Simultaneous monitoring of biofilm growth, microbial activity, and inorganic deposits on surfaces with anin situ, online, real-time, non-destructive, optical sensor

Abstract

Deposits on surfaces in water-bearing systems, also known as 'fouling', can lead to substantial losses in the performance of industrial processes as well as a decreased product quality. Early detection and localization of such deposits can, to a considerable extent, save such losses. However, most of the surfaces that become fouled, for example, in process water pipes, membrane systems, power plants, and food and beverage industries, are difficult to access and analyses conducted on the water phase do not reveal the site or extent of deposits. Furthermore, it is of interest to distinguish biological from non-biological deposits. Although they usually occur together, different countermeasures are necessary. Therefore, sensors are required that indicate the development of surface fouling in real-time, non-destructively, and in situ, preferably allowing for discrimination between chemical and/or biological deposits. In this paper, an optical deposit sensor is presented which fulfills these requirements. Based on multiple fluorescence excitation emission matrix analysis, it detects autofluorescence of amino acids as indicators of biomass. Autofluorescence of nicotinamide adenine dinucleotide + hydrogen is interpreted as an indicator of biological activity, thus it acts as a viability marker, making the method suited for assessing the efficacy of disinfection treatments. Scattering signals from abiotic deposits such as calcium carbonate or corrosion products can clearly be distinguished from biotic substances and monitored separately. The sensor provides an early warning of fouling, allowing for timely countermeasures to be deployed. It also provides an assessment of the success of cleaning treatments and is a promising tool for integrated antifouling strategies.

Identification and tracking of microorganisms from the biofilms of container walls used for water storage: Case of rural communities in Burkina Faso

“…The link between organic content and bacterial growth resulting in biological aggregates that may attach to the surface of distribution systems has been reported (Liu et al, 2013). Biofilm formation is usually promoted on the surface of a material if that material is able to supply the required nutrients for microbial growth (Strathmann et al, 2013). Therefore, the occurrence and persistence of microorganisms on the surface of EJ, PE and GS could be related to the level of turbidity and DOC in stored waters.…”

“…As a result, the adhesion of indicator microorganisms on the surface of EJ, PE and GS containers, was detected and cause formation of biofilms. Studies of Strathmann et al (2013) showed that in water storage systems, microorganisms are mainly present on internal surfaces as attached bacteria as a biofilm, with a minor part in the water phase. Biofilm formation during water storage in this study is related to temperature, pH, turbidity, concentration of organic nutrients and indigenous microorganism's community of the stored water.…”

“…In this study, temperatures ranging from 26.5 to 30.6°C were recorded in all containers, creating favorable microorganism growing conditions. Therefore, for Strathmann et al (2013), temperature is considered to be an important regulator of biofilm growth, especially in non-disinfected water. At the same time, during water storage, neutral pH was obtained in the different containers investigated.…”

Mini-review: microbial problems in paper production

“…Thus, an integrated strategy appears more realistic, successful, and sustainable. Some elements of a holistic antifouling strategy may include (1) Early warning and monitoring capacity by employing sensors in the system (Hillman et al 1985;Flemming 2003;Jahnknecht & Melo 2003;Strathmann et al 2013), particularly designed for paper mills (Klahre & Flemming 2000;Macuch & Rice 2008;Rice & Schild 2009). Such systems would allow for timely countermeasures and timely strategic cleaning.…”

Dismantling‐Free and Gentle Mechanical Cleaning of Industrial Heat Exchangers and Cooling Circuits

“…Diese Biofilme wurden in einem Teststand mit zirkulierendem Wasser unter Zugabe von Nährstoffen direkt auf den Wärmeübertragerflächen angezüchtet. Der verwendete Teststand und die Methode zur Biofilmanzucht wurde bereits zuvor in beschrieben.…”