Leaks and Spills

Tank with Corrosion Hole

We’ve recently started the first phase of our latest remediation project: the redevelopment of a former petrol station site located in a highly environmentally sensitive location.
Stage one of our work comprised identifying and removing the source of the contamination. As you can see, we are pretty confident that we found the root-cause , although we have to wonder how the former site operator didn’t know something was wrong with this tank.
We’re currently working to design and integrate our groundwater treatment system with the construction work to ensure that there are no delays to the redevelopment.

‘Sump’thing in the Ground


Excavation with Services Exposed and Sump Installed

Remediation is always challenging, but it’s made much harder when we are asked to do it at a busy filling station which needed to remain open throughout our works. Having previously determined that the contamination was confined to a relatively thin layer of gravel but was migrating offsite, we decided to install some small diameter sumps across the site in preparation for a programme of ISCO (treatment using in situ chemical oxidation).

Fitting the sumps between buried services was always going to be tricky, so we pre-excavated each location using vacuum drilling techniques. As you can see from the photographs, it was a good job that we did, with numerous pipes and ducts exposed (and duly avoided).

The excavation has now been backfilled and the pavement reinstated, leaving us with a  small manhole cover to provide access to our sump when we return to start treating the ground. The filling station remained open throughout our works.

Emergency Response – Filling Station

We were recently contacted following a spillage of several hundred litres of diesel by a customer at a filling station in Northamptonshire. The diesel had entered the site’s drainage system, which ultimately discharged into a nearby area of wetlands.

We were on-site and our spill-response trailer within two hours of receiving the first call. We liaised with site staff, the Fire Brigade, tanker service contractors and the Environment Agency and co-ordinated thesubsequent clean-up, preventing any of the fuel reaching the wetland.

We subsequently collected soil and groundwater samples which were analysed by our in-house UKAS and MCerts accreditted laboratory, with results reported back to our client within 24 hours.

For more information about the emergency response services we offer, please contact James Edley – Tel: 01296 739412


When You Need to Know Fast

Groundwater ProbingOur 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.

Project value: £10-£15k

Groundwater Treatment at Major Airport

Airport Remediation
Groundwater Treatment in Place

We have recently been appointed to carry out long-term treatment to remove a range of contaminants, including Jet-A1, glycol and iron, from dewatering effluent at a major airport in southern England. Key to our success in winning the work was:

a) Our ability to deliver a modular treatment system that could be dismantled, moved and reassembled quickly and easily to suit construction activities;

b) Our in-house laboratory’s fast analysis turnaround ensuring early confirmation that discharge consent limits are not being exceeded.

For more information please contact James Skinner.

Contract Duration: 12-18 months      Contract value: £100-£250k

When Things Get Tricky

Removing USTs with truss in foreground

Subadra have recently completed what has been, perhaps, our trickiest ever underground tank removal. The tanks at the former filling station were located close to the site boundary. Removing them might destabilise a Victorian house on the adjacent property. To prevent this a contiguous bored pile wall was installed together with a supporting steel truss. Our job was to safely ease the tanks out from under the truss without compromising its structural integrity, before cutting them up and disposing of them as scrap metal. All this on a crowded site with construction of the new structures well underway.

Contract Value £20-£50k

Food Wholesaler/Distributor Retains Subadra

Subadra have been retained by a major food wholesaler/distributor to carry out a comprehensive audit/investigation of the fuel storage and supply infrastructure at a multi-site portfolio across the UK. Key to winning the contract was our ability to complete the project within a tight timescale. This is only possible because of our unique approach whereby every aspect of the project will be carried out using in house resources, from borehole drilling through to laboratory analysis; and, of course, our competitive rates!

Water, Water Everywhere

Treatment System in Operation

We are currently assisting in the treatment of construction wastewater from a filling station redevelopment in Dorset. Working with the primary works contractor, we provided a system that is capable of pumping and treating high volumes of hydrocarbon-contaminated water from deep excavations.

Our in house designed, modular treatment plant was efficiently dealt with two both suspended solids and hydrocarbon contamination, ensuring all the effluent met the site’s discharge licence conditions.

We installed and tested the system at an early stage of the works allowing us to collect and analyse samples in our UKAS accredited laboratory and use this information to assist in obtaining a temporary discharge license from the local sewerage undertaker. This meant the
contractor was able to discharge effluent direct to the foul sewer.

With the high costs and project delays associated with tankering hydrocarbon-contaminated wastewater from site our fully mobile and modular dewatering systems are a simple and cost effective way of dealing with dewatering effluent.

Project value: less than £10k

Subadra Go Bananas

Replacement Pipework

We certainly get to work at a wide variety of different sites, but a call from a major banana distributor was a first even for us. The underground pipework carrying fuel to supply their trucks had failed and required urgent replacement. At short notice we were on site replacing the corroded steel pipework with modern plastic equivalents. We sampled the soil around the failed pipework and our in-house laboratory was able to confirm within 24 hours that no significant ground contamination had occurred. Within 36 hours the fuel supply system was back in commission and the banana trucks had started rolling again.

Black Gold?

Sadly not in this case. But what do you do if you’re digging a hole and it fills with a horrible mixture of black fuel and water? Call Subadra of course! We are able to guide you with all aspects of contaminated ground from waste disposal or how to minimise the impact on your development programme to how to discharge your planning conditions.
The site  in the photo is a filling station that is currently undergoing a full site redevelopment. When the contractor opened up the forecourt to remove the below ground fuel tanks the excavation filled with a heady mix of petrol and diesel that had accumulated over the years around the off-set fill points.
We were on-site within 2hours of being contacted. We collected water and soil samples from the excavation that were run through our in-house hydrocarbon laboratory. The results were issued within 48hours allowing the contractor to efficiently deal with the soil disposal and avoid costly delays to the works programme.