Russell and Sue Kelly of Kelly Commercial Water Treatment Ltd are some of NZ’s most experienced suppliers of pre-engineered and custom built reverse osmosis filter systems for the treatment of commercial and industrial water supplies.
For very high quality water for cleaning and rinsing procedures or product manufacturing, Reverse Osmosis water purifiers are recognized internationally by many companies, to provide long-term savings in improved water quality entering their equipment and processes.
What is Reverse Osmosis (RO)?
All water contains Total Dissolved Solids (TDS). TDS is the measurement by weight of the dissolved materials in a given volume of water. If a material will completely dissolve and is not visible in the water, it is part of the TDS of the water.
Reverse Osmosis helps to lower the TDS content of water, by passing it through a semi-permeable membrane with a pore size of less than 0.0005 microns in diameter. The purified (permeate) water produced by a Reverse Osmosis system is amongst the purest form of treated water available.
Reverse Osmosis can be effectively used for the reduction of Total Dissolved Solids in groundwater, surface water, brackish water and sea water applications – desalination.
Desalination is the process of reducing the salt content in sea water to render it usable for domestic and commercial use
Drinking Water-Reduces scaling; improves taste and clarity. Removes excess dissolved salts including Nitrates in ground water, also cysts and bacteria.
- Hospitals and Surgeries – Sterile rooms
- Ice Production — Reduces scaling to reduce production costs and improves taste and clarity.
- Laboratories, Pharmaceutical and Photographic applications.
- Toiletries, Cosmetics, Shampoo and Cleaning products are all improved.
- Humidification — Reduces scaling and dusting.
- Supermarkets — Prevents scaling in vegetable misters.
- Pretreatment — For use in deionisation systems.
- Boilers and Autoclaves — Improves energy efficiency.
- Vehicle Wash — Provides spot-free rinses.
- Water Jet Cutting — Improves operating efficiency; extends orifice life.
How Reverse Osmosis Works
Reverse Osmosis is a semi-permeable membrane process that acts as a molecular filter to remove over 99% of all dissolved minerals. Water passes through the membrane while the dissolved and particulate matter is left behind and washed away to waste.
As pressure is applied to the concentrated solution, the flow is reversed and water is passed through the membrane from the concentrated side to the dilute side.
Water molecules penetrate the thin layer of the membrane and diffuse through it molecule by molecule. Dissolved salt ions would also diffuse through this layer, except that the solubility of the salt ions in the feed is much less than that of the water. This results in water passing through the membrane more rapidly than salts, causing separation.
The driving force of the reverse osmosis process is driven by both the feed water pressure and the concentration differentials across the membrane surface. For water, the pressure effect is the most important, and for the dissolved ions in the water, the concentration difference is the most important. Therefore, increases in pressure increase the amount of treated water without causing a corresponding increase in waste flow.
Contaminants Removed By Reverse Osmosis
The RO process removes most of the dissolved mineral salts, almost all of the particulate matter and most of the dissolved organic compounds.
Preliminary water treatment systems are utilised to reduce any parameter levels that exceed the operating parameters specified by the RO membrane manufacturers, such as sediment, total hardness, iron/manganese and chlorine.
Reverse Osmosis systems remove substantial amounts of most dissolved minerals (such as salts, metals and other minerals). Bacteria and other microbiological contaminants are also removed due to their size in relation to the size of a membrane pore. An ultra-violet unit as a final pass provides 100% microbiological safeguard.