Reverse Osmosis Water Purification Research Articles

Thermal integration process for waste heat recovery of SOFC to produce cooling/H2/power/freshwater; cost/thermal/environmental optimization scenarios

High-temperature fuel cells (HT-FCs) indeed hold significant promise for enhancing energy systems' efficiency and environmental sustainability. Consequently, there is growing interest in exploring and developing innovative strategies to optimize the integration of heat recovery processes with HT-FC technology. The current research presents an innovative and environmentally friendly poly-generation unit that integrates advanced subprocesses to generate essential products. These final products include electricity, refrigeration, pure water, and hydrogen. This study signifies a significant step towards sustainable and efficient energy production while meeting diverse needs for different utilities. The design unit incorporates a novel modified dual ejector-based organic flash cycle, reverse osmosis water purification, and a water electrolyzer for hydrogen extraction, all integrated with a high-temperature solid oxide fuel cell. Energy, exergy, economic, and environmental (4E) analysis is conducted to thoroughly evaluate the proposed plan. Furthermore, a comprehensive parametric analysis and sensitivity study are performed to pinpoint the key design parameters of the poly-generation unit. To attain the optimal operational status of the poly-generation unit, a three-objective NSGA-II optimization technique is employed to fine-tune the system's performance within the exergy-cost-environmental framework. This approach aims to strike a balance between maximizing efficiency, minimizing costs, and reducing environmental impact for sustainable operations. In addition, a net present value analysis spanning a 20-year timeframe was conducted to assess the profitability of the devised unit. Based on the findings, it is evident that the sensitivity index of the fuel cell operating temperature carries substantial importance, registering a notable value of 0.60. Additionally, the optimization outcomes reveal the system's enhanced performance metrics: an exergetic efficiency of 41.11 %, a unit cost of 58.96 $/GJ, and a carbon dioxide emission reduction rate of 418 kg/MWh. Also, the unit's payback period is shortened from 11.33 years to 8.817 years. Moreover, it improved the unit's sustainability index and net present value, raising them from 1.544 to 4.98 M$ to 1.66 and 7.38 M$.

Fouling Mitigation by Surface‐Patterned Polymeric Membranes in Water Treatment: A Review of Recent Advancements in Fabrication Techniques

AbstractThe world is constantly challenged regarding managing environmental and ecological contamination due to human and industrial activities. This is because of the constant threat posed by pollution. Nowadays, membrane‐based technology is a growing field, making practically all the separation of foulant from wastewater possible. The membrane fouling resulting from the interaction between the foulant and the membrane surface presents a challenge for the technology in maintaining performance over extended periods of operation. As a result, there is a rising interest in research focusing mainly on creating patterned membrane surfaces that reduce fouling and effectively enhance the surface area. This article comprehensively overviews the most recent and cutting‐edge techniques that can be applied to modify and construct high‐performance patterned membranes suitable for ultrafiltration, microfiltration, nanofiltration, and reverse osmosis (UF, MF, NF, and RO) water purification processes. In this study, recent developments in membrane material are dissected, focusing on methods for improving surface chemistry, structure, and hydrodynamics, as well as the consequences of these characteristics on filtering performance.

Critical Analysis of Stakeholders in the Municipality of Tarija, Bolivia, in Search of Strategies for Adequate Water Governance to Implement Reverse Osmosis as an Alternative for Generating Safe Water for Its Inhabitants

The accelerated deterioration of water quality in the city of Tarija, Bolivia, has caused several water sources in the Municipality of Tarija to be discontinued due to the presence of toxic contaminants. The current water purification systems that are used in Tarija do not guarantee the elimination of heavy metals; in addition, political and social interest conflicts are a serious problem in the execution of projects and new public investment alternatives, with these being the main problems found in the sector. Reverse osmosis (RO) water purification technologies are one of the most effective contemporary alternatives for the elimination of contaminants in water, such as heavy metals; however, their application and implementation in countries with little or no experience in this type of technology require acceptance and knowledge on behalf of the interested parties. Political and social conflicts between interested parties generate scenarios that affect hydrological planning. Analysis of the actors in the urban and municipal sphere of the city of Tarija, Bolivia, provides a case study for adequate water governance and enabled us to come to a consensus for the implementation of RO. The results show 23 fundamental actors in water management in the Municipality of Tarija, with local actors being those with the greatest influence and power in decision-making. Our analysis of social networks showed an important polarization in the power of decision makers, with municipalities and legislative entities being those that decide on public investments. The interested parties showed considerable interest in the application of RO as a technology that can provide definitive, short-term solutions to the problems of water stress and the water crisis in the Municipality of Tarija and its application in small towns with a high level of social and environmental vulnerability.

