| 摘要 |
PURPOSE:To extremely effectively and rationally purify org. sewage by introducing the water treated in a first filter bed into the lower part of a second filter bed, treating the water with an upward current and further treating the treated water in an optional third filter. CONSTITUTION:Org. sewage is introduced into the lower part of a first filter bed 1 from an inflow part 4 through a pipeline, where the precipitating SS is settled and separated, and ascends through the first filter bed 1. The water treated in the first filter bed (primary treated water) is then upwardly introduced into a second filter bed 2 from a primary treated water outlet 8 through a pipeline along with the air bubbles from an air supply pipe 9, and most (about 90%) of the SS and BOD remaining in the primary treated water are removed by biological action and filtration. The treated water from the second filter bed is supplied upwardly or downwardly to a third filter bed 3 from an outlet 10 and finished (polished). The grain diameter of the third filter medium is preferably equalized with or made smaller than that of the second filter medium. |
