Seawater Desalination Plant Research Articles

Power System Analysis of Seawater Desalination Plant in Algeria with Different Load Scenarios

The cost of electricity for the reverse osmosis desalination process is up to 50% of the cost per cubic meter of water produce. Currently, the reduction of energy consumption is the main objective of the research on reverse osmosis plants. This document presents a power system analysis of the seawater desalination plant in Algeria with different load scenarios with a power of 50 MW made available by the electricity company Sonelgaz and a distribution level of 220/11/0.69/0.4 kV and a 2 MW diesel generator at the 0.4 kV level. The objective of this study is to analyze and dimension a general distribution network of an industrial customer through the power flow with different load and contingency scenarios (full load, full load N-1, low load, emergency system) to know and control its optimal and flexible operation. In a second step, the dimensioning of different protective devices is planned through a short circuit analysis of this network in order to evaluate the performance of the system. The ETAP program is used to carry out our simulation of this industrial plant and the effectiveness of the results is proven by comparisons with real measurements for the power flow analysis on the one hand and on the other hand with the results obtained by the builder for the short circuit analysis.

The Effect of Implementing the Integrated Management System in Desalination Plants in Conflict Zones: Case Study on the Gaza Strip

Water scarcity is a global issue that has extreme effects on conflict zones in particular. Therefore, seawater desalination provided a practical solution to reduce the problem. The Gaza Strip suffers from potable water scarcity due to groundwater contamination and the deterioration of the coastal aquifers. Thereby, the Palestinian Water Authority (PWA) had constructed three seawater desalination plants (SDP’s) in addition to purchasing potable water from the Israeli company (Mekorot). Due to the importance of the SDP’s, a flexible and comprehensive management system is required to ensure the sustainability of the performance. Thereby, this study aims to assess the potentiality of applying the Integrated Management System (IMS) in seawater desalination plants. This study used data collected from reports, questionnaires, and interviews, which is then analysed statistically, in order to identify the effects and barriers of applying the IMS in seawater desalination plants. The data also was used in SWOT analysis to formulate strategies for applying the IMS. The reports showed that the physicochemical water quality of samples from seawater desalination plants is compatible with PWA and WHO standards. The results from the questionnaire showed that there are positive impacts of applying the IMS on the performance of the desalination plants in terms of the financial, administrative, technical, environmental, and socio-economic aspects. However, the study identified 12 barriers which were analysed through SWOT analysis to formulate strategies to facilitate the implementation of the IMS. The highest priority and most applicable strategy is the formation of a partnership with the UN institutions to obtain international protection and facilitate the entry of the required materials.

Effect of unconventional water resources interventions on the management of Gaza coastal aquifer in Palestine

Abstract The non-conventional water resources of seawater desalination, wastewater treatment, and stormwater harvesting are promising water resources to enhance the water supply and to cope with the groundwater depletion of the Gaza coastal aquifer (GCA). In total, the current daily operation of the short-term low-volume (STLV) seawater desalination plants produces 36,000 m3 and, on the large-scale perspective, the seawater desalination capacity is planned to increase from 150,000 to 300,000 m3 per day by the years 2025 and 2035, respectively. The wastewater treatment and reuse activities are processed through three wastewater treatment plants with a total daily capacity of 130,000 m3 which is proposed to be increased to a capacity of 235,000 m3 by the beginning of 2025. Stormwater collecting and harvesting supply the water sector by about 550–820 cubic meters per day. The proposed stochastic and artificial intelligence model that was developed in this study to simulate the interactive conditions between the groundwater and the water intervention plan showed proper performance in terms of (r) = 0.95–0.99 and the root mean square error (RMSE) = 0.09–0.21. The model outputs reveal that the annual groundwater abstractions will reach 192 million cubic meters by 2040 with an annual increasing rate of +3%. By applying the model, the optimum utilization of the unconventional water resources contributes positively to the recovery of the GCA, which is experiencing a decline hot spot in the water level that reaches to −19 m below mean sea level (MSL) and is expected to drop to −28 m MSL by 2040. The impact of unconventional water resources interventions was investigated by simulating the water table trend using stochastic models and artificial neural networks (ANNs) through three scenarios. The first scenario, which addresses the non-intervention status, indicates that the groundwater table will decline by −1.5% in the northern governorates and by −51% in the southern governorates of the Gaza Strip within 2020–2040. The second scenario demonstrates the impact of the existing water interventions that revealed an interim recovery in the groundwater balance until 2025 in which the water consumption tended to increase rapidly. The third scenario illustrates the impact of applying the full water management intervention plan in which the depression cone in the groundwater level will be restored by about +10 m.