Reverse osmosis water purification and brine valorization in a Tunisian hemodialysis center

ABSTRACT The technical–economic analysis of the hemodialysis water purification process, which uses reverse osmosis with sand, softeners, and granular-activated carbon as pretreatment steps, shows that the permeate conductivity exceeds 25 µS cm−1 at 25°C due to softeners failure and that the cost of cubic meter of water produced is 2.4 €. The purification unit generated brine with a conductivity above 5 mS.cm−1 and it is discharged into the sewer. Several brine valorizations are proposed; brine recycling and simulation with IMS design software reveal that it is possible to recycle 0.2 m3.h−1 of brine and achieve 83% conversion rate with a good quality of permeate. The residual of the first reverse osmosis brine is diluted by the second reverse osmosis permeate and is to be used for toilet flushing, landscape irrigation, and sterilization steam production.

Exergy analysis of solar-geothermal based power plant integrated with boiling, and reverse osmosis water purification

• Physical exergy analysis of a hybrid power plant that generates both electricity and water. • Exergy destruction rate in integrated system components. • The costs of operating a reverse osmosis with thermal disinfection system to purify water. • Thermal analysis of a solar parabolic trough collector to determine the working fluid temperature at the exit receiver. • Sensitivity analysis of to find out the most dominant parameters in the energy conversion process has been carried out. Due to the obvious finite nature of fossil fuels and their environmental impact, renewable energy is becoming particularly crucial. Solar and geothermal energy are consolidated with boiling and reverse osmosis water purification in this research work. Power generation, boiling, and advanced water treatment with improved exergetic efficiency, reduced waste heat, and cost-effectiveness are the goals. The daytime cycle generates electricity and charges thermal energy storage at a 51.64 % exergy efficiency. The night-time cycle's output, boiling water treatment with waste heat and power generation, operates at 49.25 % exergy efficiency. Exergy and sensitivity analysis, solar collector performance parameter determination, and reverse osmosis system modelling are all done with EES, Python, and GPS-X software, respectively. The system met its goal of producing 44 MW of power with an average 50.4 % exergetic efficiency. Thermal disinfection and reverse osmosis produces 100 m 3 /day of water, which consumes 13.36% of total energy. The simulated water quality results from RO system indicated pH, hardness, TDS and alkalinity are observed to be within WHO limit for the influent from lake Ziway considered in this study Finally, controlling heat loss to the environment and replacing outdated system components of the existing unit, whose operating conditions have been employed in the analysis, are multiple alternatives for lowering the exergy destruction rate.

Phytoremediation Using Constructed Wetlands to Treat Reverse Osmosis Rejected Concentrates

Reverse Osmosis (RO) water purification systems are common over many farming areas of North Central Province in Sri Lanka for providing potable water to protect public from the Chronic Kidney Disease of unknown etiology (CKDu). About 50-70% of raw water with higher concentrations of ions release from RO systems with no beneficial use. Such a practice will end up with long term environmental impacts to soil and groundwater and therefore it is at utmost requirement to find suitable remedial technique. This research was focused to investigate the potential remedial measures for concentrated contaminants of RO rejected water through phytoremediation process using Constructed Wetlands (CW), before discharging into the environment. A field experiment was carried out focusing on the Sangilikanadarawa at Medawachchiya community based RO water supply unit. Two types of constructed wetlands (CW): surface and subsurface water bio-geo CW were established and tested to measure the removal efficiency of RO concentrates through phytoremediation and filter materials. Locally available soil, Calicut tile and biochar were used with proportions of 81, 16.5 and 2.5% by weight respectively as filter materials. Vertiver Grass and Scirpus Grossus were carefully selected for the sub surface wetland while Water Lettuce and Water Hyacinth were chosen for free water surface CW. Both constructed wetlands were fed with a uniform flow of RO concentrate and water quality parameters were tested periodically against two controls systems for a given hydraulic retention time. The results showed that the Total Dissolved Solids, Hardness, Total Alkalinity and Fluoride were reduced significantly and met desirable levels of stipulated ambient standards. This study indicated a great promise of purifying aforesaid contaminants of water which is obvious and considerable in ground water sources in the North Central Province, with a very low construction and maintenance cost in comparison to other water purifying methods as this approach directly dealt with locally available aquatic plants and ecofriendly filter materials. Therefore the invented bio-geo constructed wetland is an economical and effective option for reducing high concentrations of RO rejected water before discharging into the inland waters. Keywords: Reverse osmosis, RO concentrate, Phytoremediation, Constructed wetlands, biochar

