Rate and extent NOM removal during oxidation and biofiltration

• Ozone preferentially reacts with the high molecular weight NOM fraction.
• Advanced oxidation does not preferentially react with a particular molecular weight fraction.
• Neither biodegradable nor non-biodegradable fractions were preferentially oxidized.
• Ozone and AOPs react with biodegradable and non-biodegradable fractions equally.
• The rate of biodegradation is not affected by pre-oxidation.

The presence of natural organic matter (NOM) in drinking water treatment presents many challenges. Integrated treatment processes combining oxidation and biofiltration have been demonstrated to be very effective at reducing NOM, specifically biodegradable organics. Laboratory bench-scale experiments were carried out to investigate the effect of oxidation by ozonation or UV/H2O2 on NOM. Specifically the rate of biodegradation was studied by performing bench-scale biodegradation experiments using acclimatized biological activated carbon (BAC). For the source water investigated, oxidation did not preferentially react with the biodegradable or non-biodegradable NOM. In addition, the type or dose of oxidation applied did not affect the observed rate of biodegradation. The rate kinetics for biodegradation were constant for all oxidation conditions investigated. Oxidation prior to biofiltration increased the overall removal of organic matter, but did not affect the rate of biodegradation of NOM.

Percent reduction from raw water values shown with 90% confidence intervals. Figure optionsDownload high-quality image (186 K)Download as PowerPoint slide