Desalination is a process in which dissolved salts are extracted from saline water. Transforming water processes have been widely used in order to add value and enable the use of water for each process that requires it. One of the most remarkable examples of desalination treatment is using salty water (sea water) or brackish water (high salt content in non-marine waters) to produce drinking water or process water to develop economic activities with this resource.
On the other hand, international water scarcity have led to the development of technologies which make it possible to reuse water with different applications instead of it being discharged into watercourses, thus reducing fresh water consumption and rivers contamination.
Ecopreneur takes part in actively developing this market, providing a wide range of equipment since screening marine water until water desalination plants, including reuse projects.
To collect water from natural courses such as the ocean, rivers, lakes, and so on, equipment is necessary that will permit an efficient screening of solids to avoid damage to units installed downstream.
Ecopreneur can provide a complete screening system as follows:
- Rotary drum
Using membrane technologies requires an efficient pretreatment that allows a proper unit operation over a whole lifespan. Pretreatment technologies to be used will depend on existing pollutants. As an example, it is possible to find algae and microalgae in sea water, as well as other elements which can significantly decrease the efficiency of treatment systems such as Ultrafiltration (UF), Reverse Osmosis (RO) or Nanofiltration (NF). To prevent the efficiency loss, Dissolved Air Flotation (DAF) systems are used.
On the other hand, it is possible to find contaminants in inland watercourses such as high turbidity generated by clay, silts, and others, or contaminants associated with the presence of dissolved metals.
Regarding water transformation processes for reuse, the nature of the contaminants may vary because the water has already been used in a previous process. Therefore, to ensure the efficient operation of membrane systems, an intensive pretreatment system may be necessary for disposal of such contaminants.
Dissolved Air Flotation (DAF)
Multimedia Filters (MMF)
Various membrane technologies are used in water treatment to filter very small solid particles and in water demineralization to separate salt molecules and other dissolved elements to obtain ultra-pure water.
Micro- and Ultrafiltration
The principle of micro- and ultrafiltration is physical separation. It is the pore size of the membrane which will determine when dissolved solids, turbidity and microorganisms are eliminated. Depending on the construction of a rejection layer on the membrane, substances larger than the membrane’s pores will be completely retained, and the smaller ones will be partially retained.
Normally, micro- and ultrafiltration systems are used as pretreatment for reverse osmosis (RO) and nanofiltration (NF) systems or as filtration systems for uses such as drinking water production, tertiary treatment of effluents, biological secondary treatment systems MBR (membrane bioreactor), and others.
Reverse Osmosis (RO) and Nanofiltration (NF)
In a reverse osmosis system, water is forced through a membrane that has a very low permeability to salt and other chemical contaminants. This system makes it possible to separate all contaminants from water, including monovalent ions and molecules, obtaining pure water.
Nanofiltration is a process which uses membranes that have permeability to most monovalent ions. In this way it has the same features as RO membranes permitting the monovalent ions going to the permeate water flow. The operating pressure of NF is lower than that of RO for water that has the same features.
In general terms, there are two kinds of reverse osmosis and nanofiltration membranes. For sea water (SW), membranes are used either for reverse osmosis (SWRO) or nanofiltration (SWNF). For brackish water (BW), BWRO or BWNF membranes are used.
RO and NF systems can be integrated locally or come assembled from factory. They have a wide range of uses and sizes, from a few liters/day to hundreds of liters/second. Information about water type, application and size will permit the selection of a system that will best suits the needs of each project.