The Benefits of COD Measurement

Monday 24 Jun 2024

Wastewater treatment is essential for protecting ecosystem health and preserving our planet’s water resources. It restores the water supply, shields the environment from toxins, and maximizes water reuse. Effective management of wastewater treatment plants (WWTPs) not only saves substantial long-term costs but can also optimize industrial processes, such as brewery production, by monitoring discharge contents and timing.

Understanding Chemical Oxygen Demand (COD)

In wastewater treatment, Chemical Oxygen Demand (COD) is a crucial metric. It measures the amount of oxygen required to break down organic pollutants in water, serving as a key indicator of water quality.

COD Measurement

Chemical Oxygen Demand (COD) can be measured using various methods, both direct and indirect. Typically, COD values are determined through samples analyzed using laboratory test methods. These off-line methods, while accurate, can be time-consuming, which is a drawback since COD is a critical parameter in the biological treatment process.

Alternatives to traditional laboratory methods exist, such as automated COD analyzer systems. These on-line instruments continuously monitor a sample stream from the wastewater process, providing multiple measurements over time. Compared to off-line methods, this approach is significantly faster and simplifies the analysis of Chemical Oxygen Demand. However, on-line analyzers usually operate in a bypass of the process stream, making it an indirect measurement method.

Benefits of In-line COD Measurement

The quickest method for COD measurement is through the use of in-line process equipment, such as the Rhosonics Model 9585 COD Meter. This instrument’s sensor is placed directly into the process stream, allowing for continuous, direct, and real-time monitoring of Chemical Oxygen Demand.

The COD value is displayed instantly on the instrument, providing immediate data for process control purposes and enhancing the efficiency of the biological treatment process. This analyzer functions as an early warning system, detecting unexpected process changes and preventing WWTP inactivity.

Application in Brewery Wastewater Treatment

Wastewater treatment plants in breweries use in-line COD measurement to protect their facilities from high COD peaks. This method helps reduce overall operating costs and ensures compliance with discharge consent conditions. It prevents upset process conditions that can disrupt the biological process and allows for the immediate detection of unintended raw material spillage.

Water Efficiency in Breweries

With beer consisting of 95% water, water is a critical resource for breweries. Major breweries like Heineken are focusing on water efficiency and reducing their impact on the increasing global demand for water. Investments in wastewater treatment are crucial to this goal, and in-line COD instruments, such as the Model 9585 COD Meter, ensure high standards of wastewater treatment.

Case Study: Heineken’s Implementation

Developed in close collaboration with Heineken, the Model 9585 COD Meter led to Rhosonics becoming the preferred supplier for in-line COD instruments. This meter is now used at Heineken brewery WWTPs worldwide.

CCM 9585 COD Meter

Wastewater Treatment Plants utilize the Rhosonics Model 9585 COD Meter in pipelines, reservoirs, or launders to optimize and safeguard their biological purification processes. This model is typically applied in the influent stream of the treatment facility. The COD value is continuously displayed on the analyzer screen and remains unaffected by water hardness, detergents like caustic, or suspended solids. In addition to COD, the suspended solids load in the water can be monitored as an additional process parameter.

The COD measurement of the Model 9585 is based on hybrid ultrasonic/conductivity technology, with sound velocity being the primary measurement. The factory calibration relies on the ultrasonic properties of common organic materials, such as alcohols and sugars, ensuring accuracy unaffected by vibration, transparency, or viscosity.


In-line COD measurement optimizes WWTP operations by providing immediate, real-time detection of any changes in COD and suspended solids in the wastewater stream. Just one alarm detection of a high COD peak can justify the return on investment for the entire COD analyzer. Additionally, the in-line COD analyzer contributes to a greener and safer environment by effectively controlling water spills.

If you want to learn more about COD measurement, please contact us. Our team is ready to assist you.

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