Remediation of Blue Billy contaminated soils at Tondu

Envirotreat was commissioned to undertake remediation (E-Clay stabilisation) of Blue Billy contamination (gas purification spent oxide) at Tondu

Site Background & History

The site consisted of the former Archbishop McGrath School Campus in Tondu. The school had been demolished to make way for residential and Extra Care Facility development for Linc Cymru.

Historical mapping showed the presence of coke ovens and railway siding within the site boundaries.

Planning conditions stipulation where contamination is identified that:-

“an appraisal of remedial options, and justification for the preferred remedial option(s).”

“Prior to the commencement of the development a detailed remediation scheme and verification plan to bring the site to a condition suitable for the intended use by removing any unacceptable risks to human health, controlled waters, buildings, other property and the natural and historical environment shall be submitted to and approved in writing by the Local Planning Authority”

“Within 6 months of the completion of the measures identified in the approved remediation scheme, a verification report that demonstrates the effectiveness of the remediation carried out must be submitted to and approved in writing by the Local Planning Authority”

Previous site investigation had highlighted the presence of “Blue Billy” contamination, spent oxide from the coking of coal and historical town Gas Purification.

Remediation Works

Envirotreat undertook appraisal of remedial options from which developed an approved remediation strategy to enable reuse of treated on site. The strategy was both commercially viable and shown not to impact / delay the overall program of works.

The approved remediation strategy involved the excavation the contaminated soils and E-clay stabilisation to enable reuse on site. Following treatment and validation (by leachate testing), treated soils were reused onsite as suitable fill material as part of the overall development.


A comprehensive Validation Report was produced on completion of the works by Envirotreat. The Validation Report documented the works undertaken and confirmed that the prime drivers for the remediation had been achieved, the protection of Human Health and groundwater.

Integral Géotechnique approved the Envirotreat Validation Report prior to submission to the regulators.

This project demonstrates that contamination issues that have been historically difficult and costly to address (cyanide in this case) can be successfully treated using Envirotreat E-Clay Stabilisation technology.

Delivering land you can develop

Envirotreat are a specialist remediation solution provider and sole providers of E-Clay technology