The Mitigation of CO2 Emissions in the Sea Water Desalination Plant with Reverse Electrodialysis Power Generation

Climate change is a major issue that is very interesting to discuss. Climate change is believed to be caused by the greenhouse gas effect. CO2 is one of the gases that causes the greenhouse gas effect. Therefore, to avoid the dangers of climate change, reducing CO2 emissions is the main topic in various articles. In this article, CO2 emission mitigation is analyzed in the sea water desalination plant using reverse electrodialysis power generation. Reverse electrodialysis is a power plant that does not produce CO2 emissions which converts energy from the difference in salinity of two solutions into electrical energy through selective ion membrane technology. There are 8 sea water desalination (SWD) unit which produces 242 tons/h of clean water for industrial activity and blowdown water of 3,161 tons/h, the blowdown water is wastewater. The SWD unit requires 3.043 tons/h of seawater as feed water, 0.164 MW of electricity and 86 tons/h of steam worth 64.1 MW as an energy. The energy are met from the combined heat and power operation. Combined heat and power require of fuel oil and fuel gas which produce CO2 emissions of 1,352,445,626 kgCO2/y. From the analysis on the SWD plant, the CO2 emission is 148,411,874 kgCO2/y. By implementing reverse electrodialysis power generation, blowdown water at the SWD plant which has a salinity concentration of 680 mol/m3 can produce electricity of 0.414 MW (3,636 MWh/y). If the electricity generated is used to substitute the electricity needs at the refinery plant, the CO2 emissions that can be mitigated is 2,955,915 kgCO2/y

Clinical Autopsy of a Reverse Osmosis Membrane Module

The desalination of seawater using reverse osmosis membranes is an attractive solution to global freshwater scarcity. However, membrane performance is reduced by (bio)fouling. Membrane autopsies are essential for identifying the type of fouling material, and applying corrective measures to minimize membrane fouling. Information from full-scale membrane autopsies guiding improved plant operations is scant in the formal literature. In this case-study, a reverse osmosis membrane from a full-scale seawater desalination plant with a feed channel pressure drop increase of about 218% over the pressure vessel was autopsied. The simultaneous determination of microbial cells, ATP, and total organic carbon (TOC) abundances per membrane area allowed estimating the contributions of biofouling and organic fouling. The abundance of microbial cells determined by flow cytometry (up to 7 × 108 cells/cm2), and ATP (up to 21,000 pg/cm2) as well as TOC (up to 98 μg/cm2) were homogeneously distributed on the membrane. Inorganic fouling was also measured, and followed a similar coverage distribution to that of biofouling. Iron (∼150 μg/cm2, estimated by ICP-MS) was the main inorganic foulant. ATR-FTIR spectra supported that membrane fouling was both organic/biological and inorganic. High-resolution SEM-EDS imaging of cross-sectioned membranes allowed assessing the thickness of the fouling layer (up to 20 μm) and its elemental composition. Imaging results further supported the results of homogeneous fouling coverage. Moreover, imaging revealed both zones with and without compression of the polysulfone membrane layer, suggesting that the stress due to operating pressure was heterogeneous. The procedure for this membrane autopsy provided a reasonable overview of the diverse contributors of fouling and might be a starting point to building a consensus autopsy protocol. Next, it would be valuable to build a RO membrane autopsy database, which can be used as a guidance and diagnostic tool to improve the management and operation of RO desalination plants.

