Molecular weight distribution variation of assimilable organic carbon during ozonation/BAC process

Abstract

Assimilable organic carbon (AOC) was measured combined with molecular weight (MW) distribution during a long time operation of a pilot scale ozonation/BAC (biological activated carbon) process in a water treatment plant in China. The AOC measurement was done on different samples: raw water, water samples after sedimentation, sand filtration, ozonation and BAC filtration. MW distribution variation of AOC during ozonation/BAC process was evaluated.Results showed that AOC was mainly related to the NOM (natural organic matter) with MW , 1 kDa. The fraction of the NOM with MW , 1 kDa corresponds to 53-67% of the dissolved organic carbon (DOC) to all the samples while AOC corresponds to 2.7-5.9% of DOC. So just a small part of the fraction with MW , 1 kDa was AOC. This indicates that ozonation/BAC process removing a large part of DOC will not necessarily result in a great reduction in AOC.

Measuring Bacterial Growth Potential of Ultra-Low Nutrient Drinking Water Produced by Reverse Osmosis: Effect of Sample Pre-treatment and Bacterial Inoculum

“…Furthermore, the growth on the natural DOC was equivalent to AOC concentrations of 40-70 µg-C/L (calculated using the yield obtained in this study), forming 1.5-2.7% of the natural DOC (∼2.75 mg-C/L). This ratio is consistent with previous findings for various water types (van der Kooij et al, 1989;Hu et al, 1999;Hem and Efraimsen, 2001;Shi-Hu et al, 2008;Prest et al, 2016b). Understanding the ability of bacteria to utilize HMW compounds is essential, since such compounds form a significant fraction of DOC in drinking water.…”

Assessing biological stability of drinking water produced by reverse osmosis and remineralisation : method development and application

“…Furthermore, the growth on the natural DOC was equivalent to AOC concentrations of 40-70 μg/L Ac-C (calculated using the yield obtained in this study), forming 1.5-2.7% of the natural DOC (~2.75 mg-C/L). This ratio is consistent with previous findings for various water types (van der Kooij et al, 1989;Hu et al, 1999;Hem and Efraimsen, 2001;Shi-Hu et al, 2008;Prest et al, 2016b). Understanding the ability of bacteria to utilise HMW compounds is essential, since such compounds form a significant fraction of DOC in drinking water.…”