Biogas plants operate in demanding environments where measurement reliability, safety, and cost control are equally important. From digesters filled with viscous slurry to gas tanks exposed to moisture and foam, traditional level measurement technologies often struggle to deliver stable results over time.

Recently, we received a request from a customer regarding biogas digester level measurement. Unlike conventional automated monitoring solutions, the customer required a power-saving, stand-alone system with extremely simple operation.

The display must be large and easy to read, similar to those used on industrial weighing scales, featuring large red LED digits. It must also meet IP68 protection requirements for reliable outdoor use.

No PLC or external communication is required—only the level sensor, the display, and a power supply—ensuring maximum simplicity and long service life. The battery and display are installed inside a fully sealed IP68 enclosure. To read the measurement, the user simply opens the enclosure, turns on the switch, and immediately reads the data.

No cloud connection, no SIM card, and no solar panel are required. This simple and cost-effective local solution is exactly what the customer needs.

Challenges of Measuring Levels in Biogas Tanks

Digestate inside biogas tanks is far from a clean liquid. It is thick, contains gas bubbles and foam, and is constantly moving due to agitators. These conditions often cause signal loss or false readings when using contact-based sensors or ultrasonic devices.

In addition, biogas facilities frequently require explosion protection because methane may be present in the surrounding atmosphere.

Many operators also prefer local, on-demand measurement rather than complex automation systems. Continuous power supplies, PLCs, cloud platforms, SIM cards, and solar panels increase both system cost and maintenance workload, especially when multiple tanks are involved.

Holykell Solution

Non-contact radar level measurement is ideally suited for harsh biogas environments. Unlike pressure or ultrasonic sensors, radar technology is not affected by foam, vapor, bubbles, or changes in media density. High-frequency radar ensures stable and reliable readings even in narrow tanks or under continuous agitation.

A key design goal of this biogas monitoring solution is energy efficiency. Instead of operating continuously, the radar sensor only works when a measurement is actually required.

Working Principle

• The operator presses an IP68 waterproof push button.
• The radar sensor and display power on instantly.
• The level measurement is completed within seconds.
• The system automatically shuts down to conserve battery power.

This on-demand operating mode significantly extends battery life while eliminating the need for permanent power supplies or control systems.

Measurement results are displayed on a large, easy-to-read LED display connected to the radar sensor by cable. The bright, industrial-style digits ensure excellent visibility even in outdoor environments.

The display and power supply are installed inside a fully sealed IP68-rated enclosure. Daily operation requires no touchscreen, no configuration, and no technical training—simply open the box and press the button.

ATEX-Certified Safety for Biogas Environments

Safety is a critical requirement in biogas plants. Since methane gas may be present, all equipment installed near the tank must comply with explosion protection standards. The recommended radar level sensor is ATEX certified, making it suitable for hazardous areas and compliant with industry safety regulations.

Recommended Configuration

• HR80G 80 GHz radar level sensor, mounted on top of the biogas or digestate tank
• Large red LED display
• Outdoor-rated power unit
• IP68 sealed enclosure for the display and power unit

If you are looking for a dependable way to measure digestate or biogas tank levels without unnecessary complexity, this solution is designed for you.