G. I. M. Worm

Liquid velocity—permeate quality relationship for capillary nanofiltration

Abstract In this paper the relationship between liquid velocity and the concentration of components in the premeate is described for capillary nanofiltration (NF) membranes. Capillary NF combines the advantages of NF — good retention of bivalent ions and DOC — with the advantages of capillary membranes — robust with respect to fouling and good cleaning possibilities. Tests were performed on Twente canal water in cooperation with the Overijssel Water Supply Company. The operation mode of the tested system is dead-end with recirculation. The concentration of components in the system is not constant in time but increases during filtration. Periodically concentrate is discharged from the system. The different permeate concentrations for different liquid velocities can be explained entirely by the effect of the concentration polarization. The first experiments confirm that retention is a membrane characteristic.

Training and assessment with a faster than real-time simulation of a drinking water treatment plant

Abstract The usefulness of a human-in-the-loop drinking-water-treatment-plant simulator was investigated for training and assessment. An in-simulator transfer of training experiment was conducted with three groups training with accelerated simulation, experienced operators (EO), inexperienced operators (IO), and laymen (L60x) and a group of laymen training at real-time speed (L1x). Participants learned how to improve water quality during training. Upon transfer, when confronted with a different process disturbance than during training, L60x performed significantly poorer than EO and IO combined. No difference was found between EO and IO, and during transfer, L60x outperformed L1x. These results indicate that learning to control slow and complex processes may improve by training with a realistic simulation running at accelerated speed.