Reverse Osmosis (RO) is a separation technique that is appropriate for a variety of purposes, particularly when salt and/or dissolved solids have to be removed from an answer. It is amongst the commonest forms of water therapy.
According to Anelia Hough, water therapy marketing consultant at Allmech, leading South African producer of boilers and provider of water remedy components, there are several components to be thought-about when deciding on an RO system: the customer’s capacity requirement (i.e. water usage), the day by day manufacturing capability of the system, and the percent rejection for specific contaminants within the source water.
“Beyond this, RO plants require proper upkeep and care to ensure they perform optimally and to increase their lifespan,” she says. “Aside from common maintenance, the easiest way to guard a RO plant is by pre-treating water, which reduces the strain on the RO membrane – a costly element. It additionally helps to avoid points like scaling and bio-fouling.”
Common Issues with RO Plants
“Factors that can have an effect on a RO system’s efficiency embrace temperature, working stress, back stress, the equilibrium effect/TDS creep, % restoration, and, after all, the RO membrane’s permeate manufacturing and percent rejection ratings,” says Hough.
The most common points in RO plants embody:
• Fouling: occurs when contaminants accumulate on the membrane floor, effectively plugging the membrane. There are many contaminants in municipal feed water which may be innocent for human consumption, however massive sufficient to rapidly foul (or plug) an RO system.
• Scaling: when particles are deposited on a membrane, inflicting it to plug. As certain dissolved compounds become more concentrated, scaling can happen if these compounds exceed their solubility limits and precipitate on the membrane surface as scale. Scaling calculations are usually only primarily based on the silicate focus within the feed water.
• Biofouling: reduces precise membrane efficiency through microbial era in a biofilm that forms on the membrane floor.
• Chemical damage: on a RO membrane, this means the next permeate move and poorer high quality permeate water. Dosing of oxidant agents, corresponding to chlorine or hypochlorite, can scale back performance and in the end result in the failure of the RO membranes. Use of aggressive cleaners can even trigger chemical harm.
• Mechanical injury: can occur when a system is pressurised too shortly, damaging the RO membrane parts. One of probably the most clears indicators of damages on a RO membrane is the lack of salt rejection capabilities. There can be fairly often a rise of permeate move rate.
Pre-treatment may help to keep away from these issues, and Hough says there are numerous choices available.
Pre-treatment Options
“When choosing a pre-filter, users ought to always look for a verified effectivity score subsequent to the micron size on the filter’s technical data sheet,” says Hough.
• Multi Media Filtration: A multi-media filter is used to help stop fouling of a RO system. This sort of sediment filtration is right for a pre-treatment process to any reverse osmosis system helping to ensure long lifetime of the RO membrane parts. A properly operated multimedia filter can remove particulates down to twenty microns. A multimedia filter that makes use of a coagulant addition can take away particulates all the method down to 10 microns.
• Micro Filtration: The filters utilized in microfiltration have a pore size of approximately 0.1 micron. Bacteria and suspended solids are the one component that can be eliminated through microfiltration.
• Antiscalants and scale inhibitors: There are many chemical compounds that can be utilized as antiscalants and dispersants to improve the operation of RO. Antiscalants are a household of chemical compounds designed to inhibit the formation and precipitation of crystallized mineral salts that type scale.
• Softening by ion change: A water softener is a filtration system that removes hardness-causing calcium and magnesium minerals from water via a course of known as ion change. Standard water softeners are cation trade gadgets. Cation change involves the alternative of the hardness ions with non-hardness ions.
• Granular Activated Carbon (GAC) Filtration: Activated carbon removes residual chlorine and chloramines by a chemical reaction that includes a switch of electrons from the floor of the GAC to the residual chlorine or chloramines. The chlorine or chloramines end up as a chloride ion that is not an oxidizer.
“It’s additionally necessary to scrub the RO membrane often,” says Hough. “This involves high and low pH cleaners to take away contaminants from the membrane. We address scaling with low pH cleaners and organics, whereas colloidal and biofouling are handled with a excessive pH cleaner.”
Allmech presents the whole vary of pre-treatment and RO membrane upkeep options for RO plants, together with filtration techniques, softeners, antiscalants, chemicals and other consumables.
“At pressure gauge วัด แรง ดัน , we’re trying forward to growing this a half of our enterprise in 2022 and past, leveraging our experience in all issues related to water therapy. We even have a boiler division and we stock a complete vary of Runxin valves, so we’re well positioned to be a one-stop shop for anybody needing a water treatment or boiler specialist, and we’re expecting a busy yr ahead,” Hough says.

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