What is WAC Testing?

In this article the industrial waste specialists at WTS explain everything you ever wanted to know about Waste Acceptance Criteria or WAC testing.

The article explains what WAC testing is and why waste and soils need to be classified prior to disposal to landfill. It goes on to highlight who is responsible for classifying waste, the different types of landfill site and the classes of waste material they can accept, why WAC classification is important, and common contaminants found in UK soil. It concludes by looking at whether you can legitimately re-classify hazardous waste as non-hazardous to reduce disposal costs.

Analysis of waste for landfill disposal

All waste producers in the UK are legally responsible for making sure that the waste they produce is properly classified and sorted before being sent offsite for disposal to landfill sites.

Most waste soils are easily classified using standard analysis, but once this has been done, the next step is to check that it conforms to the current laws and rules concerning the disposal of waste material. If any of the waste produced falls into the categories of hazardous or inert waste, then there is a further step in the disposal process – the Waste Acceptance Criteria, or WAC.

Waste Acceptance Criteria or WAC testing is a process intended to assess the risks from waste materials once they are consigned to landfill. The tests involve laboratory analysis of the leachate from the waste material and are designed to determine the best methods of disposal.

Why does soil need to be classified for disposal?

The legislation which sets out the rules and requirements for disposing of waste is the 2018 Waste Framework Directive. This lengthy document defines waste simply as any object or anything which the holder discards, or needs to discard.

The regulations are enforced across the UK by government bodies including the Environment Agency, the Scottish Environment Protection Agency and Natural Resources Wales. These bodies all have the power to issue fines to companies who are found to be breaking the rules around disposal of waste. Waste classification is a form of risk assessment, and involves an examination of the composition of the waste, and performing due diligence on any contractors used to dispose of the waste.

Who is responsible for classifying waste sent to landfill?

There are still a very small number of landfill sites which will turn a blind eye to these regulations, but beware, the rules state that the responsibility for classifying the landfill waste lies with the person or business producing the waste, not the landfill operator.

Taking the time to classify your waste correctly can also save your business both time and money on project costs. Disposing of waste classed as hazardous is much more expensive than other waste classed as inert or non-hazardous, so getting the classification correct can greatly reduce the quantity of hazardous waste which requires disposal.

Waste characterisation and WAC testing

Any landfill site operator will expect to see a basic characterisation of material being disposed of, and business owners have a duty of care to do this characterisation correctly.

Firstly, get your waste characterisation test done, then organise the WAC testing with a specialist company such as WTS. Often, the two steps are done at the same time, and the testing company will give you all of the information you need to give to the landfill operator.

In very basic terms: the waste classification will tell you what you are dealing with. The WAC test will tell you what can do with it. It’s impossible to work out where something should go if you’re not sure what it is made of.

WAC testing is a process intended to assess the risks from waste materials once they are consigned to landfill.

What are the different classifications for landfill sites?

Typically, there are three different classes of landfill. These are:

Inert
With inert landfill sites, the site isn’t lined or capped, and as there is nothing to prevent waste leaching into the soil, only waste which will not break down into the surrounding ground can be disposed here.
Non-Hazardous
A landfill site for non-hazardous waste will be lined and capped, which means waste which can potentially leach can be accepted.
Hazardous
Hazardous landfill sites can accept the most dangerous types of waste, and store it securely. A sub-type of this landfill category is for non-reactive waste such as asbestos which won’t leach into the soil, but is dangerous in other ways.

How does WAC testing work?

Waste Acceptance Criteria is a framework used to determine whether or not soil waste can be disposed of at a particular landfill site. WAC testing will also provide more information about how the material might degrade or affect the surrounding area after it has been put into landfill.

There are two stages to WAC testing which are:

Stage 1
Initially, the solids are analysed to determine the organic components of the waste material, looking for some commonly found contaminants.
Stage 2
The second part of the process is the leachate analysis, which assesses the level of leaching out of the material in landfill, which might affect surface water or groundwater.

What are the different classes of WAC testing?

There are three different classes of WAC testing and they are:

Hazardous
Stable non-reactive Hazardous
Inert

Companies such as WTS which offer a “full suite” of WAC testing will perform all of the three types of tests. The most common classes of waste are the inert and hazardous groups. The stable non-reactive hazardous group is a lot rarer. The most frequently found waste in this class contains levels of asbestos deemed to be dangerous to health.

WAC testing in more detail

WAC testing isn’t designed to help business owners classify their waste, or determine its composition. A WAC test is the part of the process which follows, and which looks at which type of landfill can be used to get rid of your already classified waste.

If you have waste soil from sites which you think are possibly contaminated, then there are two stages involved in getting it tested. Firstly, a sample of the waste is collected and then sent off to the lab for testing. Once the analysis is complete the results will come back stating whether the waste is hazardous, or non-hazardous. The lab will also generate a classification code for the waste sample.

Once you have your waste code, the next stage is the WAC testing if you wish to dispose of the waste in landfill.

For non-hazardous material, then you have two options depending on what the WAC tests reveal. If your non-hazardous waste passes inert WAC testing, then you can send it directly to inert landfill which is the cheapest option. If the WAC tests fail the inert testing, or if you choose not to have it tested, then your only option is the more expensive, non-hazardous landfill.

Which contaminants to test for?

The guidance from the Environment Agency states that you should start off by testing the waste soil for any contaminants which you suspect might be present. You should base your assumptions on what you already know about the site and its history, using knowledge from staff members, maps of the site, previous ownership and uses, or any prior studies which you have carried out.

Most environmental consultants will perform a set of core tests based on the most common contaminants found on industrial sites, such as asbestos, hydrocarbons, or metals. The number of samples required for testing will depend on a range of factors. On sites where the soil varies across the site, or where previous tests have revealed high levels of contaminants, then more samples might be required.

Asbestos waste classification

Asbestos is a commonly-found contaminant found on sites in the UK and can affect how soil is classified in two ways. As the health risks of asbestos are so high, any concentration greater than 0.1% will mean that the soil is automatically classed as hazardous.

Secondly, if one piece of ACM (asbestos containing material) is present, this also means the soil is considered hazardous waste. ACM could be a piece of cement containing asbestos, or some insulation lagging.

Can you reclassify hazardous waste as non-hazardous?

It is possible, in some situations, to have hazardous waste re-classified as non-hazardous. You will need experts in waste or contaminated land to take a closer look at the results, basing their assessment on the history of the site, or a closer examination of the chemistry of the waste. Another possibility is defining a very specific area of the site where the soil is hazardous, allowing the rest to be classed as non-hazardous. This tactic can help cut the quantity of waste which requires to be disposed in expensive hazardous waste sites and can result in significant cost savings.

Options for waste disposal other than landfill

Landfill is generally considered as a last resort. Other options might include reusing the material in another way on the same site, or sending it to a treatment centre.

Waste Acceptance Criteria testing and analysis for landfill disposal

WTS offer a comprehensive range of laboratory based soil testing, analysis and waste management solutions. Our experts can provide advice and support to help you identify the most appropriate and cost effective strategies for the classification, safe management and disposal of your waste materials.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained technicians, in-field specialists and consultants we can offer professional, cost effective soil testing and laboratory analysis solutions across the whole of the UK and internationally.

Contact us today to learn how our soil analysis and waste disposal solutions can help your business improve regulatory compliance, environmental performance and reduce waste disposal costs.

Analysis of waste for landfill disposal