Assessment of toxicity and kinetic effects of erythromycin on activated sludge consortium by fast respirometry method

Background: The present study aimed to assess the acute impact of erythromycin (ERY) as an inhibitor on peptone mixture utilization activated sludge (AS) consortium. Methods: For this purpose, inhibition oxygen consumption was used based ISO 8192:2007 procedure. In method, AS consortium (10-day age) extracted from lab-scale membrane bioreactor, then, percentage for total, heterotrophic, and nitrifying microorganisms, in separate batch respirometric tests were calculated absence presence N-allylthiourea (ATU) a specific Nitrification inhibitor. Results: obtained data showed that height uptake rate (OUR) profiles amount reduced with increasing ERY dose. half-maximal effective concentration (EC50) heterotrophic nitrifier microorganisms 269.4 1243.1 mg/L, respectively. Run 1, kinetic coefficients bH, fA,H, YH, µH 2.61 d-1, 0.44, 0.4945 mg VSS/mg COD, 0.047 Also, maximum (1000 mg/L), bH., 2.27 0.3, 0.4983 0.0049 Conclusion: findings inhibitory observed decrease by OUR rapid method (ISO 8192), which offered novel insight antibiotic. chemical demand (COD) overall substrate parameter is most helpful interpreting behavior metabolic functions systems.