Enhanced Safety Through In-Situ Oxygen Monitoring in Anaerobic Digester Piping

By Barben Ametek

A major dairy foods manufacturer was expanding its processing plant and biogas treatment operations simultaneously, all while keeping both systems fully operational. As part of this upgrade, new anaerobic MBR units were installed, and the facility transitioned from flaring all biogas methane to recovering and routing it back to the plant’s boilers and process heat systems.

An anaerobic digester flare remains a critical safety and environmental control device for managing excess biogas. When biogas is combusted at the flare, methane is converted to carbon dioxide and water vapour, reducing greenhouse gas emissions and preventing uncontrolled methane release. However, as part of the biogas upgrade project, this facility now integrates cleaned digester gas directly into its thermal energy infrastructure. By using biogas as a renewable fuel source for existing boilers and manufacturing processes, the plant reduces dependence on fossil fuels, increases overall energy efficiency, and captures waste energy in a circular, sustainable manner.

During the system redesign, the site established a 1–2% O₂ operational watch zone for early detection of flammability risks within the digester process piping. Rather than monitoring for upper-limit alarms alone, the operations team needed real-time, low-level oxygen data capable of triggering meaningful process responses.

Barben Analytical’s OXYvisor optical oxygen analyzer, paired with the SafeTap2 in-situ sensing assembly, was selected as the dedicated safety instrumentation package. This configuration enabled continuous low-percent oxygen measurement directly within the process line, providing an immediate analog signal for the control system without the need for a traditional gas sample handling system.

The OXYvisor’s optical measurement technology offers substantial performance advantages in biogas environments. Because it is inherently immune to cross-interference from moisture, H₂S, CO₂, and other acid or reducing gases typical in anaerobic digestion, it eliminates the need for gas scrubbing or preconditioning. The SafeTap2 assembly further simplifies deployment by enabling true in-situ sensing, avoiding the maintenance burden, plugging, and drift issues associated with extractive sample systems.

Conclusion

Anaerobic digester and biogas systems require instrumentation that is both technically robust and maintainable under harsh, real-world operating conditions. For oxygen monitoring—especially when low-percent oxygen data is essential for LEL and flammability risk mitigation—the combination of an appropriate analyzer and a reliable in-situ installation method is essential.

The Barben Analytical OXYvisor, when integrated with the SafeTap2 in-situ sensing assembly, provides a streamlined solution for continuous, accurate oxygen measurement directly in the process piping, supporting safer and more reliable biogas operation.

Get more insights like this in the Biogas Community Magazine – Safety Edition 2026.