Silicate Scaling in Reverse Osmosis: latest updates

After weeks of investigations, analysis of autopsy reports, and countless brainstorming sessions, we reached a consensus to explain an unusual silicate scaling phenomenon. This can occur when sodium silicate is the primary species present, even in the absence of the typical problematic cations such as Ca⁺⁺, Mg⁺⁺, Fe(II)/Fe(III), or Al⁺⁺⁺.

The intense water concentration process on the surface of the RO membranes can lead to the exceptionally rapid formation of silica nanoparticles. These particles grow quickly, and within a few days, result in significantly increased operational pressures. This process seems to bypass the effects of antiscalants, which are typically designed to prevent the formation of calcium and magnesium silicate. The exact mechanism of how this bypass occurs remains a mystery. It is suspected that these nanoparticles form instantaneously in remote micro-spaces where the diffusion of the antiscalant is limited.

High recovery rates are the main culprit, forcing all dissolved silicate molecules toward the polyamide surface and creating an oversaturation that initiates crystallization. The only viable solution to continue operating the RO plant is to implement cleaning steps. The key question then becomes, “How frequent can cleanings be to remain acceptable?” Reducing the recovery rate to an acceptable limit remains the simplest and most efficient remedy available to the plant manager.”