RO desalination

Industrial RO equipment, RO desalination

This RO (reverse osmosis) water treatment and purification technology has taken the place of complete ion exchange desalination devices in the last 10 years. With this modern filtration technology, we can produce water quality up to 10 µs. The reverse osmosis (RO) device is a water filter with an opening of 0.0001 microns, with this water purification we can remove organic impurities, heavy metals and bacteria from the water.

Application areas:
feedwater for boiler, pharmaceutical industry, cosmetic industry, glass and semiconductor manufacturing, car parts manufacturing.

The RO equipment is nothing more than a high-efficiency filter equipment, the main component of which is the RO membrane. It is a special membrane that consists of a laser “perforated” plastic “quilt” that is then carefully wound around a perforated tube. The membrane or membranes thus produced are placed in a membrane housing, where they are pressurized to a high-pressure 10-25 bar of raw water during operation. Because the “gap size” of the membranes is so small that “almost” only elementary water can pass through it, while on one side of the membrane is ultrapure water, on the other side water condensed with impurities and mineral salts leaves. Purified water is called permeate, while wastewater is called concentrate.

An RO system is as reliable as the pretreatment of the RO equipment is solved, so serious emphasis should be placed on this in the design. A very important and expensive element is the membranes of the RO equipment. These can work for many years with a good pretreatment, but if the RO pretreatment is not good or incomplete, the membrane can break down in as little as a few months. Effective membranes give almost completely pure water, but they cannot provide distilled water either, so this purification is max. It can be 99.9%. If even better water quality is required, other combined technologies such as mixed bed ion exchange or EDI should be used.

The highest operating costs for RO equipment are the water loss already mentioned, the periodic maintenance cost (dry cleaning of the membranes) and the energy consumption of the booster pump. The maintenance interval of the RO equipment is also greatly influenced by the quality of the pretreatment and raw water. The energy consumption of the booster pump is decided at the design stage. You can save a lot here too. For example, by using the pressure of the mains water or the well water pump, since this pressure can be added to the pump of the RO equipment, so much less and less consuming equipment is needed.

post treatment:
post treatment is when the water quality produced by the RO equipment is not sufficient for the given task or application. For example, when producing feed water for a steam boiler, the RO equipment usually cannot produce water softer than 0.2-0.3 nk °, but even softer water is required for these applications. For post treatment can be used a sodium ion exchanger softener or a mixed bed ion exchange equipment. Post treatment also can be an another chemical addition, such as a conditioning chemical or an EDI (electrolytic desalination plant).

RO equipment:
industrial RO equipment is ususally allways build up of similar elements:

– pre-filter
– pressure pump
– membrane housing and membrane
– flow or rotameter, or its digital version
– pressure gauges
– conductivity measuring instrument

These elements are usually found on all RO equipment, but can be simplier or even more complex versions.

pre-treatment:
as already mentioned, this one is the most important part elements in the RO equipment system, the contaminants must be removed from the water or their damaging effects must be eliminated. A pre-treatment definitely consists of a pre-filter, as there is no water without floating dirt. If the dirt is too much and too large, it can quickly clog the membranes, so a pre-filter of 5 µm is used. Depending ont he composition of the raw water, a water softener may be required, antifouling chemical dosing for larger systems, an irom remover device or, in the case of main water dechlorination, an active carbon filter.