Maybe we are cynical but we usually reckon we can rely on the weather to be cold and raining, or even snowing, anytime we are asked to carry out sitework at night. So it made a pleasant change to find ourselves at the end of Runway 27R at Heathrow on a warm summer’s night last week. As a Heathrow Approved Contractor we’d been asked to carry out some urgent groundwater assessment work and because our staff and vehicles hold ‘access all areas’ passes for Heathrow, we were able to be on site quickly and with the minimum of fuss.
For more information regarding our site investigation and remediation capabilities at airports, please contact James Skinner – 01296 739411
Ok, that claim may be stretching things a little, but our forensic analysis team have recently notched up a few notable successes. We were awarded a contract to treat petrol and diesel contamination in the soil and groundwater under a filling station. The site had a history of leaks, the most recent of which was six years ago. Since then one of our competitors had been trying (and failing) to clean the site up.
We were brought in to deal with the contamination once and for all. The first thing we did was to carry out some forensic analysis of the contamination using proprietary methods we have developed over the last 20 years. Our analysis indicated that there was an ongoing leak at the site, and was even able to pinpoint where on the site it was likely to be.
Our client commissioned precision tank and line testing which confirmed a slow leak under pump island 7 – just where we had predicted. The rate of leak – 0.29litres/hour – was actually below the precision testing threshold, meaning that the fuel lines passed the test and were certified as ‘not leaking’. However, this rate of leak would result in around 2,500litres of fuel entering the ground under the site each year – more than enough to cause serious contamination.
So the lessons learnt? Firstly, tank and line testing is very far from foolproof and fails to identify leaks that can cause serious environmental issues. Secondly, the timely use of forensic analysis can prevent significant time and money being wasted on ineffective remediation work.
Actually, there is nothing mythical about Subadra being commissioned to install shallow monitoring wells at the Daedalus Airfield Development! We constructed several shallow wells over the course of two days using our Hollow Stem Auger drilling system.
Lee-on-Solent is known for its sand and a dense gravels which are more or less guaranteed to make drilling difficult. So to avoid this we used our powerful Comacchio drilling rig which ensure we reached the target depth at all the drilling locations with minimal disruption to the site. We then installed 50mm diameter wells to allow future groundwater sampling. All our materials were sourced locally to enable us to take the minimum of equipment and vehicles thus reducing our carbon footprint for the works.
We even had time to the collect soil samples for the Principal Contractor and get them
analysed for WAC by our in house lab facility. As a result of our prompt and efficient service the client retained us to carry out a more detailed geotechnical investigation at the site. No myth there then!
Our Geoprobe Drilling Systems offer something a little special when it comes to rapidly investigating a site. And when coupled with the fast turnaround from our UKAS and MCerts laboratory, our clients benefit from the best of all worlds.
We were asked to investigate a large industrial site that had a history of fuel contamination issues. The question was: how far had the contamination spread and was it migrating under the neighbouring properties. Our solution was to carry out a groundwater probing survey, comprising driving a re-useable probe into the ground to the underlying groundwater and then taking a sample of the groundwater for laboratory analysis.
We completed 54 probes in two days, accurately delineating the hydrocarbon plume. Forensic analysis of the samples by our laboratory then confirmed that there were three separate sources of the hydrocarbons, two of which were ongoing leaks, and not just the one known historic source.
We now know what the problems are, how far the contamination has spread and how to clean it up. Isn’t that better than endless phases of investigation last months and costing £££s.
We do like a challenge, so when a client asked if we could probe 65 pile locations in a single day we said yes. Just to make it more of a challenge our client also wanted soil samples taken from each location and analysed for a range of potential contaminants.
The site was an office car park crammed with cars during the week, so the probing had to take place at the weekend. With noise restrictions preventing Sunday working and project deadlines meaning the work had to be completed in a single day, we knew we would have our work cut out. Each location required us to core the surface pavement, take a soil sample from the upper metre of soil profile and probe to 3.6m depth – a total of 234m of probing. But happily, using our Geoprobe Direct Push drill rig we were able to get everything completed in time to see the kick-off of the FA Cup.
The soil samples were dropped off at our own laboratory later the same day for ‘fast track’ analysis and the results provided to the client 3 days later.
We’ve recently upgraded our laboratory’s facilities for waste classification (WAC) analysis. We already offer the fastest turnaround analysis in the UK, but we can now analyse a greater number of samples after installing our new soil tumbler. Designed and fabricated in-house, this allows us to simultaneously complete the leachate stage of the analysis on an additional 12 samples per day. These can either be samples supplied by our clients or samples taken by our technicians at clients’ sites.
If you’d like to know more about our WAC analysis or if you are a laboratory and would like to purchase a similar soil tumbler, then please contact Duncan Eastland – 01296 739431.