What is the Purpose of the Dissolved Oxygen Test?

Water quality is critical in environmental monitoring, industrial operations, and wastewater treatment. Among the key parameters assessed in water analytics, dissolved oxygen (DO) is one of the most important. It directly impacts aquatic life, biological treatment processes, and the overall chemical balance in water bodies and treatment facilities.

Prei Instrumentation offers industry-leading dissolved oxygen meters as part of our comprehensive water analytics solutions. Designed for precision and resilience, our range of sensor systems ensures accurate, real-time monitoring in both laboratory and field conditions. Whether for environmental agencies, wastewater treatment plants, or industrial applications, dissolved oxygen testing is essential for maintaining water quality and system performance.

Understanding Dissolved Oxygen

Dissolved oxygen refers to the amount of oxygen present in water. It is critical for the survival of fish, aquatic organisms, and aerobic bacteria, which support healthy ecosystems and biological water treatment.

Oxygen enters water through two main processes:

• Natural diffusion from the atmosphere
• Photosynthesis by aquatic plants and algae

The level of DO can fluctuate based on:

• Temperature
• Water flow
• Pollution levels
• Organic waste presence
• Biological activity

Monitoring these levels helps identify changes in water health and system efficiency.

What is the Purpose of a Dissolved Oxygen Test?

The dissolved oxygen test serves a wide range of purposes depending on the application.

Environmental Monitoring

Environmental scientists and agencies use DO tests to:

• Assess the health of lakes, rivers, and oceans
• Detect pollution or eutrophication
• Monitor the impact of industrial discharges on aquatic systems

Wastewater Treatment

In wastewater facilities, DO tests are essential to:

• Control and optimise the aeration process
• Ensure aerobic bacteria can effectively break down organic waste
• Prevent anaerobic conditions that lead to foul odours and inefficient treatment

Aquaculture

Fish farms rely on DO measurements to:

• Maintain optimal oxygen levels for fish health and growth
• Prevent fish stress or mortality caused by hypoxia (low oxygen levels)

Industrial Processes

Industries such as pulp and paper, food processing, and pharmaceuticals use DO testing to:

• Monitor water used in production and discharge processes
• Comply with regulatory requirements for water effluent standards

Laboratory Research

Scientists use DO meters in lab settings to:

• Conduct biochemical oxygen demand (BOD) studies
• Study microbial activity in water samples
• Calibrate other instruments used in water testing

Dissolved Oxygen Meters from Prei Instrumentation

Prei Instrumentation supplies robust, precision-engineered dissolved oxygen meters for a range of water monitoring needs. Our systems are sourced from globally recognised manufacturers and are tailored to perform reliably across various environments.

Optical Dissolved Oxygen Meters

• Use optical technology for stable and accurate readings
• Require minimal calibration and maintenance
• Ideal for long-term use in field and lab applications

Inline Dissolved Oxygen Systems

• Designed for continuous, real-time monitoring
• Commonly used in industrial processes and treatment plants
• Offer integration with existing control and SCADA systems

Tough Portable Dissolved Oxygen Meters

• Built for on-the-go fieldwork
• Rugged casing with high resistance to harsh environments
• Simple interface for fast measurements

Ultra-Tough Dissolved Oxygen Sensor Systems

• Engineered for extreme field conditions (temperature, pressure, chemicals)
• Perfect for demanding industrial or environmental scenarios

Why Choose Prei Instrumentation?

As a leading provider of advanced instrumentation for water analytics and environmental monitoring, Prei Instrumentation brings you:

• Expert guidance on selecting the right dissolved oxygen meters for your application
• High-quality sensor systems with excellent reliability and longevity
• Integration support for inline monitoring and automated systems
• Nationwide distribution and technical support across South Africa

From mining and water treatment to environmental science, we ensure your facility is equipped with the tools to meet environmental standards and operational goals.

FAQs About Dissolved Oxygen Meters

What is a dissolved oxygen meter used for?

A dissolved oxygen meter measures the amount of oxygen dissolved in water. It is vital for applications in environmental monitoring, wastewater treatment, aquaculture, and lab testing.

What is a good dissolved oxygen level?

Generally, DO levels between 6 and 8 mg/L are considered healthy for most aquatic environments. Levels below 5 mg/L may stress aquatic life, while levels under 2 mg/L can lead to hypoxic conditions.

How is dissolved oxygen measured?

DO can be measured using:

• Electrochemical sensors (galvanic or polarographic)
• Optical sensors, which use luminescence-based detection for more stable and accurate readings

Do dissolved oxygen meters require calibration?

Yes, most dissolved oxygen meters require periodic calibration to ensure accurate readings. However, optical DO meters typically require less frequent calibration compared to electrochemical models.

Can DO meters be used in seawater?

Yes. Many modern dissolved oxygen meters are compatible with saltwater environments and compensate for salinity to provide accurate measurements.

Ready to Improve Your Water Monitoring Capabilities?

Whether you’re managing a treatment facility, conducting field research, or optimising aquaculture systems, Prei Instrumentation has the right dissolved oxygen meters to meet your requirements.

Contact Prei Instrumentation today to learn more.