This article considers:

  • Observations on the classification and disposal of construction wastes.
  • The 7 Step Assessment.
  • The impact on recovery and landfill costs.

Background

The construction, demolition and excavation (CDE) sectors produce over half of the UK's waste (202.8 million tonnes in 2014) [Source: DEFRA)]. 'Mineral Wastes' (79.0 million tonnes), followed by 'Soils' (54.2 million tonnes) make up almost two thirds (66%) of the UK's total waste and the CDE sector will remain the highest waste generator despite huge improvements on resource efficiency initiatives. Excavation waste is excess material that cannot be re-used/engineered on site. Our observations are that chemical analysis from geo-environmental investigations (required under planning or for land quality levels) or Landfill Waste Acceptance criteria are still commonly but incorrectly used for waste classification.

Classification and the 7 Step Assessment

To be clear, all Waste classification should follow the 7-step approach in the Environment Agency Technical Guidance Note WM3 Guidance on the Classification and Assessment of Waste summarised below:

  • Step 1: Does the waste need to be classified?

(i.e. Is it within the legal definition of waste?)

  • Step 2: Identify the Code(s) that may apply

(The European Waste Catalogue (EWC) Code within the List of Waste Regulations 2005 (Schedule 1)).

e.g. for 54.2 million tonnes of soil this could be:

  • 170503 - Soils and stones containing hazardous substances MH
  • 170504 Soils and stones other than those mentioned in 170503 MN

 

  • Step 3: Identify the assessment needed to select the correct code

Waste can be:

  • absolute hazardous
  • absolute non-hazardous
  • either hazardous or non-hazardous, (these are called mirror entries e.g. in the soils example above).

The assessment needed depends on the type of code. For absolute hazardous or non-hazardous code entries no further assessment is required. If an assessment is needed consider the next 3 steps: Step 4: What is the composition?

  • Step 5: Are there 'hazardous substances' (e.g. asbestos, lead, arsenic etc.) or 'Persistent Organic Pollutants'? (e.g. DDT, dieldrin, endrin etc)
  • Step 6: What are the hazardous properties?

Determining if it is hazardous requires sampling and analysis (following Appendix D of WM3). This will identify hazardous substances and the lab analysis can be compared with WM3 concentration limits to determine its properties e.g. if it is carcinogenic.

  • Step 7: Assign and describe the classification code

(e.g. 170504 Soils and stones other than those mentioned in 170503 MN)

Recover and landfill costs

Waste is an extremely complex subject and in the context of a project may not be a high priority but in our experience the correct assessment of waste opens up opportunities to consider what can be diverted from landfill or whether material can benefit from the lower band landfill tax (2.80pt instead of 88.95 pt standard rate). With policy changes to landfill tax proposed in 2018, widening the application of landfill tax, correct classifications could significantly reduce project costs.