Desalination and Water Treatment

Water treatment and desalination from water treatment company Veolia Water Technologies South Africa (Veolia) is provided to both municipalities and industry. For municipal purposes, Veolia has the capacity and resources to construct large-scale, permanent desalination plants, which can be seen from established plants in the Eastern and Western Cape where the transformation of seawater to drinking water occurs.

Water desalination processes tailored for use in industrial water treatment are delivered in the form of small scale package water treatment plants. These desalination package plants are also used by some municipalities for residents in remote areas not connected to the municipal pipeline infrastructure. Both large scale and small scale desalination plants can be tailored to treat either brackish water or seawater

Internationally, Veolia was distinguished at the Global Water Awards 2017 for 2 desalination plants:


Seawater desalination processes and technologies

Image of a seawater desalination water treatment plant using a
range of water technologies and reverse osmosis.
Image of a seawater desalination water treatment plant using a range of water technologies and reverse osmosis.

To begin seawater desalination water treatment, a stable, high quality feed water is required – this optimises membrane durability. Depending on the water purification system, from here water heads either to the distillation solution or membrane solution. For distillation processes, the technology used to vaporise is Multiple Effect Distillation (MED), a low temperature sea water distillation process used to evaporate seawater in numerous stages – up to 14 stages in some instances – at temperatures of 70° C or lower to produce clean distillate water. 

A thermal desalination plant contributes to purification of water
through multiple effect distillation water treatment.
A thermal desalination plant contributes to purification of water through multiple effect distillation water treatment.

Membrane treatment on the other hand, involves pre-treatment that prevents fouling and scaling using Veolia’s water technologies like Actiflo® for clarification, Multiflo™ for enhanced clarification and lamella settling, and Spidflo™ and Filtraflo™ for flotation and gravitational flow respectfully. The next step is reverse osmosis via membrane filtration. Highly pressurised filtration is made through semi-permeable osmotic membranes to reach an osmotic equilibrium. This process is suitable for both high and low salinity concentration. The technology used for this process is called Sirion™, a reverse osmosis system developed for pure water production, seawater desalination and water reuse applications. This is followed by degassing to ensure a pH adjustment with CO² stripping, which is required for some industrial projects. 

An
image of a Sirion Skid for reverse osmosis desalination – also called membrane
treatment.
An image of a Sirion Skid for reverse osmosis desalination – also called membrane treatment.

Remineralisation is the next step required to meet potable drinking water standards and, thereafter the water is disinfected. These water solutions make it ready for delivery to water networks or for use from the containerised plant.

Watch and see how Veolia desalinates seawater to potable water standards! 

Brackish water desalination

Image
of brackish water desalination plant that can also be used for industrial water
treatment with various desalination technologies.
Image of brackish water desalination plant that can also be used for industrial water treatment with various desalination technologies.

Acid Mine Drainage (AMD) and other less toxic inland water streams with high levels of total dissolved salts can be transformed into high grade potable water with brackish water desalination solutions from Veolia. 

Similarly to seawater desalination, the purification of brackish water can be achieved through either membrane processes or thermal processes, both of which can be done with large scale permanent water treatment plants and containerised package plants. The latter is ideal for use in industry as well as for municipal demand in remote areas, and provides the ideal solution for areas subject to seasonal water shortages. 

Image of a containerised
desalination plant for inland brackish water.
Image of a containerised desalination plant for inland brackish water.

Containerised Potable Water Treatment Plants from Veolia can be tailored to desalinate both seawater and brackish water 

Desalination and water purification in the mining industry

Image
of a desalination plant using desalination technologies, like AMDRO™, for
example, tailored for the mining industry.
Image of a desalination plant using desalination technologies, like AMDRO™, for example, tailored for the mining industry.

Veolia partners with industry experts to formulate the ideal water treatment solution for a particular industry. In the mining sector, for example, exploration, engineering and mining companies’ experts’ opinions are brought into the equation when developing solutions to treat mine water. A result was Veolia’s AMDRO™ technology, a patented technology for desalinating acidic wastewater with high concentrations of metals and calcium salts. It combines Veolia’s ACTIFLO® high rate clarification process with filtration, RO and ion exchange to generate high-quality effluent with minimal pre-treatment requirements.

