Submerged membrane photocatalytic reactor for removing trihalomethane precursors in drinking water treatment plants

Spanish researchers have evaluated the feasibility of several technologies for the removal of trihalomethane (THM) precursors. The latter are usually humic substances found in real surface water, which are transformed into potentially carcinogenic THMs during further disinfection by chlorination.

The aim of this work was to compare an activated carbon bed (ACB), ozonation reactor, and submerged membrane photocatalytic reactor (SMPR) with TiO2/UV in terms of reduction efficiency of these THM precursors after chlorination.

Taguchi’s parameter design methodology was selected to study the most relevant factors that might influence the removal of THM precursors with each technology, keeping the number of experiments to a minimum.

According to the study, the ozonation reactor showed low removal percentages of THM precursors (40–50%), while the SMPR and activated carbon bed were more efficient technologies.

The SMPR achieved 86% removal of THM precursors when operating at optimal conditions of TiO2 catalyst concentration of 0.5 g/L (PC500® from Cristal Global).

The activated carbon bed attained 87% removal of THM precursors when Filtracarb® CC60 8 × 30 (steam activated mineral coal) was used with a hydraulic retention time of 15 min.

Desalination, Volume 330, 2 December 2013, Pages 28–34.