Biodegradation of Laundry Wastewater Under Aerobic and Anaerobic Conditions: A Kinetic Evaluation

ABSTRACT: This research was conducted in a batch mode in a laboratory‐scale setup to study (1) the biodegradation of laundry wastewater under aerobic and anaerobic conditions and to quantify the degradation at steady‐state in terms of kinetic parameters and (2) the inhibition caused by laundry wastewater on growth‐substrate utilization by un‐acclimated ethanol‐enriched aerobic and anaerobic microbial cultures. The chemical oxygen demand (COD) removal was above 95% under aerobic condition; however, the COD removal varied between 70 and 88% under anaerobic condition. The steady‐state kinetic parameters k, Ks, Y, μm, and kd were 1.75 d–1, 21.67 mg COD/L, 0.4 mg volatile suspended solids (VSS)/mg COD, 0.7 d–1, and 0.06 d–1 respectively under aerobic condition; corresponding values under anaerobic condition were 4.7 d–1, 173.67 mg COD/L, 0.06 mg VSS/mg COD, 0.3 d–1, and 0.04 d–1. Laundry wastewater caused a competitive inhibition at doses above 200 mg/L under aerobic and anaerobic conditions.