Project: Abbey Quarter, Glasgow
Timescale: 10 months
Hotspots of heavy metal contaminated hazardous material had inadvertently been excavated and stockpiled with clean material leading to cross-contamination. With expensive disposal costs and a further 3,500m3 still to be excavated, our client was facing a £1m liability on their project and asked ERS to assist with disposing the material at a price that aligned with their original budget.
All works had been halted after the cross-contamination incident until a solution could be agreed. Having previously successfully completed a remediation project on another part of this site, ERS was asked by the client to return to help with disposal of the hazardous material.
Laboratory analyses showed that the material which had been cross-contaminated was now considered hazardous waste. However, from experience ERS had gained during the remediation works we were confident that not all the material would be hazardous and could be segregated. We initially collected one sample per 50m3 for independent laboratory analysis. This demonstrated the proportion of hazardous material aligned with our expectations and the client budget. However, a higher frequency of sampling, and testing was required to ensure the waste was correctly sentenced.
In-house pXRF testing of samples at our treatability laboratory showed a superb correlation with the accredited laboratory results. The laboratory results we were used to broadly delineate the worst contamination within the stockpiles, and on-site pXRF analysis was then used to further refine the delineation of lead and zinc levels, using thresholds set by our in-house technical specialists. This way, we ensured that each load of material was correctly sentenced.
The excess material was cleared within 5 days, at a price that aligned with the client’s original budget. The client then asked ERS to stay on to assist the ground works contractor by trial pitting and sampling of the remaining 3,500m3 material ahead of excavation.