Feasibility of municipal solid waste (MSW) as energy sources for Saudi Arabia’s future Reverse osmosis (RO) desalination plants

Abstract The Kingdom of Saudi Arabia (KSA) generates between 1.4–1.75 kg/person/day of Municipal Solid Waste (MSW) that accounts for over 16 million tons of MSW/year. The solid waste collected from different sources is dumped in landfills, thereby creating environmental concerns. In this paper, the potential of solid waste as an energy source (Waste to Energy (WTE)) for Reverse Osmosis (RO) water purification was evaluated. The KSA is known for its acute fresh water shortages and uses desalination technology in meeting its daily water requirements; a process that is energy intensive. The evaluation of the energy content of MSW shows a potential to produce about 927 MW in 2015, based on a total mass burn, and about 1,692 MW in 2032. The MSW-WTE plants can produce about 1.5% of the targeted 120 GW of energy for 2032. For the R.O system, it will give approximately 16.8% of the daily fresh water needed for total mass burn and 2.4% with the recycling option.

Unexpected new phase detected in FT30 type reverse osmosis membranes using scanning transmission X-ray microscopy

FT30 type thin film composite membranes used for reverse osmosis water purification are very difficult to analyze. With the remarkably thin polyamide layer and surface modification of the polymers now being reported, a new analytical technique is needed to determine the surface structure and chemical distribution in the active layer. In this study we show that scanning transmission X-ray microscopy (STXM) can be used to determine the spatial distribution of polyamide and polysulfone and we report on the detection of an unexpected new phase. The new phase was identified as a homopolymer of the meta-phenylene diamine (MPD) that forms in MPD solutions and can be incorporated into the discrimination layer during the interfacial reaction with the TMC to produce a mixed polyamide polyMPD layer. The detection of this second phase was only made possible by STXM. At the levels detected in membranes in this study (less than 8%) the second phase had no effect on the flux or salt passage of the membranes, however at higher levels a change in the membrane properties most likely would occur and the quantity of the polyMPD present should be eliminated or controlled.

Cross‐sectional audit of blood lead levels in regular outpatient haemodialysis patients dialysing in north London

Blood lead was measured and found to be high in one haemodialysis patient with atypical abdominal pain and peripheral neuropathy. This prompted an audit of blood lead concentrations in prevalent haemodialysis patients under the care of a University Teaching hospital. Blood lead was determined in 271 prevalent adult haemodialysis patients regularly dialysing three times a week, in five dialysis centres and/or on the home dialysis programme. All samples were carefully collected into lead-free plastic containers, and measured by graphite furnace atomic absorption spectrometry. 25.5% of haemodialysis patients had abnormal blood lead concentrations (>200 microg/L), compared with 59% with high-normal values of 100-200 microg/L, and only 15.5% with normal values (<100 microg/L). Blood lead increased with haemodialysis vintage (r = 0.38, P < 0.001), the use of a single carbon filter and reverse osmosis water purification device unit (r = 0.29, P < 0.001), but reduced by urine output (r = -0.44, P < 0.001). Despite UK government legislation to reduce permissible lead contamination of drinking water, blood lead was increased in 84.5% of prevalent haemodialysis patients. Single reverse osmosis machines and carbon filters may not be as effective at filtering out possible lead contamination compared with large industrial reverse osmosis devices and carbon filters, and thus blood lead testing should be considered for home haemodialysis patients, particularly in those areas where monochloramines are used to sterilize domestic water supplies.

5494573 Reverse osmosis water purification diagnostic system : Schoenmeyr Iva; Mihld Mike Mission Viejo, CA, United States assigned to Aquatec Water Systems Inc

5494573 Reverse osmosis water purification diagnostic system : Schoenmeyr Iva; Mihld Mike Mission Viejo, CA, United States assigned to Aquatec Water Systems Inc

The Army water supply program: An overview

The US Army is a highly mobile, military force that must have the capability to operate worldwide. To ensure operational readiness of the troops, adequate quantities of safe drinking water must be available. The Army's reverse osmosis water purification units (ROWPUs) have met this challenge for the past 15 years. However, the world is rapidly changing and so is the Army. Force structure and doctrine designed to meet a Cold War threat are being updated. The new Army, whose mission now seems to include humanitarian as well as combat duties, has new water supply requirements that must be met. The MTC will require the expertise and commitment of both industry and government to meet this challenge. Together, the needs of the Army's ultimate weapon — the Soldier — will continue to be met.

