Biofouling, regrowth, hygiene

Team
Thomas Egli, Frederik Hammes, Cordula Berger

Goal
To establish methods for quantification of Assimilable Organic Carbon (AOC) and aplly them to evaluate microbial re-growth on components generated from oxidation processes.

Description
Usually, concentrations of bio-available natural organic matter (NOM) in waters used to produce drinking water are very low, nevertheless microbes are able to utilize parts of it and grow. This fraction of NOM is known as assimilable organic carbon (AOC). A bioassay for detection of AOC has been developed by Van der Kooij (KIWA, The Netherlands). It has been observed in practice that the use of oxidation processes for the disinfection of drinking water makes previously "recalcitrant" or only slowly degradable NOM better bio-available i.e. generates AOC. The result of this is extensive microbial re-growth in the subsequent treatment and distribution systems.

AOC determination will be complimented by natural organic matter (NOM) characterisation, specifically with regards to oxidation processes, using both laboratory-scale experiments and real drinking water treatment samples.

Furthermore, the effect of nanofiltration on AOC removal is assessed, also in combination with NOM characterisation.