Hybrid membrane and thermal seawater desalination processes powered by fossil fuels: A comprehensive review, future challenges and prospects

Novel Tri Hybrid Desalination Plants

Seawater desalination: A review of technologies, environmental impacts, and future perspectives

The implementation of reverse osmosis (RO) technology in PLN is noticeably increased than multi-effect distillation (MED) and multi-stage flash (MSF). Today, RO has about 39 percent of the design total capacity of plants, while the rest is MSF and MED represent respectively, 31 percent and 30 percent of the total installed desalination capacity in PLN. This paper is concerning the performance evaluation of small capacity desalination units (≤ 50 m3/h), which is the most widely used capacity in PLN. These desalination units have been evaluated for its capacity factor, availability factor, plant capacity factor, GOR and other parameters related to performance have been examined too. It is found that with around 10 years of operation, MSF and MED units are operating below their designed capacity with average plant factor ranging from 0.70 to 0.75 for six months. GOR is found to be lower than designed values. Low-performance ratios are the result of high steam consumption and low production rates of distillate water. With around 2 years of operation, the RO unit is operating slightly below than the designed value. Low-performance ratios are the result of the decreasing production rates of product water and the low quality of product water. In this study, power consumption is examined too. The power consumption of MSF is greater than the electrical energy consumed by MED and RO.

Libya, like many arid countries, relies heavily on groundwater resources, which are increasingly scarce. With a 1950 km Mediterranean coastline offering an abundant but highly saline water source (35,000 38,000 ppm), seawater desalination is essential to meet national water demands. This study presents a techno-economic evaluation of three desalination technologies—Reverse Osmosis (RO), Multi-Stage Flash (MSF), and Multi-Effect Distillation (MED)—for a 1200 m³/day plant. RO design was conducted using ROSA software, while MSF and MED were modeled thermodynamically.RO requires significantly lower seawater intake (117 m³/h) compared to MSF (475.7 m³/h) and MED (200 m³/h), with corresponding plant efficiencies of 43%, 10.5%, and 25%. RO produces potable water (190 ppm TDS), while MSF and MED yield ultra-pure water (~50 ppm TDS), necessitating remineralization. RO operates without steam input, unlike MSF and MED (7.3 m³/h steam), and demands 235 kW of electrical power versus 245 kW (plus steam) for MSF and 50 kW (plus 7.5 m³/h steam) for MED. RO’s high brine pressure (53.5 bar) enables energy recovery, whereas MSF and MED discharge warm brine at low pressure, posing environmental challenges. Economically, unit water costs are $0.37/m³ for RO, $1.52/m³ for MSF, and $1.21/m³ for MED. Overall, RO is the most technically and economically viable option for this capacity under Libyan conditions.

Distillation vs. membrane filtration: overview of process evolutions in seawater desalination

Chapter 2 - Desalination Technologies

Seawater desalination — SWCC experience and vision

Reverse osmosis is the leading technology for desalination of brackish water and seawater, important for solving the growing problems of fresh water supply. Thermal technologies such as multi-effect distillation and multi-stage flash distillation still comprise an important portion of the world’s desalination capacity. They consume substantial amounts of energy, generally obtained from fossil fuels, due to their low efficiency. Hybridization is a strategy that seeks to reduce the weaknesses and enhance the advantages of each element that makes it up. This paper introduces a review of the most recent publications on hybridizations between reverse osmosis and thermal desalination technologies, as well as their integration with renewable energies as a requirement to decarbonize desalination processes. Different configurations provide improvements in key elements of the system to reduce energy consumption, brine production, and contamination, while improving product quality and production rate. A combination of renewable sources and use of energy and water storage systems allow for improving the reliability of hybrid systems.

