their accuracy has been tested against iterative numerical procedures. Errors in the membrane area of both stages are below 10% under normal operating conditions. Therefore, the method can be usefully applied for quick initial estimates and for discriminating between competing processes. Two design examples are presented: sea-water desalination and sugar solution concentration. Recoveries of up to 40% can be expected even for highly concentrated sea-water (50 000 ppm). Concentrations of more than 35 wt.% can also be obtained with relatively low energy. In both cases reverse osmosis proves to be competitive with evaporative processes.     

小型反渗透膜系统优化结构设计

提出了纯水制备反渗透膜系统优化设计的经典模型。导出了相应的简化模型。描述了用现行设计软件实现优化设计的具体计算过程。明确了系统优化结构的两个判据。在此理论与方法指导下，得出了对应低难溶盐给水条件的膜系统最优“六支段饱和结构”，并结合浓差极化指标严格界定了低难溶盐给水的各难溶盐临界饱和度，从而为小型反渗透膜系统的设计提供了一套完整的优化理论，优化方法与优化结构。     

Pretreatment and cleaning of hyperfiltration (reverse osmosis) membranes in municipal wastewater renovation

Membrane fouling is a common cause of poor performance in hyperfiltration systems especially when treating wastewaters usually because it reduces the product flux to uneconomical levels. In the present paper various membrane cleaning methods are reviewed and related factors affecting process performance such as pretreatment, system geometry and membrane choice are discussed. Several leads in developing new membrane cleaning and pretreatment methods are also presented.     

Cellulose acetate reverse osmosis membranes: Optimization of preparation parameters

Asymmetric cellulose acetate based membranes usually employed in reverse osmosis as well as in separations in aqueous systems can possibly be applied in the so‐called salinity process of energy generation. For these applications, membranes with a relatively high water permeability (sometimes also called water flux) and low salt permeability (or high salt rejection) are required. In this study the authors present the optimization of such membranes, which concerns the preparation parameters. The membranes studied were prepared from a solution whose composition were previously optimized.⁴ The authors concluded that the optimum preparation parameters are as follows: thickness of the liquid film of 100 μm; 30 s allowed for evaporation of the solvent; and temperature of coagulation bath of 0–4°C and 80–85°C as annealing temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 134–139, 2007     

KDF过滤介质在反渗透预处理中的应用

介绍了一种反渗透预处理的新方法,阐述了应用KDF过波介质控制结垢形成,减少悬浮固体,减少氧化剂,控制细菌和藻类,减少重金属和减少硫化氢的机理,并给出了应用实例。     

电厂补给水反渗透系统的优化运行与清洗

反渗透膜污染是电厂补给水反渗透系统应用中最大的问题之一。对反渗透膜的污染及其化学清洗方法进行了综述,主要内容包括反渗透膜污染物的种类、污染物形成的原因以及清洗时机的选取、清洗药品的选择、影响清洗效果的主要因素、清洗系统构成、清洗方法和清洗效果的评价,并提出了几种防护措施。     

正渗透膜生物反应器运行过程中溶质反渗对微生物群落的影响

以氯化钠为驱动溶质,采用正渗透膜生物反应器(forward osmosis membrane bioreactor, FOMBR)处理生活污水,考察其在运行过程中溶质反渗对系统内微生物群落造成的影响。稳定运行状态下的第7、14、20天的混合液污泥样品分别称为A1、A2、A3,并对微生物群落物种丰度、群落结构、聚类等进行了分析。结果表明：正渗透膜生物反应器运行20 d内水通量从9.5 L/(m²·h)下降到8.17 L/(m²·h),反向盐通量从29.52 g/(m²·h)增加到35.06 g/(m²·h)。整个运行过程中溶质反渗对微生物群落结构的变化有着一定的影响,3个样品共产生1496个OTUs,各样品间共享的OTUs不尽相同;溶质反渗对3种样品的微生物群落多样性、菌群丰度等影响较小。PCA分析中A2和A3两个样品距离更近,组成更相似,热图聚类分析再次验证A2与A3相似性更高;3个样品斜率较小且非常接近,并且A1和A3两个样品所含物种的丰富程度和均匀程度几乎一样;3个样品的活性污泥群落结构在门、纲、目分类水平上均具有较高的多样性,各分类水平上的菌群丰度存在一定的差异。     

反渗透技术在市政污水回用于热电厂的工艺应用

以大连市某热电厂中水回用工程为实例,介绍了用于中水回用的预处理-反渗透工艺.运行结果表明:该工艺设计合理,出水指标符合热电厂循环冷却水水质要求,具有良好的经济效益和环境效益,对热电厂中水回用的设计运行具有借鉴意义.     

Design of reverse osmosis networks for multiple freshwater production

Reverse osmosis (RO) desalination, which produces multiple freshwater from seawater, has been studied in this work. An optimization method based on process synthesis has been applied to design the RO system. First, a simplified superstructure that contains all the feasible design for this desalination problem has been presented. In this structural representation, the stream split ratios and the logical expressions of stream mixing were employed, which can make the mathematical model easy to handle. Then, the membrane separation units employing the spiral wound reverse osmosis elements were described by using a pressure vessel model, which takes into account the pressure drop and the concentration changes in the membrane channel. The optimum design problem can be formulated as a mixedinteger non-linear programming (MINLP) problem, which minimizes the total annualized cost of the RO system. The cost equation relating the capital and operating cost to the design variables, as well as the structural variables, has been introduced in the objective function. The problem solution includes the optimal streams distribution, the optimal system structure and the operating conditions. The design method could also be used for the optimal selection of membrane element type in each stage and the optimal number of membrane elements in each pressure vessel. The effectiveness of this design methodology has been demonstrated by solving a desalination case. The comparisons with common industrial approach indicated that the integrative RO system proposed in this work is more economical, which can lead to significant capital cost and energy saving and provide an economically attractive desalination scheme.     

Advanced reverse osmosis process with automatic sponge ball cleaning for the reclamation of municipal sewage

These experiments were conducted with secondary effluent from the terminal plant at Osaka, Japan, in order to determine the potential of the sponge ball cleaning system as an advanced reverse osmosis membrane cleaning technique. It was confirmed that sandfiltration of the feed as a method for reverse osmosis pretreatment and the use of chemical cleaning reagents to restore flux levels were unnecessary, when sponge ball cleaning was used.As a result, the product water flux was maintained at 0.65 ～ 0.75m³/m² day at 25°C and membrane rejection was more stable. No damage to the membrane, which would mean a decline of rejection ability, was recognized by scrubbing of the membrane surface by sponge rubber balls.It was confirmed that tight membranes were more suitable than loose ones because firstly it was easier to remove membrane fouling, secondly the product flux was nearly equal, and finally the product water was of better quality.