The paper presents procedure, results and conclusions drawn from laboratory studies of nitrification and denitrification chambers of two-phase biological reactors with recirculation system, for a designed wastewater treatment plant of 270 000 m3/day capacity, for the city of Gdańsk.
On the 1:17 physical model, observations of stream lines and measurements of the velocity field in some characteristic regions have been performed.
The measurements have been carried out for 14 different configurations of the reactor operation, depending on the aerator turbines, mammoth rotors and prototypical mixers with horizontal axle and with guide-ring.
Based on these studies, and having introduced some structural innovations aimed at improving flow uniformity around aerators and rotors, a variant optimal from the point-of-view of hydraulic properties and energy consumption has been proposed for realization.
Moreover, using results of some other investigations performed on a structure in technical scale, conclusions concerning the following questions have been presented:
I/ the importance of uniform velocity distribution in the reactor for final effeot of operation of the wastewater treatment plant,
II/ relationships between velocity, discharge and hydraulic efficiency of the wastewater treatment plant chambers,
III/ the influence of geometry of chambers and of recirculation on the efficiency of the purification process.
The paper includes drawings, figures and short descriptions of the following experimental techniques used in the investigations: the method of varying temperature field, the colorimetric method, the conductometric method and the method using a current micrometer. A video film on the study is available.
Shape derivative for a two-phase eigenvalue problem
and optimal configurations in a ball