Techno-economic comparison of three different types of powering systems

Economic and environmental factors play a crucial role in the transitioning of water desalination technologies from conventional energy sources to alternative sources, solar energy being in the forefront. This paper investigates the technical and economic merits of using three different types of powering systems: the National Electric Grid (Grid), a Standalone (Off-Grid) Photovoltaic (PV) System, and a Grid Connected (On-Grid) PV System to power a 100 m³/day reverse osmosis seawater desalination plant in the Mediterranean city of Tripoli-Libya. The cost analysis of product water showed significant savings in favour of On-Grid PV as a power source. Also, in this paper, the effect of interest rate on the cost of the water produced was studied. An additional finding of this paper was the impact of Off-Grid PV system oversizing to account for times of low solar irradiance on the level of utilization of the total electricity produced.

Spatio-temporal variability of sea surface temperatures in the Red Sea and their implications on Saudi Arabia coral reefs

The Red Sea is a conspicuous water body that hosts important coral reef ecosystems. This semi-closed sea is exposed to warming either by climate change or by anthropogenic stressors. The desalination plants along the Red Sea coast of Saudi Arabia dispose tremendous effluents of hot water from cooling systems, which is expected to impact the neighboring coral reef patches. The main objectives of this study were to delineate the spatial variations and the temporal trends of sea surface temperatures (SST) in the Red Sea using geospatial analysis with focusing on water temperature anomalies adjacent to seawater desalination plants. Monthly sea surface temperatures data were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite for the period 2003-2019. Annual SST changes and decadal trends were obtained from interpolation analysis and robust statistical metrics, respectively. Results showed that the Red Sea has three distinguished temperature zones with the coldest at the north and the warmest at the south. In addition, global warming is remarkably apparent in the northern part of the Red Sea (0.8 °C/decade). About one third of the Saudi corals occur at the northern part, while the remaining coral patches settle in the middle and southern parts of relatively lower SST trends. However, some corals in the middle section of the Red Sea occur proximate to regions of abruptly high SST trends due to the discharge of hot waters from desalination plants, particularly south of Jeddah. The continuous human-induced heating by hot water disposal could be fatal to coral reef ecosystems nearby desalination plants.

Open loop heat pipes for high-efficiency desalination plant

A seawater desalination plant based on open loop heat pipes (OLHPs), coupling with the low pressure steam turbine (LPST) extraction, is presented in this work. The steam extracted from the LPST is a heat source for the sea water evaporation. The sea water circulation is provided by the siphon effect, while the sea water evaporation takes place in the specially designed heat pipes. It can utilize low-grade power plant heat for high-efficiency seawater desalination and realize co-generation of electricity and fresh water without using any additional mechanical equipment. The prototype of the installation is implemented at an existing thermal power plant in Guangdong, China. Results of this study show that the plant can start up quickly and operate stably by using power plant condensation heat. A freshwater production rate of 20.5 L/h can be sustained when working with 55 °C heat steam and the value increased to 64.8 L/h with 86 °C heat steam. The successful operation of the plant has provided valuable experience for low-grade power plant heat harvesting and an efficient approach for seawater desalination.

Enabling the use of seawater for hydrogen gas production in water electrolyzers

Hydrogen gas will play an increasingly critical role in developing a carbon-neutral energy infrastructure, but it will need to be produced by water splitting using renewable electricity sources. A recent study by Veroneau and Nocera in Proceedings of the National Academy of Sciences (PNAS) suggests an electrolyzer that produces desalinated water from abundant seawater by using forward osmosis.

