Wastewater treatment in a bioreactor with a variable number of immobilized sludge carriers

Abstract

The use of microorganisms attached to inert synthetic substrates in wastewater treatment increases the oxidative capacity of a bioreactor. In this article, the dependence of the concentration of freely floating sludge on the specific length of a inert biological module carrying immobilized sludge was studied. Experiments were carried out in a physical bioreactor model presenting a transverse vertical section of an industrial bioreactor aerotank. The concentration of freely floating sludge was controlled by the method of light transmission using a lux meter. A mathematical expression was obtained for calculating the dependence between the concentration of freely floating sludge and the number of specific meters of brush filtering modules placed in a bioreactor. This expression gives the concentration of freely floating sludge at a given length of immobilized sludge carriers. The mass of immobilized sludge along the running metre of a brush- filtering module was determined, depending on the specific number of brushes in a bioreactor. It was shown that the mass of the immobilized sludge on a biological module depends on the number of brushes and their location in the cross vertical section of a bioreactor. The installation of biological modules in the central space of the bioreactor along its length increases the amount of immobilized sludge compared to their installation along the width of the aerotank. It was found that the efficiency of air medium-bubble regeneration of immobilized sludge does not depend on the specific length of brush filtering modules: the reduction in the specific length from ~60 to ~10 run.m/m 3 in all the experiments corresponded to 93% regeneration efficiency. An increase in the total amount of freely floating and immobilized sludge allows for an intensification of the wastewater treatment process.