DESALINATION OF SEA WATER OR SALOBRA
Applications
The desalination of seawater and brackish water is applied to obtain drinking water for:
- Populations;
- Hotels;
- Industries;
- Remote islands;
- Irrigation of agricultural and leisure areas.
Characteristics of the waters to be treated
- High or medium salinity, ranging from 2000-2500 mg / l in brackish water to 35000-42000 mg / l in sea water;
- Inexhaustible source of water;
- Small variability of water quality to the same absorption zone;
- The main presence of sodium chloride, although with different chemical components, depending on the capture area;
- Possible significant variations in temperature depending on the time of year, sea currents and the catch system;
- The higher the external temperature or the insulation, the higher the salinity;
- Lower salinity in the riparian zones of large rivers;
- Salinity and composition are different from one sea to another;
- Algae may be present in shallow water.
Technology applied in treatment
The reverse osmosis technique is used, whose characteristics are:
- It is the process in which pressure is exerted on water so that it passes through a semi-permeable membrane.
- Separation, due to the effect of osmotic pressure, of all salts and chemical compounds, in the order of 99.5%;
- The temperature, which influences, must not be lower than 4 ° C or higher than 35 ° C;
- The contamination of the membrane will depend on the previous treatment applied to the incoming water;
- The higher the turbidity, the higher the degree of pretreatment.
System Advantages
- Modular, compact and transportable;
- Occupy a small deployment area;
- For the chemical cleaning produced, only energy and some reagents are used;
- Eliminates or greatly reduces contaminants in water, in the order of 99.5%;
- Produce drinking water with low salinity 500 mg / l, suitable for human consumption, according to the WHO quality criteria.
System disadvantage
- Works at high pressures;
- High energy consumption, even with energy recuperators;
- High salinity concentrate reject volume 30-55%, depending on incoming salinity; High concentrations of salt in concentrate.
Conclusions
- The use of desalination techniques, both in brackish and marine waters, may be, in certain circumstances, the only alternative to obtain drinking water;
- 24/24 h service guarantee.
