The Arley Consulting Company Limited

SITE HISTORY: Bleach Works and Paper Mill
DEVELOPMENT: Residential

Services undertaken:

  • Desk Study
  • Site Investigation
  • Quantitative Risk Assessment
  • Supervision of Remediation Scheme
  • Routine Monitoring







The Arley Consulting Company Limited was commissioned by Persimmon Homes to undertake a comprehensive ground investigation and contaminated land assessment at the 5 Ha residential development in Bury.  The site had formerly been used as a bleach works and a paper works prior to demolition in 2008.  The site had been subject to several site investigations over the last 15 years.  Key locations at the site included infilled reservoirs, buried tanks, wells and significant areas of hydrocarbon contamination.  In addition, Kirklees Brook was located adjacent to the site.

This  phase of the study included a review of all previous  site investigation  information which was used to provide  indicative information  on  the  typical  ground  conditions   at   various locations  across  the  site.   Following  assessment  of   this information, TACCL liaised with Bury MBC and the EA to design  a comprehensive site investigation for the whole site.   The  site investigation  works  were  designed  to  confirm  some  of  the findings of previous site investigation and to investigate areas previously  not covered, all of which considered the  conceptual model  prepared  for the site.  The full justification  for  the site  investigation was detailed in the Desk Study report, which was approved by Bury MBC and the EA.


A detailed site investigation was designed based on the findings of   the  preliminary  conceptual  model  which  had  identified potential  risks  to  human health, controlled  waters  and  the environment.  The investigation comprised trial pits and  cable percussive  boreholes.   Soil and water samples  were  collected using  strict quality assurance procedures and selected  samples were analysed for specific chemical contamination.

On   receipt  of  all  site  investigation  a  quantified   risk assessment was undertaken in accordance with UK legislation  and policy.   The  assessment utilised the CLEA model  to  determine potential  risks  to  human health  and  the  EA  P20  model  to determine risks to controlled waters.  Potential risks to  human health and controlled waters were identified and a pragmatic and effective  remediation strategy was prepared.   The  remediation works were detailed in a remediation strategy for the site which was approved by Bury MBC and the EA.

The remediation comprised the excavation and on site remediation of  some  1,500 m3 of organic contamination using bioremediation techniques.  TACCL supervised the excavation of the contaminated material  and  recovered validation samples from  the  base  and extent of each excavation.  The excavated material was placed on a  treatment  area prepared by the remediation contractor.   The material undergoing  treatment  was  regularly  tested   until treatment  was completed and the soils were re-used at the  site, minimising off site disposal costs and promoting sustainability.

In addition some 25 m3 of hydrocarbon contaminated water was pumped from prepared sumps and removed from site.

TACCL also validated imported material to be used in the capping of  the  gardens  and the landscaped areas and  checked  correct thickness  had been achieved.  In addition, TACCL inspected and validated  the installation of the gas mitigation measures  that were required in all new builds.

As requested by the EA, TACCL undertook routine monitoring of Kirklees Brook during the development works. Samples were recovered every 3 months from upstream, midstream and downstream locations and tested for a wide range of potential contaminants.