Water monitoring Simple but effective approaches to groundwater remediation
With over 400,000 hectares of brownfield land situated around the UK, finding safe, effective and efficient ways of remediation represents a tantalising opportunity for domestic and commercial property developers alike. However, given the age – with some sites dating back hundreds of years – and uncertainty of their origin, identifying, treating and removing the contaminants found within brownfield land is no easy task. Here, Mike White, a specialist in groundwater treatment at QED Environmental, explores one of the most effective methods for groundwater remediation.
depends on the site in question - whether it is a legacy brownfield site that has been left untouched for decades, or perhaps it is a site adjacent to an existing facility that has unintentionally been contaminated - there are so many variables that must be taken into account. Even once the contamination type has been identified, the responsibility for treatment can prove to be a grey area, especially on old industrial sites where the company responsible for the original pollution may have ceased to operate. Regardless of who ultimately bears the
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responsibility for having to undertake the groundwater remediation, perhaps the most important challenge is establishing whether the contaminated water can be treated to such an extent that it meets the Environment Agency’s discharge criteria. This is what would effectively allow it to be
released back into the ground. Should sufficient treatment not be achieved, those responsible for the site will have to remove all contaminated groundwater and transport it to a sewage treatment works. Such an approach would naturally incur an incredibly high cost, for you are not simply disposing of the one or two per cent of contaminant found within the water, but also the remaining ninety-eight or ninety nine per cent of the total volume of water. This could be very easily involve the removal of upwards of several megalitres of water. As such, the ability to treat contaminated water on site, remove the pollutants, and then safely release it back into the substrate at a permittable level is by far and away the most attractive proposition. Filtration systems provide the first treatment
layer and will help remove any solids, as well as any light or dense non-aqueous phase liquids, from the groundwater. However, the treatment process becomes more challenging when it comes to what is known as the ‘dissolve phase’. Here, volatile organic compounds (VOCs) or dissolved gasses have effectively diffused into the water itself, which means filtration alone will not be enough to remove the contaminants. One of the most effective solutions for treating
48 November 2021 Instrumentation Monthly
hen it comes to the treatment of contaminated groundwater, there is no ‘one size fits all’ solution. So much
Stripped back
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