Water use is lower for QC, SE and WI in the design without acid recycling, while other regions benefit from the partial acid recycling design, see Figure . For all regions, the difference is minimal between partial acid recycling and no acid recycling. WU mainly comes from direct water consumption for CNC purification and indirect water for power generation. Direct WU is similar for different regions; the indirect WU can vary significantly according to the corresponding energy profiles. Almost all the power generation technologies consume water.