OVERVIEW
Today reverse osmosis represents the safest and most convenient technique for the desalination of water of various sources. This treatment replaces more and more other water desalination technologies thanks to the optimum binomial between qualitative results and low operating costs.    


Advantages
In fact reverse osmosis guarantees reduced energy consumption and low consumption of chemical products. Furthermore, the parameters of waste water are within the limits for the discharge, thereby downsizing the more than ever noted problem for the disposal of eluents (which exists for example for water softeners and ion exchange resin demineralization units).  


HOW IT WORKS
Reverse osmosis is the process that occurs when a saline solution is placed into contact with a membrane that is absorbent to water (and not dissolved salt) at a pressure that is over the osmotic pressure of the solution itself. The passage of a water poor in salts (permeate) occurs through the membrane, whereas on the outside of the membrane a waste water rich in salts (concentrate) is obtained.

Here below is a list of the main parameters that are used in the planning stage of reverse osmosis and desalination processes:

-    Salinity of the water to be treated
-    Temperature of the water to be treated
-    Recovery factor
-    pH
-    SDI
-    Hardness
-    Alkalinity

The comprehension of the water characteristics must be added to these essential factors in particular, in order to improve possible pre-treatment, it is fundamental to verify the presence of:  
-    Suspended solids
-    Polluting metals, such as iron and manganese for example
-    Bacterial concentration
-    Chlorine or oxidizing agents in general (except oxygen)
-    organic substances, sulphides, oils.

PRE-TREATMENT
Before the reverse osmosis section it is important to determine the most suitable “pre-treatment” based on the characteristics of the water to be treated so as to guarantee the greater operating continuity of the system and reduce washing frequency. Correct pre-treatment prevents relatively rapid lodgement of the membrane due to grime and/or physical impurities, lodgement due to precipitation of encrusting salts and/or metals, bacterial proliferation, contact with oxidising agents.

USAGES

• Desalination of brackish water to obtain drinking, irrigational or industrial water.
• Demineralising of well or tap water for industrial use (heating plants, food, pharmaceutical, electronics industry, etc..).
• Desalination of sea water to obtain drinking water

OUR STANDARD PRODUCTION
Our production of reverse osmosis units for the desalination of water covers a wide range of solutions which are different based on:

• The type of water to be treated, tap water, brackish or sea water;
• The type of use, drinking water, irrigational or industrial water;
• The productive capacity, from 200 l/h to 25 m3/h of permeate for brackish or tap water.

The desalination units efficiently operate in a continuous manner, consequently the necessary productive capacity is given from the daily need of permeate divided by the 24 hours that the unit is operating. It is advisable to have an accumulation tank of the produced permeate.   


OPERATIONAL LIMITS
In order to guarantee the long lasting performance of the membranes, the intake water of the reverse osmosis unit must respect the following limits:

• SDI < 3
• Iron < 0.05 mg/l
• Manganese < 0.05 mg/l
• Chlorine and oxidant 0.0 mg/l
• Bacterial and organic substances concentration following the requirements of a drinking water
• Absence of oils, sulphides and polluting substances in general 

Tap or low salinity water demineralising units 

OVERVIEW

The reverse osmosis tap water demineralising units are used for the production of demineralised water for industrial use (heating plants, food, pharmaceutics, electronics industry, etc..).
The models have productive capacities that range from 200 l/h to 2200 l/h of produced permeate. The demineralisation units efficiently operate in a continuous manner, consequently the necessary productive capacity is given from the daily need of permeate divided by the 24 hours that the unit is operating. It is advisable to have an accumulation tank of the produced permeate.   
The desalinisation units are equipped with a sequestrant agent dosage group that prevents the precipitation of incrusting salts on the membranes. Furthermore, the unit may require an additional dosage group or alternatively an active carbon filter to reduce the chlorine present in the water to be treated. Post-treatment made up of a degassing tower can be introduced in the event that it is necessary to eliminate the carbon dioxide that is present in the permeate and increase the Ph. The use of a station for the periodic washing of the membrane is always advisable. For the production of ultrapure water the equipment consists of mixed bed resins and UV after the dissalation unit.