Zur Theorie des Belebtschlammverfahrens

Summary

• (1) The rate of concentration decrease of various substrates (sugars, fatty acids, amino acids) after addition to suspensions of activated sludge was estimated simultaneously with the oxygen and CO₂ metabolism of the sludge (micromanometric method).

• (2) It was demonstrated that the resorption of sugars by sludge occurs at a higher rate than the respiration and oxydative assimilation of these substrates. Substrate respiration with fatty acids and amino acids is terminated however simultaneously with the complete elimination of the substrates from the sludge suspensions.

• (3) It is concluded that the physiological reactions, measured as ‘elimination’ of both the electrolytes and non electrolytes used as substrates, is identical with the resorption of the subtrate molecules by the sludge organisms and that physicochemical reactions such as adsorption are of no practical significance.

• (4) In certain instances the substrate proportions respired and oxydatively assimilated could be measured. In accordance with pure cultures of microorganisms the oxydative assimilation of a carbon source by activated sludge is reduced in favour of respiration when a nitrogen source such as ammonia can be assimilated simultaneously.

• (5) In presence of ammonia as a nitrogen source the resorption of the carbon compounds is significantly accelerated.

• (6) It is concluded that turbulence in the aeration bassins of activated sludge plants is a limiting factor for the rate of the elimination of substrates by sludge.