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The issues of scaling, pipeline corrosion, and the growth of sludge, bacteria, and algae within circulating cooling water systems have been consistently limiting the enhancement of production efficiency in enterprises. The trending new electrochemical water softening technology, with its environmentally friendly, high efficiency, and low energy consumption characteristics, offers a fresh approach to addressing the stable operation of industrial circulating water systems. This paper begins by detailing the mechanisms of active scale removal, sterilization, and algae control facilitated by electrochemical water softening technology. Subsequently, it compares and analyzes the crucial core components of electrochemical devices (including the selection and preparation of anode and cathode materials, as well as the power system). Furthermore, it introduces the main types and installation modes of electrochemical equipment available in the market. Additionally, it uncovers the key factors influencing the efficiency of electrochemical descaling and validates the impact of electrochemical water softening technology on industrial circulating water systems through illustrative examples. Lastly, the paper concludes by summarizing and forecasting the future development direction of this technology. [ABSTRACT FROM AUTHOR]

Treatment and/or disposal of concentrated brines, which have total dissolved solids content in the region of 70,000 ppm up to full saturation, are a common and important problem around the world. The success of any desalination technology for such an application depends on the reliability of the process, product quality, capital cost, energy consumption, complexity of the process and safe disposal. A comprehensive study of the reasons why desalination technologies have limited scope in the treatment/disposal of these brines is considered in terms of economical and technical aspects. Zero liquid discharge systems and other promising desalination technologies (such as osmotic power plants and freeze-melting processes)which could be used for treating high saline brines have also been investigated in this paper. [ABSTRACT FROM AUTHOR]

For the past several decades, we have seen significant improvements in the desalination industry, mostly intended to increase efficiency and reduce the energy consumption of desalination plants but also to improve the reliability, operability, and longevity of membrane systems. Except for introducing pressure exchanger energy recovery devices, most improvements have been incremental rather than disruptive; in most cases they were small adjustments that made a plant more effective, efficient, or reliable. This paper describes a completely disruptive new method of desalinating seawater: subsea desalination. A patented method combining seawater reverse osmosis (SWRO) membranes with subsea technology is well-proven and has been used extensively in the offshore oil and gas industry for decades. The subsea desalination concept places a membrane desalination plant below sea level, obtaining two very immediate and distinctive benefits: (1) higher and consistent feed water quality and (2) hydrostatic pressure from the column of water that provides all the required pre-membrane pressure. In the paper, we will describe the subsea system design and its advantages, which are substantial and game-changing, explaining how the cost of water can be reduced, reliability improved, and environmental benefits enhanced with such a solution. Specific benefits of the membrane configuration will be discussed, describing the system advantage regarding energy consumption, permeate quality and reduced brine salinity. The paper also presents the set-up and results of subsea field tests where it was proved that the reverse osmosis (RO) membranes performed as predicted by the DuPont WAVE design software. [ABSTRACT FROM AUTHOR]

Seawater reverse osmosis (SWRO) desalination has been in wide use for over 25 y. This paper examines limitations of the prevalent membrane configuration, based on a single stage consisting of one or more membrane housings operating in parallel with 6-7 elements per membrane housing. A brinestage configuration using interstage pressure boosting is proposed to address limitations in single stage systems including high biofouling potential, excessive permeate salinity and high energy consumption. Membrane array optimization requires careful review of concentration polarization (Beta or CP) and the feed flow rate through each membrane element (Qele), (a proxy for cross-flow velocity). CP is the formation of a salinity gradient normal to the membrane surface generated by a combination of boundary layer formation and permeation. CP is often characterized by the term Beta, which is defined as the ratio of salinity at the membrane surface divided by the bulk feed salinity. A high Beta means that the membrane surface is exposed to elevated salinity (hence higher osmotic pressure and increased salt passage) and a greater concentration of foulants. These conditions increase the required pressure, increases permeate total dissolved solids (TDS) and promotes fouling of membrane spacers and surfaces. A high Qele is preferred to minimize boundary layer thickness and to better scour feed channel spacers and the membrane surface. This paper explores a brine staged SWRO membrane array that achieves preferred levels of Beta and Qele to achieve improved biofouling resistance and lower permeate TDS while providing a recovery of 60% in typical SWRO applications using standard membranes, pressure vessels and energy recovery devices (ERDs). Major membrane suppliers have endorsed high recovery SWRO using brine staging as described in this paper. The focus also includes optimal ways to implement brine staging over very large SWRO systems using turbochargers in a unique configuration that maximizes brine stage performance as well as energy recovery efficiency. The paper also addresses related ERD technologies and variable frequency devices that together can reduce energy consumption as well as provide a substantial reduction in capital costs (CAPEX) and operating costs (OPEX) with realistic reductions of 16% in mega-scale SWRO facilities. [ABSTRACT FROM AUTHOR]

Waste water treatment plants (WWTPs) are considered as energy-intensive industries. A comprehensive assessment of energy efficiency in sewage treatment reveals issues of energy waste, offers insights into the energy consumption structure, fosters optimization of energy management, and enhances overall energy utilization. However, the mathematical modeling for energy efficiency evaluation becomes challenging due to the ambiguity and uncertainty of the parameters regarding energy consumption and various indicators. In this paper, the newly constructed evaluation method was used to quantify the energy efficiency. This method employs dimensional reduction, projecting the numerical values of unit energy consumption for various pollutants onto a lowerdimensional space, and then computing the projected eigenvalues. Larger eigenvalues indicate higher energy efficiency. Based on the evaluation results, the back propagation (BP) neural network is used to simulate the sewage treatment process. The results demonstrated that when the inflow load is small and the concentration of pollutants is high, the energy efficiency of sewage treatment plants performs well. When the inflow load is high and the concentration of pollutants is low, the energy efficiency of sewage treatment plants is poor. Meanwhile, the energy consumption could be decreased by 11.61 %, 14 %, and 15.26 % respectively in different scenarios. [ABSTRACT FROM AUTHOR]

The rise in living standard and the rapid development of the economy have led to an increase in the daily production of domestic wastewater. Environmental policies aim to reduce pollution, and appropriate technologies in the field of wastewater heat recovery could contribute to this goal. Technologies such are heat pumps and heat exchangers enable wastewater heat recovery and contribute to reduction of wastewater thermal pollution at the source. Also, using the recovered heat can meet some of the energy needs of buildings and reduce CO2 emissions. This paper reviews the literature on wastewater heat recovery in buildings and the opportunities to reduce energy consumption and greenhouse gas emissions through the use of wastewater heat recovery technologies. Also, the paper presents the methodology for evaluating the effects of the potential of wastewater heat recovery in buildings, and gives an analysis of the key factors affecting the wastewater heat recovery potential. Given the constant potential of heat recovery and its widespread availability at the source, this study concludes that future strategies for creating more sustainable societies will rely more heavily on heat recovery from wastewater. [ABSTRACT FROM AUTHOR]

