1999 Volume 22 Issue 2 Pages 133-138
Generally, an impermeable plate has been used as the substratum of rotating biological contractors (RBC). In this study, ‘wire nets’ are used for the permeable substratum of RBCs. As a result, the following findings were elucidated : (1) The substrate removal rate of the permeable substrata is higher than that of the impermeable ones due to bio-mass existing in the space of the substratum and the increase of bio-film thickness. (2) The stable treatment performances are attained in case of short- and long-term change of loading. (3) After detaching bio-film from the substratum, the substrate removal rate of the permeable substratum is not decreased by reactivating of the remained bio-film. Concluding from the above results, when permeable substratum is used in RBCs and any detachment is occurred on the bio-film, the detachment face retrieves a new bio-film surface. Dominant microorganisms in the deep bio-film can be activated. Then it is predicted that the substrate removal rate increases more than the one in the impermeable substratum.
