Reverse Osmosis (RO) is a separation technique that is suitable for a variety of purposes, especially when salt and/or dissolved solids have to be removed from an answer. It is certainly one of the most typical kinds of water treatment.
According to Anelia Hough, water remedy consultant at Allmech, leading South African producer of boilers and supplier of water therapy elements, there are several factors to be thought of when choosing an RO system: the customer’s capability requirement (i.e. water usage), the daily production capability of the system, and the p.c rejection for specific contaminants within the supply water.
“Beyond this, RO crops require correct upkeep and care to ensure they operate optimally and to extend their lifespan,” she says. “Aside from regular maintenance, the best way to protect a RO plant is by pre-treating water, which reduces the strain on the RO membrane – a pricey part. It additionally helps to avoid issues like scaling and bio-fouling.”

Common Issues with RO Plants

“Factors that can have an result on a RO system’s performance embrace temperature, operating strain, back pressure, the equilibrium effect/TDS creep, % restoration, and, after all, the RO membrane’s permeate manufacturing and % rejection ratings,” says Hough.
The most typical points in RO crops include:
• Fouling: happens when contaminants accumulate on the membrane surface, successfully plugging the membrane. There are many contaminants in municipal feed water which are innocent for human consumption, however giant enough to rapidly foul (or plug) an RO system.
• Scaling: when particles are deposited on a membrane, inflicting it to plug. As diaphragm seal dissolved compounds turn out to be extra concentrated, scaling can happen if these compounds exceed their solubility limits and precipitate on the membrane surface as scale. Scaling calculations are normally only based on the silicate concentration within the feed water.
• Biofouling: reduces actual membrane efficiency via microbial generation in a biofilm that types on the membrane floor.
• Chemical damage: on a RO membrane, this means a better permeate move and poorer high quality permeate water. Dosing of oxidant agents, similar to chlorine or hypochlorite, can reduce performance and finally end result in the failure of the RO membranes. Use of aggressive cleaners also can trigger chemical damage.
• Mechanical harm: can occur when a system is pressurised too shortly, damaging the RO membrane components. One of probably the most clears signs of damages on a RO membrane is the dearth of salt rejection capabilities. There is also very often a rise of permeate circulate fee.
Pre-treatment might help to keep away from these issues, and Hough says there are numerous choices obtainable.
Pre-treatment Options

“When choosing a pre-filter, users should at all times search for a verified effectivity rating subsequent to the micron size on the filter’s technical information sheet,” says Hough.
• Multi Media Filtration: A multi-media filter is used to help stop fouling of a RO system. This type of sediment filtration is right for a pre-treatment process to any reverse osmosis system helping to ensure lengthy life of the RO membrane parts. A well operated multimedia filter can remove particulates down to 20 microns. A multimedia filter that makes use of a coagulant addition can remove particulates right down to 10 microns.
• Micro Filtration: The filters utilized in microfiltration have a pore size of roughly 0.1 micron. Bacteria and suspended solids are the one element that can be removed by way of microfiltration.
• Antiscalants and scale inhibitors: There are many chemical substances that can be utilized as antiscalants and dispersants to enhance the operation of RO. Antiscalants are a family of chemicals designed to inhibit the formation and precipitation of crystallized mineral salts that type scale.
pressure gauge 10 bar by ion trade: A water softener is a filtration system that removes hardness-causing calcium and magnesium minerals from water by way of a process called ion trade. Standard water softeners are cation trade units. Cation exchange includes the replacement of the hardness ions with non-hardness ions.
• Granular Activated Carbon (GAC) Filtration: Activated carbon removes residual chlorine and chloramines by a chemical response that involves a switch of electrons from the surface of the GAC to the residual chlorine or chloramines. The chlorine or chloramines end up as a chloride ion that’s now not an oxidizer.
“It’s also necessary to clean the RO membrane frequently,” says Hough. “This involves high and low pH cleaners to remove contaminants from the membrane. We address scaling with low pH cleaners and organics, while colloidal and biofouling are treated with a excessive pH cleaner.”

Allmech provides the whole range of pre-treatment and RO membrane maintenance solutions for RO vegetation, including filtration systems, softeners, antiscalants, chemicals and other consumables.
“At Allmech, we’re looking ahead to growing this a part of our business in 2022 and beyond, leveraging our expertise in all issues related to water therapy. We also have a boiler division and we stock a comprehensive vary of Runxin valves, so we’re properly positioned to be a one-stop store for anybody needing a water treatment or boiler specialist, and we’re expecting a busy yr forward,” Hough says.

Scroll to Top