To address the issue of precise control of dissolved oxygen (DO) concentration and nitrate nitrogen level in wastewater treatment processes (WWTPs) under the premise of low energy consumption, a multivariable event-triggered model predictive control (ETMPC) strategy based on recursive bilinear subspace identification (RBSI) is proposed in this paper. Since WWTPs have strong non-linear, multivariable coupling and large delay characteristics, the RBSI algorithm with a forgetting factor is used to build the model predictive control (MPC) in this paper. In RBSI-ETMPC, first, to overcome the difficulties in establishing an accurate mathematical model due to the complex reaction mechanism in WWTPs, the BSI algorithm with linear and non-linear advantages and the RBSI algorithm with adaptive updating of parameters are utilized to establish the state space identification model of the wastewater biochemical reaction process. Then, the RBSI predictor equation obtained by the data-driven method is utilized as the MPC prediction model. Under the condition of meeting the event triggering strategy, the sequential quadratic programming algorithm is adopted to solve the quadratic performance function and update the control input at the next time. Finally, four experimental verifications under three working conditions, including a constant setpoint, variable setpoint and variable setpoint with input or output pulse interference, are carried out using international benchmark simulation model no. 1. The experimental results demonstrate that the values of the integral of absolute error, integral of square error and maximal deviation from setpoint of the RBSI-ETMPC decreased by 82.81%, 96.62% and 71.89%, respectively, for the variable setpoint control of the DO concentration under rain weather conditions compared with the recursive linear subspace identification (RLSI)-MPC. Furthermore, the longest trigger interval of the proposed RBSI-ETMPC is 0.8 h, which can save considerable computing resources. [ABSTRACT FROM AUTHOR]

This paper compares the efficiency and thermal performance of regular pyramid solar stills to those modified with silica or aluminum oxide nanoparticles. The amount of exergy lost by the pyramid solar still's various parts has been estimated, studied, and discussed. The exergy of evaporation is greater at the improved solar stills, and evaporation occurs at a faster rate. Also, compared to regular stills, the upgraded ones have higher energy and exergy efficiency. The impact of varying factors on the performance of solar stills is briefly discussed as well. Maximum energy efficiency for mixes of aluminum oxide and water is 55.29% and for mixtures of silica oxide and water is 41.38%, whereas for the typical still it is just 35.68%. In addition, conventional stills, stills based on silica oxide nanoparticles, and aluminum oxide all had exergy efficiencies of 11.48% or lower throughout the day. [ABSTRACT FROM AUTHOR]

Seawater reverse osmosis (SWRO) is the dominant desalination technology in the world today. However, terrestrial SWRO is energy- and land intensive and more than 50% of the process is typically related to pre-treatment, not the RO process itself. Today's plants also have a negative impact on the local land and marine environment. This paper describes the design of a subsea SWRO system, Flocean, and its vast life-cycle benefits, including lower energy consumption, reduced cost of water, improved reliability, and enhanced environmental sustainability. Installed in water depths of 300-600 m, this approach brings several key advantages that result in significant cost and environmental savings through simplifications in design and operation: (1) In the disphotic zone from 200 m, less than 1% of sunlight reaches the system. This results in a high and consistent feed water quality as no plants grow and therefore there is significantly less life including algae and bacteria. Consequently, the need for pre-treatment is significantly reduced and, in some cases, even eliminated. (2) The system uses ambient hydrostatic pressure to reduce overall energy consumption by 30%-50%, even compared to modern SWRO systems with energy recovery systems. One of the many environmental benefits of the subsea desalination system is the brine discharge which has far less impact on marine life than current terrestrial SWRO systems. Access to high-quality, high-pressure feed water allows for chemical-free pre-treatment and low recovery operation without significant impact on the cost of water. The result is not only an energy-efficient system, but also a chemical-free brine that matches the salinity of the surrounding ocean. In addition, the brine is dispersed at deep sea in areas of low biological productivity. It all adds up to a green discharge product that is ideal for preserving the marine environment. The system was initially proven for oil and gas subsea water treatment applications and based on four decades of subsea technology experience in Norway. [ABSTRACT FROM AUTHOR]

The importance of energy storage methods increases in the global energy industry. One of such methods is the production/generation of hydrogen and its further use called power-to-gas technology. Without highly efficient, reliable and cheap energy storage solutions, the energy sector, especially in Poland, may face significant problems related to climate protection and reduction of greenhouse gas emissions to the atmosphere in the nearest future. One alternative way to store and transport hydrogen is to blend small amounts of hydrogen (up to about 15%) into existing natural gas networks. When hydrogen is required, it can be separated near end-users using separation membranes. The paper presents the possibilities of using membrane technology in the process of obtaining hydrogen as fuel after its storage. The membrane separation technology can be used to separate mixtures of various gases, such as H2, O2, CO, CO2, or CH4 . The paper presents selected problems of the analysis of the hydrogen separation process from a mixture with natural gas for polymeric membranes with different separation properties. The structure of the separation system has been selected in order to obtain the appropriate purity of the separated gas. The energy consumption of the process of hydrogen separation from a mixture with natural gas was determined for such a system [ABSTRACT FROM AUTHOR]

With the increasing number of water conservancy and hydropower projects, in order to better meet the objective requirements of energy saving and consumption reduction, this paper puts forward the research on electrical energy-saving control methods of hydraulic engineering based on cloud computing. From the point of view of analyzing the main causes of power waste in water conservancy projects, this paper constructs a data model of electrical energy consumption of water conservancy projects based on cloud computing, completes the electrical energy-saving design of water conservancy projects through a data energy-saving algorithm classification and data energy-saving algorithm based on dynamic voltage and frequency scaling, realizes the evaluation of energy efficiency index of electrical energy consumption data, and finally designs a three-phase asynchronous motor dual CPU system based on cloud computing design. Through the experiment, it is proved that the energy-saving effect is obvious, which effectively improves the utilization rate of water conservancy and electric power energy, greatly improves the quality of people's lives, and provides a reference for improving the operation effect of water conservancy projects. [ABSTRACT FROM AUTHOR]

The installed capacity of seawater reverse osmosis (SWRO) as the main means to solve the water resource crisis is increasing year by year. However, the current SWRO is mainly composed of membrane components, high pressure pumps, booster pumps and energy recovery devices. In this paper, a new multi-action internal curve seawater desalination high-pressure pump with energy recovery function was proposed, which can recover the pressure energy of concentrated seawater and pressurize the raw seawater at the same time. The working principle and internal structure of the pump were described in detail, and the design of a pulsation-free structure was illustrated. The operating pressure and specific energy consumption of the proposed system with different membrane component structures, feed water flow rate and recovery rate were analyzed. The final design of the membrane component structure had one segment for each stage with three containers in each segment and eight reverse osmosis membranes in each container. The recovery rate and the feedwater flow rate of the proposed system were 40% and 531 m³/d, respectively. The specific energy consumption of water production reached 1.65 kWh/m³ in a validation test. The water production cost and the system volume were both significantly reduced. [ABSTRACT FROM AUTHOR]

