SWRO Desalination Plant Research Articles

Design of SWRO Desalination Plant for Nuclear Research Center

Libya has an infinite water resource available inthe coastal towns and cities being located on Mediterranean Sea with 1950km coast. Therefore, the need for desalinatedwater for Nuclear Research Center NRC located in Tajurais currently about 1200 m3/day. To cover the center presentand future water needs for research and developmentactivities, two thermal sea water desalination plants have been assembled in the site. One of the plants uses MultiStage Flash technology and the other one uses Multi EffectDesalination technology with capacity of 1200m/day eachone. Detailed design for 1200m3/day seawater reverseosmosis SWRO unit is carried out using ROSA S oftware to make the technical comparison with other MSF and MEDunits. The unit labeled an S W30XLE-440i by the results ofthe Software is selected since it required the lower feedpressure of 55.5bar and highest salt recovery of 45% with total dissolved solid of 190ppm. From the technical point ofview, the study showed that SWRO required lower seawater inlet flow rate than MSF and MED. The unitsefficiency are 43%, 10.5% and 25% for SWRO, MSF, andMED, respectively. Further the Product quality TDS 190ppm for RO unit is suitable for drinking water, whilethose of MSF and MED 50ppm. Energy consumption asheating steam is not required for the S WRO unit; however,a steam flow rate 7.3m 3/hr is required by MSF and MEDunits. These make SWRO unit friendlier to the environment and most proper technically under these situations.

Comparative analysis of centralized and decentralized control systems for NUWIEBAA SWRO desalination plant

This paper discusses the differences between centralized and decentralized planning and control systems in the context of desalination water treatment plants. The parameters considered include area, capacity, arrangement, lifetime, initial cost, operation and maintenance, and troubleshooting. It is noted that decentralized control systems may not be the best option from an economic perspective, but have the advantage of lower running costs. The hardware and software for decentralized systems are also more expensive than centralized systems, however, the operation and maintenance costs for decentralized systems are lower by 75% due to reduced staffing. These models have been applied in reverse osmosis desalination plants to find better solutions for operation and maintenance.

Energy Efficiency Optimization in Onboard SWRO Desalination Plants Based on a Genetic Neuro-Fuzzy System

This work presents a novel intelligent control system based on a Genetic Neuro-Fuzzy tool to optimize and improve the performance of a seawater reverse osmosis desalination plant (SWRO) on board a marine vessel. This investigation pays special attention to minimizing energy consumption to improve the energy efficiency of this marine installation. The system analyzes measurements of different variables—seawater pH, seawater conductivity, permeate flow rate, permeate conductivity, and total energy consumed—in order to provide the most appropriate value of permeate flow rate control and operating pressure of the high-pressure pump (HPP). This intelligent method allows the plant to achieve output values nearer to the desired setpoints set by the plant operators.

SWRO concentrates for more efficient wastewater reclamation

Developing technical alternatives to increase the volume of remediated waters is a promising way to alleviate pressure on natural water basins. However, the extra energy consumed in Wastewater Treatment Plants (WWTPs), mainly powered by fossil fuels, hampers this strategy. This work focuses on promoting efficient upgrading alternatives of treated waters by recovering energy within the treatment process. The approach consists on the recovery and integration of Salinity Gradient Energy (SGE) generated from the contact between SWRO brines and reclaimed wastewaters in reverse electrodialysis modules. The analysis of opportunity of implementing integrated processes in Spanish WWTPs near SWRO desalination plants is tackled. 16 SWRO-WWTP pairs have been inventoried, 10 of them located in Jucar and Segura river basins, hot spot areas for water reclamation. A gross power density of 0.46 W/m2 (71 Wh/m3 reclaimed water) of SGE has been generated in the contact between SWRO brines and reclaimed wastewater, increased up to 0.23 kWh/m3 in the most favourable scenario. Estimates of freshwater withdrawals savings up to 434,387 m3/day within the selected installations are obtained. Decrease in water abstraction and integration of renewable source of energy in the remediation process will contribute to water sources protection and water industry decarbonisation.

Life cycle assessment of salinity gradient energy recovery by reverse electrodialysis in a seawater reverse osmosis desalination plant

LCA of lab-scale and large-scale stand-alone RED stacks and an up-scaled RED system co-located with a SWRO desalination plant.