AMDRO™ technology is applicable for the phosphate, coal mining and steel industries, as well as general industry for acidic industrial wastewater desalination.

Let us help you build a containerised desalination plant for your requirements. Send us an enquiry or phone us on +27 (0) 10 040 7310. 

Preserving water through desalination

Veolia advocates its ‘3R’ principle approach – Reduce, Recycle & Reuse, promoting companies and municipalities to switch to a sustainable water use and recover approach.

Billions of litres of desalinated water can be wasted through leakage in water networks and reducing this wastage is the first step in preserving water. This is especially the case with desalinated water, as the cost of producing it is much higher compared to conventional potable water production. Leak reduction can be achieved through water network monitoring to reduce the flow of leaks, which also provides early leak detection and anticipates sections of a network that may require preventative maintenance.

Water reuse consists of water that can be used as a substitute to potable water for many applications such as landscaping irrigation, wetlands refills and industrial processes. For many of them, water reuse requires further polishing and other controls to ensure the water complies with the applicable standards. Providing an effective sewage treatment system will impact the environment positively, as the effluent can be reused for various applications. 

We Know Water! Approximately 15% of the world’s desalination plant capacity was designed and constructed by Veolia internationally. 

Water recycling as a term can be interchanged with water reuse, but there are resources that can be recycled in the desalination processes which differs it from water reuse. For example, energy recycling is an environmental contribution to the desalination process. Thermal desalination and reverse osmosis both require large amounts of energy, but by recycling the energy both water and money are saved. MED in the thermal process using low pressure steam, which is the low grade waste heat from another source, usually a power plant. This reduces the reliance on additional electricity.

Containerised water treatment plants ensure you get the benefits of Veolia’s water treatment plants where ever you need them to be!

Desalination technologies

Reverse osmosis (RO) and nanofiltration achieve desalination via membranes, while multi effect distillation (MED), evaporation and crystallisation are thermal processes to achieve desalinated water. These technologies are designed to treat industrial or municipal wastewater, seawater, brackish groundwater, surface or potable water. Other technological processes that are effectively used for desalinating water is multi-stage flash (MSF) and hybrid systems using both thermal and RO.

Selection of the most appropriate solution depends on the source of the feed water and the required quality of the treated water.

Membrane Solutions

Less energy intensive than thermal processes, this process is typically for water with a lower dissolved salt content and includes reverse osmosis and nanofiltration.

Membrane separation processes are used for:

  • Seawater desalination
  • Process and potable water production
  • Boiler feedwater and pharmaceutical water polishing and demineralisation
  • Process and municipal effluent rehabilitation and recycling
  • As part of a ZLD process

Thermal Solutions

Ideally used for water with high dissolved salt content where the pressure needed for a membrane system to achieve equivalent results would be too much. This process reduces energy costs as it uses a low-cost energy source.

Multiple effect desalination MED units (low temperature seawater evaporator) enable multiple effect distillation, of which there are two:

  • Multiple Effect Distillation with Thermal Vapour Compression (MED-TVC)
  • Multiple Effect Distillation with Mechanical Vapour Compression (MED-MVC)

All of Veolia’s products and components are sourced from reputable suppliers and OEMs locally and internationally, providing our customers with the highest quality products that achieve the highest possible water quality.

Southern African desalination case studies

Small scale desalination plants

  • Ndlambe Municipality (Cannon Rocks and Boknes), Eastern Cape, produces produce 750 m³ of SANS 241-compliant potable water per day.
  • Mauritius holiday resort comprises the development of two reverse osmosis desalination plants producing a combined 0.125 mega litres of treated water each day.

Desalination plants

  • A turnkey desalination plant that supplies 10 ML of potable water to the Mossel Bay Municipality, and 5 ML of process water to Petro SA.
  • A turnkey seawater desalination plant in Plettenberg Bay producing 2 ML of potable water per day.
  • A turnkey seawater desalination plant that produces 2 ML of potable water per day for Knysna municipality.
  • A 1,7 ML per day seawater desalination plant in Lamberts Bay that helps alleviate pressure on the region's water system.
  • An RO desalination plant at Transnet’s iron ore terminal in Saldanha

For more information on desalination and water treatment solutions, please complete the following form:

Desalination and Water Treatment Plant enquiry

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