How to comply with the designation

The designation has three main risk control measures:

Feedstock controls
Pasteurisation requirements
Contamination thresholds

Feedstock controls

The designation specifies what feedstocks you can use for producing low-risk digestate. Some feedstocks are classified as elevated risk. Digestate produced with elevated risk feedstocks need additional pasteurisation. You can see the pasteurisation requirements below.

The designation does not allow biosolids or sewage sludge. This is due to the high risks of contamination from these waste types.

Pasteurisation requirements

The designation has two options for pasteurisation. You must apply one of these options to comply with the pasteurisation requirements of the designation.

Process-based pasteurisation
Outcome-based pasteurisation

Process-based pasteurisation

The process-based pasteurisation option uses time and temperature for reducing risk.

Low-risk feedstocks must meet one of the process-based pasteurisation requirements. Elevated-risk feedstocks must undergo both process-based pasteurisation requirements.

Digestion or pasteurisation requirements

Low-risk feedstocks

For anaerobic digestion (AD): maintain temperature at 55°C or above for a minimum of 72 hours

For treatment pre-AD or post-AD: maintain temperature at 70°C or above for a minimum of one hour.

Elevated-risk feedstocks

For anaerobic digestion (AD): maintain temperature at 55°C or above for a minimum of 72 hours

AND

For treatment pre-AD or post-AD: maintain temperature at 70°C or above for a minimum of one hour.

Outcome-based pasteurisation

The outcome-based pasteurisation does not rely on time and temperature for pasteurisation.

Using this option, you need control risks with:

a risk assessment
process validation
a monitoring program
microbial contaminant thresholds.

These requirements are specific to the outcome-based pasteurisation option. However, we expect you to understand this information to produce safe digestate.

Contamination thresholds

The designation sets out contamination limits for chemical, physical and microbial contaminants. The digestate cannot exceed the specified upper limits for any of the contaminants and pathogen indicators set out in Appendix 1 of the designation.

When using digestate, you should also consider the impacts of any other contaminants of concern, which may be present but are not be listed within the designation, and ensure that you are effectively managing your risks of harm and meeting your obligations under the GED.

Risk assessment

The risk assessment must:

identify potential biological hazards associated with the feedstocks and process used
show how the process reduces these risks
provide metrics and parameters for risk reduction
include assessment for typical and foreseeable atypical operating conditions and situations.

Validation

The outcome-based pasteurisation method must show:

a reduction in indicator organisms
the material is below the thresholds for microbial contamination.

Monitoring program

You must establish a monitoring program and implement it to ensure microbial risk reduction. It must include:

monitoring process parameters
adequate sampling
analysis to show the findings.

You must determine the frequency of monitoring and validation in line with best practice for risk management.

You must maintain the following documents and records:

the process and risk assessment of the process
validation test records
records of implementation of the monitoring program, including sampling and analysis
sampling and test records and analysis.