The resea rch and application progress of the isobaric ERD technique for SWRO desalination plant

The resea rch and application progress of the isobaric ERD technique for SWRO desalination plant

Process modeling and simulation of an SWRO desalination plant: case study of Gijang SWRO desalination plant in Korea

Process modeling and simulation of an SWRO desalination plant: case study of Gijang SWRO desalination plant in Korea

Coupling pressurised water reactor to large scale SWRO desalination plants: an economic assessment

Coupling pressurised water reactor to large scale SWRO desalination plants: an economic assessment

Coupling pressurised water reactor to large scale SWRO desalination plants: an economic assessment

Water management via rational use, reuse practices and water desalination is the key element for mitigation of water shortage. This paper addresses small-scale nuclear systems as a cost-effective energy alternative for large-scale desalination plants. An empirical cost model has been derived and validated based on reported cost indicators and selected cases. The capital cost of 150,000 m³/d seawater desalination plant coupled to small nuclear reactors has been estimated to be between 3 and 11 M$/MWe, respectively. In addition, specific cost of nuclear desalination-steam cycle system SWRO (conventional pre-treatment), ranges between 0.046-0.064 $/kWh and 0.62-0.667 $/m³ for energy and water, respectively. Cost indicators of different desalination systems show that product water cost ranges between 0.62 and 0.779 $/m³ when applying nuclear power as an energy source for RO, RO/MED, MED while when applying oil/gas as an energy source the product water cost ranges between 1.12 and 1.89 $/m³.

Energy-efficient hybrid FCDI-NF desalination process with tunable salt rejection and high water recovery

Seawater and brackish water constitute ~ 97% of the water on Earth. Therefore, future water shortages could be alleviated if we develop more efficient and cost-effective desalination technologies. Reverse osmosis (RO) has been established as the best available technology for commercial seawater (SW) desalination during the last two decades. Because the standard SWRO membrane element is designed to achieve a very high salt (NaCl) rejection (> 99%) with a low water recovery (~ 15%), current SWRO desalination plant design is based on the staging of arrays of RO membrane elements to achieve an overall water recovery of ~ 50% with an energy consumption of 3–4kWhperm3 of water treated. Moreover, SWRO desalination plants generate substantial amounts of brines that must be disposed of. In addition, SWRO desalination plants require post-treatment including remineralization. Here, we report an energy-efficient hybrid desalination process for high salinity brackish water. This new desalination process couples flow capacitive deionization (FCDI) with nanofiltration (NF). Our experiments and energy calculations using a 10000ppm NaCl solution as model brackish water show that the energy consumption of the new FCDI-NF unit (0.460kWh_totalm−3) is lower by 16–20% than the best reported energy consumption (0.571kWhm−3) and the 1-stage practical minimum energy consumption (0.550kWhm−3) of a brackish water reverse osmosis (BWRO) unit treating the same feed at 70% water recovery, while final total dissolved solids (TDS) are in the drinking water range.

Success behind advanced SWRO desalination plant

With ongoing water stress worldwide, finding long-term solutions to severe drought is imperative. This article looks at the commissioning and development of the Sorek Desalination Plant in Israel, the world's largest and most advanced SWRO desalination plant – and how a project of this size is tackled.

CCD series no-22: Recent advances in RO, FO and PRO and their hybrid applications for high recovery desalination of treated sewage effluents

The performance of the osmotic-pressure RO, FO and PRO processes is analyzed on the basis of a uniformed model with water flux derived from the modified conventional expression Jw=β∗A∗(Δπ−Δp) where β (<1.0) stands for the FO actual/ideal flux ratio of a given membrane in a defined salinity gradient and also applies to PRO; whereas β=1.0 applies to RO membranes. The β parameter takes account of the detrimental effects on flux in FO and PRO membranes and becomes unity for RO membranes. The uniformed model is explored to evaluate the various aspects of RO, FO and PRO and some of their FO–RO and PRO–RO hybrids, with emphasis on advanced closed circuit desalination RO (CCD) and PRO (CC-PRO) techniques and widespread feed sources such as treated sewage effluent (TSE) and seawater (SW) or seawater brine (SWB) from SWRO desalination plants. The results of this comparative study reveal that the desalination of SW and TSE with CCD proceeds with low energy of near absolute energy conversion efficiency at the ultimate state-of-the-art, unattainable by the conventional techniques practiced today. With regard to FO and PRO, this comparative study reveals that the effectiveness of both processes depends on the actual/ideal flux ratio (β) which manifests membranes' detrimental effects. Moreover, this study also shows that PRO power generation is also a function of the permeation/draw flow ratio (δ) apart from β and the salinity gradient and that operating at high δ (e.g., 40) of high power density (PD) yields low net electric power density (NEPD) which takes into account the power consumption of the auxiliary components in the PRO system. The distinction between PD and NEPD considered in the context of the SW–SE and SWB–TSE salinity gradients suggests that such applications are unlikely to become economically effective for energy generation and the same conclusion is also true for the application of the FO–RO and PRO–RO hybrids for the desalination of TSE which proceeds most effectively by direct CCD with exceptionally high recovery and low energy.

