Desalination by Reverse Osmosis, Nanofiltration and Reversible Electrodialysis

Reverse Osmosis (RO) membrane technology, Reversible Electrodialysis (EDR) and Nanofiltration (NF) permit removal of salts present in water, which would not be possible with other conventional treatments such as chlorides, nitrates, sulfates and magnesium.

In RO and NF processes, the inducing force is the pressure forcing a water flow passing through a membrane, thus retaining salts on one side of the membrane. For EDR, in contrast, an electric current is applied for the electrochemical separation in which the ions are transferred across the membrane from a less concentrated solution to a higher concentration solution.

Each membrane technology has an optimum field of application depending on the characteristics of the water to be treated, resource availability and the receiving environment. Therefore, Global Omnium/Aguas de Valencia uses the best suited technology to each supply.

RO and NF technologies retain molecules according to their sizes, thus also eliminate the organic substances, herbicides, bacteria and viruses.The RO is appropriate when the salinity is high and a heavy cut of salts is required, especially monovalent salts.NF has a higher flow rate than RO, and would be used when the ions to remove are divalent.

EDR is competitive where a high degree of conversion is required, water having a medium conductivity, the ions to remove are divalent and/or nitrates, and in the case of large plants due to the distribution of a higher fixed personnel cost.

Global Omnium/Aguas de Valencia currently operates three EDR plants with a combined capacity of 32,000 m³/day, and 9 OI plants with a capacity of 20,000 m³/day, being the pioneers in EDR plant construction for nitrate removal in Spain.

Therefore we specialize in the design, financing, construction and operation of desalination plants and denitrification as well as consulting on the commissioning and/or reception of plants by the Administration.