Abwasserreinigung mit immobilisierten Mirkoorganismen unter Verwendung von porösen, kugeligen Sinterglasträgern

In continuous culture the microoganisms necessary for the microbial transformations should be retained in the reaction vessel. This is possible by immobilization of the microorganisms or in separating them and return. In this work we used spherical particles of sintered glass material to immobilize aerobic microorganisms. On account of the porous structure a large surface area is available for the colonization with bacteria. The particles used were 1 - 6 mm in diameter. The dimensions of the pores measured 125 - 315 Mym corresponding to the informations of the producers. Bacterial growth was possible due to the large surface are resulting from the porosity of 55 - 60 % and the distribution of the pores. Diameter of the pores, passages, as well as connections between them are essential respecting microbiological aspects. From the economical aspect it is considerable that the glass material can be reused. Insignificant degree of abrasion of the particles is another important fact. No pro blems were observed according to the abrasion in gas-liquid-solid fluidized bed reactors if they were properly operated. Aerobic microorganisms taken from a waste water plant were immobilized in a fluidized bed reactor in continuous culture. Submers biomass was washed out to measure only degradation of the substrate by immobilized cells. Synthetic waste water (OECD communal waste water) was used as substrate in the experiments which were continued for a period of 3 - 6 months. Already after 24 hours microbial colonization was microscopically visible and measured by gravimetry. In steady state conditions the experiments showed direct relation between the concentration of immobilized biomass and the surface area of the carrier, this means that more bacteria grew on small spherical particles if the distribution of the pores was in the above mentioned range. Maximum capacity of the degradation was 89 - 95 % in respect to the concentration of substrate in the feed, corresponding to a loadi n