Antiscalant is a pretreatment for reverse osmosis system that is highly effective in preventing the membranes from scaling. Before the feed water enters the reverse osmosis membrane, an Antiscalant is injected into the water and sent the through the system. The chemicals creates a time delay between the bicarbonate and the calcium magnesium. The delay allows the water to pass through the membrane before any chemical reaction, in which scale can form, occurs.
Multimedia Filtration is often used upstream of RO/NF to remove suspended solids. However, MMF media is only efficient at removing particles larger than 20 microns.
RO)-Membrane cleaning is needed in case the performance of the membrane system is decreasing as consequence of fouling. This fouling can be of different origin like inorganic-, organic- and suspended matter. Also known as respectively scaling, biofouling and fouling. Mainly, every kind of fouling will lead to increased resistance over the feed channel and increased limitation of available membrane surface. Subsequently followed by energy and production losses..
Membrane biofouling is defined as the adherence and growth of algae and bacteria on a membrane surface. The process of biofouling will affect the performance of a membrane system. First by the attachment and growth of microorganisms and algae on the feed spacer which will lead to an increased resistance over the feed channel. Second, by covering the membrane surface with a layer of biomass and blocking the feed water from the area where ROor nanofiltration can take place. As consequence, more feed pressure (i.e more energy ) is needed for the same mass flow of produced water.