Water Pretreatment System for Rapid Preconcentration of Bacteria

Monolithic Adsorption Filtration (MAF) 1.Cyprus Research & Innovation Center Ltd (CyRIC), 72, 28th Octovriou Ave, Engomi, 2414 Nicosia, Cyprus 2.Analytical Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenberg 4, 85748 Garching Author contact email: [email protected] Affiliations Conclusions The study successfully demonstrates a water pretreatment system that uses a two-stage filtration approach combining Crossflow Ultrafiltration (CUF) and Monolithic Adsorption Filtration (MAF). The system enables efficient and automated water sample enrichment, achieving a recovery rate of up to 63% for bacterial concentrations at 10⁶ cells/10 L. Water Pretreatment System for Rapid Preconcentration of Bacteria M. Moyseos1, M. Seidel2 and P. Demosthenous1 Introduction Water management authorities must monitor both the source and the treaded water, where pathogens contaminants are generally present at low concentrations. Rapid quantification methods are needed combining concentration processes and very sensitive detection systems. Because the numbers of these microorganisms are often quite low, large volumes of water are usually needed. However, efficient pretreatment of large water volumes, at the source, is a pressing problem for water resource management and in-line continuous monitoring. The proposed methodology and prototype system target fast realization of water analysis pretreatment steps, avoiding the use of separate, time-consuming and manual laboratory procedures. The presented prototype system uses innovative, highly efficient and low-cost Monolithic Adsorption Filters (MAF) for the preconcentration of E.coli bacterium. This subsystem executes crossflow monolithic adsorption filtration (cMAF) to enrich microorganisms in water. The flow of the water is executed tangentially over the MAF disc, and this allows the capturing of microorganisms mainly on the surface of the MAF avoiding its blocking. This configuration allows larger sample volume and high flow rates for the sample collection. Water sample is concentrated by cMAF, where the sample is separated into waste and concentrated microorganisms which are held back by MAF. The concentrate stream is recirculated in a loop using a peristaltic pump. Filtration process is controlled by four solenoid pinch valves: the sample valve (V4), the recirculation valve (V6), the elution valve (V7) and the waste valve (V5). The concentrate sample is obtained on the MAF surface, which is eluted with an elution buffer, pumped via a syringe. Acknowledgements The Project is funded by the European Union Recovery and Resilience Facility of the NextGenerationEU instrument, through the Research and Innovation Foundation. Crossflow Ultrafiltration (CUF) Two-filtration processes are used by the preconcentrator, which are i) a CUF filtration at the left-hand side of the system, and ii) a MAF filtration at the right-hand side of the system that is equipped with an automated filter exchange mechanism for the MAF filters. The Preconcentration System Validation of the System For the validation of the preconcentration system performance, initial samples of different concentrations of E.coli, 10⁵ cells/ml, 10⁶ cells/ml, 10⁷ cells/ml, were used. The initial samples were added into 10 L of water for creating E. coli concentrations of 10⁵ cells/10 L, 10⁶ cells/10 L, 10⁷ cells/10 L respectively. After running the ‘concentration procedure’ of the 10 L water, the 1 ml concentrated sample was collected and compared with the initial sample for calculating the bacteria-recovery ratio. This subsystem executes crossflow ultrafiltration to enrich microorganisms in water. In the first step, a water sample is concentrated via membrane FX-80. The sample is separated into filtrate water and concentrated microorganisms, which are held back by CUF. The concentrate stream is recirculated in a loop using a peristaltic pump. Filtration process is controlled by six pinch valves: the sample valve (V8), the recirculation valve (V1), the elution valve (V3), the deaeration valve (V2), and for the cleaning procedure the sterilized-water (V9) and the NaOCl valve (V10). Transmembrane pressure is measured using three pressure sensors located at the FX-80 filter’s inlet (Pin), outlet (Pout) and filtrate side (Pfilter). Transmembrane pressure can be adjusted via a Restriction Valve.