Investigation into the microbiology of a high rate jet loop activated sludge reactor treating brewery wastewater

Abstract

The microbiology of a jet loop activated sludge reactor treating brewery wastewater has been investigated, with a venturi system combining liquid pumping with air diffusion being the basic feature of the system. The high F/M ratio, the high growth rate of the bacteria and the high levels of turbulence registered in the jet loop reactor caused the disappearance of filamentous bacteria and the production of a cloudy effluent. The population in the reactor was mainly formed by aerobic bacteria all belonging to the Pseudomonas species. Facultative anaerobes were present in small numbers, namely Klebsiella oxytoca, Klebsiella pneumonia ssp. pneumo., Vibrio fluvialis and Aeromonas hydrophila. Very high levels of respirometric activities were recorded for the mixed liquor of the reactor. The respirometric activities of individual isolates were also found to be remarkably high, especially when treating brewery wastewater. The magnitudes of their activities were a function of their relative abundance within the reactor.