9. Outputs
Appropriate measures related to the outputs from the waste treatment process.
The following measures apply to all processes and operations.
1. You must record in the waste tracking system:
- that you have treated a waste
- what output materials you have produced and their weight
- what the treatment residues are and their weight
2. You must keep records of recovered and certified ‘non-waste’ materials leaving the site, including the:
- type of material
- batch number
- date of export off-site
- tonnage exported off-site
- area dispatched to
The following measures apply to all processes and treatments from aerobic processes.
1. Material stored after composting and screening must not cause pollution and you must demonstrate it is stable.
2. You must use the correct LoW code and description for the waste outputs you produce.
3. You must only describe your waste compost as ‘off-specification’ using LoW 19 05 03 if it has completed the composting cycle and 1 or more of the following criteria apply, it:
- does not meet a market specification such as publicly available specification (PAS) 100 – for example, it has failed a PAS 100 test parameter
- is composed of waste not listed in the Compost Quality Protocol
- is composed of waste not considered typically suitable for biological treatment, for example from the waste types listed in relevant standard rules permits
- is not certified compliant with the Compost Certification Scheme
You cannot describe your compost as ‘off-specification’ for waste that has only been through sanitisation (and not stabilisation). This is because it has not completed a full compost treatment. It must be sanitised and stabilised before you can be described it as compost.
4. You must correctly characterise and describe partially treated (sanitised) waste that will be transferred off-site to complete the composting process elsewhere. This waste is either 19 05 01 or 19 05 02. LoW 19 05 03 should not be used for classifying sanitised only waste.
Waste outputs from MBT or MHT are described as either compost like output (CLO) or refuse derived fuel (RDF).
These outputs are not suitable for use on agricultural land. For more guidance on applying these outputs to non-agricultural land read the guidance How to comply with your landspreading permit.
The waste code for these outputs is 19 12 12 – compost like output derived from residual waste streams.
If you export RDF you will need to notify this under the transfrontier shipment regulations – see the guidance about importing and exporting waste.
1. You must test your digestate to confirm that it is stable and has minimal biogas potential to prevent fugitive emissions.
Digestate separation
2. You must separate digestate in a way that prevents or mitigates emissions.
3. Where digestate is from food waste, you should treat it in a building with an appropriate air ventilation and extraction system. This must direct exhaust air to an abatement system or for recovery. You must design the extraction system so that:
- it provides a safe working environment
- air exchanges meet the recommended ventilation standards
4. You must effectively minimise fugitive emissions from dewatered digestate fibre and digested sewage sludge cake. This applies to all stored material. For example, you must store it:
- under a suitable cover
- in an enclosed building fitted with an air ventilation and extraction system
- in field stores in line with farming rules for water
5. You must separate and process digestate on an impermeable surface with a contained drainage system that meets CIRIA 736.
Composting digestate fibre
6. If you compost digestate fibre, you must compost it following the requirements for the aerobic treatment of waste.
7. You must compost digestate fibre to promote aerobic conditions either in:
- an enclosed building fitted with a suitably designed ventilation, extraction and air abatement system
- the open, either with negative aeration connected to an appropriate air extraction system with abatement, or a suitable covered system
8. You must control the risk of bioaerosols and demonstrate this by carrying out a site specific risk assessment.
Drying digestate
9. You must contain, collect, extract and treat all the emissions generated when drying digestate by applying heat.
10. All extraction and abatement systems must be appropriately engineered, sized and designed to a relevant industry standard to treat the emissions produced. These emissions may include:
- ammonia
- residual biogas
- odorous chemicals
- particulates and bioaerosols
11. You must consider within your risk assessments any health and safety hazards associated with all of your digestate treatment and storage areas. For example:
- biogas release from processing digestate
- potentially creating confined spaces within bunds and buildings
12. You must comply with health and safety regulation concerning DSEAR and confined spaces.
Ammonia recovery from drying digestate
13. You must have the activity in your permit and comply with any relevant emission limits.
14. Raw materials used in this process must be stored in areas with secondary containment. Ammonia must be stored safely in a building.
15. The end user must comply with the farming rules for water and landspreading guidance.
Contingency measures
16. You must have contingency measures for managing any untreated or unscreened digestate in the event of technology failure. You must consider potential hazards (for example the release of residual biogas emissions and ammonia) and manage these in line with appropriate measures.