Nanofiltration Process for Enhanced Treatment of RO Brine Discharge

Brine discharge of reverse osmosis (RO) desalination plants represents a challenge for both inland and coastal desalination plants. Zero-liquid discharge (ZLD) can be accomplished by using additional stages of RO, which can recycle that brine water, but the key challenge is the high concentration of divalent salts. These divalent salts (especially calcium and magnesium salts) forms a scaling layer on the RO membrane surfaces and hence shorten the life-time of the membranes. In this study, the nanofiltration (NF) procedure was used to remove divalent ions from the brine discharge to minimize the load on additional stages of RO membranes. One of the most critical considerations influencing the selection of an effective NF is the water type, which is expected here by calculation of some hydrochemical parameters (major ions, hypothetical soluble salts (electrolyte), and saturation indices). NF experiments were undertaken on a lab-scale using a low-pressure hand-made system of 4–7 bar. Synthetic single salts solutions and two real brine water discharge (brackish (BWRO) and seawater (SWRO) desalination plants) were used as a feed solution for NF system. The chemical characteristics of the RO-feed, RO-brine, NF-permeate, and NF-reject in were investigated. Electrolyte concentrations and saturation indices were determined based on the concentration of the major ions and the NETPATH software package, respectively. Calculations reveal that the brine concentrate samples contained mostly MgSO4 and MgCl2 soluble salts. The results show that 79–89% of the total dissolved salts (TDS) and 96–98% of the total hardness (TH) were retained using the NF process. The salt rejection of the NF membrane follows the order of CaSO4, Na2SO4, MgSO4, MgCl2, and NaCl with a percent of 97.4, 97.3, 95.2, 93.4, and 79%, respectively.

Modeling and optimization of small-scale NF/RO seawater desalination using the artificial neural network (ANN)

The performance of seawater hybrid NF/RO desalination plant including permeate conductivity; permeate flow rate and permeate recovery. Under different feed parameters time, inlet temperature, inlet pressure, inlet conductivity and inlet flow rate were modelled by Artificial Neural Network (ANN) back-propagation based on Levenberg– Marquardt training algorithm. The optimal ANN model had a 5-8-3 architecture with a hyperbolic tangent transfer function in hidden layer and linear transfer function at the output layer. The ability of ANN performed model was compared with multiple linear regression (MLR). The results show that MLR is not satisfactory for predicting the performance of NF/RO hybrid desalination process with a correlation coefficient about 0.6. The trained ANN model has presented a good agreement between the prediction and the experimental data during the training with reasonable statistical metrics values (RMSE, MAE and AARD). The coefficient of determination values for the prediction of permeate conductivity, permeate flow rate and recovery by ANN were 0.969, 0.942, and 0.963, respectively. Therefore, the ANN model can successfully predict the performance of NF/RO hybrid seawater desalination plant.

Energetic, economic and environmental assessment of zero liquid discharge (ZLD) brackish water and seawater desalination systems

The discharge of brine (saline wastewater) from brackish water and seawater desalination plants poses a major threat to the natural environment. This research study presents an energetic, economic and environmental assessment of zero liquid discharge (ZLD) desalination systems in the Eastern Mediterranean. Two scenarios are considered: (i) ZLD brackish water and (ii) ZLD seawater systems, both aimed at producing saleable freshwater and mixed solid salt. Results showed that the energy consumption in scenario 1 (9.48 kWh/m3) is 2.38 times lower than in scenario 2 (22.55 kWh/m3) due to the 7 times lower feed salinity. The differentiation in energy demands is also translated to costs since scenario 2 (US$1.04/m3) is 1.24 times more expensive than scenario 1 (US$0.84/m3). Both scenarios are 3.18 times cheaper than the disposal method of the evaporation pond, while they are in the same cost range as the land application and deep-well injection. Whether only freshwater is sold or both freshwater and mixed solid salt are sold, both scenarios are profitable as the profit ranges from US$215.05/day to US$302.55/day. Concerning CO2 emissions, scenario 1 (5.91–6.45 kg CO2/m3) has lower values than scenario 2 (14.05–15.33 kg CO2/m3) as the energy demanded in scenario 1 is significantly lower.

Beneficiation of saline effluents from seawater desalination plants: Fostering the zero liquid discharge (ZLD) approach - A techno-economic evaluation

Zero liquid discharge (ZLD) and the utilization of saline effluents (brine) for resource recovery have recently attracted interest. A major environmental threat is the discharge of brine from seawater desalination plants. This research study presents two different ZLD systems to utilize brine by recovering not only freshwater, but also solid salts with commercial value. Two ZLD systems are considered in this techno-economic assessment: (a) system 1, which produces both freshwater and mixed solid salt, and (b) system 2, which produces freshwater, mixed solid salt, and pure solid salt (NaCl). The results showed that in terms of specific energy consumption (SEC) and freshwater cost, system 2 was costlier than system 1. In particular, system 2 (31.81kWh/m3) had a 1.4 times higher SEC than system 1 (22.55kWh/m3) as well as system 2 (US$1.37/m3) had a 1.32 times higher freshwater cost than system 1 (US$1.04/m3). Nonetheless, system 2 was 1.52 times more profitable than system 1 as pure NaCl production increased revenue significantly. Moreover, systems 1 and 2 were even profitable exclusively from the selling of freshwater. Overall, the results showed that both ZLD systems are promising options for sustainable brine management and utilization that follow the circular economy model.

