Application of model fitting technique to enhance bacterial regrowth potential (BRP) measurement for drinking water supply monitoring

Abstract

The bacterial regrowth potential (BRP) method was utilised to indirectly measure the assimilable organic carbon (AOC) as an indicator for the assessment of the microbial regrowth potential in drinking water distribution systems. A model using various microbial growth parameters was developed in order to standardise the experimental interpretation for BRP measurement. This study used 82 experimental BRP data sets of water samples collected from the water treatment plant to locations (customer taps) in the distribution system. The data were used to model the BRP process (growth curve) by a data fitting procedure and to obtain a best-fitted equation. Statistical assessment and validation of the model obtained equation by fitting these 82 sets of data were conducted, and the results show average R2 values were 0.987 for treated water samples (collected at the plant prior to chlorination) and 0.983 for tap water (collected at the customer taps). The F values obtained from the F-test are all exceeded their corresponding F critical values, and the results from the t-test also showed a good outcome. These results indicate this model would be successfully applied in modelling BRP in drinking water supply systems. HIGHLIGHTS The bacterial regrowth potential method combined with the in-house developed model has shown to be a good indicator for assimilable organic carbon measurement.; A four-parameter logistic non-linear model, which is a form of Hill equation (BRP-Hill model), was developed and successfully modelled BRP in drinking water systems.; This study used microbial growth parameters to describe the bacterial growth curve from the BRP-Hill model.;

Keywords

• assimilable organic carbon
• bacterial regrowth potential
• drinking water
• modelling