Abstract
The purpose of this study was to evaluate the applicability of online flow cytometry for assessing the adsorption process in surface water treatment. The research was conducted under real operating conditions at a plant treating up to 100,000 m³/day using coagulation, sedimentation, filtration, ozonation, adsorption (on WG-12 activated carbon), and disinfection. Daily water samples were collected from August to November 2024, including a period of raw water deterioration due to floodwater. Flow cytometric analysis was performed online every 30 minutes to determine microbial viability and activity. Findings revealed increased TOC removal efficiency with higher organic content, but also elevated microbial release from the adsorption bed during peak contamination. Flow cytometry effectively distinguished between microbial activity levels and responded faster than traditional turbidity monitoring. This method offers practical benefits for real-time water quality control and disinfection management. The study demonstrates the originality and value of integrating online cytometry into adsorption process monitoring in water treatment.