Composting Telemetry Monitoring and Alarm System

Customer Challenge

Large scale composting facilities must carefully monitor the temperature of compost batches to ensure safe processing and compliance with regulatory requirements.

In this case, Eltek data loggers with GenII transmitters were used to monitor temperature within a large-scale composting operation. The facility needed to process both vegetable matter and animal by products while complying with DEFRA Animal By Products Regulations and the corresponding European regulation EU 142/2011.

The customer required a monitoring system capable of providing reliable temperature data throughout the composting process, while also producing records suitable for regulatory inspection and audit purposes.

The solution needed to operate in a demanding industrial environment where heavy machinery is used to move large quantities of organic material. Equipment had to be robust, reliable, and capable of operating in harsh conditions.

 

Why

Composting facilities must ensure that organic material reaches and maintains specific temperatures for defined periods to achieve proper sanitisation and meet regulatory standards.

The facility processes food waste, green waste, and organic fines, which consist of residue from black bin waste that can pass through a 12-millimetre screen. Aerobic sanitisation is used to produce compost suitable for brown field site restoration.

The composting system is designed primarily for batch tunnel in vessel composting systems, although it can also be used in other composting applications. The process typically involves a vessel measuring approximately 3 metres by 3 metres by 10 metres with a retractable roof. Each vessel can contain between 100 and 200 tonnes of feed stock.

The composting process normally includes a two stage pasteurisation process. This requires the compost to reach at least 60 degrees Celsius for a minimum of 48 hours under the United Kingdom Animal By Products Regulations, or alternatively 70 degrees Celsius for one hour under the European standard.

Veterinary inspectors from the Animal and Plant Health Agency require clear evidence that these temperature requirements have been achieved. Reliable temperature monitoring and accurate data records are therefore essential.

 

The Eltek Solution

Eltek developed a compost monitoring system designed to measure temperature within compost batches and provide continuous records of the composting process.

Temperature is monitored using specially designed stainless steel lance probes inserted into the compost material at predetermined positions and depths. The probes are connected by robust cables to a transmitter located outside the compost vessel. The material being processed is referred to as the batch.

A total of eight probes is considered ideal to calculate a mean batch temperature greater than 60 degrees Celsius for 48 hours. However, data from six probes is considered sufficient by inspectors, which provides redundancy should a probe fail.

The monitoring system uses heavy duty stainless steel probes connected to a rugged transmitter that sends temperature data wirelessly to a receiver and logger located in an office environment. The data can then be analysed and processed using a desktop computer.

The system is designed to operate reliably in harsh environments where heavy equipment is used to move compost material. The rugged construction of the probes and transmitters ensures reliable performance under demanding conditions.

The monitoring system can also be adapted for other composting methods. A wireless probe version is available for wind row composting applications.

 

Measurable Results

The monitoring system provides continuous temperature data that allows operators to confirm that compost batches meet the required sanitisation standards.

The Darca Compost software has been designed specifically for compost recycling applications and enables users to track each batch of compost as it moves between physical storage containers known as bays.

Batches are grouped as either current batches, typically less than six months old, or historical batches for easier management within the software. The software automatically calculates the results of the required regulatory temperature tests and informs the user whether a batch has passed or failed.

Key functions of the software include:

• Data table showing all temperature readings along with the calculated average of the active probes

• Graphical display of batch temperature data and mean values with batch movements indicated

• Batch movement tracking between storage bays 

• Event diary for recording operational activities

• Summary view showing batch details, movements, probe data, test results, and events

• Data export to CSV format for further analysis in Microsoft Excel

• Printed batch records including summary information and graphs

These features provide a clear and traceable audit trail for regulatory inspections.

 

Strategic Impact

The Eltek compost monitoring system enables composting facilities to meet strict regulatory requirements while maintaining efficient operations.

By providing reliable temperature monitoring, automated calculations, and comprehensive record keeping, the system supports compliance with national and European composting standards.

The rugged design of the monitoring equipment ensures reliable operation in harsh industrial environments, while the flexible system design allows it to be adapted to a variety of composting processes.