• The research employs a holistic approach by integrating techno-economic, environmental, and social criteria to assess the sustainability of hybrid desalination systems. • RO-MED hybrid desalination configuration is evaluated to be the most sustainable based on the global sustainability index (GSI: 83%). • MSF-RO was found to be the least sustainable due to its substantial energy consumption and high environmental footprint. Water scarcity is one of the most critical global challenges, with nearly 4 billion people affected by acute water shortages. Desalination has emerged as a key solution to meet the growing demand for freshwater, especially in arid regions. However, standalone conventional desalination technologies such as multi-stage flash (MSF) and reverse osmosis (RO) face challenges in terms of high energy consumption, low water recovery rates in some cases, and certain environmental impacts, which hybrid desalination systems can mitigate. Despite the growing interest in hybrid desalination technologies, there is a gap in their sustainability analysis, making it difficult to determine the most sustainable option for freshwater production. Therefore, this study conducts a comprehensive sustainability assessment of seven different hybrid desalination configurations with double-stage RO as the control. The analysis focuses on key indicators of sustainability, including energy efficiency, water recovery, environmental impacts, and social acceptance of the produced freshwater. The results reveal that the RO system, when combined with multi-effect distillation (MED), had a global sustainability index (GSI) of 83 %, which is the most sustainable configuration, outperforming RO-RO (GSI of 75 %). In contrast, the MSF-RO system ranks the lowest with a GSI of 24 %, due to its high energy consumption and carbon emissions. The study highlights the potential of hybrid systems, particularly RO-MED, to address water scarcity more sustainably. These findings offer practical guidance for policymakers and industry stakeholders in selecting desalination technologies that balance water security, energy efficiency, and environmental impact. Future research should explore integrating renewable energy sources into hybrid systems to further reduce environmental impacts.

Interconnection between renewable energy technologies and water treatment processes

Nowadays, the drinking water shortage is increasing, mainly due to rapid population growth, climate change, wasteful overuse of water, and pollution. Under the current circumstances, a quarter of the world's population will not have access to good quality drinking water. Thus, another solution must be adopted in areas with insufficient freshwater. One possible line is the desalination of seawater, one of the most practical solutions to solve the problem of drinking water shortage along the oil availability shore and continues to expand globally. Water produced may also be utilized for irrigation, reducing a region's reliance on imports, contributing to the local economy, and improving food supplies. However, this process is not a consequences-free procedure; it may cause several environmental and human health problems.The three most applied desalination technologies are reverse osmosis (RO), multi-stage flash distillation (MSF), and multi-effect distillation (MED). In this study, the emissions of greenhouse gases (GHGs) of drinking water produced from seawater using these three technologies with fossil and renewable energy sources were investigated based on two methods: life cycle assessment (LCA) using SimaPro life cycle analysis software and carbon footprints. As a result, RO technology has significantly lower CO2 emissions than thermal technologies. The RO combined renewable energy is the most environmentally friendly; provides outstanding benefits in terms of human health and ecosystem quality. This technology may still evolve in the future to produce longer-lasting, cheaper membranes, and the energy requirements of this process are lower with applying modern energy recovery systems.

This work presents a detailed thermo-economic analysis of unit water costs from dual-purpose cogeneration plants. The power levelized cost was first calculated for stand-alone steam, nuclear, and combined-cycle power plants. The cost of energy needed to operate the desalination systems connected to power plants was evaluated based on two different approaches: power- and heat-allocated methods. Numerical models based on the heat and mass balances of the power and desalination plants’ components were developed and validated. Comprehensive and updated data generated using Desaldata libraries were correlated to estimate the capital, labor, overhead, and maintenance costs for different desalination systems. The levelized water cost produced by multi-effect distillation, multi-effect distillation with vapor compression, multi-stage flash, and reverse osmosis systems connected to different power plants was estimated. The impact of various controlling parameters, including the price of natural gas, nuclear power plant installation cost, and the desalination capacity on water cost, was investigated. For all simulated cases, the levelized water cost evaluated using the heat-allocated method was found to be lower by 25–30% compared to that estimated using the power-allocated method. The cost of water produced using reverse osmosis remains below that produced by other desalination technologies. However, using the heat-allocated method to estimate the levelized water cost narrows the gap between the costs of water produced by multi-effect distillation and that produced by seawater reverse osmosis. The results also show that the use of the multi-effect distillation process in a cogeneration configuration rather than multi-effect distillation with vapor compression can result in a lower water cost. The profit analysis shows slight differences between the profit of a power plant connected to a reverse osmosis system and the profit of a power plant connected to a plain multi-effect distillation system.

Environmental impact of desalination technologies: A review

Current progress in integrated solar desalination systems: Prospects from coupling configurations to energy conversion and desalination processes

Energy consumption and water production cost of conventional and renewable-energy-powered desalination processes