CCD series no-19: The lowest energy prospects for SWRO through single-element modules under plug-flow and closed-circuit desalination conditions

The future targets of the SWRO desalination industry to reduce significantly energy consumption are realized already today by the newly emerging closed-circuit desalination (CCD) technology with demonstrated energy consumption of 2.12 kWh/m3 for Mediterranean water (4.0%) and 1.72 kWh/m3 for ocean (3.5%) water without the need for energy recovery with energy saving greater than 35%. The fundamental differences between CCD and the conventional plug flow desalination (PFD) techniques are evaluated in the present study by rigorous theoretical model simulations of CCD compared with multi-stage PFD of the same single-element modules under the same conditions in the flux range of 13.0–0.1 lmh. The results of this study reveal that CCD under fixed flow and variable pressure conditions behaves as near-perfect multi-stage PFD with energy dependence on recovery also manifesting increased frequency of CCD cycles and residence time. The origin of energy savings by CCD and multi-stage PFD compared with conventional single-pass through multi-element module is revealed and explained. While multi-stage SWRO designs are economically prohibited by high fabrication costs, CCD designs are simple and inexpensive and should play a major role in future design of SWRO desalination plants of low energy consumption and high energy conversion efficiency without the need of ERD.

Cost assessment in SWRO desalination plants with a production of 600 m3/d in Canary Islands

Water resources available in the island of Fuerteventura come mostly from small-scale capacity seawater desalination plants. Desalted water demand in the island has grown considerably in the last decade forcing managers to adapt desalinated water supply constantly. Additionally, the operating cost of the plants is relevant. The staff, chemical consumption, cartridge filter, and membrane replacement cost are essential in order to establish more efficient operation conditions of a reverse osmosis desalination plant. This article aims to study and compare the mentioned cost of six different seawater reverse osmosis desalination plants with the same production of 600 m3/d in the island of Fuerteventura. The results show for each of the six cases how costs can be reduced and the essential role of automation dealing with the staff cost with the particular capacity of 600 m3/d.

Performance of hydraulic turbocharger integrated with hydraulic energy management in SWRO desalination plants

Hydraulic turbocharger is a common energy recovery device used in reverse osmosis water desalination plants to recover the stored energy in brine. Also, it can be used to control the pressure variation due to the change of plant operating conditions. The aim of the current work is to apply the computational fluid dynamics (CFD) to investigate the balance between the hydraulic turbocharger turbine and pump sections. The effect of changing the rotor speed and the effect of auxiliary line size and valve opening on the performance of the hydraulic turbocharger are also investigated. In addition, the effect of these changes on the plant specific energy consumption (SEC) is discussed. The results of the current work present the variation of the hydraulic turbocharger performance with the rotor speed. It also shows that increasing the turbine auxiliary line diameter reduces the turbine inlet pressure. The CFD results show that opening the auxiliary line reduces the turbine inlet pressure which reduces the rotor speed and the pump boosting pressure.

Subsurface intake systems: Green choice for improving feed water quality at SWRO desalination plants, Jeddah, Saudi Arabia

An investigation of three seawater reverse osmosis facilities located along the shoreline of the Red Sea of Saudi Arabia that use well intake systems showed that the pumping-induced flow of raw seawater through a coastal aquifer significantly improves feed water quality. A comparison between the surface seawater and the discharge from the wells shows that turbidity, algae, bacteria, total organic carbon, most fractions of natural organic matter (NOM), and particulate and colloidal transparent exopolymer particles (TEP) have significant reductions in concentration. Nearly all of the algae, up to 99% of the bacteria, between 84 and 100% of the biopolymer fraction of NOM, and a high percentage of the TEP were removed during transport. The data suggest that the flowpath length and hydraulic retention time in the aquifer play the most important roles in removal of the organic matter. Since the collective concentrations of bacteria, biopolymers, and TEP in the intake seawater play important roles in the biofouling of SWRO membranes, the observed reductions suggest that the desalination facilities that use well intakes systems will have a potentially lower fouling rate compared to open-ocean intake systems. Furthermore, well intake system intakes also reduce the need for chemical usage during complex pretreatment systems required for operation of SWRO facilities using open-ocean intakes and reduce environmental impacts.

