Work on contaminated land can involve a number of physical stages to clear and remediate contaminated soil and work on affected structures. Understanding what these stages are can help in the management of a site and in communicating with contractors.
Site Preparation and Access Controls
The site is fenced off and a welfare facility provided for workers before any ground is broken. A wheel-wash point is provided at the exit from the site for contaminated mud to be cleaned from vehicle tires. A site management plan outlines who can enter the site and what part of the site they can access.
Excavation and In-Ground Treatment
Remediation methods vary depending on the contaminant. Highly contaminated ‘hotspots’ are typically excavated and removed from site whereas low level contamination can be effectively treated on site using appropriate methods.
Managing and Testing Excavated Material
Spoil from excavation is typically stockpiled in spoil bays that are typically surfaced with heavy-duty membrane and then sampled by the geo-environmental engineer to classify the material for disposal or potential reuse.
Dust, Odour, and VOC Controls
The wheel-wash points record the clean up of contaminated mud, the air monitoring records are noted on a daily basis and the site has provision for the control of dust using bowsers for example. Volatile organic compounds are monitored at the site boundary and action levels agreed with the client. If these levels are exceeded then work will cease until the levels have dropped to an acceptable level.
Validation Sampling Before Sign-Off
Validation sampling to determine if all contaminated soil has been removed involves a surveyor collecting a number of samples in a grid pattern from the base and sides of the dig. The results of the samples are compared against the remediation targets for the site and a validation report issued to enable handover of the site.
All stages of soil remediation on site are recorded and therefore there is a clear paper trail from commencement of works to completion and handover of site.
Leave a Reply