Field testing of a geotextile as a manure reservoir liner

Abstract

Leakage monitoring was performed for three years on a swine manure earthen reservoir built of coarse soils and lined with a nonwoven geotextile. Measured leakage rates through the liner were of the order of 2 liter/m 2 day during the summer months, after lowering the level of slurry in the reservoir. but reached levels of 200 liter/m 2 day in the spring. The higher leakage rates were attributed to fall and spring rainfalls which diluted the waste. The measured leakage rate in terms of total Kjeldahl nitrogen (TKN). through the geotextile liner, ranged from 0·5 to 240 g/m 2 day when 0·6 g/m 2 day is the limit required by the Quebec Ministry of the Environment. Chemical oxygen demand (COD) leakage rates were of the order of 1·0 to 200 g/m 2 day while NH 4-N and K leakage rates ranged from 0·3 to 150 g/m 2 day. Thus, levels of measured TKN leakage exceeded the environmental regulations of the Quebec Ministry of the Environment in the spring but reached acceptable levels during the summer. Geotextile liner performance must be improved before meeting the requirements of environmental authorities. Nevertheless, the field results show a 1000 fold reduction in permeability as compared with water and are consistent with the leakage rates obtained during previous laboratory trials. If geotextile liners could become acceptable liners by further reducing their leakage by an order of magnitude of 10, manure reservoir construction costs could be reduced by 50%, as compared with those of concrete structures.