Grant from landfill tax credit scheme for research into use of recycled aggregates in PPS systems.

This grant was funded by Waste Recycling Environmental Ltd with additional funding from The Environmental Protection Group Ltd. Pervious pavement research primarily looking at use of recycled aggregates and effects of car engine oil on plant growth in the planted PPS systems which utilised such aggregates. Funding was partly used to create a long term test rig and fund an MSc by research project. The long term test rig which this grant part-funded was still producing publishable data in 2020.

The work on using recycled aggregate showed great initial promise in relation to oil retention but the long term test rig was observed for 3 years after its installation and the deposit of tufa from calcium salts released from the free lime in the aggregate created doubt in the long term suitability of the material. The plant experiments, which used molecular methods to identify the expression of genes for various enzymes, indicated that the main harm to plants from oil pollution onto planted PPS systems was due to induced local drought in the root zone.