Self-Fertilizing Textiles for Use in Oil Degrading SuDS Devices: An Update on Progress and Latest Developments

Retaining and degrading oils lost from automobiles, close to the source, is an important function of pervious pavements and related devices. Aerobic biodegradation is an efficient oil remediation technique provided the oil can be physically retained and water, oxygen, and inorganic nutrients are available. Although external inputs and the construction materials can contribute, the level of P is often limiting. Artificial inputs of nutrients using horticultural fertilizers on pervious pavements has been found to produce effluents with unacceptably high nutrient concentrations but great promise has been shown by incorporating a slow release mechanism into the geotextile, to create a self-fertilizing medium which both hosts microorganisms in an aerobic structure and responds to their demands for nutrients when provided with a carbon source. This paper reviews the progress to date on the development of such materials. Changing the process of converting fibre into a continuous filament non-woven textile has reduced the undesirable early pulse of P which was considered to be likely to attract regulatory disapproval. The ability of this process to lay down different filament types in layers in the fabric has also enabled the distribution of the nutrient to be concentrated in the upper layers of the textile, which is likely to encounter the oil first, and to allow the nutrient loaded fraction to be made more amenable to the nutrient scouring action of microorganisms without compromising the resistance to degradation of the load bearing lower layers. The physical oil retaining properties, P release rates and biocompatibility of the of the two-layer textile are studied. The study is ongoing and further results will be reported at the congress.