Studies on the Regulatory Behaviour of Aquatic Ecosystems and its Significance for the Biological Phosphate Removal

Abstract

Bquatic ecosystems have the ability t o compensate for oscillations of the inputs (substrate concentration, dilution rate, temperature). The mechanisms of this buffering capacity are studied in this paper (see fig. 7). The inputs exert an influence on the biomass and the activity of the organisms (activity = specific rate of RNA-synthesis or specific P-removal rate [pg/mg biomass * day]). The activity is regulated either directly by the inputs and/or indirectly by t h e biomass. The activity decreases with an increase of the biomass (see fig. 5 and 6). The product of biomass and activity determines the transient response (= effective performance) of the system which is better buffered than biomass or activity alone.Considering the theory developed in this paper the effect of shock loadings on t h e phosphate removal in preimpoundment basins of drinking water reservoirs is discussed. Inhaltsverzeichnis

Equilibrium and stability in laboratory model of sewage ponds and polluted rivers

“…An inverse relationship between biomass and activity per unit biomass (specific activity) may be one of the homeostatic mechanisms which are responsible for this functional stability (BENNDORF u. STELZER 1973, UHLMANN 1973. The lower the biomass, the higher the specific activity.…”

Microbial self‐purification in an experimental continuous‐flow system

“…Another approach, however, is reasonable as well -i. e. biocenoses developed from mixed undefined inocula and adapted to the conditions of a particular experiment. It was found that the "purification effect" of such an experimental system is rather constant (depending mainly on the input parameters such as initial substrate concentration and dilution rate) irrespective of fluctuations and changes in biomass (BENNDORF & STELZER, 1973, CRAMER, 1974.…”

Mathematische Modellierung der Veränderung der Wasserbeschaffenheit in Trinkwassertalsperren

“…I n den letzten Jahren wurden grundlegende Untersuchungen zur Ermittlung biologischer Zusammenhiinge bei der Veranderung der Wasserbeschaffenheit in Trinkwassertalsperren unter der Zielstellung angestellt, eine Prognose der Beschaffenheit bei Bnderung gewisser wesentlicher Parameter geben zu konnen (HOHNE 1970;UHLMANN, BENNDORF und ALBERT 1971;KLAPPER 1972;HOFMANN 1972;STRAS-XRABA 1973a;BENNDORF und STELZER 1973;BENNDORF 1973). Eine Abstraktion der dargelegten biologischen und biochemischen Zusammenhiinge erfolgte durch die Angabe streng deterministischer mathematischer Gleichungen (BENNDORF 1973;NELSON 1971) und Algorithmen zur Bestimmung einzelner wesentlicher EinfluBfaktoren (STEEL 1972;STRA~KRABA 1973b;DI TORO, O'CONNOR und THOMANN 1971).…”