Monitoring of pH inhibition on microbial activity in a continuous flow reactor by pseudo toxic concentration (CPT) concept and time delay model

Abstract

The pseudo toxic concentration (C(PT)) concept was introduced as a quantification method to describe pH as an inhibitor concentration. In this research, the applicability of the C(PT) concept model for the detection of pH inhibitions was expanded for a continuous flow activated sludge reactor. A pilot equipped with an inhibition detection system was installed. Inhibitory wastewater was injected for 1 h and the relative activity was calculated by the maximum respiration rate. At the same time, the coefficients for the C(PT) concept model were estimated. At the dynamic conditions, the estimated relative activity by the C(PT) concept model showed time lag compared to the measured one. However, the time lag problem was successfully resolved by introducing a transfer function into the C(PT) concept model. The C(PT) concept model combined with a transfer function (C(PT) + TF model) successfully tracked the variation of the relative activity under dynamic conditions. The C(PT) + TF model could detect 50% inhibition faster than the respirometry based method by approximately 10 min. Moreover, it had additional advantages such as being inexpensive, easy to install and simple to operate. In conclusion, the C(PT) + TF model was an effective and convenient detection method of pH inhibition.

Identification of process operating state with operational map in municipal wastewater treatment plant

“…During this period, ICA technologies have been significantly enhanced, which have made the control of WWTP's operation possible based on various models as well as simple PID controllers (J.R. Ko et al, 2006;Poo et al, 2006). Various control strategies for the stable operation of WWTP have also been proposed, with some having been applied to field treatment plants, such as SMAC (smart control of wastewater system; Krüger, 2004).…”