Risk Management Any unacceptable ground conditions identified by the Phase 2 investigation can be resolved by one or more of the following risk management techniques: Further Investigation
Environmental Remediation Where contamination exists these risks can be removed or reduced to an acceptable level by implementation of remedial measures. The experience of BRD consultants covers designing, implementing and managing various remediation techniques, including but not limited to: | ||
| On site landfill facilities: If the development scheme is sufficiently large then unsuitable materials can be relocated to a purpose made engineered landfill facility, thus removing the economic burden of off-site disposal | |
| Off site disposal: Traditionally referred to as 'dig and dump', contaminated materials are removed from the site to an off-site disposal facility, which could comprise one of the new soil treatment facilities or a traditional landfill site. | |
| Capping solutions: A simple solution for many sites whereby contaminated soils can be covered using either uncontaminated soils, recycled aggregate or an engineering membrane, in order to provide a barrier and therefore prevent future residents coming in to contact with the contamination. |
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| Soils washing: With certain soil types and contaminants it is possible to physically wash the soil (using specific plant) and remove the contaminants in the washings, which in some cases leaves an uncontaminated soil for re-use in the development. | |
| Bioremediation: Bacteria and other organisms will decompose some contaminants. By controlling the soil conditions, for example by adding fertilisers, water and air, these natural processes can be accelerated and the soils remediated. | |
| Chemical treatment: By adding certain chemicals to the soil it is possible to chemically alter some contaminants so they become less toxic. Such chemicals can range from iron filings through to complex specific 'designer' compounds. |
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| Barrier systems: These tend to comprise the installation of a vertical containment system that effectively seals off the contaminated source and limits migration either off site or to other parts of the site. | |
| Monitored natural attenuation: Natural processes, such as dilution, dispersion, volatilisation, biodegradation, etc, will act to reduce the concentrations of some contaminants in the soil and groundwater. Careful monitoring of these processes through a structured management plan can offer a cost effective remediation solution. | |
| Thermal desorption: Certain soil types can be passed through a thermal processor in order to remove organic contaminants. The gases given off are then treated in a scrubber prior to emission. Following the treatment the soils can be reused. | |
| Waste stabilisation: By the addition of certain chemicals to contaminated soils, the contaminants can be stabilised so that the soils can be reused. A simple example could be the use of cement or lime to immobilise certain leachable metals. | |
| Groundwater treatment: A variety of technologies exist which can range from physically pumping out the groundwater and treating it, to introducing chemicals through boreholes to treat the contamination in-situ. | |
BRD are well placed to advise clients on a wide range of remedial options and can design and supervise the implementation of such remedial measures. BRD can also deliver demolition and remediation as a single contract package thus providing a complete reclamation solution. Managing Geotechnical Hazards Where geotechnical hazards are identified by the investigation, recommendations for alternative types of construction can be made. For example, in the case of foundations, specialist piled foundations may be required rather than conventional strip footings. Alternatively ground hazards can be minimised by undertaking some form of ground improvement such as dynamic compaction or installing vibro-stone columns. BRD's experience of brownfield sites means that potential geotechnical hazards can be identified prior to construction starting so that a plan for the management of these risks can be designed. Click here for case studies of Risk Management projects | ||
Following the initial phase of investigation, it may be prudent to undertake further work to more accurately define the nature or location of the ground hazards. Further investigation may comprise additional exploratory holes to increase the data set, use of alternative investigation techniques than that used in the initial phase which may be more appropriate to map and/or assess the ground hazard, or further monitoring. In the case of monitoring, repeat site visits for gas or groundwater testing can detect changes in contaminant levels over time. The increased confidence in the assessment of data from additional investigation can reap rewards for Clients by reducing or even removing the requirement for remedial works.