Improved chelators and sequestrants for Army Reverse Osmosis Water Purification Units (ROWPUs)

Mobile Reverse Osmosis Water Purification Units (ROWPUs) have been used by the armed forces to provide potable water for field applications. The current water purification systems, consist of the 600 gph, 3000 gph and 150,000 gpd ROWPUs. The ROWPU can provide potable water from any available water source such as fresh, brackish, and seawater and can also purify water that has been contaminated by nuclear, biological and chemical (NBC) warfare agents. The ROWPUs are fielded with certain chemicals that are used to clean the elements and to prevent fouling and scale formation on the membranes. The antiscalant (sodium hexametaphosphate) currently used in the field, is reputed to be an effective antiscalant for constituents typically found in subsurface waters such as silicates of calcium and magnesium, etc., but not necessarily for surface waters containing organic matter, organometallic complexes, or heavy metals. The U.S. Army Belvoir Research, Development and Engineering Center has a contract with Pacific Northwest Laboratory (PNL) to evaluate an effective antiscalant agent that will be effective with multiscalant components and over a wide range of temperatures. The overall development program consists of three phases. The first phase was the market investigation in which 16 potential chemicals were recommended for further evaluation. The second phase of development was the operational analysis which was divided in two stages: 1) bottle screening tests to identify the most promising antiscalants and 2) bench-scale tests in reverse osmosis (RO) membrane test cells to obtain performance data with a test configuration more representative of actual ROWPUs. The final phase of development will be the evaluation of the most promising antiscalants in a single RO element test stand at the Belvoir Research, Development and Engineering Center. This paper presents the results of the second phase tests that were conducted during the operational analysis in which two types of tests were performed. The bottle screening tests were conducted to assess the ability of the antiscalants to inhibit the precipitation of calcium carbonate and calcium sulfate, which are inorganic scalants frequently encountered in water purification and water distribution systems. Based on the results of the Bottle screening studies, the most promising antiscalants were tested in the bench-scale test stand using the flat-plate test cells with view ports to facilitate visual observations with multi-component challenge feed solutions. Permeate flow rates, water conductivities, and visual observations were used to determine the effectiveness of the antiscalants.

Evaluation of a pressure boosting pump/turbine device for reverse osmosis energy recovery: Extended testing on a seawater desalination system

The energy recovery device tested is a freely running turbine driven centrifugal pump used to recover the brine stream hydraulic energy in reverse osmosis (RO) systems and to transfer that energy in the form of a pressure boost to the feed stream. Features of the energy recovery (ER) device include extremely compact size, simple installation, and ease of operation. The Naval Civil Engineering Laboratory (NCEL) operates the Seawater Desalination Test Facility located at Port Hueneme, California, where various energy recovery devices have undergone extensive performance testing relative to a military 600 gallon per hour (gph) Reverse Osmosis Water Purification Unit (ROWPU). One particular device tested has a brine-driven single stage turbine, and feed pressure boosting single stage centrifugal pump joined together by a common shaft. To date, this ER device has operated over 3,000 hours with periodic measurements of performance parameters and internal inspections of the unit to characterize rates of wear.

Reverse osmosis as a concentration technique for soluble organic phosphorus in fresh water

The chemical nature and availability of soluble organic phosphorus for algal growth is largely unknown. A commercially available reverse osmosis water purification system was adapted for concentrating the soluble organic phosphorus fraction form 100-l volumes of drainage water collected from tile drains underlying an intensively managed grassland area in the Lough Neagh catchment. After membrane filtration the drainage water was recirculated through the reverse osmosis module while the permeate was removed from the system. During a single passage across the reverse osmosis membrane, 20% of the sample was discarded as pure water while the remaining 80% of the sample was pumped back to the reverse osmosis cartridge. Recirculation was continued, with the addition of an intermediate sodium ion-exchange step to prevent the precipitation of insoluble (largely calcium and magnesium) salts, until the volume was reduced to 2.5 l. The recovery of soluble organic phosphorus based on the original sample concentration was almost 93%. A further tenfold increase in concentration was achieved without salt precipitation or loss of soluble organic phosphorus by vacuum-assisted rotary evaporation. The mild, efficient concentration process developed a soluble organic phosphorus concentrate suitable for chemical fractionation and algal availability studies.