Soil aquifer treatment (SAT) is a managed aquifer recharge technology that involves the utilization of treated wastewater as a source. Widely implemented in countries like Australia, Israel, and Spain, SAT offers technical (flexibility), economic (lower investment cost), and environmental (lower energy consumption) advantages that invite people in other countries to assess its potential. There have been numerous research studies and experiments conducted on the process level of SAT, focusing on how to eliminate pollutants and improve water quality. However, research at the system level is limited, which hampers its widespread application, especially in developing countries. In this paper, I provide a comprehensive guideline that highlights important factors to consider when implementing SAT as a technology. Proper site selection and careful planning steps, including pretreatment, hydrogeological factors, and economic calculations, can significantly improve the performance of an SAT system. The regulatory component acts as a barrier to the expansion of SAT facilities worldwide due to the lack of harmonization in regulations. This study includes the details and results of an examination of the legal framework and establishes comparative guidelines and water quality parameters that must be met by SAT projects utilizing reclaimed water. The maintenance and monitoring of the SAT system are also essential to anticipating and addressing potential issues such as clogging. Lastly, the social aspect, which is of utmost importance, should be carefully considered. It is advisable to ensure transparent communication with end users from the early stages of the project. These key elements are interconnected, and none should be considered less significant than the others. [ABSTRACT FROM AUTHOR]

This paper investigates the use of low-cost natural iron ore in the preparation of binary metal layered double hydroxide (ZnFe-LDH) nanostructures via a hydrothermal process. In particular, the photocatalytic degradation of Rhodamine B under UV light irradiation is utilized. Natural iron ore is used to prepare the iron(III) precursors (Fe3+) necessary for building the ZnFe-LDH nanostructures. Preparation is done at 80°C-100°C for 36 h and does not involve a calcination process. The physicochemical characterizations of the prepared samples are carried out via X-ray diffraction, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, and photoluminescence. After confirming the existence of the ZnFe-LDH nanostructures via their functional groups and elemental compositions, it is noted that they have high crystallinity and small crystal sizes. The morphologies of the ZnFe- LDH nanostructures are irregular, with small particles agglomerated on their surfaces. While good optical properties are enhanced as the preparation temperature is increased, the results show that crystallinity, crystal size, particle uniformity, and narrow bandgap energy play important roles in the subsequent photocatalytic reactions. The optimum conditions for the photodegradation of 10 ppm Rhodamine B solution are reached with 1.00 g/L of ZnFe-LDH nanostructures prepared using the hydrothermal method at 100°C for 36 h. At maximum efficiency, the photodegradation process can be completed at a rate constant of 0.2060 min-1 in 20 min and an EEO of 44.74 kWh/ m³ with the addition of a 0.9% v/v H2O2 electron acceptor. Photocatalyst efficiency decreases by just 12.5% across five test cycles. [ABSTRACT FROM AUTHOR]

With the acceleration of industrialization and urbanization, China’s domestic water consumption has increased year by year. To improve the efficiency of household water use, China has issued mandatory national standards for Minimum Allowable Values of Water Efficiency and Water Efficiency Grades for Water Closets (GB 25502-2017) and Minimum Acceptable Values and Grades of the Energy Efficiency and Water Efficiency for Smart Water Closets (GB 38448-2019) and implemented a water efficiency labeling scheme. Based on scenario analysis, this paper designs a BAU scenario without implementing water efficiency standards and labeling scheme, a Standard Scenario where only water efficiency standards are implemented, and a Standard + Labeling Scenario where water efficiency labeling is carried out based on implementing water efficiency standards. By analyzing the market share and water efficiency distribution of ordinary and smart toilets in 2021–2025, the water consumption of toilet flushing and bidet functions in the three scenarios above were calculated. Compared with the BAU scenario, it is estimated that under the Standard Scenario, the annual water savings is 1.39~3.35 × 108 m³, and the cumulative water saving is about 10.75 × 108 m³ in five years; Under the Standard + Labeling Scenario, the annual water saving is 1.39~5.45 × 108 m³, and the cumulative water saving is about 17.39 × 108 m³ in five years. [ABSTRACT FROM AUTHOR]

The rising cost of energy has put extreme pressures on the design and operation of municipal seawater reverse osmosis (SWRO) facilities especially in localities where electricity rates are high. To meet this challenge, creative approaches to SWRO system design and energy recovery devices (ERD) selection and utilization are required. Any successful approach will have to take into consideration not only the energy transfer efficiency of the particular ERD, but its level of complexity, ease of start-up, and capital costs in order to build a system with the lowest possible specific energy consumption (SEC). This paper will describe how a 4,500m³/day municipal SWRO facility with energy costs exceeding 0.28 kH-h and an ERD supplier recently met this challenge and produced a system with a SEC of < 2.46 kW-h/m³. The first section of this paper will review three ERD technologies available on the market today: the Pelton impulse turbine; isobaric chambers; and hydraulic pressure boosters. Attention will be given to not only how their brine energy transfer efficiency is arrived at, but also to each system's level of complexity, ease of start-up and operation, and capital costs. The second section will describe the final system design including the selection of the high pressure feed pump and membrane design. The final section will review actual performance data from the facility showing how the system ran with a SEC of 2.46 kW-h/m³. [ABSTRACT FROM AUTHOR]

Energy-water-environment nexus is very important to attain COP21 goal, maintaining environ)ment temperature increase below 2°C, but unfortunately two third share of CO2 emission has already been used and the remaining will be exhausted by 2050. A number of technological developments in power and desalination sectors improved their efficiencies to save energy and carbon emission but still they are operating far from their thermodynamic limits. The theoreti)cal thermodynamics limit for seawater desalination at normal conditions is about 0.78 kWh/m³ depending on the initial salt contents. However, practical plants are operated at several folds higher than this limit due mainly to inherent losses in the processes that were incurred in removing dissolved salts. Technological advancement in thermally driven processes hybridization have set the new bench mark for lowest energy consumption that has boosted the water production trend of desalination industry. In this paper, we presented multi-effect desalination (MED) hybridization with pressure swing adsorption (PSAD) cycle to overcome lower brine temperature limitations to boost overall performance of the system. The synergetic effect from hybridization of MED-PSAD permits a higher overall operational range and inter-stage temperature differences, leading to a boost in water production up to 2–3 folds. We showed that the proposed hybrid cycle can achieve highest performance SUPR = 20% of thermodynamic limit: one of the highest performance reported in the literature up till now. These figures can be translated to less than US$ 0.47/m³ – a lowest specific cost ever reported in the literature. The proposed cycle is not only tested at pilot scale, but also successfully commercialized into industry and received many international awards as one of the most efficient and sustainable desalination technology. [ABSTRACT FROM AUTHOR]

This paper presents a control system for the operation of desalination plants powered by locally generated renewable energy. To cope with the variability of the water demands and the available energy, the amount of water produced must be manipulated optimally. This is carried out by regulating a variable speed pump, using hybrid predictive control, which takes into account the operational limits of both the pump and the process. The operation is complex because the scheduling of the cleaning operations and the optimization of the energy consumption must be performed simultaneously to the control of the plant, fulfilling a set of additional constraints. The paper uses a continuous reformulation of the problem in order to simplify the optimization process. Simulations of a specific plant show that an optimal operation reduces the extra energy consumption, and makes it possible to supply the variable water demand. [ABSTRACT FROM AUTHOR]

