Treatment performance in water and wastewater systems is defined by measurable water quality parameters. pH, residual chlorine, turbidity, ORP, and COD are among the most important of these, each providing information about a different aspect of the treatment process or the quality of the water being produced. Online sensors that measure these parameters continuously transform water quality monitoring from an occasional manual activity into a real-time operational tool.

pH sensors provide continuous measurement of acidity or alkalinity, enabling automatic dosing control and instant detection of pH excursions that could affect biological treatment, chemical processes, or effluent compliance. In biological treatment systems, pH outside the optimal range reduces the activity of treatment organisms. In RO systems, incorrect pH can damage membranes or cause scaling.

Residual chlorine sensors monitor disinfection performance, ensuring that chlorine levels remain within the range needed for effective pathogen removal while avoiding the problems of over-dosing. In distribution systems and swimming pools, continuous chlorine monitoring provides assurance that disinfection is being maintained consistently.

Turbidity sensors measure the clarity of the water and are used to monitor filtration performance, detect filter breakthrough, and assess the quality of treated effluent. A sudden increase in turbidity downstream of a filter indicates a problem that needs to be investigated immediately.

ORP (Oxidation-Reduction Potential) sensors are used in disinfection control and in monitoring the redox conditions in biological treatment processes. COD (Chemical Oxygen Demand) analysers provide continuous measurement of organic load, which is important for monitoring treatment efficiency and effluent quality in industrial wastewater applications.

Online sensors for all of these parameters are available as standalone instruments or as part of integrated water quality monitoring systems.