Accumulation of aluminium in patients with acute renal failure.

Serum aluminium was monitored in 19 patients admitted with acute oligo-anuric renal failure. The maximum serum aluminium obtained during the course of treatment was greater (p less than 0.05) in 4 patients treated by haemodialysis alone, mean +/- sem 3.78 +/- 0.71 mumol/l than in 4 patients treated only by haemofiltration, 0.60 +/- 0.22 greater (p less than 0.05) during treatment with haemodialysis, 2.7 +/- 0.62 mumol/l than during treatment with haemofiltration, 1.36 +/- 0.15 mumol/l. There was a significant positive correlation between the maximum serum aluminium during treatment with haemodialysis and the number of hours of haemodialysis given (r = 0.76, p less than 0.001). There was no significant increase in serum aluminium due to the administration of human albumin solutions. The aluminium content of dialysate water represents a major source of aluminium in patients with acute renal failure; prevention by reverse-osmosis water purification is recommended.

The hydraulic turbocharger™: a new type of device for the reduction of feed pump energy consumption in reverse osmosis systems

Pump Engineering, Inc. (PEI) has developed a new type of reject stream energy recovery device for brackish and seawater reverse osmosis systems called the Hydraulic Turbocharger™ (HTC). The device is a feedwater lubricated, free running, high speed turbine driven pump that provides a pressure boost to the RO feed stream resulting in a reduction in high pressure pump energy requirements. A pre-production prototype was tested at the Naval Civil Engineering Laboratory (NCEL), Port Hueneme, CA in conjunction with the development of a 1200 gph Reverse Osmosis Water Purification Unit (ROWPU). Testing consisted of approximately 2000 operating hours in a simulated RO system operating at a nominal 60 gpm of feed flow using Pacific Ocean seawater to determine unit reliability under actual seawater operating conditions. The device operated without any failure although a performance loss did occur that was attributed to galvanic corrosion between graphite and bronze sealing surfaces. Bronze/graphite interfaces were upgraded to either silicon nitride/graphite or silicon nitride/bronze surfaces and testing resumed to determine performance characteristics of the new seal and bearing configurations.

Contaminants in Clinical Reverse Osmosis Water Purification Systems

To the Editor.— Reverse osmosis (RO) membrane separation processes have been successfully used by industry for several years to generate high purity water for injectables. More recently, miniature RO plants have been designed to produce injectables and dialysate solutions for hemodialysis and peritoneal dialysis in health care facilities. Existing commercial systems based on asymmetric cellulose acetate membranes have good separation properties for a number of solutes. 1 However, their behavior is such that certain compounds are not excluded; in fact, a few are transported preferentially and concentrated by the membrane. 2,3 This is in contrast with widely held views in engineering circles that regard RO membranes as sieves that filter largeand medium-sized molecules without regard to their chemistry. Poorly separated compounds include many common municipal water impurities such as pesticides, natural products, and industrial contaminants, which are found in high concentrations in some localities at certain times of the year.

Contaminants in clinical reverse osmosis water purification systems

Contaminants in clinical reverse osmosis water purification systems

Analysis and optimization of a reverse osmosis water purification system—part II. Optimization

A mathematical model of a reverse osmosis water purification system that can be used in process optimization studies and cost equations that relate the capital and operating costs to the design variables is developed in Part I of this work. In this part, the model is used to determine design and operating variables of the system, which minimize the cost of water production. Several three multistage reverse osmosis systems are considered. They are a multistage operation without the use of a flow-work exchanger and with a variable membrane area at each stage (System 1), that with equal membrane area at each stage (System 2), and a multistage operation with the use of a flow-work exchanger and with variable membrane area at each stage (System 3). In the optimization study, the recirculation rate in each stage, the brine composition leaving each stage, the ratio of membrane area to feed at each stage, and the operating pressure in each stage are controlled to arrive at a minimum water production cost.

Analysis and optimization of a reverse osmosis water purification system Part I. Process analysis and simulation

A mathematical model of a reverse osmosis water purification system that can be used in process optimization studies is developed. A boundary layer flow model is used to relate water production rate to the operating pressure, Reynolds number, and membrane area. Cost equations that relate the capital and operating costs to the design variables are also developed. These relations are then used in economic analysis of several reverse osmosis systems. The results of computer simulation of single stage processes are presented. The model is believed to be accurate enough to describe the process and yet simple enough to be used in the simulation, design, and optimization of the process.