| 摘要 |
<p>A sewage treatment unit comprises at least a treatment zone 12, a settlement zone 16 and means for removing treated effluent from the settlement zone wherein the means is an air-lift arrangement 50 with an inlet 64 associated with a protective member (80, Fig 2) arranged to shroud the inlet and has an upper end provided with a removable closure means 78. In use foul water, preferably treated effluent containing small particles in suspension enters the treatment unit through a pipe 19 and is encouraged to aerate and mix in the treatment zone 12 with air supplied from aerator 38, the water then passes to the settlement zone 16 via holes in a tube 15 and finally the air-lift arrangement 50 acts to air-lift treated water from the settlement zone to an outlet 58 via tubes 62, 54. Preferably, the sewage treatment unit is installed below ground and can treat dwellings not connected to a main sewer.</p> |
