Anaerobic digestion (AD) is a process where organic waste is broken down by microorganisms in the absence of oxygen, producing biogas and a nutrient-rich digestate. For this process to run efficiently and in line with permit conditions, AD sites must have strict waste acceptance procedures in place. Waste acceptance requirements must be in line with the site's permit.

For detailed guidance on waste acceptance for Anaerobic Digestion, please visit the Environmental Agency's website (Section 6).

Pre-Acceptance

An operator must implement pre-acceptance procedures for all new waste streams. All procedures must be followed for all new waste streams to ensure that enough is known about the waste, e.g. composition, characteristics and predicted age.

This will also confirm whether it is technically and legally suitable before it arrives on site.

Waste should only be accepted if it:

• Is of the quality and type listed in the environmental permit
• Is included within the 6-digit codes in the list of waste
• Matches the written description that accompanies it
• Is consistent with the description in the written supply agreement (if applicable)

What is included in a written supply agreement?

• Type and specific source locations of the material
• Brief description of the source type(s) and processes from which it arose
• Description of its physical form, e.g. percentage of total solids or moisture content
• Acceptance criteria

Sites may require incoming loads to be pre-booked, and all loads must match the pre-acceptance information.

Waste Acceptance Procedures

• When waste arrives on site, it must be visually checked before it is accepted. If you need to take samples, they must be representative of the load and taken by an authorised person.
• Acceptance samples are retained on site for an appropriate time after the waste has been treated or removed from the facility.
• Use a waste tracking system to record pre-acceptance, acceptance, storage, treatment and transfer, also to monitor whether there is sufficient storage capacity to accept waste on site

If the waste matches the pre-acceptance information and meets all permit and acceptance criteria, it can be delivered to the waste reception area or appropriate feedstock tank.

Need to learn more about waste acceptance for Anaerobic Digestion for your upcoming Continuing Competence touchscreen test?

If you're a Technically Competent Manager (TCM) preparing for your Continuing Competence test as part of the CIWM Operator Competence Scheme, then our COTC revision course is the perfect way to refresh your technical knowledge prior to sitting the test.

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