In this Issue:
The Warewithal: A look back in time
Case Study: Rapid response
Staff News: New starters & Apeing about
As I approach my half century, I thought it would be good to have a look back at my 28 years experience within the geo-environmental industry. When I first started back in 1989, the main focus of the ground assessment was geotechnical, with a small section at the back on contaminants in relation to the ICRCL values. Things started to change in the 1990's with the introduction of the Environmental Protection Act. Numerous guidance documents were issued by the Environment Agency, DEFRA and British Standards, as well as from “across the pond” in the form of the RBCA framework. The potential chronic risk from ground contamination and the way contaminants behaved within groundwater were being understood as well as the potential financial liability.
In 2002 DEFRA/Agency issued the CLEA framework documents, however they did not “future proof” their format resulting in all bar one being withdrawn in 2008. The industry was left in limbo until the new guidance was issued in 2009. Since 2012 there has been a growing understanding of the potential risk from asbestos fibres in soils and the 2016 CAR Soil publication has now formulated an industry standard for its management during construction and demolition.
Remedial options for the management of contaminated soils prior to the introduction of the landfill tax in 1996 were limited to “dig and dump” as it was relatively cheap and quick. Now there are numerous in situ and ex situ methods for soil and groundwater treatment that will limit the amount of materials leaving site. The use of a CL:AIRE Materials Management Plan has enabled the reuse of site won materials without it falling under waste legislation. Improvements with in-situ groundwater methods means that both aerobic and anaerobic decaying contaminants can now be chemically targeted, thus reducing the time required for clean-up.
Unfortunately following the 2008 recession and subsequent austerity measures, there has been a 30% cut back in resources within the UK regulatory bodies and the industry appears to be moving towards more self-regulation. This in my opinion is dangerous as there needs to be a fully independent body that holds the industry to account to ensure that commercial pressures will not jeopardise the protection of human health and the environment. Unfortunately, it might take an equivalent “Grenfell Towers” incident for this drive towards deregulation to be halted.
Rapid response to a Developer in need
This summer WDE were asked by a residential developer to assist them with contamination issues associated with a former gas works site in Suffolk. However, there was a slight difference from the norm as construction had already commenced! With much of the groundworks completed and half the plots already constructed, the speed of WDE’s response was paramount. A targeted ground investigation was scoped to delineate the plume and to enable a remedial design to be formulated.
WDE were able to identify the source of the contamination (remains of a historical gas holder) and delineate the DNAPL and dissolved phase plume across site. The selected remedial options needed to be completed within 3 months, to limit the damage to constructed units and infrastructure as well as providing adequate protection to the sensitive receptors.
Following this brief, WDE held discussions with Regenesis and Rake Remediation and a remedial design was formulated comprising augmented pump and treat using active and passive oxidisers along with a “plume stop” barrier at the site boundary to limit migration offsite towards the surface water. The unsaturated impacted soils were also treated onsite via the formation of a Bio-pile by Symbiotic Solutions and once compliant will be reused on site as backfill under a CL:AIRE Material Management Plan.
WDE have been monitoring the effectiveness of the remedial methods and the bulk of the remedial works are due to be completed by the end of October, following which there will be a period of post remedial monitoring. It is hoped that construction can recommence shortly afterwards.
Jacob Fenton joined WDE in the summer and is currently being trained in our way of doing things. Michael Emery and Rowena Cameron have successfully completed their probationary period.
To celebrate the half century of the MD, all staff went "Go Ape" for the day.