[Microfloral study of the active ooze in the 3-stage treatment of sewage].

The work was done with the microflora of active sludge from purifying constructions of a fattening plant which consisted of three aerotanks arranged one after another. In all stages of the constructions, the biocenosis of active sludge was represented by identical groups of microorganisms whose quantitative composition was the same in all of the stages. At the same time, the oxidative activity of the cenoses in sludge and the activity of certain enzymes were maximal in the second stage. The oxidation activity of microorganisms in the first stage was limited by the concentration of dissolved oxygen. The growth of microorganisms in the third stage was limited by the content of organic substances in the sewage, and the processes of nitrification here were more intensive. The results have shown that it is expedient to have a three-stage system of purifying constructions and to cultivate specific biocenoses in each of the stages.