A Waste Acceptance Criteria (WAC) test determines whether waste meets the leaching limits for disposal at a particular type of landfill. It is commonly required for excavated soils, construction waste and other materials destined for landfill, helping to establish whether potentially harmful substances could leach from the waste and pollute the surrounding environment.
What types of WAC test are available?
WAC testing includes different laboratory methods, selected according to the waste and the assessment required:
• Basic characterisation (Level 1): Establishes the waste’s composition, properties and leaching behaviour to determine which landfill class can accept it. The prescribed up-flow percolation test (BS EN 14405) is used for leaching assessment where required. • Compliance testing (Level 2): Checks regularly generated, consistent waste against the parameters established during basic characterisation. Batch leaching methods in the BS EN 12457 series are used. • On-site verification (Level 3): The landfill operator checks incoming waste to confirm that it matches its description and supporting documentation.
The BS EN 12457 series includes several batch leaching methods with different procedures and liquid-to-solid ratios. The appropriate method depends on the testing requirements. WAC testing is distinct from waste classification testing, which determines whether waste is hazardous or non-hazardous.
When is a WAC test necessary?
Testing is normally required when waste is being characterised for disposal at a landfill for inert waste, hazardous waste or stable non-reactive hazardous waste, as well as for certain gypsum-based materials. The landfill operator must confirm that the waste meets the applicable acceptance criteria and that the site’s environmental permit allows its disposal.
Some specified waste streams may be exempt from testing for basic characterisation. However, contaminated or potentially contaminated soil, mixed construction waste and materials from sites with a history of industrial use may require additional assessment. Always check the requirements with the receiving facility before arranging testing.
How much material is required?
For compliance testing using the BS EN 12457 series, the Environment Agency specifies a 2 kg sample. Larger samples may be necessary for physically variable materials, such as soil containing stones or brick fragments, where a representative smaller sample cannot be obtained.
Basic characterisation may require different sampling arrangements and quantities. The number of samples also depends on the size of the waste batch and whether the material is homogeneous or heterogeneous. Contact your laboratory before sampling to confirm the required quantity, preparation method and sampling plan.
Arrange your WAC test
Providing the correct sample and background information helps avoid delays and ensures the results are suitable for the intended disposal route. Confirm the requirements with your laboratory and receiving landfill before sending your sample.