Without some means of scale inhibition membrane elements will scale and plug due to precipitation of salts, such as calcium carbonate, calcium sulfate, barium sulfate and strontium sulfate. Membrane systems operates with high recovery ratios, so the concentrate water often exceeds the solubility limits of gypsum and calcite, which leads to crystallization on membrane surfaces. The build-up of scale results in permeate flux decline, which leads to a need for cleaning the membranes.
Acidification – where you add acid to reduce ph
Ion exchange softening
Antiscalant addition
Antiscalants are often the best method, giving better economy and excellent control. Antiscalants are surface active materials that interfere with precipitation reactions in three primary ways:
1. Threshold inhibition:
Increases the solubility limit of soluble salts.
2. Crystal modification:
Distorts crystal shapes so scale crystals appear more oval in shape, and less compact. The result is a soft scale that is less likely to foul the membrane.
3. Dispersion:
Adsorption of product on scale crystals and colloidal particles to create a high anionic charge, which keep the crystals separated. The high anionic charge also repels the particles from the membrane surface that has a fixed anionic charge present.
Our product overview below provides general information on each of our most used cleaners making the choice of cleaner easier.
Antiscalant
Antifoulants / Biocides
Acidic Cleaners
Alkali Cleaners
Organic Cleaners
pH Booster
Other highly specialized cleaners are available for special applications.
We will be happy to help you select the best combination of products for your specific application.
