What is the Best Seawater Desalination System?

The growing inadequacy of freshwater for personal, commercial, and industrial use has proliferated the adoption of seawater desalination systems. As of 2008, seawater desalination was the primary supply of fresh potable water for an estimated 75,000,000 people. Adverse climate change and consequent aridification have immensely increased reliance on seawater desalination.

Presently, there are over 22,000 seawater desalination systems spread out across the globe with the Middle East and Northern Africa accounting for approximately 50% of the plants. The demographics in coastal cities are continually on the rise with some coastal regions in Australia, the Middle East, and Southern California exhibiting population concentrations of over 75%.

Annually, it is estimated that the use of seawater desalination systems grows by roughly 7% to 9% as both arid and non-arid countries up their efforts in reinforcing freshwater supply. Seawater desalination systems exploit an infinite resource and are essentially not subject to climatic changes. Further proliferation in their adoption is guaranteed as innovation continues to lower the financial and environmental costs of seawater desalination systems.

Figure 1 Seawater desalination equipment.

Seawater Desalination System?

A seawater desalination system is simply a water treatment plant that converts seawater into potable water by significantly shrinking the concentration of total dissolved solids. Seawater desalination systems are specialized to desalt highly saline seawater and ultimately provide industries and humans with an alternative freshwater source.

For optimal performance, seawater desalination systems are equipped with maximum TDS levels ranging from 35,000 to 45,000ppm. Different desalination projects demand distinct volumes of freshwater hence seawater desalination systems are manufactured with varying capacities and production rates.

Presently, there are numerous desalination techniques utilized by seawater desalination systems. The diversity in desalination processes grants users control over the target contaminants to eradicate and the quality of water generated. The principal desalination processes utilized in seawater desalination machines are reverse osmosis, distillation, and electrodialysis.

Types of Seawater Desalination Systems.

The diversity in seawater desalination systems’ application necessitates the production of different specialized equipment. As such, existing seawater desalination equipment harbors different customizations, which favor specific applications. Underneath we look at the various seawater desalination systems manufactured by NEWater.

● Industrial Seawater Desalination Systems.

NEWater manufactures comprehensive seawater desalination systems custom-built to continually desalinate seawater for both onshore and offshore industries. The demand for clean product water in industrial applications is astronomical and the deterioration in freshwater reservoirs has most industries coveting alternative sources.

Reverse osmosis desalination systems are commonly utilized in industries to provide high-grade water for product formulation, human consumption, and cleaning of equipment. To accommodate various scales of industrial applications, NEWater manufactures RO desalination units with standard capacities of up to 900,000 GPD.

Figure 2 Industrial seawater desalination system.

● Commercial Seawater Desalination Systems.

The effects of global freshwater scarcity have been detrimental to most commercial enterprises. Consequently, seawater desalination has emerged as a dependable remedy for most coastal and arid-based businesses.

NEWater’s commercial desalination plants are available in standard capacities ranging from 350 to 15,000 gallons per day. This provides small, medium, and large businesses with a consistent supply of fresh water at all times. Capacity demands not accommodated by our standard systems are custom-built by our proficient engineers.

● Skid-mounted and Containerized Seawater Desalination Systems.

For mobility, NEWater manufactures seawater desalination machines fitted onto metal frames or containers. Containerized seawater desalination systems are typically desalination equipment mounted on 20 feet or 40 feet containers. Both skid-mounted and containerized plants are suitable for both indoor and outdoor applications.

They have high desalination rates often lowering TDS levels to approximately 500mg/L from over 35,000 ppm. We assemble the systems at our facilities before subjecting them to rigorous testing for quality assurance.

Figure 3 Containerized seawater desalination system.

The Working Principles of Seawater Desalination Systems.

The removal of dissolved salts and other undesired contaminants from seawater can be achieved in several ways. Desalination systems ordinarily utilize membrane-based desalination, thermal desalination, or ion exchange to alienate freshwater from seawater. Regardless of the desalination technology deployed, seawater desalination plants ultimately generate potable water and a highly concentrated waste product (brine or concentrate).

Reverse Osmosis.

