As part of a £400K earthworks package Ash Remediation Management removed in excess of 3500 tonnes of non-hazardous asbestos contaminated soils and hardcore.
Okehampton
Matlock
Malvern Gasworks
Gould Street Gasworks
Knebworth
Former Biwater Works
Ellesmere Port
Wallasey Gasworks
Client – National Grid Properties
Principal Contractor – BAM Nuttall
Consulting Engineer – Amec
Location – Wallasey
Contract Value – £200K
Wallasey Gasworks were commissioned in 1861 and it is currently divided into operational and non operational areas. Measuring 4.4 hectares, the site is owned by National Grid Properties and under a voluntary remediation scheme large parts of the non operational site underwent bioremediation treatment.
Intrusive site investigation identified several contaminants including benzene and phenol at intolerable concentrations. The remedial objective ‘to reduce the contaminant concentrations to QRA derived acceptable levels’ evolved from this and prompted Ash Remediation Management’s involvement with the project. Ash Remediation Management designed and implemented an aerated ex-situ bioremediation solution for the treatment of around 6500m3 of impacted material.
Prior to site mobilisation a series of trials were completed to maximise the efficiency of the on-site stage of works. These investigations included analysis of microbial populations, the contaminant profile and site geology.
Initially, material was conditioned (based upon the findings of the trials) with a combination of composts, fertilisers and microbes. From here material was transferred to a bunded biopile area with associated drainage, sump and aeration systems. The aeration system facilitated the removal of volatile contaminants through the negative pressure generated by the fan or blower unit. Rather than simply discharge these volatile compounds to the atmosphere, an activated carbon unit was used to adsorb these harmful gases.
During the treatment stage of the programme, several biopile monitoring parameters were routinely evaluated to help maximise the efficiency and effectiveness of the biopile. The measurements included contaminant, O2 and CO2 concentrations as well as temperature and RH levels. The findings of the monitoring were frequently interpreted and reported to the client providing evidence of the efficacy of the bioremediation.
Although many other earthworks activities were taking place in and around the Ash Remediation Management working areas, the scheme completed ahead of the agreed project timeframes providing a high standard of health and safety throughout.
Electricity Substation, Bromsgrove
Client – PXP West Midlands Limited Partnership
Principal Contractor – Ash Remediation Management
Consulting Engineer – Wardell Armstrong
Location – Bromsgrove
Contract Value – £200K
The site was previously occupied by an electricity substation and site investigations identified elevated concentrations of Total Petroleum Hydrocarbons. This lead to the formulation of the remediation objective “ to ensure future site occupants are not exposed to unacceptable levels of soil and groundwater contamination and that risks to controlled waters are reduced to an acceptable level”.
Ash Remediation Management was appointed the Principal Contractor and the objective was addressed via a two stage demolition and remediation programme. Firstly, the decommissioning of the substation was completed and secondly, the hydrocarbon impacted material underwent aerated ex-situ bioremediation.
Ash Remediation Management is committed to WRAP’s initiative ‘Halving Waste to Landfill’ and throughout the project huge emphasis was placed on recycling and reuse. During the decommissioning work >95% of material was recycled on site and the bioremediation process again proved to be a successful, more sustainable alternative to landfill.
The bioremediation programme was completed ahead of the anticipated schedule in a little over 10 weeks. During the bioremediation treatment phase numerous parameters were monitored and controlled to maximise the contaminant breakdown rate. This high degree of management also had the indirect benefit of controlling the geotechnical properties of the material undergoing treatment. This was demonstrated by the ease at which the treated material was reinstated and compacted to achieve the required plate bearing and nuclear density gauge levels.
The project was completed on time, on budget and continued Ash Remediation Management’s zero health and safety accidents record. Ash Remediation Management strive to minimise the impact of their work on residential and commercial neighbours by completing projects in as sensitive an approach as possible. The Bromsgrove remediation scheme was no exception to this and the project was completed without causing disturbance to the public or others users of the industrial park.