FOULING AND SCALING STUDIES OF ELECTRODIALYSIS REVERSAL (EDR) FOR HIGH WATER RECOVERY APPLICATION

Abstract

Reverse osmosis (RO) is widely implemented to either desalinate or reclaim water to meet increasing water demand. Typically, RO can achieve 50 – 75% water recovery. However, increasing beyond the RO’s water recovery rate of 75% would pose limitations such as scaling risk and energy inefficiency. Thus, a solution is required to further increase the water recovery rate. In this thesis, electrodialysis reversal (EDR) was explored as a solution to increase overall water recovery. As the RO concentrate (ROC) contained high concentration of organic compounds, lab-scale experiments and pilot-scale EDR were conducted with ROC as feed water to identify fouling and scaling risks in the EDR. The effects of pre-treatment chemicals (anti-scalants and disinfectants) on the EDR membranes were investigated in lab-scale experiments. Moreover, a pilot-scale EDR was monitored over one year and a dosing regimen was implemented to observe any improvement in the performance and operation.