In the framework of a regional scientific cooperation project between USA, Israel, Jordan, and the Palestinian Authority, Jordan (represented by the National Energy Research Center (NERC) has received two desalination units. The first unit is a US-military RO-desalination unit (ROWPU), producing 21.3 m³/d of fresh water and operated with diesel generator. The second unit designed for brackish water also produces 21.3 m³/d flesh water, and is accompanied by a complete 16 KWp-PV system. This paper describes the water situation in Jordan, the potential of solar radiation in the area, site selection criteria, and the designing, sizing and simulation of a photovoltaic power supply system for the second RO-desalination unit. Also the paper contains measurement and evaluation data concerning the water quality, energy consumption and efficiency of the (ROWPU), which has been installed and operated by NERC in the village of Qatar in Jordan. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to evaluate the efficiency of nitrate removal from ground water with membrane processes, including direct: electrodialysis (ED), reverse osmosis (RO), nanofiltration (NF), and hybrid process coupling NF with RO/ED. Both energy consumption and water product quality were considered to assess process efficiency of direct and hybrid systems. The blending strategy was adopted only for permeates that are lower than the standards for drinking water in terms of nitrate by mixing the permeate with brine. Results indicate that the nitrate removal efficiency in RO system and ED was about 95%, 3% and 91%, 48% more than that of the NF system. Thereby, the energy and cost efficiency of ED is relatively higher than RO. Considering the nitrate removal efficiency of NF-RO and NF-ED hybrid system, the results show that the NF-ED quality of nitrate content is better than that of NF-RO. In addition, the water recovery of NF-ED is relatively higher. However, the energy consumption and energy cost of both NF-ED and NF-RO hybrid systems are similar with a particular benefit of NF-ED. However, the portion of blending rate with NF-RO permeate is equal to 65% and to 45% of RO. Having said that, the NF-RO hybrid system is technically more attractive than others to obtain water with 50 ppm of nitrate and a target recovery rate of 95.42%, despite their moderately higher energy cost. At the same time, NF-RO hybrid minimizes the fraction of brine disposal dumping to sewage, making it environmentally friendly. [ABSTRACT FROM AUTHOR]

Desalination provides a quality effluent for either urban or industrial use, but it produces waste that has an environmental impact. Zero-liquid discharge (ZLD) of brine aims to increase the efficiency of the desalination process, obtaining a solid that can be reused while minimizing environmental impacts. This article reviews the research on ZLD in order to measure the interest of the scientific community and evaluate the challenges of ZLD processes. A total of 238 publications were analysed. The temporal evolution of the number of published papers shows the growing interest of the scientific community in this field. Results highlight that in the future, ZLD processes need to improve several aspects, such as improving membranes to increase their performance at lower operational costs. In addition, it is necessary to reduce energy consumption and improve the control of scaling and fouling. The incorporation of more environmentally friendly energy sources could also help reduce energy costs of ZLD processes. Moreover, more suitable ways are needed to collect and separate the solids from the obtained concentrate and make better use of them. [ABSTRACT FROM AUTHOR]

Forward osmosis (FO) has emerged as a method for desalting saline water and power production. It utilizes a chemical potential difference, or a salinity gradient to permeate fresh water through membranes. This paper investigates the feasibility of using the FO process for seawater (SW) desalination in terms of consumed energy, capital costs, water recovery, operation & maintenance, water quality, and the final product water cost. The study covers FO by itself, and when combines with other desalting systems such as reverse osmosis, multi stage flash (MSF), and multi effect distillation as pretreatment method. This paper reviews first the principles of fluid and solutes flow in the FO membranes, concentration polarization, the difference between the FO, pressure retarded osmosis processes, draw solutions, and the solutes involved in these draw solutions. Then, the main characteristics of the FO membranes and their commercial availability are presented. Previous experimental work and a commercial plant using FO for desalination are also given. The use of FO as pretreatment for other desalting methods is presented in light of two proposed research projects. The first research project proposes utilizing FO as pretreatment for processing treated wastewater and SW in one system. The second project utilizes FO as pretreatment for a once-through MSF desalting method. The analysis proved energy reduction in the energy consumption of both desalting systems by more than 50 and 18%, respectively. [ABSTRACT FROM PUBLISHER]

The multieffect desalination (MED) process is one of the most efficient thermal desalination processes due to its low energy consumption. Due to the recent developments in the desalination industry, latest desalination plants are more cost effective than the older technology-based plants. The primary goal of this paper is to investigate a mathematical model of an MED system in such a way that, it is able to predict the optimum number of effects. The number of effects for a specific plant is a major factor in determining thermal economy and capital amortization. Also the gain output ratio of an MED unit is totally dependent on steam economy and is directly proportional to the number of effects. The total cost of water is dependent on two chief costs: steam cost and capital cost. In this paper, a compromise has been made between these two costs to find optimum number of effects that would produce the minimum sum of the two cost components. [ABSTRACT FROM AUTHOR]

Over the last 10 years, there have been significant developments in new devices for energy recovery, new membrane materials and new sizes and orientations of reverse osmosis (RO) plants, all designed to reduce costs and improve efficiency. The fundamental issue of keeping membrane surfaces clean to ensure efficient RO plant operation has seen relatively few recent developments. This is surprising as any fouling of the membrane surface will have a dramatic effect on energy consumption and plant efficiency. Many researchers have focused on identifying and studying the foulants in great detail, but there have been few studies in how to remove it. Commodity acid and alkali compounds are still widely used due to the perceived lower application costs. Specially blended cleaning chemicals incorporating detergents, surfactants and chelants are also in wide use and are increasingly accepted by the market to be economically and environmentally viable. “Strategically pairing chemical agents that have complementary cleaning mechanisms so a higher cleaning efficiency can be attained” has been described by Wui. The authors have established a research project to explore in detail the use of novel physical and chemical cleaning methods. These included effervescent chemicals, physically generated bubbles and high ionic strength cleaners designed to agitate the cake layer on the membrane surface, assisting deposit removal. A series of experiments using flat sheet test rigs and pilot plant have been completed and the results presented in papers at IDA Tianjin 2013. This paper explains how the multiple cleaning mechanisms remove foulants and presents new data from a food processing plant which recycles wastewater through an RO plant is presented. Historically, cleans were conducted every one to two weeks due to the very high fouling rate. An air inductor and specially formulated cleaning compound cleaners A & B incorporating effervescent and high ionic strength demonstrated that the plant could be cleaned more efficiently and in a shorter timescale than using conventional cleaners. The presence of microbubbles has a dramatic effect on cleaning efficiency as a result of agitation of deposits on the membrane surface. The differential pressure of the first-stage plant was reduced for 4.5 bar to consistently less than 1 bar. The quantity of permeate produced increased from 15 to 24 m3/h. The underlying fouling rate was dramatically reduced so cleans are now conducted on a 6–8 week cycle rather than a 10-day cycle. These improvements occurred because cleaning using microbubbles has been more effective and the membrane surface much cleaner than previously. A clean membrane surface does not foul as quickly as a dirty membrane surface due to surface roughness. The potential for enhanced membrane cleaning by combining different chemical and physical mechanisms is an exciting area of research. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) has developed into one of the most commonly applied technologies for the reduction of the salt content of a feed stream. While it is a widely applied purification process, the market is continuously challenging suppliers for innovation to increase the economics and sustainability. This paper will review and analyse the field performance of Dow FILMTEC™ new high-flow/low-energy seawater reverse osmosis elements—SEAMAXX™. This new seawater RO membrane, which has the highest permeability currently available, is based on innovation related to membrane chemistry. SEAMAXX can be used to increase the recovery of an existing system or to decrease the energy consumption. In either case, the final cost of water is estimated to be between 10 and 15% lower compared to previously available state of the art RO elements. This paper will focus on three different cases studies where the expected performance of SEAMAXX has been validated. Two of these cases correspond to small-size and medium-size pilot trials completed at the Water Technology Center of Dow Water and Process Solutions in Tarragona, Spain. The third experience is a commercial installation which has been in operation with SEAMAXX elements since May 2013. In this particular facility, a retrofit of the RO system was undertaken such that existing 11-year-old FILMTEC membranes were replaced with next generation SWRO membranes. This commercial installation, located in the Canary Islands (Spain) treats the seawater (Atlantic Ocean) well to produce drinking water. In this third case, the performance of the desalination plant will be compared with the performance of the previous elements as well as with the predicted or expected performance of SEAMAXX according to ROSA™(reverse osmosis system analysis) simulation software and DOW™FT-NORM normalization tool. Rejection of dissolved salts and in particular, rejection of Boron has been carefully monitored by regular analysis in Dow’s R&D Lab and in external certified laboratories. After almost one year in operation, the performance of SEAMAXX has been validated through different seasons and different sets of operating conditions, confirming the expected savings in energy consumption. [ABSTRACT FROM AUTHOR]

