Geotextile membrane for use as a filter/separation layer in SUDS
'Inhibtex is a thermally bonded, nonwoven geotextile membrane for use as a filter/separation layer to optimmise the cleansing of water entering a permeable paving attenuation system. It has been developed jointly by Terram and Hanson Formpave specifically for use within the Hanson Formpave 'Aquaflow' permeable paving Sustainable Urban Drainage System (SUDS).
The fibres of the geotextile encourage the growth of a microbic biofilm habitat. These microbes biodegrade any organic matter found in the run-off, with a capacity to consume 400g of hydrocarbon per annum. Also, any non-degradable matter such as heavy metals and silts are trapped in the laying course, so optimising the cleansing of water entering the Aquaflow paving system.
The fabric is manufactured from polypropylene and polyethylene. During the manufacturing process, small dishes are created on the surface of the hairs from which the geotextile is manufactured. This is very important in the early establishment of a microbial biomass which is responsible for eating and degrading oils in the water. It is also important during dry periods when the microbial population can retreat into the dishes where moisture is to be found. Thus when it rains again the microbial biomass is quickly re-established.