Geotextiles as sealing liners for earthen manure reservoirs: Part 1, geotextile porosity

The development of an inexpensive but durable sealing liner is required for earthen manure storage facilities built of coarse sand or gravel. Fine porosity geotextiles can be used for this purpose, as manures seal media of small pore sizes. Non-woven geotextiles of 20, 30 and 40 μ m in equivalent porosity were subjected to pressure heads of 0·9, 1·8 and 2·7m of swine slurry for 1800h. Infiltration rates decreased from 5×10 −5 m/s to less than 1×10 −7 and 2×10 −8 m/s within 150 and 1000h, respectively. Although some of the experimental combinations gave significantly higher infiltration rates, all geotextiles demonstrated minimum seepage rates ranging from 1·3 to 1·8×10 −8 m/s after 100 to 1400h. In all cases, seepages were highly contaminated. Highest COD levels were observed for the 2·7m heads as well as the 20 μ m fabric. This 20 μ m fabric produced significantly higher infiltration rates, probably because of its lower permeability which encourages a less compact manure seal at its surface.