Comparative economic and environmental assessments of centralised and decentralised seawater desalination options

This study presents comparative life cycle assessments (LCAs) and levelised cost (LC) analyses of desalination supply systems, integrated with a spatial–temporal model at three geographical scales: a centralised scenario and two alternative decentralised scenarios. For the centralised scenario we focused on a proposed 320,000m3/day SWRO desalination plant to support future urban expansion in the northern corridor of Perth, Western Australia. The alternative, decentralised scenarios each integrate several medium sized plants into the same geographical water demand area as the centralised scenario and also produce 320,000m3/day in total. Results indicate that environmental impacts would be ~20% lower and LC 7% to 18% lower for the decentralised scenarios than for the centralised scenario. Contribution analysis revealed that, for the centralised scenario, although economies of scale resulted in lower environmental impacts from the desalination plant construction and operation phases, these savings were outweighed by the environmental impacts associated with the construction and operation of the water transfer mains required to connect the large plant to the network. Perth water stakeholders and policy makers can use our results to inform development decisions, and the proposed LCA method can be implemented in other metropolitan areas for desalination planning.

Does chlorination of seawater reverse osmosis membranes control biofouling?

Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full–scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

Corrosion of stainless steel components in seawater reverse osmosis desalination plants—investigations on adapted internal cathodic protection

Stainless steel is widely used in seawater reverse osmosis units (SWRO) for both good mechanical and corrosion resistance properties. However, many corrosion failures of stainless steel in SWRO desalination units have been reported. These failures may often be attributed to un-adapted stainless steel grade selection and/or to the particular aggressive seawater conditions in “warm” regions (high ambient temperature, severe biofouling, etc.). Cathodic protection (CP) is a well-known efficient system to prevent corrosion of metallic materials in seawater. It is successfully used in the oil and gas industry to protect carbon steel structures exposed in open-sea. However, the specific service conditions of SWRO units may seriously affect the efficiency of such anti-corrosion system (high flow rates, large stainless steel surfaces affected by biofouling, confinement limiting protective cathodic current flow, etc.). Hence, CP in SWRO units should be considered with special care and modeling appears as useful tool to assess an appropriate CP design. However, there is a clear lack of CP data that could be transposed to SWRO service conditions (i.e. stainless steel, effect of biofouling, high flow rate, etc.). From this background a Join Industry Program was initiated including laboratory exposures, field measurements in a full scale SWRO desalination plant, and modeling work using PROCOR software. The present paper reviews the main parameters affecting corrosion of stainless steel alloys in seawater reverse osmosis units. CP on specific stainless steel devices was investigated in order to assess its actual efficiency for SWRO units. Severe environmental conditions were intentionally used to promote corrosion on the tested stainless steel products in order to evaluate the efficiency of CP. The study includes a modeling work aiming at predicting and designing adapted CP protection to modeled stainless steel units. An excellent correlation between modeling work and field measurements was found.

Ocean current and temperature analysis using satellite data for the effective operation of SWRO desalination plant in Gijang-gun, Busan, South Korea

The salt concentration of seawater is a significantly sensitive factor in the seawater reverse osmosis desalination plant that applies different pressures in freshwater production, depending on the salinity of the seawater. For the efficient operation of the plant, it needs to be grounded on investigations and analyses of seawater salt concentration and water temperature distribution and change. The conventional research methods, however, have temporal and spatial limitations. This research uses the latest satellite data to analyze the flows and the seasonal temperature distributions of ocean currents that affect mostly the changes in the seawater salt concentration in the neighboring waters of the seawater desalination plant that is being built in Gijang-gun, Busan, South Korea. The results of this research showed that the ocean current in the neighboring waters of Gijang-gun, Busan had a relatively slow velocity (average: 0.05 m/s) but formed very comprehensive flow shapes as the warm and cold currents met and that the degree of the salinity change was significant because the temperatures of the sea surface differed considerably in summer unlike in the other seasons.