| 摘要 |
<p>A plant containing filter bed contains a bottom gravel bed below a soil matrix. The bottom gravel bed extends along part of a length of the filter bed from an inlet and is hydraulically connected thereto. Preferably the bottom gravel bed extends at a downwardly directed inclination relative to a bottom of the filter bed at a downward inclination in the throughflow direction in the range of 1% to 5%. Due to the length of the bottom gravel bed, the hydraulic gradient and thereby the throughflow through the soil matrix is internally set, i.e. within the soil matrix in adaptation to an infiltration cross-sectional area.</p> |
