Changes in dissolved organic matter and oxygen consumption in different bank filtration simulations at different scales

Both concentrations and compositions of dissolved organic matter (DOM) and the availability of oxygen affect transformation processes in close-to-nature drinking water treatments such as bank filtration and artificial groundwater infiltration. This study focused on quantitative and qualitative analyses of DOM in different saturated sand column systems of different dimensions, histories and operating conditions using fluorescence spectroscopy. The study revealed the presence of two fluorescent DOM (fDOM) fractions (humic-like compounds) through parallel factor analysis (PARAFAC). DOM, fDOM and specific UV absorbance (SUVA) at 254 nm were reduced and correlated in indoor systems. In outdoor columns, the removals of DOM and fDOM were comparably high, but the increased SUVA indicated an increase in aromaticity. Dissolved oxygen consumption corresponded to organic content in sand, independent of residence times. Overall, bank filtration is an effective option to remove biodegradable DOM under outdoor natural conditions.

Automated summary

This study analyzed the quantitative and qualitative properties of dissolved organic matter using fluorescence spectroscopy in different sand column systems. The findings showed the presence of two fluorescent DOM fractions and a correlation between DOM, fDOM, and SUVA at 254 nm in indoor systems. In outdoor columns, while the removal of DOM and fDOM was high, there was an increase in aromaticity. Dissolved oxygen consumption was influenced by organic content in sand and not residence times. Bank filtration was found to be effective in removing biodegradable DOM under outdoor natural conditions.