Hydraulic conductivity of gravel and sand as substrates in rock-reed filters

摘要: Abstract Long-term use of a constructed wetland to treat landfill leachate requires that the saturated hydraulic conductivity be maintained and clogging avoided prevent overland flow, which bypasses treatment process. This paper describes application an equation developed for prediction cumulative drainage volume from hillslopes measure (Ks) substrates used in rock-reed filters. Outflow was measured at five intervals during first 26 months operation. The values Ks) obtained by compared favorably with calculated more dificult method based on Darcy's law. Results indicate finest substrate (a sand-and-gravel mixture) became almost completely clogged, presence reeds (Phragmites australis) did not maintain or increase conductivity. Hydraulic pea-gravel (0.5-cm diameter) coarse-gravel (3-cm decrease 26-month period.