Elimination of persistent odorous compounds from drinking water

MIB (2-methyl isoborneol – C₁₁H₂₀O) and geosmin (trans-1, 10-dimethyl-trans-9 decalol-C₁₂H₂₂O) are the major taste and odour causing compounds in drinking water. The objective of this study was to investigate the adsorption of these odour causing compounds by three types of activated carbon fibres (ACF) with different micropore size distributions, namely ACC-25, ACC-20 and ACC-15. Adsorption for both MIB and geosmin was well defined by Freundlich isotherms. For MIB, the adsorption capacity increased with an increase in micropore volume of the adsorbents whereas in the case of geosmin, the adsorption was much more complex. Isotherms were also conducted for ACF adsorption for MIB and geosmin in the presence of natural organic matter (NOM) to better understand competitive adsorption. Overall, the ACF ACC-25 was the most effective adsorbent for both MIB and geosmin and was least affected by the competitive effect of the NOM because of its wider distribution of micropores. Adsorption isotherms were also conducted with a granular activated carbon F-400 to compare adsorption with the ACFs. F-400 was found to have significantly lower adsorption capacity for both MIB and geosmin when compared to the ACFs and also the presence of NOM significantly reduced its adsorption capacity due to competitive adsorption.