Chemicals are used to wash the membranes (coiled spiral, tubular, hollow fiber, ceramic) to remove the fouling of different organic / inorganic / biological nature which, depositing on the membranes themselves, can gradually reduce their permeability.
The process accelerates its course progressively due to the increase in surface roughness and therefore an increase in the possibility of adhesion. It is therefore necessary to plan carefully the frequency of washing, as well as the type of the same (depending on the soiling agent) using specific detergents.
These detergents are grouped into the following categories:
- Alkaline cleaners: they are used for the removal of organic fouling. Their composition includes alkaline components, sequestering agents, surfactants, wetting agents, ... The pH varies from 11.5 to 14, while the operating temperature varies from 25 to 80 ° C.
- Acid detergents: they are used for the removal of inorganic fouling. Their composition includes acid components, sequestering agents, surfactants, wetting agents ... The pH varies from 1 to 2, while the operating temperature varies from 25 to 60 ° C.
- Anti-encrusting: prevent the growth of the crystal lattice of the main salts: Calcium carbonate, Calcium sulfate, Barium sulfate, Silicon, Iron.
- Sanitizers: they sanitize membranes in Polyamide, Polysulfone, PVFD and remove bacterial films and microbiological deposits.
- Enzymatic detergents: they are used for the removal of fouling by starches / proteins / fats. Their composition includes enzymatic surfactant components, bleaching agents, metasilicates….