Abstract: The influent water of the ultrafiltration (UF) system in a power plant has been changed from tap water to reclaimed water to realize the recycling and comprehensive utilization of reclaimed water. The changes of the key performance indicators of the UF system during the water source switching period are studied in this work. It is found that the change of reclaimed water has less effect on the influent and product water turbidity, while the operation mode of the UF system has a significant impact on the influent and product water turbidity. In comparison with that in continous operation, the influent turbidity is increased by 162.5% and the product water turbidity keeps unchanged when the UF system is in intermittent operation. In addition, there is a good linear relationship between the filtration efficiency and the influent water turbidity of the UF system, that is, the greater the influent turbidity is, the higher the filtration efficiency will be. After the reclaimed water is used, the trans-membrane pressure drop of the UF system is increased by 30%. The comprehensive analysis on the routine operation data of the UF system shows that the discontinuous operation and the influent water quality deterioration are the main reasons for the trans-membrane pressure drop increase of the UF system.

Key words: thermal power plant, reclaimed water, ultrafiltration, turbidity, turbidity removal rate, trans-membrane pressure drop