What is the role of post treatment in industrial RO Plants?
The efficiency of industrial reverse osmosis technology has increased with time. This is made possible by creative design, improved membrane materials, more effective pumps, and increased pre and post-treatment procedures, used in Industrial RO Plants.
In this blog, we will understand the role of post treatment in industrial RO Plants!
If rejected water from Industrial RO facilities is not treated properly, corrosion may occur in pipes and fixtures farther down the line, including the distribution system.
The post-treatment procedure includes the addition of chemicals to modify the quality of the water. A small amount of raw water is mixed with permeate before disinfection and distribution, when the water quality permits less, or in some cases, the use of corrosion control chemicals. If corrosion takes place, it may result in problems with everything from aesthetics (such as "red" water produced by iron), to major public health risks (e.g., elevated lead concentrations).
Post-treatment may be required depending on how the product water will be used at the point of use; for instance, RO permeate must be re-mineralized before being distributed for potable consumption.
Major Post Treatment Methods in Industrial RO Plants
· pH Balancing
· Alkalinity Correction
· Calcium Supplementation
· Anti-corrosion agents
1: pH Adjustment
By changing the pH, insoluble chemicals are produced on exposed pipe walls. Passivation serves as the operational mechanism for this corrosion management strategy. The pH level is altered using chemicals like lime, soda ash, sodium hydroxide, potassium hydroxide, and carbon dioxide. The optimum source waters for pH adjustment include, low to moderate hardness and alkalinity (between 80 and 150 mg/L as CaCO3).
Calcium carbonate precipitation is routinely substituted with this treatment technique. Some issues with pH alteration include increased production of disinfection by-products at pH levels over 7.9, lower chloramine disinfection efficacy at pH levels below 7.8, and a higher risk for calcium carbonate scaling in the distribution system pipe, at pH levels above 7.9.
2: Alkalinity Correction
Alkalinity adjustments are frequently used to produce insoluble compounds on the pipe walls of distribution systems. By including pipe components in a metal hydroxide/carbonate protective layer, carbonate passivation is accomplished.
Alkalinity can be changed with the help of lime, soda ash, sodium bicarbonate, sodium hydroxide, potassium hydroxide, and carbon dioxide. The use of sodium bicarbonate is mainly preferred for alkalinity correction.
Although, sodium hydroxide only slightly increases the water's alkalinity, it can significantly alter the pH.
3: Calcium Supplementation
This corrosion control method works by altering the equilibrium of the calcium carbonate for the source water. The purpose of this treatment method is to coat the pipe walls in a protective layer of calcium carbonate.
Calcium carbonate precipitation is accomplished by modifying the pH and alkalinity of the source water, and neither calcium addition nor removal is necessary.
The key to this treatment strategy is creating the ideal conditions for calcium carbonate saturation to take place. To create the ideal conditions for the calcium and carbonate ions, to overcome their solubility limitations in water, the pH/alkalinity is changed.
4: Odour Control
Due to the fact that H2S is a gas, it cannot be removed by membrane methods. It may be essential to do a post treatment with a single or two stage odour control system, in order to get rid of H2S and other produced gases like CO2 (if excessive pre-treatment acids are added).
5: Corrosion Inhibitors
Polyphosphates, zinc phosphates, and silicates are the three main types of inhibitors, which are frequently utilized. The inhibitors prevent corrosion through a number of different ways, such as buffering the water at the proper pH, securing the corrosion by-products, particularly lead and copper, inhibiting scale growth, and developing a coating film on the pipe walls.
According to operational data, the source water's pH, alkalinity, calcium and total hardness, chloride, sulphide, iron concentrations, and dissolved oxygen levels all affect the inhibitor choice.
What do we offer?
Look for reverse osmosis (RO) systems from respected firms like Netsol Water Solutions, to get the most out of Industrial RO Plants for your industrial applications. We offer different post treatment methods to make sure that industrial RO Plants can work effectively, and the rejected water is safe to discharge.
For further information, contact us at +91 9650608473 or email at enquiry@netsolwater.com
