Filtration and membrane separation: the ACWA approach
13 October 2010, News release from ACWA Services
As source water contamination becomes an increasingly high-profile issue and regulatory requirements for water quality become ever more onerous, choosing the correct combination of filtration systems is vital.
With new contaminants such as pharmaceuticals and endocrine disrupting chemicals being found in raw water sources, water utilities are having to consider increasingly sophisticated filtration systems to ensure their supplies remains pure.
ACWA is able to provide solutions covering the entire filtration spectrum and all associated technologies - the company is not tied to any particular supplier, which ensures it can provide a completely unbiased service, choosing the most appropriate membrane for each application for an optimum, affordable solution tailored to exact client requirements.
There is a wide spectrum of filtration available, and ACWA has found over its many years of designing and installing such solutions that it is usually necessary to combine two or more technologies to achieve the required results economically.
For example, every Reverse Osmosis (RO) plant has a minimum pretreatment of 5-micron cartridge filtration and in many cases, pressurised sand filtration would be used to pretreat the cartridge filter to minimise running costs. Ultrafiltration can also be an attractive pretreatment option for RO, and was chosen for ACWA Emirates' high-profile desalination project in Dubai's prestigious Palm Jumeirah development.
Every project is studied thoroughly by ACWA's experts to balance capital and running costs to achieve the optimum whole-life cost. The client's final water quality requirement will determine the main filtration technology chosen, and the raw water quality and project economics will determine the best pre-treatment technology option.
The type of contaminants to be removed will dictate the type of filtration chosen - for instance larger particles can be removed using manual or automatic strainers, while smaller particles must be treated using mechanical filtration or membrane systems of decreasing pore sizes: cryptosporidium require microfiltration of no more than 2 microns retention. The smallest r particles such as viruses and endotoxins will need treatment by ultrafiltration (systems are available with a variety of filtration cut-off points from 0.01 to 0.001 microns).
Even smaller particles such as insecticides and antibiotics may require either nanofiltration (which removes particles greater in size than 10-9 metres) or RO, which can remove even dissolved salts and metal ions.
Robert Ingham, ACWA Services Manager for Membrane Systems says: "ACWA has extensive experience gained from major projects around the world involving the design and installation of every type and combination of filtration system. Our expertise and impartiality enable us to provide clients with the ideal solution for all their treatment environments."
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