Electrodialysis Reversal at Tutuka Power Station, RSA-Seven Years' Design and Operating Experience

Abstract

The operating and design experience gained during the past seven years of the Electrodialysis Reversal Plant at Tutuka Power Station was evaluated. Factors like plant design and performance measures such as water recovery, salt rejection, current efficiency and CaSO4 saturation were investigated. The valuable operating experience has led to several design improvements to the EDR units, the clean in place system and the feed water pretreatment. Water recovery of 75%, salt rejection of 65% and current efficiency of 86% were achieved. Water recovery and salt rejection can be improved upon as very low CaSO4 saturation analyses were recorded. Plant availability varied between 90% and 57% but is expected to return to 90% as throughput increases. Membrane life has proven to be in excess of guarantee figures. Total production cost of R361,82/M1 was achieved. In conclusion the plant has successfully achieved its aims during the past seven years.