Microrespirometric model calibration applied to wastewater processes

Microrespirometry is a recently developed method that combines classical respirometry and microreactor systems, for the characterization of microbial cultures. This method, which allows multiple simultaneous replicates from a single low-volume biomass sample, can improve and simplify the model calibration exercise by providing more and better experimental data. To follow up on the interest in microrespirometry, two model wastewater treatment processes were set up and used for model calibration: an aerobic degradation of 4-chlorophenol by acclimated sludge, and a synthetic wastewater treatment by activated sludge, which were well described by a Haldane model and a modified ASM3 model, respectively. For each process, the model parameters were estimated by model fitting, minimizing the objective function for each replicate independently, and minimizing the objective function for all replicates simultaneously (multiresponse approach). Parameter confidence intervals were determined for all parameter estimates, and the impacts of measurement errors, number of replicates, and parameter correlation were assessed. It was observed that the multiresponse approach presents several advantages, including single-step parameter estimation, independent of the number of replicates, and determination of confidence intervals that include the main sources of uncertainty. It was concluded that microrespirometry is a high-throughput and convenient method for model calibration.