Determining stoichiometric parameters of detached biomass from a HSSF-CW using respirometry

•Determination of yield coefficients in CW using a static respirometer is presented.•Three different types of OUR profiles were identified with different biomass behaviour.•Initial yield ranged 0.41-0.67 and storage yield ranged 0.75-0.83 gCOD gCOD−1.•The proposed method will allow analysing samples from CW field units.

This study investigated the possibility of measuring yield coefficient values for the biomass of a laboratory-scale horizontal sub-surface flow constructed wetland (HSSF-CW) using a static respirometer. The respirometric tests used 300 mL bulk volume of biomass-laden gravel samples from the HSSF-CW, from which the biomass was detached by a vigorous washing with 1 L of tap water. The presented tests were performed using sodium acetate as standard substrate and had a duration of 6-21 h. The obtained value ranges for initial yield and storage yield were, respectively, 0.41-0.67 and 0.75-0.83 (gCOD gCOD−1), comprising the literature ranges reported for activated sludge and vertical flow constructed wetlands.