Forward osmosis (FO) is a natural process, occurring in the cells of all living things when liquids of differing solute concentrations are separated by a semipermeable membrane at ambient temperatures. FO differs from reverse osmosis (RO) in that natural osmotic pressure, resulting from the difference in solute concentration in the two liquids, is the sole driving force for the transport of water across a membrane. The purpose of this paper is to illustrate the energy/cost of water trade-offs when comparing RO and FO technology for water purification. Trials of the FO system were conducted by a third party consulting firm, Carollo Engineers and the US Navy to monitor energy consumption, with results demonstrating the feasibility of operating an FO plant at one-sixth the electrical energy of current RO systems, i.e. 0.8 kilowatt hours per cubic meter of water. The FO process uses “waste” or low-grade thermal heat to drive the systems energy requirements of <70 mega joules per cubic meter of water. The availability of a low-cost heat source largely dictates the selection of the proposed technology. FO has two claimed advantages over RO, (1) lower energy consumption and (2) lower fouling. In this paper, we will discuss the findings of both in a year-long sea water desalination trial. [ABSTRACT FROM PUBLISHER]

Renewable energies can benefit the water sector, reducing the cost and the environmental impact of water production. This paper presents a technical and economic assessment of a photovoltaic generation project to supply energy to a grid-connected seawater reverse osmosis (SWRO) desalination plant and of an associated battery energy storage system (BESS) using lithium-ion batteries. It examines the case study of the SWRO desalination plant on Porto Santo Island (Madeira, Portugal). The assessment is supplemented by a sensitivity analysis of several variables. The findings indicate that photovoltaic generation in desalination plants results in a lower levelized cost of energy (LCoE) and reduces the consumption of fossil fuel energy from the electrical grid. This can lead to lower desalinated water costs and greenhouse gas emissions. A feasible rated power range was identified for the photovoltaic plant in this case study, taking the internal rate of return, net present value, payback and LCoE into consideration. The results also point to a higher LCoE when a lithium-ion BESS is used. [ABSTRACT FROM AUTHOR]

The term availability can be defined as the probability of a system or piece of equipment, when used under the specified conditions, operates satisfactorily at any given time. The availability of the equipment installed in a seawater reverse osmosis (SWRO) facility is extremely important to the price, quality, and quantity of the final product--water. There are three critical components in the SWRO processes; the main high-pressure feed pumps, the reverse osmosis (RO) membranes, and the energy recovery device (ERD) system. The role that ERDs play is undeniably critical to the success or failure of an RO facility's ability to produce and deliver water economically. The largest operating expense for an SWRO facility is the power consumed, which accounts for approximately 30% of the total RO operating expense. Typically for large facilities (>50,000m³/d), the ERDs responsible for reducing energy consumption are only 1-2% of the entire initial capital cost-a small fraction-but one that can offer a substantial return on investment through energy savings. Selecting the proper ERD system can save millions of dollars over the life of a plant and provide owners and operators with a secure and reliable means of water production. This paper will focus on the economic benefits and importance of the availability of ERDs in SWRO desalination plants. [ABSTRACT FROM AUTHOR]

In this paper, the results of the complete life-cycle assessment (LCA) analysis of the water cycle in two Spanish urban areas are presented. First case study was Zaragoza city (700,000 inhabitants), with enough surface water resources for drinking purpose. Second case was the Mancomunidad del Sureste, a highly populated and touristic area in a water-scarce island (Gran Canaria). Main objective of the paper was to show, from an environmental global perspective, which was the relative pollutant weights of the diverse water cycle stages in an urban area, in order to put the efforts in reducing the environmental penalties associated to the water cycle. Results showed that environmental load associated to energy consumed in dwelling uses (to produce hot sanitary water) exceeded by far the environmental impact provoked by water cycle infrastructures (water treatment plants, water supply and drainage networks, and wastewater treatment plants). Additionally, it is very important to remark that new water supply alternatives (seawater desalination plant as well as reclaimed wastewater) studied here were energy intensive solutions, and the environmental charge during its life cycle was also very significant. [ABSTRACT FROM AUTHOR]

The Water Development Department of Cyprus has awarded to a consortium of two companies: Netcom (Cyprus) and Mekorot Development Enterprise Ltd (Israel), a BOT project for the design, build operate and maintain of a 40,000m³/d SWRO plant. The plant will have the intake and water product delivery infrastructure already in place so as to be able to increase production to 60,000m³/d within a short notice from the client. The consortium, namely MN Limassol Water Co, has some tough criteria to meet such as product water: (a) TDS less than 600 ppm, (b) Boron less than 05 ppm, (c) Turbidity less than 1NTU, and (d) Alkalinity not less than 30 ppm HCO3 as well as the tender stipulated high energy costs of 10 €/kWh. The tender specifications, high energy cost as well as the increased costs of materials and supplies due to the developed world crisis took place due to signing the contract back in 2009; and the current plant construction and operation phase has shaped the design of the plant with innovative and unique features. Furthermore, the Limassol desalination plant will be the largest SWRO--ultra filtration and reverse osmosis (RO) plant in Europe meeting the challenges of EU Desalination and Environmental standards. The above are described in this paper. The paper further describes a comprehensive model developed by Mekorot, optimizing the energy required for the first RO pass in relation to downstream second RO pass and ion exchange processes for different types/suppliers of first pass membranes. The model was tested for the whole expected operating range of seawater temperatures as well as seasonal variations. The scenarios investigated using the comprehensive model has resulted in choosing the optimum RO first pass membrane giving the lower total water cost of the produced water. [ABSTRACT FROM AUTHOR]

