The Site Investigation… What are they really for?

So, let’s look at some of the reasons why these Si’s are often not fit for waste classification purposes:

• • Insufficient sampling frequencies – The Si may have been done on a budget, or conducted at the time whilst the site was still active prior to development, both of which would inhibit where samples could be taken from.
  • Irrelevant areas of the site tested – Often where the waste is being generated from, either in location or depth, is not where the soils have been sampled and analysed, meaning they are a complete unknown.
  • Sampling techniques – Often due to site restrictions at the time of the investigations small window samples are needed to be taken, these can be cores of just several inches in diameter and can easily miss contamination that may be present in the ground. Often a site is assumed to be “clean” but when excavation starts in earnest, a host of issues are uncovered.
  • Incorrect testing for waste classification – Assessing soils for risk to health and the environment has a different set of criteria to waste classification, therefore some of the analysis may not be suitable, or certain contaminants may not have been tested for. A regular example is when asbestos is found. From a risk perspective any asbestos is generally unacceptable, so they merely test for its presence. However , it needs to be quantified from a waste perspective, which is often missing, causing delays and uncertainty.
  • NO WAC – WAC leachate analysis is required to determine wastes suitability to landfill, and this is most commonly used to determine if soils are suitable for inert landfill disposal (often the most cost-effective disposal solution). Si’s are designed to assess risk, not landfill suitability, yet every contractor wants to know “is my muck inert”?
  • Other wastes go unassessed – The most common example would be the presence of coal tar in asphalt. Asphalt is rarely (if ever) tested during a Si, however the prevalence of hazardous coal tar is far more common than most realise and is often mishandled by the waste producer.

This is a common process that generally leads to one of two scenarios:

Waste is misclassified and/or mismanaged due to time constraints and commercial reasons

OR

The project is delayed due to the need for further sampling and analysis so the waste can be properly classified and managed. Often this can cause issues if contamination is identified, it can seriously affect budgets, or if the contractor has taken risk on the project can seriously affect profitability.

We would be naive to think all sites should conduct waste classification analysis from the outset, however, the keys are:

• • Understand the limitations of the available site investigations.
  • Assess the possible risks that may yet be undiscovered.
  • Create a waste sampling strategy early, so that waste can be managed effectively and there aren’t too many surprises when ground is broken.

If you need someone on your side that can assist your business with this, get in touch with SoilEx.