Reverse osmosis accounts for over 50% of the global desalination usage owing to its cost-efficiency and satisfactory salt rejection rates of up to 99.7%. The process is chiefly principled upon the use of pressure to distort the natural osmotic flow.

To mitigate membrane fouling and protect the machinery from corrosion, RO seawater desalination systems commence desalination by pre-treating the feed water. Pre-treatment involves chlorination, media filtration, carbon filtration, water softening, and chemical dosing. The appropriate pretreatment mechanism is determined by the feed water concentration and composition as well as the desired potable water quality.

Consequently, high-pressure pumps are deployed to force the pre-treated seawater via perforated membranes. The 0.0001 micron-sized perforations of the semi-permeable membrane block the passage of dissolved salts, microorganisms, chemicals, and other unwanted constituents. The water collected is often fresh and with appropriate post-treatment, can be used for a number of applications.

Figure 4 Reverse osmosis desalination process.

Distillation.

On the contrary, thermal distillation processes have their foundation rooted in the deployment of heat to alienate fresh water from seawater by evaporation. Undesired constituents with higher boiling points are left behind as the freshwater turns into vapor. Subsequently, the vapor is condensed and fresh product water is derived. Thermal distillation/desalination is broadly classified into:

Vapor Compression.

Vapor compression derives the required heat energy used to evaporate the seawater from vapor compression. Principally, vapor compression uses either mechanical compressors or steam jets to generate heat by condensing the vapor. Ideally, VC seawater desalination systems are perfect for small applications given that their daily production capacity is roughly 3000 m3. They commonly operate at temperatures lower than 70°C hence it is unlikely to experience scaling and corrosion of equipment.

Figure 5 Mechanical vapor compression system.

Multi-stage Flash Distillation.

Multi-stage flash distillation is undoubtedly the most commonly used thermal desalination technology with a whopping 36% global usage rate. Desalination of seawater using MSF involves different stages, which in some systems range from fifteen to twenty-five. The heating of the seawater commences at high pressure and as the water passes through the subsequent stages, the pressure is proportionately lowered. Each MSF stage has a heat exchanger tubing, which condenses the steam consequently resulting in the collection of fresh potable water.

Multi-effect Distillation.

MED is renowned for its appeal to large-scale seawater desalination enabled by its enormous capacity ranges, high salt rejection rates, and energy efficiency. The use of multi-effect distillation dates back to the 1950s and this technique functions by evaporating water at varying temperatures and pressure levels. The vapor from subsequent effects is utilized to heat water from the next effect thereby optimizing power usage.

Figure 6 Multi-effect desalination.

Composition of Seawater Desalination Systems.

The quality of components used and the level of technology integrated into seawater desalination systems immensely influence the machine’s performance level. A reverse osmosis seawater desalination machine, for instance, is composed of the following key components.

Reverse osmosis skid.

For protection and optimal longevity, components of RO desalination plants are fitted onto non-corrosive metal frames (mainly powder-coated stainless steel). The steel frames can withstand the powerful vibrations of the high-pressure feedwater pumps hence prolonging the longevity of your system.

High-pressure pumps.

To reverse the osmotic flow in reverse osmosis systems, high-pressure pumps are mandatory. Higher horsepower increases the intake pressure and ultimately boosts your system’s desalination rate.

Cartridge filters.

Seawater is synonymous with seaweed, debris, and other large-sized constituents that may potentially harm the membranes. To avert premature damaging of the membranes, seawater RO desalination systems are fitted with filters that eradicate the large particles. Typically, the cartridge filters are polypropylene filters measuring five microns.

Figure 7 Cartridge filters.

Semi-permeable membranes.

Seawater RO membranes are made of specialized proteins to facilitate the maximum rejection of dissolved salts and other constituents. The dimension and quantity of RO membranes deployed in a seawater desalination plant depend on the desired potable water quality and the system’s capacity.

User interface.

The user interface is the control panel from which you operate the plant. The control panels in automatic, semi-automatic, and manual desalination plants differ greatly. Based on the system’s objective, NEWater utilizes solid-state microprocessors or advanced PLCs to create a user interface that is to maneuver around.

