RO concentrate treatment by a hybrid system consisting of a pellet reactor and electrodialysis

► Pellet reactor was used to remove the scaling potential of RO concentrate in ED. ► Calcium was precipitated with a high efficiency ranging from 70 to 95%. ► After pretreatment, ED could operate in a stable way with high current efficiency. ► A hybrid system (pellet reactor, ED) is suitable for RO concentrate treatment.