Modelling bacterial growth in drinking water: effect of nutrients

Abstract

This paper presents a model of growth of naturally occurring heterotrophic bacteria in the bulk water phase in the absence of disinfectant. The model considers growth with carbon, phosphorus and nitrogen balance, death and lysis of dead bacteria and conversion of less biodegradable organic carbon to assimilable organic carbon. Experimental data from two raw and two treated waters were used to test the model. The model describes the increase of live and dead bacterial cells in the water phase and its output closely matches the experimental data. Such a model has the ability to characterise water nutrient status as well as to predict behaviour of indigenous heterotrophic bacteria. The ability to predict bacterial population dynamics with respect to nutrients is beneficial for water treatment optimisation. The model, based on microbiological measurements, helps to characterise treated water quality and project performance in terms of water quality into a distribution system.