Advanced Technologies for Stabilization and High Performance of Seawater RO Membrane Desalination Plants.

Seawater desalination plants that use reverse osmosis (RO) membranes have become a core part of social infrastructure, and should be designed to meet the needs of product water quality and production capacity, while considering various environmental factors such as the seawater quality, temperature and geographical features. Furthermore, stable operation while overcoming various problems should be achieved alongside the increasing demands for energy saving and cost reduction. As no universal plant apparatus and operation technology meets these various requirements, the plants need to be customized for individual solutions. This paper reviews and summarizes the proven technologies, including their advantages/disadvantages, and points to cutting-edge technologies related to the design and operation maintenance of seawater intake, pre-treatment and the RO desalination process.

Analytical study of optimum operating conditions in semi-batch closed-circuit reverse osmosis (CCRO)

Energy-efficient desalination technologies are of prime importance due to the continuously increasing global demand for freshwater and its associated carbon footprint. Membrane-based desalination technology with energy recovery devices shows much better energy efficiency than any other desalination process. However, for brackish water desalination as well as for small-scale seawater desalination plants, the energy recovery devices are not recommended due to high capital cost and low return on investment. A novel method called closed-circuit reverse osmosis (CCRO) was proposed in 2002 to reduce the unutilized energy in these systems. However, the dependence of the SEC on operational parameters in the CCRO process was not fully understood until now. We have demonstrated an analytical model of CCRO setup for domestic water desalination. If operated with continuously increasing pressure in such a way that the rate of permeation remains constant at an optimum value, the corresponding SEC line with respect to recovery will be parallel and slightly higher than the thermodynamic energy limit line, and the system will be more energy efficient.

Experimental studies of the efficiency of a solar system, including a passive water heater and an active seawater distiller

In the hot climate of the Mangistau region, located on the eastern coast of the Caspian, there are no sources of freshwater. Of the available groundwater deposits, only three are suitable for drinking water supply. The scarcity is felt in remote areas and coastal areas, where the population uses groundwater.The provision of the population is carried out by a seawater desalination plant. In the hot summer period, due to high temperatures, the productivity of desalination plants decreases (the water in the channels reaches 30 °C, and the plants are designed for 20 °C). This factor provides opportunities for the development of desalination plants using this heliopotential.Easy to manufacture, environmentally and economically viable solar desalination plants are essential for coastal areas where water is scarce.The article presents the results of experimental studies of the heliosystem, which consists of a passive solar water heater (SWH) and an active solar desalination plant (SW). Water is heated in the SWH pool and supplied to the lower SW pool-1, in which the desalination process is achieved by cooling the water pool-2.By reducing the temperature in the SW volume, the condensation temperature is reached. The coating of 2 layers of glass with an air gap reduces heat losses and raises the temperature in the installations by 10–12 °C and keeps it at night. Horizontal glass coverings provide a large area for solar radiation to enter the pool surface. Heat transfer by convection, in the volume between the "cold" and "hot" basins, is determined using the convection coefficient, which depends on the product of the numbers Gr and Pr. According to the results of experiments, the daily productivity of the desalter was 1.97, 1.83 and 2.31 l/m2 on the day of July 20, 21 and 22, 2019. The maximum value of the total heat transfer coefficient for SVN was 32.9 W/m2 °C, for SW 49.4 W/m2 °C.