Additionally, different applications may demand the addition of other supplementary components such as the pre-treatment chamber, membrane-cleaning components, chemical dosing system, and a post-treatment unit.

Attributes of a good seawater desalination system.

The existing market offers a diverse line of seawater desalination systems but sadly, very few meet the desired quality, durability, effectiveness, and cost-efficiency threshold. Unscrupulous manufacturers and suppliers take advantage of unsuspecting clients by supplying them with low-quality equipment at exorbitant rates.

Shopping from NEWater protects you from such unscrupulous dealers and guarantees you premium seawater desalination equipment. To aid you distinguish mediocre products, we have summarized traits synonymous with high-quality seawater desalination systems.

Figure 8 Skid-mounted RO seawater desalination system.

Low Energy Consumption.

Desalination systems irrespective of the desalination process (distillation or reverse osmosis) rely on power. Over the years, excessive power consumption has been a stumbling block to seawater desalination. The breakthrough in energy recovery, partly spearheaded by NEWater has however resulted in more energy-efficient seawater desalination plants.

The primary forms of energy utilized in seawater desalination are mechanical energy and thermal energy. Numerous factors influence energy consumption in seawater desalination plants.

  • TDS concentration of the seawater.
  • The system’s capacity and the high-pressure pump’s horsepower.
  • Desired potable water quality.
  • A region’s power frequency and voltage options.

Efficiency in energy consumption is a key attribute of decent seawater desalination systems. NEWater provides desalination plants equipped with energy recovery technology, which has been instrumental in lowering energy consumption. Frequently, we use HTC-300 recovery devices endowed with hydraulic turbine configuration, which are responsible for up to 30% cuts in energy consumption.

The drop-off in energy consumption since the 1970s has been immense. Reverse osmosis seawater desalination currently consumes approximately 3 kWh/m3 to 7 kWh/m3 of power while a few years back, the consumption was roughly 16 kWh/m3. Energy consumption in seawater distillation processes is as follows:

  • Mechanical vapor compression: 7–12 kWh/m3
  • Multi-effect distillation: 6.5–11 kWh/m3
  • Multi-stage flash distillation: 13.5–25.5 kWh/m3
Adequate Capacity.

The ideal seawater desalination system has a capacity perfectly befitting your intended application. NEWater manufactures systems with varying capacities to suit diverse scales of application in homes, industries, and commercial entities. Our industrial seawater desalination systems operating on reverse osmosis are available in standard capacities ranging from 8000 GPD to 660,000 GPD.

On the other hand, we have commercial seawater RO desalination units with standard capacities ranging from 380GPD to 15,000 GPD. From our vast line of standard seawater desalination devices, you have the liberty to select a system that has a capacity range in line with your production objectives. Additionally, our engineers build customized desalination systems with personalized capacities and production rates.

Figure 9 500 liters per day RO desalination plant.

Impurity Removal Rate.

Principally, a seawater desalination system is only as good as the contaminants it eradicates. Different projects demand different grades of desalinated water and different systems have different salt rejection rates. Reverse osmosis is highly effective in eradicating dissolved salts from seawater with a maximum desalination rate of 99.7%.

Seawater from different seas or oceans exhibits different impurity concentrations and compositions (often measured as total dissolved solids TDS). The average TDS level of typical seawater is approximately 35,000ppm. A good seawater desalination system shrinks the TDS level to below 1000ppm, which is the bare minimum for fresh potable water.

Supreme Quality.

Unscrupulous manufacturers often use low-quality materials and components to manufacture seawater desalination equipment thereby adultering the system’s quality. High-quality equipment guarantees you a prolonged lifespan and minimizes the need for frequent repairs/replacements.

NEWater’s seawater desalination machines are manufactured using non-corrosive stainless steel, which can withstand prolonged exposure to highly saline seawater.  Our premium RO membranes have a life expectancy of 3 years while the whole system guarantees a minimum service life of 15 years. Consequently, high-quality seawater desalination systems can continually support heavy usage without dwindling in impurity rejection rate.

Prevalent electricity voltage/voltage.