Population growth, climate change and urbanization are the main challenges to meet the water demand for the next decades. The global gap between sustainable water supply and water demand is expected to grow above 2,700 km³ by 2030, equivalent to 40% of total water demand. Desalination is an established method to make fresh water--mostly as a last resort. Its contribution to water supply is minor on a global scale. In some regions, though, it is difficult to imagine a sufficient water supply without desalination. But is this technical fix sustainable? In its main part, this paper sheds light on the major issues that call the sustainability of desalination into question. Examination of a number of criteria indicates that the energy demand for desalination is by far the most important issue. Further relevant impacts are wastewater discharges, waste disposal and visual impact. In retrospect, it is noted that energy demand has already shaped today's desalination market, since energy-efficient membrane-based desalination technology has gained market share compared with the more energy-intensive thermal desalination technologies. This development has been supported by a substantial decrease in the specific energy demand of seawater reverse osmosis (SWRO) plants. As a result, state-of-the-art SWRO plants require approximately 3-5 kWh/m ³ compared to some 10 kWh/m³ or more two or three decades ago. But almost all desalination plants are powered by fossil energy resources. Hence, using renewable energy (RE) resources instead would be a big step forward towards sustainability. Case studies prepared for three projects in the MENA region demonstrate that selecting RE sources for a desalination plant is economically feasible when compared to non-subsidized fossil fuel. This paper is based on our viewpoint as engineering consultants. It is a summary of studies, reports and surveys conducted on this issue by us in past years. It is intended to give an idea of the options that are available today to make seawater desalination sustainable. [ABSTRACT FROM AUTHOR]

Desalination has simply been too expensive for major application in Australia and the world, but rising costs of developing our remaining water resources (partly due to climate change), coupled with a growing demand for water supplies of varying quality for domestic, mining and industrial purposes, are making us look more closely at the rapidly developing desalination technologies. Water agencies in Australia have increasingly become involved in desalination initiatives. This has led to a greater understanding of desalination technologies, specifically seawater reverse osmosis (SWRO) and brackish water reverse osmosis (BWRO) and their consequent use as water supply options for industrial, mining and municipal purposes. A comparison of the basic features of the Australian market, the rapid adoption of the technology, the costs, the technology variations and its expected future to the rest of the world markets will be undertaken. Arguments in relation to the sustainability of Australia's SWRO plants and SWRO in general are presented. The paper will argue why SWRO is one of the most sustainable water sources in Australia and the world, replacing conventional sources for future development. This paper will touch on financing, contracting, design, operational and environmental characteristics related to SWRO and demonstrate why Australia's projects are leading the world in terms of sustainable desalination. Australia's six major seawater desalination plants, "The Big Six" will be discussed. New technologies and other forms of desalination and their applications, such as the growth of BWRO desalination in the coal seam gas extraction industry and SWRO in mining will be mentioned. Future developments in desalination will be discussed. The general status of world desalination will be presented. [ABSTRACT FROM AUTHOR]

The high pressure hydraulic energy management integration (HP-HEMI) energy recovery device (ERD) centralizes brine hydraulic energy recovery, feed pressure and low control and brine pressure and low control into one compact and fully integrated unit. The objective is to dispense with feed pressure control valves (i.e. elimination of throttling losses) as well as a variable frequency drive (VFD) on the high pressure feed pump (HPP) resulting in the twin benefits of a substantial reduction in energy consumption and capital costs. This paper reports on test results of a production HP-HEMI coping with recoveries and pressures that accurately simulate an SWRO system dealing with typical feed temperature and membrane fouling variations. The paper further reports on development of a PLC control scheme that regulates feed low and brine low via adjustment of the HP-HEMI control features to meet a wide variety of membrane operating conditions. The paper also outlines future research concerning mitigation of equipment failure and further enhancements of system control. [ABSTRACT FROM AUTHOR]

In order to reduce the energy consumption of seawater desalination, this paper proposes an operation test method of seawater desalination device based on information fusion. Based on the theoretical analysis and calculation of energy consumption of seawater desalination system, the influences of feed water salinity, recovery rate, energy recovery device, high-pressure water pump and other factors on energy consumption and water quality of seawater desalination system are analyzed. An energy-saving integrated desalination process with differential pressure exchange energy recovery device is proposed, and a differential pressure exchange energy source matching with a small desalination system is independently developed. The results show that the produced water quality of the desalination device basically meets the design requirements, and the energy consumption of the motor and pump is only 2.0 kWh/m3 without considering the loss of the motor and pump, which can greatly reduce the water production energy consumption of the system, and has a certain application value. [ABSTRACT FROM AUTHOR]

A continuous electrodialysis metathesis (EDM) process for converting Na2SO4 to high-value K2SO4 fertilizer was proposed and investigated in this paper. After 6 h, a stable production could be obtained. The concentration of K2SO4 output could be as high as 0.683 mol/L, with a purity of 93.4%–96.5%. The specific energy consumption was 166–300 kWh/ton K2SO4, and the current efficiency was 74.7%–84.5%. Meanwhile, the concentration of by-product NaCl could also reach 2.226 mol/L. The results showed that the effects of stack voltage, feed flowrate, feed concentration, and temperature were similar to those occurring in the normal electrodialysis process. There was a restriction relation between the ions from the two desalination compartments, due to the Donnan equilibrium and electrostatic effect. Therefore, a mole ratio of 1:2 between Na2SO4 and KCl in feed solutions would be of benefit for the synthesis process. An EDM process combined with reverse osmosis and vapor mechanical recompression was proposed and evaluated. The result of the economic evaluation showed that gross profit by converting the Na2SO4 wastewater to K2SO4 is nearly 475.13 CNY/ton. [ABSTRACT FROM AUTHOR]

The R version of the Kedem–Katchalsky–Peusner (KKP) network equations belongs to the group of basic research tools for membrane transport. These equations contain the Peusner resistance coefficients (Rij, Rdet) used to assess the transport properties of membranes. The aim of the paper was the frictional interpretation of these coefficients for binary solutions of non-electrolytes on the basis of the Spiegler model. The subject of the study was the transport properties of synthetic polymer membranes made of regenerated cellulose and used in hemodialysis (Nephrophan, Ultra-Flo 145 Dialyzer) for aqueous glucose solutions. The research method was the R version of the KKP network equations and the Kedem–Katchalsky–Spiegler equation for binary solutions of non-electrolytes. The method of frictional interpretation of the Peusner resistance, coupling, Kedem–Caplan–Peusner energy conversion efficiency and dissipated and free energy fluxes using the Spiegler friction coefficients (fij) was presented. The presented procedure for evaluation transport properties of membranes can be helpful in explaining the mechanisms of membrane transport and conducting energy analyzes of membrane processes. Therefore, this procedure can be used for the selection of a suitable membrane for practical, (e.g., industrial, water and wastewater technology and/or medical) applications. [ABSTRACT FROM AUTHOR]

This paper presents a performance evaluation and economic analysis of a reverse osmosis (RO) and pressure retarded osmosis (PRO) hybrid process to propose guidelines for its economic competitiveness use in the field. A model to predict the performance of a hybrid process using RO and PRO was developed based on a solution-diffusion model modified with film theory. The effects of external and internal concentration polarization (ICP) on PRO efficiency were considered in the model. Moreover, a simple cost model was applied to analyze the effects of seawater TDS and feedwater for the PRO process, water and salt permeability of PRO membrane, and membrane and energy cost on the RO-PRO hybrid process. The results show that the water transport coefficient, ICP, and seawater and feedwater TDS are important factors affecting the performance of the PRO process. On the other hand, the effect of the salt transport coefficient is not substantial. The RO-PRO hybrid process can be economically competitive with the RO process when electricity is expensive, the PRO membrane cost is cheap, and the power density and PRO recovery process are high. [ABSTRACT FROM PUBLISHER]

