Detection of Biofilm on Water Supply Technical Materials with the Application of an Impedance Sensor

Abstract

In favourable environmental conditions microorganisms can adhere to surfaces and reproduce, forming biofilm. Such a structure causes biodeterioration, i.e. biological degradation of technical materials. The issue is of high importance in the case of distribution of treated water to end-point consumers. An important factor determining the formation of biofilm is the type and character of the surface which can stimulate or inhibit its growth. The article presents innovative results of research involving measurement of growth of biofilm on technical materials used for the construction of water supply networks by means of an impedance sensor. The research was conducted at a laboratory scale continuously for 6 months, reflecting actual conditions occurring in water distribution systems. After half a year culture of environmental microorganisms in the bioreactor, an almost 100% increase in the value of relative impedance was recorded by means of a sensor placed inside the bioreactor. A comparison of the surface coverage of technical materials and the sensor with bacteria (fluorescence in situ hybridization) showed that the sensor could be used for technical materials made of polybutylene, polypropylene, and polyvinyl chloride. Observations (scanning electron microscopy) of the surface of the plastics used to build the water supply network pipes (new materials, with biofilm present, and after detaching the biofilm) showed significant changes in the structures of the materials due to biofilm formation. The largest changes in the structure were observed on the polyethylene and polypropylene surfaces. The proposed sensor could be applied in the measurements of biofilm adhesion to selected technical materials.

Impedance Analysis for the Study of Biofilm Formation on Electrodes: An Overview

“…The effect of mass transfer processes on electron transfer At +0.497 V vs. SHE Frequencies and amplitude not reported Geobacter sulfurreducens / Glassy carbon rotating disk electrode [46] Evaluate a small overpotential approximation for extracellular electron transfer ±5mVrms with a peak-to-peak potential window of ~15 mV, (1×10 5 to 1×10 -1 ) Hz Geobacter sulfurreducens / Gold [80] The comparison electroactive properties of mutant and wild type biofilms 10 mV at OCP, (5×10 4 to 1× 10 -3 ) Hz.…”

“…However, there are a few studies about Kramers Kronig residuals for biofilm growth; this absence may be associated with difficulty maintaining a steady state (causality) when bacteria are present on the electrode forming a biofilm and conditions change over time. Babauta et al (2014) [46] obtained a residual percentage for Geobacter sulfurreducens biofilm. Some percentage values achieved 5 to 10 % at frequencies between 10 -2 to 1 Hz.…”

“…These studies are relevant in medicine (drug development), environment (biogeochemical cycles), and biotechnology [64]. On the other hand, strong electroactive bacteria are studied to better understand the extracellular charge transfer by applying a potential, and its study is focused on understanding an electroactive biofilm to improve the current production of a BES device [30,42,46,[68][69][70]. Therefore, a general classification was made in the capacitance and R2, R3 analysis; each section was divided into two groups: non-electroactive / weak electroactive biofilms; and another group of strong electroactive biofilms.…”

“…1(b)). For G. sulfurreducens tests have been carried out, the biofilms were grown in situ on an electrode that was subsequently analyzed by Marsili et al (2008) and rotated by Babauta et al (2014) in order to study electron transfer between biofilms and electrodes [45,46]. In addition, Romero et al (2021) employed an electrochemical cell filled with a culture media with urea, then ureolytic microorganisms (with capabilities to hydrolyze urea) were inoculated [23].…”

A graphene microelectrode array based microfluidic device for in situ continuous monitoring of biofilms

“…Electrochemical impedance spectrometry (EIS) is widely used in biolm detection due to its advantages of being fast, sensitive, label-free, cost-effective and easy to miniaturize. [23][24][25] The shape and material of the electrode are the predominant factors affecting the detection of bacterial biolms by electrochemical impedance analysis. Recently, EIS technology using microelectrodes has shown many advantages in biolm detection, especially in in situ and continuous monitoring uses.…”