Dr Bewley is remediation service line leader at URS Corporation Ltd. He will be speaking at Brownfield Briefing's Special Challenges to Groundwater Remediation conference on 25 March, so we caught up with him ahead of the event.
1. At the Special Challenges to Groundwater Remediation conference, what do you feel are the key issues surrounding the topic you are speaking on?
The current economic conditions make the need for cost-effective measures for remediation increasingly important. We have to balance the pressures for clean up of our key water resources with the need for pragmatic solutions. The geological formations within which groundwater is distributed can be very complex and differences in permeability both between and within strata will have a major influence on where the majority of the mass of contamination is distributed. In such circumstances it is therefore crucial to understand what can realistically be achieved by way of a particular remedial technique and how particular approaches may be brought to bear in combination to achieve the optimal solution.
2. What do you predict will be a major environmental issue in 2020?
Global warming represents by far the most significant environmental issue that we have to face and by 2020, even under the most optimistic scenario, we shall be witnessing major changes in our lifestyles and the way we need to manage our natural resources. The availability of water will be one of the most challenging issues we shall face globally and the UK will be no exception. This will have significant implications for the need to exploit more marginal supplies of groundwater and will provide a significant impetus to the need for developing more effective remedial approaches to address residual contamination associated with these.
3. What has been your favourite project/issue to follow in the past 18 months?
My favourite issue in the past 18 months has been the growing acceptance of the need to consider sustainability in remediation. Firstly, because this extends the need to consider the 'wider environmental' issues of what we do in the field of ground remediation most notably with regards to global warming which has to be the most significant environmental challenge that mankind faces. Secondly because it underpins the need for pragmatism in what we can expect remedial approaches to do, which is of huge benefit to all stakeholders - and facilitates the use of more innovative approaches.
4. If you could change one piece of legislation/regulation what would it be and why?
I would include a regulation to formally abolish the use of total petroleum hydrocarbons (TPH) in any criterion for soil or groundwater remediation and use specific indicator compounds instead. TPH embraces a multitude of different compounds of physicochemical properties and is almost meaningless as a single index of quality or toxicological significance.
The difficulties in attempting to measure low concentrations accurately are well known and at high concentrations the entraining of droplets of oil make measurement of what is truly 'dissolved phase' equally problematic. Additionally there are issues relating to the inclusion of natural material. All in all, this is not a useful measure and in my experience leads to more problems in interpretation than any other compound.