The desalination process parameters like current efficiency (CE), energy consumption, and acid–base production for the fabricated bipolar membrane (BPM) electrodialysis unit (five compartments of 120 cm2active areas) were investigated in this paper using monopolar- and bipolar-based ion-exchange membranes (IEMs). Also, the performance of the fabricated unit in removing NaCl was assessed in terms of salinity. Polystyrene–ethylene–butylene–polystyrene was functionalized to prepare the monopolar and bipolar IEMs. In the case of BPM, platinum was used as the intermediate layer. The synthesized IEMs were characterized thermally and by contact angle measurements. A commercially procured monopolar and bipolar ion-exchange membrane made of polystyrene–divinylbenzene was also evaluated for the purpose of comparison. The electrodialysis process using these IEMs reached the highest CE of 66 and 38% with the lowest energy consumption of 0.24 Wh and 1.60 Wh for the synthesized and commercial membrane, respectively. [ABSTRACT FROM AUTHOR]

This paper has the purpose of evaluating the environmental impact of the consumption of bottled water rather than tap water in the city of Porto Alegre (Brazil) using carbon emission and embodied energy calculations for both possibilities. The calculations took into account the bottled water production, transport, and waste generation. In addition, the quality of tap water was tested in key restaurants to evaluate whether the tap water of the city was drinkable (potable). Six key restaurants were interviewed throughout the city to collect data regarding the water bottle consumption, and to obtain water samples. The results revealed that bottled water is less environmentally friendly since it uses more energy inputs than tap water (respectively, equal to 4,640 and 1.66 MJ/m3). Results also shown 100% (6 out of 6) of the tested waters were drinkable (potable). The key conclusions are that energy and carbon footprints are important tools to determine sustainability issues, and can be applied by researchers and policy-makers to evaluate environmental aspects of water consumption. [ABSTRACT FROM AUTHOR]

This paper presents a study for energy requirements of lab-scale membrane distillation (MD) unit. This lab unit consists of flat-sheet membrane module with two circulation pumps, heater, and cooler to study the effect of different operating conditions on both specific energy consumption (SEC) and energy efficiency (ηE) via vacuum enhanced direct contact MD method. The flux and the two parameters of energy (SEC,ηE) were measured using different temperatures, different feed flow rates, and different feed salt concentrations. The two membranes used were neat polypropylene (PP) membrane and PP/multi-walled carbon nanotubes (MWCNTs) composite membrane. The membranes were synthesized via phase inversion process, using xylene as a solvent, methyl iso-butyl ketone as a coagulant and dispersion medium for MWCNTs. The results showed that the highestηEwas 39.5 with SEC 1,649.2 kW h/m3at flux 52.5 kg/m2 h using 15 L/min feed flow rate of synthetic feed water with salt concentration 10,000 ppm at 55°C feed temperature. On the other hand, using our prepared membrane for the desalination of oil field water, the values ofηEand SEC were 12.1 and 4,189.5 kW h/m3, respectively. [ABSTRACT FROM AUTHOR]

In the present paper, 24factorial design method was employed for optimization of two responses: residual fluoride and specific energy consumed. The study was based on interaction effect of four factors namely, current, initial fluoride concentration, time, and inter-electrode distance. A regression model equation was developed which was validated by highR2values of 98.78 and 99.80% for residual fluoride and specific energy consumed, respectively. Optimization was targeted for residual fluoride concentration less than 1 mg/l and minimum specific energy consumption. The optimized conditions as suggested by the model for initial fluoride concentration 6 mg/l were: applied current—0.27 A, inter-electrode distance—20 mm, treatment time—46.70 min, specific energy—5.85 J/mg, and residual fluoride—0.77 mg/l. These results were used for experimental verification, which was in good agreement with the predicted results. [ABSTRACT FROM PUBLISHER]

Our earth is a water planet; nearly two thirds of the earth’s surface is covered by ocean water. But the shortage of fresh water is a major problem in many areas, especially in rural villages near to the sea or islands. Now, renewable energy-based desalination system is rising around the world due to the adverse environmental effect and high-energy requirements of the conventional fuel-based desalination system. This paper describes the prospect of an off-grid stand-alone wave-powered reverse osmosis desalination system for those areas. A simulation model for the prediction of the wave power delivered for a given value of the wave height and period is adopted. Based on the availability of the wave data, the amount of the water produced at different sites of Malaysia can be calculated in this paper. In addition, this paper deals with an economical analysis of wave energy production for reverse osmosis desalination system. [ABSTRACT FROM PUBLISHER]

A fundamental part of oxy-combustion zero-emission power plants is the ambient air separation unit. Amongst the various technologies utilized to perform this process, membrane gas separation might be applied as well. This paper is a continuation of previous research on operation of polyimide membranes in such power units. The presented results of computational analysis are based on experimental research, regarding the energy-related parameters of the nitrogen/oxygen separation from ambient air using commercial capillary polymer membranes. Empirical, continuous functions describe the variability of the essential parameters for membrane separation modules of variable configuration and are used as a fundamental part of the model, used within the presented research. Energy consumption and efficiency of the air separation unit are investigated as the most influencing of these parameters. Analyses are performed for three variants of unit configuration: serial connection of membrane modules, unit with retentate recirculation and unit with permeate recirculation. The results of the research indicate the essential differences in total energy consumption for the subsequent configurations. Both the highest energy demand of the air separation module, equal to 1.61 kJ/m3 O2, and the lowest, equal 0.02 to kJ/m3 O2, were obtained for the retentate recirculation (for the 800 and 1,500 L/h stream flows, respectively). Satisfactory operational parameters of the separation process were indicated for both the permeate recirculation and serial modules connection variants, with an acceptable rise in power demand, corresponding to a maximum value of 205 W and 88 W, respectively. [ABSTRACT FROM AUTHOR]

Membrane capacitive deionization (MCDI) is a promising new technology for brackish water treatment. Although many authors show the advantages of MCDI by comparing its energy consumption with pressure driven-methods, such as reverse osmosis or nanofiltration, membrane capacitive deionization should rather be compared to electrodialysis (ED), widely considered the most economical desalination technology for low salinity brackish water treatment. In this paper, MCDI is compared with ED by desalting model sodium chloride solutions (0.7-1.0 g/dm3). The results show higher energy consumption of MCDI than of ED when generating 0.5 g/dm3 product: 0.428-0.499 kWh/m3 for MCDI and 0.034-0.230 kWh/m3 for ED, depending on the feed concentration and used membrane. [ABSTRACT FROM AUTHOR]

