Unified Basis for the Respirometric Evaluation of Inhibition for Activated Sludge

Abstract

This paper explores the merit of the oxygen uptake rate (OUR) profile obtained by means of respirometry as the basic mechanistic instrument for evaluating activated sludge inhibition. Experimental OUR data are generated using the synthetic peptone-based substrate and inhibition is tested with 60 mg/L hexavalent chromium and 33 mg/L nickel additions, corresponding to EC50 levels determined using the standard ISO 8192 procedure. Experimental results are evaluated by model calibration using ASM1 modified for dual hydrolysis and ASM3 modified for simultaneous growth. Model evaluations indicate that inhibition affects not only growth, but also other significant microbial mechanisms such as substrate storage and hydrolysis, leading to conclude that the proposed approach will enable to visualize the overall impact of the inhibitory compound on every stage of substrate biodegradation, through inspection and evaluation of the entire OUR profile.

Pyrosequencing reveals the inhibitory impact of chronic exposure to erythromycin on activated sludge bacterial community structure

“…Peptone mixture was selected mainly because it was prescribed as standard substrate for inhibition studies based on respirometry [34][35][36][37] and its COD composition includes a number of fractions with different characteristics similar to real wastewaters [34].…”

Comparison of experimental methods for determination of toxicity and biodegradability of xenobiotic compounds

“…The basis is that respiration rate can be reduced in the presence of toxicants. Although some assays use other methods for quantifying respiration rate, the most common criterion is the oxygen uptake rate (Guisasola et al 2003;Ren 2004;Insel et al 2006).…”

Is the naphthalene sulfonate H-acid biodegradable in mixed microbial cultures under aerobic conditions?

“…A peptone-meat extract mixture, referred as peptone mixture in the text for simplicity was selected mainly because it is the standard organic carbon source for the ISO inhibition tests (ISO 8192, 2007) and it may be used with the same characteristics in the experiments. The biodegradation characteristics of the peptone mixture are well tested and documented in the literature and quite similar to those associated with domestic sewage (Insel et al, 2006;Katipoglu et al, 2010).…”