Controlling harmful algal blooms (HABs) by coagulation-flocculation-sedimentation using liquid ferrate and clay

Harmful algal blooms (HABs) occur worldwide and threaten the quality of marine life, public health, and membrane facilities in Seawater Reverse Osmosis (SWRO) desalination plants. The effects of HABs on seawater desalination plants include extensive membrane fouling, increased coagulant consumption and plant shutdown. To determine how to mitigate such effects, this study assessed if low doses (0.01 mg/L, 0.10 mg/L, and 1.00 mg/L) of liquid ferrate (58% yield) and kaolin or montmorillonite clays alone could remove algal organic matter in coagulation-flocculation-sedimentation (CFS) pretreatment desalination systems. Results showed that 0.01 mg/L of liquid ferrate coagulant removed 42% of dissolved organic carbon (DOC), 52% of biopolymers (BP), 71% of algal cells, and 99.5% of adenosine triphosphate (ATP). At a dose of 0.01 mg/L, clays exhibited high removal of turbidity (up to 88%), BP (up to 80%) and algal cells (up to 67%). The combination of liquid ferrate (58% yield) as a coagulant with kaolin or montmorillonite clays as coagulant aids in CFS pretreatment led to 72% removal of DOC, 86% of BP, and 84% of algal cells with a fixed dose of 0.01 mg/L for each. Findings from this study can help SWRO plants improve the performance of pretreatment systems during algal bloom events by reducing the consumption of coagulants while also maintaining high removal efficiencies.

Commercial Pressure Retarded Osmosis Systems for Seawater Desalination Plants.

The development of renewable energy technologies is of global importance. To realize a sustainable society, fossil-resource-independent technologies, such as solar- and wind-power generation, should be widely adopted. Pressure retarded osmosis (PRO) is one such potential renewable energy technology. PRO requires salt water and fresh water, both of which can be found at seawater desalination plants. The total power generation capacity of PRO, using concentrated seawater and fresh water, is 3 GW. A large amount of energy is required for seawater desalination; therefore, the introduction of renewable energy should be prioritized. Kyowakiden Industry Co., Ltd., has been working on introducing PRO to seawater desalination plants since 2001 and is attracting attention for its ongoing PRO pilot plant with a scale of 460 m3/d, using concentrated seawater and treated sewage water. In this study, we evaluated the feasibility of introducing PRO in existing desalination plants. The feasibility was examined based on technology, operation, and economy. Based on the number of seawater desalination plants in each country and the electricity charges, it was determined whether the introduction of PRO would be viable.

Improving the Performance of Photovoltaic by Using Artificial Intelligence Optimization Techniques

Photovoltaic (PV) systems are taking a leading role as a solar-based renewable energy source (RES) because of their unique advantages. This trend is being increased in the field of Seawater desalination. This paper presents a study on the Seawater Desalination Plant (SWDP) located in Egypt feeding from the utility network. The main challenge in such a non-linear system with a high level of variability is the optimum sizing of the SWDP with the proposed whole solar-powered while keeping good dynamic performance. In this article, a solid electrical load analysis is presented to assess the optimal design of SWDP fed by the PV system. Moreover, optimal maximum power point tracking controllers (MPPTCs) are developed to enhance the dynamic performance of SWDP fed by the PV system. To accomplish this study, a real grid connected seawater desalination plant located in Egypt is implemented. The selected SWDP is producing 700 m3/day. The real experimental data of the plant were extracted through daily readings of electricity consumption and water production meters. This experimental data is then introduced to the HOMER program to suggest the optimal components of the PV system based on the minimum net present cost. The developed power plant consists of a Photovoltaic (PV) array, DC/AC converter, load and grid. Also, to tackle the challenge of the low conversion efficiency of the PV system, three MPPTCs are investigated to improve the dynamic performance of the proposed SWDP fed by the PV system. Incremental Conductance in conjunction with three artificial intelligence (AI) optimization techniques (Particle Swarm Optimization, Grey Wolf Optimization (GWO) and Harris Hawks Optimization) is developed for the assessment of the dynamic performance of the presented SWDP fed by PV. The system was constructed, modeled and simulated through MATLAB/SIMULINK. The attained results of the three methods are promising in extracting the maximum power with minimum error from the PV system while improving the performance of SWDP. The obtained simulation, as well as experimental results, proves the efficacy of the suggested optimal design strategy.

Influence of wind energy in a seawater desalination plant by reverse osmosis

Influence of wind energy in a seawater desalination plant by reverse osmosis