| 摘要 |
<p>A filtration system for polluted water comprises a plurality of portable, open topped tanks 10 with air inlet holes 12, 13 and 14 at different levels in its longitudinal side walls. Angle iron members 15 overlie the air inlet holes and increase the rigidity of the tank 10. The tank 10 contains filter bed layers 16 to 19 in which common reed plants 21 are grown before the tank is transported to the site of use. (Fig. 2). <IMAGE></p> |
