Optimization estimation of kinetic parameters for heterotrophic biomass based on batch respirometric method

Based on activated sludge models (ASM) modified by dual hydrolysis mechanism, kinetic parameters for heterotrophic biomass were estimated by nonlinear optimization algorithm in combination with batch respirometric tests. Parameter estimation results of two wastewater treatment plants (WWTP) in Shanghai showed that, the modified model after optimization provided the best model fit with the experimentally determined oxygen uptake rate profiles. At 26°C, the heterotrophic decay rates for activated sludge from Quyang WWTP and Bailonggang WWTP were respectively 0.58, 0.55 d^-1, and similar maximum specific growth rate (both about 4 d^-1) and half-saturation constant (2.00, 2.36 mg/L) were obtained. The hydrolysis rate of slowly biodegradable organics in wastewater from the Bailonggang WWTP was significantly higher than that of the Quyang WWTP, which was mainly attributed to its smaller particles after long-pipeline transportation.