Evaluating the impacts of treatment modifications on regrowth potential in distribution systems: a new screening procedure using water quality modeling

Abstract

The treated water Biodegradable Organic Matter (BOM) content is one of the main factors controlling bacterial regrowth in Distribution Systems (DS). This paper presents an approach to predicting regrowth potential with the objective of helping utilities in the preliminary selection of alternative treatment scenarios. The proposed approach comprises four phases: (i) applying, at bench scale, different types of treatment to a raw water to obtain treated waters to be tested for their regrowth potential; (ii) applying an experimental procedure to the various treated waters which consists of the study of bacterial growth during a Biodegradable Dissolved Organic Carbon (BDOC) test; (iii) partitioning BDOC into three classes of various biodegradability compounds by fitting the bacterial growth curve with a biodegradation model; (iv) using the BDOC and partitioning data to simulate bacterial growth in a DS with a model describing bacterial dynamics in the DS. The various phases of the approach are detailed using a case study for which different types of treatments were tested.

Keywords:

• Bacterial regrowth
• Biodegradation
• Biodegradable organic carbon
• Distribution system
• Drinking water
• Water quality modeling

Acknowledgments

The authors thank the SEDIF (Syndicat des Eaux d'Ile de France) and the CGE (Compagnie Générale des Eaux) for authorizing the use of the SANCHO Model. The authors also thank Jacinthe Mailly for her help during laboratory work.