Most developments will require a quantity of soil to be removed from site, be it from levelling a site to facilitate development or from excavations for foundations, buried services etc. Unless the soils are uncontaminated and naturally occurring, these soils will be classified as a waste; only uncontaminated and naturally occurring soils can be reused on site.

Waste Acceptance Criteria Testing (WAC) is often wrongly perceived as the procedure of classifying waste soils as either non-hazardous or hazardous for disposal. In fact, the first step is to carry out chemical analysis of the waste for contaminants reasonably expected to be present as per the Environment Agency’s “Guidance on the Classification and Assessment of Waste (1st Edition 2015), Technical Guidance WM3.”

Lustre is able to sample for, and schedule chemical analysis of your waste soils and efficiently classify any hazardous properties it may have. Once a waste has been chemically characterised, a WAC test needs to be undertaken. WAC testing is designed to replicate how waste soils will behave once deposited in a landfill, primarily by the analysis of leachates derived from the waste. For the leaching part of WAC, it is now expected that laboratories will undertake a single stage 10:1 leaching in accordance with BS EN 12457-2, which is a change from the previously used two stage cumulative leaching at 2:1 followed by 8:1. This change provides a significant time and cost saving to the waste producer. Once undertaken, the WAC test, in conduction with the chemical analysis, will inform which category of landfill may legally accept the waste.

The process to determine the category of landfill is therefore as follows:

 

Step 1: Chemical testing for potential contaminants based on the site’s history and other relevant information. Screening of chemical data in a hazard tool based on WM3 requirements to determine if non-hazardous or hazardous.

Step 2: WAC testing to determine appropriate landfill type based on soils expected behaviour in the landfill.

The results of the above process will be one of the following scenarios:

 

Non-hazardous (Chemically): If the waste soils are believed to be inert, a WAC test will confirm this. If no inert thresholds are exceeded, then the waste soils are suitable for an inert landfill. If inert thresholds are exceeded, then the waste soils will require disposal at a non-hazardous landfill.

Hazardous (Chemically): If the waste soils are classified as hazardous then a WAC test is definitely required. If the WAC results do not exceed the hazardous thresholds, then it is suitable to be sent to a hazardous landfill. If, however, the hazardous thresholds are exceeded then the waste soils will require pre-treatment at a specialist facility.

 

If your project is likely to involve the disposal of waste soils, or if you would like some advice, please get in touch with us to discuss how we can help.