COATEX EM 201 ASP Anti-scaling Agent for Reverse Osmosis Units
COATEX EM 201 ASP
for Reverse Osmosis Units
COATEX EM 201 ASP
for Reverse Osmosis Units
COATEX EM 201 ASP 1/4
COATEX EM 201 ASP is a liquid polymer specifically designed to prevent mineral scale formation in reverse
These systems are used for water purification, using multiple types of water such as brines, sea water and
mineral loaded water.
Its molecular weight distribution has been carefully engineered to insure a maximum of efficiency in this
The remarkable property of this polymer is its ability to perform well below stoichiometric quantities by
threshold effect, which allow uses between 0.5 and 10 ppm depending on the salinity of the water.
The presence of the polymer will inhibit the formation of highly structured crystals that are responsible for the
scaling commonly encountered in these units.
In the presence of minute amounts of COATEX EM 201 ASP, the minerals will crystallise in small irregularly
shaped portions that disperse well and tend to redissolve easily.
Furthermore, COATEX EM 201 ASP will inhibit bacteriological growth, thus eliminating fouling due to slime
Nature: Polycarboxylic polymer in aqueous solution
Appearance (20°c): Pale amber, clear liquid
Solids content : 35 ± 1%
pH : 3.5 ± 1
Specific gravity : 1.140 ± 0.01 (20°C)
Solubility : Fully soluble in water
Purity : The high purity of COATEX EM 201 ASP insures a non reactivity with
membranes and allows overdosing without any damage to the RO units as
proven in field tests.
* These characteristics are not specifications.
– Field and laboratory tests have proven the effectiveness of COATEX EM 201 ASP at very low levels (even
below 1 ppm).
– The use of COATEX EM 201 ASP will increase the yield (permeate/feed water) of the reverse osmosis
units (up to 80%).
– COATEX EM 201 ASP is non polluting and non toxic.
– It will prevent membrane fouling and biomass growth in the dilution tanks (Slime suppression).
– Its composition makes it inert toward membranes and thus perfectly safe to use in all kinds of processes.
– By allowing stable operations, COATEX EM 201 ASP will dramatically reduce maintenance shutdown and
thus increase profitability of the entire operation.
COATEX EM 201 ASP 2/4
5 ppm of polymer
4 ppm of polymer
9 ppm of polymer
2 ppm of polymer
Antiscaling efficiency of the COATEX EM 201 ASP
with different minerals
– By eliminating the use of strong acidic solution for membranes cleaning, COATEX EM 201 ASP will
noticeably increase the life of RO units as well as eliminate the hazards inherent to sulphuric acid handling.
– Its low viscosity will authorize a use without dilution and no special need for an exotic metering pump.
– If dilution is wanted, no micro-organism will develop in normal conditions.
– COATEX EM 201 ASP stability is not affected by temperature or dilution. If temperature was to drop below
-5°C, the product could crystalline in its commercial form but would return to its normal aspect upon warming.
– COATEX EM 201 ASP does not contain strong acids and thus will not cause corrosion, thereby extending
the life of RO units.
– COATEX EM 201 ASP does not contain phosphates and is not polluting, which will be favorably looked at
by Water Agencies.
– It will prevent Calcium and Barium Sulfates scaling while acidic treatment will not.
– COATEX EM 201 ASP will inhibit phosphate scale while acidic treatment is inefficient in this
For example, the use of COATEX EM 201 ASP
on a RO unit operating at 60 bars (860 P.S.I.),
with a brine containing 23 grams per litre of salt,
has enabled to reach a yield of 80%
(concentration ratio = 3). In the same conditions,
a conventional treatment gave a yield of 35%
(concentration ratio = 1.25). With sea water feed,
typical yields of 50% can be achieved.
Thus, for the same permeate flow rate, the cost of
pre-treatment can be significantly reduced with
the use of COATEX EM 201 ASP.
The efficiency of COATEX EM 201 ASP has been
measured with different methods, all based on the
loss of soluble cations after heating or
concentration of a clear solution. A solution of
minerals is prepared and is either concentrated by
ebullition or simply heated. Under these
conditions, a mineral scale is formed after a
certain time. The liquid is then filtrated and the
remaining cations are measured by the
appropriate analytical method. Two trials are
made, one with COATEX EM 201 ASP as an
adjuvant, and the other without adjuvant.
Used at a low level (1 to 10 ppm), COATEX EM 201 ASP avoids scale deposition on membranes with
minerals such as Calcium, Magnesium, Strontium, Barium and Iron salts (as carbonates, sulfates,
COATEX EM 201 ASP 3/4
0 1 2 3 4 5 6 7 8 9 10
Recovery per ppm = f(ppm)
The use of COATEX EM 201 ASP prevents the precipitation of supersaturated minerals like Calcium
carbonates or sulfates which could occur when operating at high concentration ratio of feed water (as in
brine or sea water).
A field test performed with decreasing amounts of COATEX EM 201 ASP has been used to estimate the
optimum dosage. This test has been run on two parallel units, with and without product. After 12 days, the
untreated unit has been stopped for cleaning due to a serious decrease in flow. The efficiency of the treated
unit has remained constant down to 5 ppm of product. A slight decrease of recovery has been noticed at
1.25 ppm and 0.5 ppm have been found to be insufficient. Overdosage is shown to have no influence on the
efficiency of the RO unit.
The wide range of effectiveness of COATEX EM 201 ASP is a definite advantage when overdosage may
occur or when the quality of the feeding water cannot be controlled.
This curve gives the optimum dosage for COATEX EM 201 ASP by the ratio
Recovery/dosage in ppm.
As shown, one can use between 1 to 5 ppm to get the best economics.
The optimum is located at 0.8 ppm; however, below this level, the recovery diminishes rapidly.
The information contained in this data-sheet is the result of our study and experience. It is offered in good faith but cannot be, in any
way, a guarantee, and no liability is assumed (17/12/02).