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Either from your spear pump, bore or direct from sea water, Sodium Chloride or Salt, is one of the most common elements in water.
For removal of salt from water there are limited solutions available. To safely and efficiently remove salt, from water, reverse osmosis or desalination, incorporating membrane rejection technology, is considered one of the best methods available.We have Desalination and High Rejection Seawater Units, for most applications. Download Product PDF here
What percentage of salt, does a desalination system remove?
Desalination machines are built to certain specifications - relative to the water quality and the amount of rejection required. It is now possible to remove up-to 99.8 % of salt content from sea water, that may begin with a salinity of around 35,000 ppm. Advanced high rejection membranes are now available and membrane technology has been developing rapidly over the past few years. Membranes are available for a broad range of applications these days, including low salinity, medium salinity and high rejection, for seawater.
Membrane Construction Video - click here
How do you determine the amount of rejection required from a desalination plant?
Firstly, the conductivity or TDS range, is determined. As stated prior, the average salinity in the west pacific is appprox. 28,000 - 35,000 ppm. Membranes are constructed with a range of pore sizes, put simply, the finer the pore size, the higher the rejection of salt content.
The actual term for this process, is expresses as a 'recovery rate'. The recovery rate is the 'amount of fresh water recovered from a given amount of raw water, or feed water' (the source of the water being treated) Recovery is proportionate to the salinity of the feed water. Example: If there is a high salinity level in the feed water, then the recovery of fresh water will be relatively low. In the case of a bore water source, with very low salinity, then the recovery rate will be quite high. Summary: Recovery rates will vary, depending on the actual salinity of the given feed water source. As reverse osmosis occurs at approx. 450 psi, low salinity water requires much less pressure to be exerted, for the saline water to 'Give-up' its fresh water content. As a result, low salinity machines used on brackish water, bores, spears and river water, in theory, should last longer, as there is less stress on pumps, membranes and other components within the system. High rejection membranes will require more regular service as they are working harder to reject more salt, and running at higher pressures, to achieve the same result. This means membrane fouling occurs at a faster rate.
What is TDS?
TDS is the abbreviated term for 'Total Dissolved Solids' Salt content is sometimes also measured by the amount of conductivity. (the ability for current to flow through the water) Current flow, through water, is enhanced by high salt content. It is this environment, which causes a lot of problems relating to corrosion and electrolysis, especially in boats and with some land based installations. Common results are pump failures and very severe corrosion if left unchecked.
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