Kinetics of heterotrophic biomass and storagemechanism in wetland cores measured by respirometry

摘要

Although oxygen uptake rate has been widely used in activated sludge for measuring kinetic andnstoichiometric parameters or for wastewater characterization, its application in constructednwetlands (CWs) cores has been recently proposed. The aim of this research is to estimate the kineticnand stoichiometric parameters of the heterotrophic biomass in CW cores. Respirometric tests werencarried out with pure carbonaceous substrate and real wastewater. Endogenous respiration wasnabout 2 gO2 mu00013nhu00011n(per unit of bed volume), while the kinetic parameters obtained for CODnoxidation were very high (maximum rate per unit of bed volume of 10.7–26.8 gCOD mu00013nhu00011n) whichnindicates high biodegradation potential in fully aerobic environment. Regarding to stoichiometricnparameter, the maximum growth yield, YH, was 0.56–0.59 mgCOD/mgCOD, while the storage yield,nYSTO, was 0.75–0.77 mgCOD/mgCOD. The storage mechanism was observed in CW cores during CODnoxidation, which leads to the transformation of the external soluble substrate in internal storagenproducts, probably as response to intermittent loads applied in CW systems, transientnconcentrations of readily biodegradable substrate and alternance of feast/famine periods.