Although modern vehicles no longer leak oil as they did decades ago, oil droplets and other particles from exhaust emissions are continuously deposited on our roads. Once there, they remain until washed off by rain, particularly during heavy downpours when stormwater drainage systems cannot cope. So, with major flooding on the increase, oils and other compounds are escaping into the surroundings and water table – a problem that will worsen if rainfall increases by the predicted 40% by 2050.
Of these pollutants, oil derivatives are one of the worst offenders and historically one of the hardest to deal with. But now a new weapon in the engineer’s armoury is rapidly proving its worth. Called Smart Sponge®, the product has a unique molecular structure based on polymer technologies that is chemically selective to hydrocarbons.
Developed initially to deal with oil spills, the sponge absorbs the pollutants and transforms them into a stable solid for recycling, providing a closed-loop solution to water pollution. As it absorbs hydrocarbons, it swells and maintains porosity and filtering capabilities. And in its Smart Sponge Plus® form it will destroy micro-organisms such as E-coli, streptococcus and legionella bacteria.
One of the first authorities to take an interest was Wiltshire Council, where gully wastes were routinely sucked out and taken to depots for ‘drying out’ and disposal of the highly contaminated waste. By using Smart Sponge®, the idea was to remove the hydrocarbons to acceptable levels so that the dry waste could be recycled as a fertiliser. The sponge was tested by deploying it in three separate areas embracing 17 locations within both gullies and an oil separators. In the trial, water samples were taken and concentrations of petroleum hydrocarbons (PAH) measured every three months. Remarkably, initial PAH levels fell from an average 8500ppm to 0.009ppm after a year, clearly proving that the product far exceeds EU legislation criteria in reducing PAH contamination. Wiltshire Council is now aiming to recycle the spent material as a waste-to-fuel energy source generating 10,000–18,000 BTU/lb.
The Council has since embarked on further projects with the technology, most recently by deploying it in the gullies leading to a pond in one of Wiltshire’s largest towns. The pond collects the run-off from the highway and in the past has been a contentious issue as regards wildlife and the environment. So far, the effects have been extremely positive, preventing harm to life on and within the pond.
Commenting on the trials, Sarah Peterson of Wiltshire’s Weather & Drainage team said: “We are now looking into deploying smart sponge technology on a larger scale, to prevent damaging substances reaching the water system. Indeed, the aim is to install the technology into all highway inceptors in the county and develop further projects with local communities.”
In the light of Wiltshire’s positive experience, West Lothian Council recently deployed Smart Sponge® products as part of a pilot exercise to improve its surface water run-off quality – one of a number of responses to community concerns affecting the Dedridge Burn in Livingston. The products are also being included as one of several measures to help improve water quality where runoff issues into sensitive receptors such as designated Sites of Special Scientific Interest (SSSI). The council’s trial is being conducted in liaison with Smart Sponge® Products and is being independently monitored by specialists from the Scottish Agricultural College (SAC).
Graeme Hedger, Senior Professional Officer with the Council’s Roads & Transportation Services team, said “I am excited at the potential improvements in water quality that might be achieved at a relatively low cost. If the trial proves successful, we hope to be able to roll out these products to deal with a range of water quality issues in other locations.”
Written by Graham Martin-Loat, Smart Sponge Products Ltd.
For further details contact Smart Sponge® - telephone 0845 2939880 or email solutions@smartsponge.co.uk
