Water treatment and desalinization
The major consumers of water are oil refineries and petrochemical plants. Water is used to generate steam and for cooling. In processing installations located along the coastline, even upon availability of drinking water it is impossible to use it due to inadequate physical and chemical characteristics, or due to lack of water to meet all the needs of the enterprise. That is why there is a need of special water treatment processes regardless of the presence of available water source.
We have developed specific solutions for the following cases:
Artesian water treatment
Artesian water is the most common source for the majority of civil and industrial projects as in water-bearing layer at shallow depth over the ground level there are large reserves of water. This water has the following characteristics:
- the salinity from low to moderate;
- low content of microorganisms, bacteria, algae, fungi;
- low water turbidity and the concentration of suspended solids, that may increase due to particular circumstances
In accordance with the abovementioned artesian water treatment involves filtration using coarse filters to remove suspended solids. Filtration efficiency may be increased by the use of chemical additives (brightening) or by using membranes (micro-filtration, ultra-filtration). If the concentration of dissolved solids is too high for industrial or domestic use, the process of desalination by reverse osmosis should be applied.
Well water treatment
Water from rivers and lakes is the most common and accessible source of raw water. While the salinity of river or lake water is sufficiently low because of its limited contact with the ground (unless the outflow of salt water from the sea) and its turbidity and concentration of microorganisms vary greatly depending on the season or storm conditions.
Ground water treatment may involve several steps, such as clarification of water by coagulation and flocculation as well as filtration using coarse filters to remove residual suspended solids.
Filtration efficiency may be increased by the use of chemical agents (coagulation agents or filter aids) facilitating coagulation of solids and increase of process efficiency. Micro-filtration and ultra-filtration are effective alternatives to chemical and physical processes due to the high efficiency potential of retention of suspended solids, bacteria and high-molecular hydrocarbons.
If water from estuaries of rivers is contaminated by a sea water flow, desalination technology by reverse osmosis may be used.
Desalination of sea water
Desalination of sea water is carried out in cases of lack of artesian water or well water. Particularly this process is used in deserts and in places where well water is of a very bad quality. The major element of the desalting process is installation of a reverse osmosis with pumping of salt water by a cross-flow to elements with sufficient pressure to overcome the high osmotic pressure and to achieve a satisfactory recovery rate.
Energy-saving solutions using membrane separators with a high degree of energy recovery are used: it accumulates energy, then this energy under the high pressure is transferred to the incoming feed water. This way energy consumption per unit of desalinated water is reduced.
Seawater is a living habitat with lots of microbes and algae, so the primary goal in the treatment of seawater is filtration and purification from the bacteria. Membrane techniques (ultra-filtration and micro-filtration) or coarse filters may also be used for filtration.
A key factor of the design of desalting installation for seawater is to choose the correct material taking into account corrosivity of seawater.