30 Jul Whitford’s Technologically Advanced Purified Water Solution – Reverse Osmosis Plant
In a previous blog about Whitford Manor Estate, I wrote about the membrane bioreactor (MBR) plant we are installing to manage the wastewater requirements for the development.
I briefly mentioned that Stewart & Cavalier are also installing a reverse osmosis plant, the Mena Water system, to treat the bore water that will provide fresh water to the 150 homes in the estate. I’m sure you will be as fascinated as I am in how this amazing solution works.
The first thing I found out is that Osmosis is not so very new. Osmosis was first observed in 1748 by Frenchman Jean-Antoine Nollet, however, it was not until 1950 at UCLA that semi-permeable membranes were considered for purification of water – initially the desalination of seawater. In 1977, the first municipal plant in the US was commissioned in Cape Coral, Florida, with an initial operating capacity of 11350 cubic metres per day. Our requirements at Whitford, of course, are nowhere close to these figures, but the principals are very similar.
The scientific description of osmosis is “the spontaneous movement of solvent molecules through a semi-permeable membrane to a region of high solute concentration.” You might have learnt about this in your biology lessons at school – plants absorbing water from the soil through their roots is the most commonly used example.
Reverse osmosis uses pressure to force the solvent through a semi-permeable membrane that retains the solute on one side, in the case of the Mena water plant, delivering a process for water purification. This is not simply a fancy type of filtration – filtering is essentially just excluding molecules by size. Reverse Osmosis also involves diffusion, making the system capable of removing salts and other impurities such as bacteria, and in the case of the Whitford Manor Estate development, boron.
Reverse osmosis is the only viable option for this installation. The alternative would be a costly and operationally complex precipitation process, requiring a much larger footprint than the 40′ shipping container that the Mena Water plant is packaged in.
Another huge advantage of the Mena Water system is that the tanks can be buried underground with the plant on top, reducing the footprint dramatically. In the Manor Estate development the entire wastewater system will be beautifully disguised by an architecturally-designed boathouse on the shore of stormwater overflow ponds that will be a visually attractive feature of the subdivision.
The Mena water system is suitable to purify and treat seawater, high brackish, brackish, and even industrial or municipal water when treated with the Membrane Bioreactor (MBR) prior to the Reverse Osmosis (RO). Applications include drinking water, food industries and even the medical industry, e.g. kidney dialysis.
Bore water is common throughout New Zealand with differing treatment requirements. Some regions are high in iron, some, like Whitford, require the removal of other trace elements. No matter what the contaminant is, reverse osmosis is a much more effective treatment solution than filtration or precipitation. The Mena Water reverse osmosis plant is an effective solution. If you have a requirement for purifying water, contact Ross Burrell Sales Engineer / Business Development on +64 27 533 4966 or email us
