Predicting biofilm thickness and biofilm viability based on the concentration of carbon-nitrogen-phosphorus by support vector regression

Abstract

Current tools to predict biofilm thickness and viability in spatial distribution are poor, especially those based on chemical oxygen demand (COD), total nitrogen (TN), and total phosphate (TP) due to their limited data and complex calculations. Here, support vector regression (SVR) was used to predict biofilm thickness and viability in a reactor filled with carriers of crushed stone globular aggregates. Analyses combined confocal laser scanning microscopy and flow cytometry with Kriging interpolation revealed that biofilm thickness varied from 22 to 31 μm, and biofilm viability decreased from 80 to 30% in the flow direction of the reactor. The biofilm thickness at the bottom was thicker than that in the upper layer, but biofilm viability contrasted with biofilm thickness in the vertical distribution. The values of biofilm thickness and viability were predicted at a layer 35 cm from the bottom of the reactor with mean squared error values of 0.014 and 0.011, respectively. Correlation coefficients were 0.996 and 0.997 between carbon-nitrogen-phosphorus (C-N-P) removal with biofilm thickness and viability in spatial distribution, respectively. This study provided an important mathematical method to predict biofilm thickness and viability in spatial distribution based on the concentration of C-N-P.

Small-Scale Heterogeneity in Drinking Water Biofilms

“…For example, heterogeneity was ascribed to differences in treatment processes, e.g., treatment units (Ma et al, 2017; Bruno et al, 2018), filtration type (Pinto et al, 2012; Lautenschlager et al, 2014), or filtration media (Vignola et al, 2018). Also, changes in the exposure to disinfection and disinfectant residuals (Servais et al, 2004; Potgieter et al, 2018), as well as differences in the composition and quantity of nutrients (Niquette et al, 2001; Bester et al, 2010), radial-spatial orientation (Lin et al, 2016; Liu et al, 2017), and temperature (Liu et al, 2013) were shown to cause biogeographical heterogeneity. The most dramatic variations in drinking water systems occur in the built environment.…”

Feeding the Building Plumbing Microbiome: The Importance of Synthetic Polymeric Materials for Biofilm Formation and Management

“…In addition, each system typically has warm and cold water outlets ( Figure 2), with hoses, taps, and various connected home appliances (e.g., a washing machine), all of which will potentially create unique and very different environments. From a microbiological point of view, bacteria that enter a building plumbing system from the DWDS experience an immediate and considerable change in environmental conditions, and it is common knowledge that a change in environmental conditions will often result in a change in bacterial numbers [40], viability [41], activity [42], and composition [43].…”