We have been working with Scottish Water, Zero Waste Scotland and Jacobs on an exciting cross industry project to explore the potential of waste grit from the waste water treatment works. The project aims to recover valuable construction materials from the water treatment system to recycle and sell back to the construction industry which will minimise repairs and downtime for Scottish Water’s network as the build up of gritty materials is abrasive and causes blockages.
Sand is used in Scotland’s water treatment works as a filter medium but grit also makes its way into our water network through road surface runoff. Tens of thousands of tonnes of grit and sand from the water treatment systems end up in landfill each year.
Scottish Water remove this waste from their networks during the filtration process and deliver it to our recycling facility in Pumpherston, West Lothian. At our site, our state-of-the-art recycling plant processes the waste, turning it into high quality recycled materials. Sand is one of the top 2 most consumed resources in the world and as such, we are at risk of depleting the earth’s stocks by 2050.
Understanding the untapped value in sand laden waste like that found in Scottish Water’s networks and creating symbiotic relationships between those who have waste and those that can recycle and repurpose it. These relationships are the foundation of the circular economy and will be instrumental in meeting the Net Zero and Zero Waste targets set by Scotland and the UK.
The project is set to have a significant reduction on carbon emissions (6,623 tCO2e p.a.) which is a result in a transportation, landfill and embodied carbon emissions as a result of recycling the material. The emissions savings are the equivalent to a boeing 747 flying around the world 530 times.
Applications & Uses
If the sand isn’t being sent back into Scottish Water’s assets as a filter medium or construction product then it has 2 main uses in the construction industry: as a pipe bedding and as an ingredient in concrete production. Sand is ideal for pipe bedding as it can be packed around pipes to protect them from sharper materials such as 6F5 Capping that may be used as a subbase on top of pipes that are laid below the surface of roads or pavements. Its gritty properties also make it ideal in concrete production for binding the other ingredients together.