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RO Membrane Cleaning
(Recommended about every 6 months to 1 year.
Periodic cleaning of the membrane(s) can improve system performance. In normal operation, mineral
scale, biological matter, colloidal particles, and organic substances can foul the membranes and reduce
performance. The best prevention is to use a well-designed pre-treatment system incorporating efficient
sediment removal, de-chlorination (if chlorine-based sanitisers are present), and softening or chemical
dosing for the removal of scale forming minerals.
WARNING:
Cleaning chemicals are dangerous and can cause injury and damage to the environment. It is
the user’s responsibility to comply with all applicable federal, state, and local regulations.
General Safety Precautions
When using any chemical indicated here in subsequent sections, follow accepted safety practices. Consult
the chemical manufacturer for detailed information about safety, handling and disposal.
1.
When preparing cleaning solutions, ensure that all chemicals are dissolved and well mixed before
circulating the solutions through the membrane elements.
2.
It is recommended the membrane elements be flushed with good-quality chlorine-free water after
cleaning. Permeate water is recommended; but a de-chlorinated potable supply or pre-filtered
incoming water may be used, provided that there are no corrosion problems in the piping system.
Operate initially at reduced flow and pressure to flush the bulk of the cleaning solution from the
elements before resuming normal operating pressures and flows. Despite this precaution, cleaning
chemicals will be present on the permeate side following cleaning so divert the permeate stream to
drain for at least 10 minutes or until the water is clear when starting up after cleaning.
3.
During recirculation of cleaning solutions, the temperatures must not exceed 50°C at pH 2-10, 35°C at
pH 1-11, and 30°C at pH 1-12.
Cleaning Procedures for organic fouling
1.
Prepare the cleaning solution as listed below
* Preferred 0.1% (wt) Soda Ash
pH 12, 30°C maximum
* Alternative solution 0.1% (wt) NaOH 0.025% (wt)
pH 12, 30°C maximum
NOTE!
●
(wt) Denotes weight percent of active ingredient.
●
Cleaning chemical symbols in order used: NaOH is sodium hydroxide.
