Modeling of pollutant removal by powdered activated carbon in a raw water aqueduct

• A mathematical model to describe PAC-pollutant dynamics was developed.
• PIV, rotating flume and lab jar tests were employed to determine the model parameters.
• The model was validated using the onsite and flume experiments.
• Various PAC feeding strategies as emergency response have been assessed.

This study provides new parameters for the use of powdered activated carbon (PAC) in a raw water aqueduct under emergency response. Here, we developed a coupled model that dynamically predicts simultaneous PAC transport and pollutant removal in the water aqueduct. To calibrate the model, we have performed a Particle Image Velocimetry (PIV) settling experiment to determine the dynamic settling velocity, PAC deposition experiments in a rotating flume to quantify the bottom shearing effects, and jar tests to determine the dynamic pollutant adsorption rate. The model was validated against a field chemical oxygen demand experiment in a water aqueduct in Shanghai (China) and a laboratory nitrobenzene flume test. Then, given a certain pollution concentration arising from an accidental pollution event, the model could be used to predict the optimal flow rate and PAC dosage for the establishment of mitigation measures.