Power options in different regions are subject to change. Primarily, seawater desalination systems are available in the following power options 220-380-415V/50Hz/60Hz. For compatibility, it is paramount that you first establish your region’s primary electricity frequency and voltage. Based on the information provided by the client, NEWater’s engineers manufacture customized seawater desalination equipment with the stipulated power options.

Cost-efficiency.

The cost of seawater desalination systems is often a culmination of different production, market, and operational variables. Good seawater desalination systems guarantee decent returns on investment within shorter periods. Typically, the overall cost of desalination plants encompasses the equipment’s price, set up expenses, power consumption, labor charges, maintenance expenses, and fixed asset depreciation rate.

RO seawater desalination systems, which are predominantly used in seawater desalination, have a power consumption rate of approximately 2.25 yuan per ton of water. With a production capacity of 10,000 tons per day, RO plants spend roughly 0.05 yuan/ton of water in chemical treatment and 0.04 yuan/ton of water in upkeep.

Similarly, membrane substitution charges revolve around 0.05 yuan/ton of water while labor-related expenses are roughly 0.2 yuan per ton of water. Lastly, the asset depreciation of an RO seawater desalination system is approximated to be 0.12 yuan per ton of water thereby bringing the comprehensive cost to approximately 4.54 yuan/ton of water.

The use of cost-efficient technology and components by NEWater results in the availability of high-quality seawater desalination equipment. To reap the benefits of our premium, cost-efficient desalination solutions, get in touch with our technicians for a customized system.

The Advantages of Using NEWater’s Seawater Desalination Systems.

Figure 10 NEWater’s containerized desalination system.

The principal benefit associated with seawater desalination systems is the provision of an alternative source of fresh potable water. In an era where freshwater reservoirs are depleting alarmingly, aridification is on the rise and population growth in coastal cities is proliferating, seawater desalination is at the very least revolutionary.

NEWater’s desalination systems are not your ordinary desalination solution, they provide much more than just clean potable water. Our systems guarantee longevity, power efficiency, and overall cost-efficiency. Underneath, we expound on the diverse returns users of NEWater desalination systems continually reap.

  • Adequate impurity rejection rates ranging from 95% to 99.7%. Both distillation and membrane-based desalination processes eliminate most of the microorganisms, dissolved salts, and chemicals found in seawater. The result is often fresh potable water with a TDS level of 300-1000ppm.
  • Fairly low energy consumption with a minimum energy usage of 3Kw/h. Our reverse osmosis desalination systems are equipped with energy recovery devices, which massively enhance the reputation of our systems as cost-efficient solutions.
  • They aid environmental conservation efforts by alleviating the strain on freshwater sources and treating wastewater prior to disposal. Additionally, solar-powered desalination systems mitigate the emission of carbon.
  • NEWater’s desalination systems guarantee durability and dependability. They can relentlessly desalinate huge volumes of feed water while depicting optimum productivity and efficiency. Our RO desalination equipment averages between 15 to 20 years while our RO membranes have a service life ranging from 3 to 5 years.
  • Our quality assurance department rigorously tests them prior to shipping meaning their quality and reliability are unquestionable. They are also ISO 9001 certified and hold a high-tech product certification.
  • In designing and developing seawater desalination systems, NEWater uses information provided by the client to manufacture a personalized solution. This ensures that your system bears the ideal pre-treatment system and the water generated is of the required quality.
  • Compared to other manufacturers, NEWater’s desalination systems are fairly priced and our prices are categorized among the market’s best prices. Investment in our desalination equipment guarantees quick returns thanks to our competitive prices and high-quality devices.
  • We provide turnkey desalination systems that are essentially plug-and-play. This makes installation easy, hasty, and unsophisticated especially with the aid of our installation manual. NEWater also provides on-site installation services at customer-friendly rates.
  • Our desalination systems attract a plethora of after-sale services including one-year warranty protection, lifetime repair services, and doorstep delivery.

For an in-depth understanding of seawater desalination, related systems, and technology, do not hesitate to contact our specialist. We offer 24/7 customer support and our desalination solutions are tailored to provide convenience, efficiency in operational costs, and optimum effectiveness.

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