Ammonium removal in drinking water using natural zeolite
The traditional method for ammonium removal and also for removal of organic components in drinking water processes is based on biological treatment in sand filters. The efficiency of such a system is proven but it could also release few traces of microorganisms or components on which microorganisms can regrow in the drinking water. This may be due to the complex processes in the sand filters (biological activity to remove methane and ammonium, removal of iron flocs and oxidation of manganese) and is undesirable. Sometimes the ammonium concentration in the finished water comes close to the norm for drinking water of 0.2 mg/L. By removing the ammonium in a separate step, sand filtration can probably be better controlled. Furthermore, in the cold season, biological activity in sand filters decreases resulting in a lower ammonium removal efficiency. This efficiency drop is currently compensated for by the addition of phosphoric compounds in sand filters, which consequently complicates further treatment.