Embedding Sustainability Principles in Remedial Design and Implementation
18 June 2007, News release from Atkins
Sustainability considerations at the remedial design and delivery stage should represent more than just lip service, explains Steve Pearmain of Atkins
There has been a lot of justified attention in the media lately about the importance of incorporating sustainability principles into new build developments in order to reduce the energy, waste, environmental and natural resource impacts associated with such, and initiatives such as the BRE's EcoHomes scheme are a welcome step forward in this regard.
What is often overlooked however, in many brownfield regeneration schemes, is the critical importance of embedding sustainability principles into the land contamination remediation aspects of a project.
Sustainability is a somewhat nebulas term, in that a precise definition can be difficult to pin down, and its current status as the latest essential accessory makes this even more difficult.
Stripped back to its Brundtland Report roots it is probably best defined as 'meeting the needs of the present without compromising the ability of future generations to meet their own needs'. With this in mind, the core environmental sustainability drivers insofar as they relate to land remediation can probably be best summarised as: energy efficiency, waste minimisation, ecosystem preservation, natural resource conservation and local environmental quality protection.
It's therefore probably no surprise that remedial schemes that involve the following, or a combination thereof, will score pretty poorly from an environmental sustainability perspective:
- A large number of vehicular movements (many over long distances);
- The use of energy hungry site plant;
- The generation of large waste streams for off-site disposal;
- A requirement for large volumes of natural imported infill materials;
- Damage to locally (or nationally) sensitive habitats; and
- Uncontrolled emissions of pollutants to land, air and water.
Fortunately guidance and methodologies exist, which if followed, can help reduce the environmental impacts of a particular scheme by actually embedding sustainability principles within the assessment, remedial design and implementation phases.
1) Designing and implementing a suitably robust site investigation followed by site specific quantitative risk assessment modelling is an early stage in this mitigation process. If undertaken diligently these exercises will result in the identification of the relevant pollutant linkages that actually require addressing and consequently inform the design of an appropriate and proportionate remedial scheme. A poor brownfield site characterisation has the tendency to steer a project towards adoption of the 'precautionary principle' and the consequential risk of implementation of an inappropriate over specified solution.
Conversely a poor characterisation may also result in an inadequate assessment of potential liabilities and an under specified remediation, with all the residual risks this entails.
2) Retain the services of a professional ecologist and where in doubt undertake a Phase 1 Habitat Survey prior to commencing the site investigation. The ecological diversity that can be found on many brownfield sites can be very surprising. If sensitive flora or fauna are present you need this information at the project outset stage, as it could have a big effect on your programme, and you will need to consult and plan regarding the most appropriate mitigation measures.
3) The production of formal remediation options appraisal reports has become a fundamental component of the remedial design process since the release of CLR11. This exercise scores the potential remedial solutions against various pertinent criteria including effectiveness, cost, durability, sustainability, stakeholder views and environmental impacts. Typically this entails a scoring system with a fixed maximum for the sum of the constituent parts. Weightings can be applied to these individual assessment criteria however (providing it's not a Part 2A site), and if current indications are anything to go by, then sustainability and environmental impact considerations may well enter the premier league in the near future. It's important that they are given the prominence they deserve in the overall assessment process and that remediation options that score badly are discounted wherever practicable.
4) If we agree that the primary objective of sustainability is not to 'compromise the ability of future generations to meet their own needs', then it stands to good reason that carbon accounting should form part of the optioneering process. The remediation solution you implement will contribute to global warming to some degree, and that contribution should be calculated to inform the optioneering assessment. Atkins has invested in developing its own web-based interactive Remediation Options Carbon Calculator (ROCC) which will be available to assessors later in the year.
5) The remedial solutions identified during the optioneering process should be incorporated into an overarching remediation strategy document that clearly identifies how the scheme can be practically delivered at the site level. Once this document has received all the necessary regulator and stakeholder approvals the project proceeds to detailed design and the production of an Implementation Plan. This should include details on the quality control measures that will be implemented on site to ensure that the remedial scheme objectives are not compromised during actual delivery. There is little point endeavouring to ensure that your project has the right environmental sustainability credentials at the design phase if it all falls apart as soon as you get on site!