Dissolved Ozone Monitor

A Dissolved Ozone Monitor is a specialized analytical instrument that continuously measures the concentration of ozone (O₃) dissolved in water. When ozone is used for water treatment, disinfection, or oxidation processes, knowing the actual amount of ozone present in the liquid phase is essential for accurate process control, safety, regulatory compliance, and optimization of treatment effectiveness. These monitors are widely used in drinking water plants, wastewater treatment facilities, bottled water systems, cooling towers, pharmaceutical water systems, and industrial process streams to ensure that dissolved ozone levels meet target thresholds and maintain treatment performance.

Core Technology & Data

Measurement Principles

Dissolved ozone monitors typically use electrochemical or membrane-based sensing technologies where ozone diffuses across a gas-permeable membrane into a sensor cell, generating an electrical signal proportional to the ozone concentration in dissolved form. These sensors provide real-time, continuous data and can be integrated with control systems to adjust ozone dosing accordingly.

Some monitoring systems also use optical (UV absorption) or amperometric sensor techniques to quantify ozone dissolved in water, offering high accuracy with minimal interference from other dissolved species.

Integration & Control

Modern dissolved ozone monitors often include features such as:

• • Digital or analog outputs (e.g., 4-20 mA, RS-485) for integration with PLC and process controllers
• • On-board data logging and graphing capability for trend analysis and compliance documentation
• • PID control integration for automated ozone dosing adjustment based on real-time measurements
• • Multiple range sensors supporting low parts-per-billion (ppb) to higher parts-per-million (ppm) dissolved ozone concentrations

These capabilities make dissolved ozone monitors indispensable for process automation, feedback control, and quality assurance in ozonation systems

Benefits & Performance Highlights

1. 1. Continuous, Real-Time Monitoring
   Dissolved ozone monitors deliver real-time data on ozone concentration in water, allowing operators to see exactly how much ozone is present at any moment and react quickly to changing process conditions.
2. 2. Improved Process Control
   By integrating dissolved ozone feedback into control systems, treatment processes can optimize ozone dosing, reducing wasteful over-ozonation and ensuring sufficient ozone for effective disinfection and oxidation.
3. 3. Enhanced Water Treatment Safety
   Accurate dissolved ozone measurement helps ensure that water treatment targets are met without excessive ozone, which can off-gas and pose safety or regulatory challenges if not monitored.
4. 4. Versatile Industrial Use
   These monitors are used across applications such as:
   • • Municipal drinking water systems
   • • Bottled water plants and food processing water
   • • Pharmaceutical water systems
   • • Wastewater polishing and effluent controls
   • • Cooling towers and recirculating water systems
     They support automated control and help maintain product and process quality.
5. 5. Multiple Sensor Options
   With electrochemical, membrane, or UV optical sensors, dissolved ozone monitors can be chosen based on:
   • • Required accuracy and range
   • • Water quality conditions
   • • Maintenance and calibration preferences
   • • Real-time control needs
     This flexibility ensures reliable measurement in both clean and challenging water environments.
6. 6. Supports Regulatory Compliance
   

   By providing continuous records and accurate ozone concentration data, these monitors help facilities demonstrate compliance with water treatment standards and safety thresholds where dissolved ozone is regulated.

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ATIs Model Q45H/64 Dissolved Ozone Monitor is the ideal choice for on-line monitoring and control of ozonation systems. Capable of measuring DO3 concentrations as low as 0-200 PPB full scale, the system provides the sensitivity needed for demanding applications such as pharmaceutical grade water or semiconductor wash water. And with the standard 0-2 PPM range, the monitor is ideally suited to water bottling systems or municipal water treatment. Even high range applications requiring 0-20 or 0-200 PPM can be easily accommodated.

Unlike on-line colorimetric and most amperometric monitors, Q45H systems utilize a membrane-covered polarographic sensor that does not require the addition of chemical reagents. The Q45H system has no moving parts, so there are no pumps or motors that burn out or tubing breaks that create maintenance nightmares. All normal maintenance items are included with each system.

Utilizing a highly selective polarographic membraned sensor, dissolved ozone can be monitored interference-free, with little maintenance. There are no moving parts and what little maintenance is required can be done in just a few minutes. Installation is simple and you can be up and running in a few hours.

Available in loop-powered transmitter or AC operated analyzer, the Q45H/64 is well suited for almost any DO3 measurement requirement. Even a portable data-logging version is available for temporary installation or process studies. And for even more flexibility, the instrument is available with an optional pH sensor input that allows a single unit to provide both dissolved ozone and pH analog outputs.