WRc Ash Factory: ESA IBA protocol monitoring and more

The Challenge

Incinerator bottom ash (IBA) is the heterogenous mix of glass, ceramics, metal items, clinker and ash which remain after the combustion of waste in an energy from waste (EfW) plant. Depending on the feedstock, the proportions of those fractions will vary, but there is a need to characterise and classify it to ensure appropriate management and/or recovery of the valuable components. 

Sampling and testing this matrix is challenging due to the heterogeneity of the material and because concentrations of potentially hazardous compounds are low compared to detection limit of standard analytical methods. In addition, the regulatory context for classifying wastes is still evolving. In the 2000s, zinc wasn’t on the list of metals to be included in a hazardous property assessment, now hundreds of compounds need to be considered. Therefore, the potential for misclassification is high.

The Solution

In conjunction with the Environmental Services Association, WRc developed the ESA IBA Protocol. Since the initial 2010 version, WRc has developed an Ash Factory to provide an end-to-end solution for producers of residues from a range of thermal treatment operations.

• Start-up monitoring for new facilities – commissioning is a stressful time for operators so we provide support before, during and after start-up monitoring with a direct line to our team for any queries including next steps. We advise which samples require testing for which parameters, carry out multi-stepped sample preparation in our own labs, arrange all the testing including in vitro irritancy and metal speciation as required, and present tiered IBA hazardous property assessments in bespoke classification reports.
• Routine monitoring – once on the ESA Protocol we provide interpretive IBA reports and early warning of trends in key parameters that may require intervention. We also include permit compliance monitoring and an annual characterisation report on IBA and air pollution control residues.
• Holistic support for routine clients – this covers assessments of a wide array of feedstocks and thermal treatment residues, consultancy for each step between and bench-marking against our anonymised datasets.

The Outcome

The majority of UK EfW operators sign-up to WRc’s routine monitoring Ash Factory services. This brings them peace of mind that they are not in danger of mis-classifying they waste while knowing they do not have to check a single analytical certificate or investigate whether the methodology is compliant with CLP, WM3 or the latest regulatory position.

Through the development of the ESA Protocol and robust monitoring of IBA for over twenty years, 2.5 M tonnes/year of incinerator bottom ash is recycled as an aggregate as a substitute for virgin materials, avoiding landfill.

Find the ESA IBA Protocol here.