Reverse osmosis (RO) water treatment technology has been used for years, by many businesses to remove dissolved particles from water, by forcing the water through a semi-permeable membrane. But, even after treatment from RO Plants, there is certain amount of water that is rejected, which is known as the RO reject water and we can treat it to further reuse it.
Let’s look at the treatment methods of RO reject water produced by Commercial RO Plants.
What is RO reject water?
Desalinating water to produce purifying drinking water or the water for re-use, are the two more common uses for RO reject water. The micropores in the membrane allow the water and other molecules, with lower molecular weights to pass through, producing a stream of purified water known as the permeate.
The specific molecular weight of the molecules allowed to pass through, is dependent on the chosen membrane. The membrane traps larger molecules as well as some water that does not pass through the barrier. The concentrate or RO reject is the name given to this concentrated stream.
How to treat rejected water produced from Commercial RO Plants?
For RO reject / RO concentrate wastewater streams, evaporators have proven to be efficient technology. In short, it is an established technique for lowering the water content of water-based waste. The water component of water-based waste is converted to water vapour in the evaporator, leaving the higher boiling pollutants behind. This significantly reduces the volume of waste that must be transported off-site.
Since, evaporation technology has historically required less "hands-on" work than other wastewater treatment techniques, it has a much lower labour cost. Compared to membranes and other physical/chemical treatment methods, evaporation technology can manage a significantly larger spectrum of waste streams. Finally, evaporation concentrates waste streams far more effectively than other techniques, resulting in a lower disposal volume and expense.
Removal of RO reject water through evaporators
The saturation concentrations of the individual salts at the mentioned temperatures, often nearly match the evaporator concentration endpoints. At the mentioned elevated temperatures, the saturation values of many sodium and potassium salts, including sodium sulphate, sodium chloride, potassium chloride, and potassium nitrate, vary from 400,000 to 600,000 mg/liter.
According to basic math, concentrating effluent from the RO process, from 30,000 mg/liter to 400,000 mg/liter results in a volume reduction of roughly 92.5%. A volume decrease percentage of roughly 91.6% would result from concentrating from 50,000 mg/liter to 600,000 mg/liter.
Achieving Zero Liquid Discharge (ZLD)
Evaporation can be used to concentrate the RO reject / RO concentrate, which can then be further dewatered with additional equipment, when there is a desire or need to achieve zero liquid discharge (ZLD).
An Evaporator is used to handle RO reject and RO concentrate in the first step of the process, and it produces distilled water and concentrate. A concentrate storage tank receives the concentrate, which separates into layers of slurry and supernatant
Applications of treated reject water produced from Commercial RO Plants
1. Agriculture and irrigation for food crops
2. Landscape irrigation for private and governmental properties
3. Structural and non-structural firefighting
4. Toilet water
5. Fountains used for ornamentation
6. Industrial process water that might come into contact with employees
7. Industrial or commercial cooling or air conditioning
8. Artificial snow can be created
9. Cleaning and sanitization
10. The boiler's feedwater
Benefits of treatment of reject water produced from commercial RO Plants
1: Reverse osmosis reduces the amount of raw water consumed at the beginning, and the amount of water that is released into sewer systems.
2: For processing, industrial processes can use a tremendous amount of freshwater, but recycling wastewater would reduce that amount in half. The price of getting raw water would go down as a result.
3: Additionally, since a sizable portion of wastewater would be used as raw water, less wastewater would need to be discharged, lessening the load on discharge sewers.
4: To recycle or reuse up to 80% of rinse water, it can also be utilized in conjunction with an existing filter system, or other pre-treatment technologies.
5: Grey water, or water used for rinsing processes, is typically simpler to cure, even if most wastewater does not contain a large amount of reusable water.
To assist you with this process, Netsol Water provide RO Plants of high-quality. For further information or to make a purchase, please contact us at +91-9650608473 or enquiry@netsolwater.com
