Permissible parameters for the circulation rate of the sludge mixture in airlift reactor-clarifier with suspended layer

Donbas National Academy of Civil Engineering and Architecture, Faculty of Engineering and Environmental Systems, Derzhavin str. 2, Makeevka, Donetsk People’s Republic

^* Corresponding author: d.v.zavorotnyi@donnasa.ru

Abstract

Factors affecting the permissible limits of sludge mixture circulation rate are given for airlift reactor-clarifier with a suspended layer. The upper limit of the circulation rate is justified as a function of some geometric dimensions of the bioreactor and the hydraulic load on the clarifier to comply with conditions of a suspended layer existence. The lower limit of the circulation rate was obtained on the basis of two conditions: the duration of the active sludge stay in anoxic conditions and the observance of recommended rates in the construction in order to avoid the settling of active sludge. Theoretical and empirical dependences of the maximum permissible values of the circulation rate on the main geometric parameters and on productivity of the airlift reactor-clarifier are presented.