Aerobic biodegradation kinetics of tannic acid in activated sludge system

Biological treatment of simulated tannic acid (TA)-containing wastewater by activated sludge was investigated to find the optimal biodegradation conditions and investigate the aerobic biodegradation kinetics. Activated sludge was acclimatized to simulated wastewater with TA concentration up to 950 mg/l over a period of 27 days. Batch experiments on TA biodegradation under different pH, temperature, aeration conditions and with different initial substrate concentrations were conducted. The initial biomass concentration was kept at 2000 mg/l. By comparing the degradation rates under different conditions, the optimal ranges of pH, temperature and DO for TA biodegradation in the activated sludge system were determined: pH ≈ 7, temperature = 20–35 °C, DO > 1.0 mg/l. A biodegradation kinetic model that takes into consideration substrate inhibition and endogenous decay was established, and its kinetic parameters were determined. The estimated values of μmax, Ks, Ki, kd and Y were 0.208 h−1, 226 mg/l, 522 mg/l, 0.0092 h−1 and 0.594, respectively.