The primary goal of water ...
Published by Nello Acetino
The primary goal of water entering an RO is to have an SDI of less than 5, but much better if it is less than 3 for various reasons that I don't talk about here. Now, what counts is therefore to reduce the suspended solids to the minimum possible, in particular the colloids present in the water. Putting cartridge filters reduces SDI but must therefore be measured! And also if the water is dirty there is the risk of having to change the cartridge filters too frequently ...
Also do not underestimate that there are several dissolved salts that can quickly go into over-saturation concentrating in the permeate (an example is Barium which, if present even in small quantities, can generate a precipitate of barium sulphate, clogging the membranes).
That said, returning to what was said at the beginning, a solution could be to insert MF or UF membranes before the ROs if you can't get a good SDI before the RO. Both UF and MF technologies rely on size as the primary factor determining which suspended solids and high molecular-weight dissolved organics are retained by the respective membranes.
Due to the microporous nature of MF and UF membranes, the
pressure required to drive water through them is significantly lower than for RO membranes, typically less than 100 psi.
Also do not underestimate that there are several dissolved salts that can quickly go into over-saturation concentrating in the permeate (an example is Barium which, if present even in small quantities, can generate a precipitate of barium sulphate, clogging the membranes).
That said, returning to what was said at the beginning, a solution could be to insert MF or UF membranes before the ROs if you can't get a good SDI before the RO. Both UF and MF technologies rely on size as the primary factor determining which suspended solids and high molecular-weight dissolved organics are retained by the respective membranes.
Due to the microporous nature of MF and UF membranes, the
pressure required to drive water through them is significantly lower than for RO membranes, typically less than 100 psi.
1 Comment
Obviously you will also need to dose an excellent antifoulant before entering the membrane since with a Recovery of 75% the brine water concentrates 4 times and this also implies massive precipitation phenomena of various inorganic salts, in particular calcium carbonate. , but also Iron, Sulphates, Strontium, Phosphates etc represent threats to be controlled
Published by Nello Acetino