In this study, antipyrine was selected as the typical pharmaceutical and personal care products (PPCPs) and the abatement of antipyrine was investigated by the catalytic ozonation with a magnetic Fe3 O4 @SiO2 @CeO2 catalyst. Focusing on the kinetics of the antipyrine degradation at different initial concentrations of antipyrine, the ozone dosages, initial pH values, the antipyrine degradation mechanism, and catalytic mechanism was explored. The results showed that the core/shell Fe3 O4 @SiO2 @ CeO2 catalyst exhibited high activity in the degradation of antipyrine. Types of intermediates, such as anisole, nitrobenzene, n-phenylpropinamide, and aniline were detected by gas chromatography– mass spectrometry and high performance liquid chromatography techniques during the catalytic ozonation process. The presence of the radical scavenger tert-butyl alcohol during catalytic ozonation promoted the degradation of antipyrine unexpectedly instead of inhibiting the generation of hydroxyl radicals from ozone decomposition. The results implied that the high removal efficiency was mainly attributed to the interfacial effect of Fe3 O4 @SiO2 @CeO2 catalyst. The energy consumption was also analyzed and discussed. This paper could provide basic data and technique reference of catalytic ozonation for the PPCPs wastewater treatment. [ABSTRACT FROM AUTHOR]

Sea water reverse osmosis (SWRO) desalination constitutes a successful technology for covering local fresh water supply shortage in many areas of the world and especially in isolated areas such as islands and coastal regions. SWRO units can be combined with renewable energy (RE) technologies such as photovoltaic and wind generators. Small-scale SWRO units combined with energy recovery devices can decrease drastically the energy consumption of the SWRO units. Furthermore, it is proven that the operation of a desalination unit in part-load conditions can result in lower specific energy consumption compared to continuous full-load operation. This paper presents an experimental comparison between two small-scale SWRO units equipped with different energy recovery devices in order to lower the specific energy consumption. The first SWRO unit consists of a hydraulic energy recovery device of the Clark pump type which plays also the role of the high-pressure pump in a conventional reverse osmosis unit. The second SWRO unit is equipped with two types of Danfoss pumps (a rotary piston pump and a motor pump), based on the axial piston principle. The main objective of the comparison is the identification of the energy recovery device with the lowest specific energy consumption of the SWRO unit. Both units are installed at the Laboratory of Agricultural Engineering of Agricultural University of Athens and they are tested under full- and part-load conditions. The experimental operation of the SWRO units in part-load conditions is achieved by varying the speed of the motor pump assembly, the pressure and the flow rate of the feed water. During the evaluation of the measurements results, an optimum operating window was drawn regarding the operation of the SWRO desalination units in part- and full-load conditions. More specifically, the minimum measured specific energy consumption of the Clark SWRO unit was found to be 5.7 kWh/m3at a pressure of 44 bar while the Danfoss SWRO unit showed a minimum specific energy consumption of 4 kWh/m3at a pressure of 59 bar. With these results, a SWRO unit equipped with an energy recovery device operating under full- and part-load conditions is suitable for future direct connection with RE systems such as photovoltaic and wind turbines. [ABSTRACT FROM AUTHOR]

The thermal desalination systems like multi-effect distillation and multi-stage flush have gone through a strong development process to increase energy efficiency and to improve energy recovery. While these improvements have led to lowered energy consumption, different concepts could be necessary to adapt the thermal desalination systems to renewable energy sources. A specially designed low-temperature desalination driven by low-grade waste heat can be used to desalinate seawater and to clean polluted water with a higher conversion ratio than existing systems. The reason for this improvement is a drastically improved heat transfer of this system, using spray systems for evaporation, and condensation. It was tested in a demonstration plant in El Gouna, Egypt, in cogeneration with diesel generators which used 7 MWthto desalinate 500 m³/d. This paper introduces a model of the low-temperature desalination process, which is derived from experimental data and technical specifications. It required the development of energy, mass, and material balances of the media streams with respect to the measured data from the demonstration plant. The model is implemented using the energy process simulation software “Ebsilon Professional” and combined with a 10-MWthconcentrating solar power (CSP) plant. The results show the cogeneration of 2.2 MWelpower in the CSP plant and 520 m³/d fresh water in the desalination. Furthermore, the output depends on various process parameters like cogeneration fraction, temperature levels, and input salinity, which are analyzed and discussed. [ABSTRACT FROM AUTHOR]

The desalination market based on reverse osmosis is a growing market thanks to much lower energy consumption compared to thermal desalination. This leading position implies that a lot of efforts should be done to improve both its acceptability and cost to thwart its detractors. For those reasons, the further improvement of the energy consumption is a key factor and one of the main objectives of the desalination community. It is well known that temperature has an impact on membranes’ feed pressure. For equivalent feed water quality and operational conditions, high temperature water will require less pressure to produce the same amount of permeate. Based on this reality, some projects are considering the opportunity to recover cooling waters from cooling towers or MSF/MED cooling system as seawater feed to RO plants to reduce electrical consumption, in particular on hybrid, IWPP, or co-location projects. But temperature has also an adverse effect on the permeate water quality that could result in increasing the 2nd Pass flow requirement or the use of tighter membranes. The present paper analyses the impact on electrical consumption and design of the complete RO plant using a heated seawater source. Through case studies based on typical middle east seawaters, 41 g/l and 45 g/l and two different permeate water quality targets, 200 mg/l and 500 mg/l TDS, it attempts to conclude if overall benefits can be identified in such conditions. [ABSTRACT FROM AUTHOR]

The Palmachim Seawater desalination plant supplies to the Israeli water net potable water in accordance with all contractual requirements of water quality and quantity. The plant was commissioned in 2007 and produced up to 110,000 m3d−1(30 million m3/year). During 2009–2010, the plant production capacity was expanded up to 150,000 m3 d−1(45 million m3/year). Recently, the plant production capacity was further increased, doubling production rate up to 300,000 m3 d−1(90 million m3/year). This paper provides a general overview of the work undertaken along the years to accomplish the final assembly of the plant. The main plant characteristics are described, notably the small footprint, high operational flexibility, low energy consumption, and low chemicals usage. In addition to the physical constructions, the recent expansion incorporated several significant process modifications, aiming to improve the efficiency of the plant. A description of the characteristics of two main modifications is displayed: the use of new generation seawater reverse osmosis membranes in the desalination trains that enabled a reduction in energy cost and changes in the post-treatment hardening that led to a significant reduction in the chemicals consumption. [ABSTRACT FROM PUBLISHER]

A wide range of technologies are commercially available for water purification. However, not all of these technologies are suitable for use in rural, underdeveloped regions. Here, I present a systematic method for selecting the most appropriate technology for a particular community, using rural Ghana as a case study. In Ghana, over half of the population lives in rural areas, and two-thirds of these residents lack access to safe drinking water. Ghana has made significant strides using innovative water treatment techniques; however, there are still many hurdles. Simple and inexpensive, on-site water filtration technologies are a promising method for removing protozoans and other micro-organisms that pose significant health risks in underdeveloped, rural areas. In this review, several of these commercially available on-site water filtration technologies are assessed based on the following factors: effectiveness, cost, energy consumption, environmental impacts, and waste generated. This analysis suggests that for rural communities in Ghana, LifeStraw®and ceramic clay pots are the most appropriate technologies. Implementation of these technologies poses potential benefits in terms of cost effectiveness and economic growth. Although this paper focuses on northern Ghana as a case study, the methodology presented here can be readily extended to specific scenarios in other developing countries. [ABSTRACT FROM PUBLISHER]