Together with acid recycling, water is recycled from the evaporator and then is cooled down and reused in the UF stages. WU reduction is linearly related to the reduction of the number of UF stages (the first few UF units filtered the most acid, so water reduction is not linear to acid recovery). Consumption of fresh water can be reduced by 29% (or 94%), with the increase in acid recovery at 80% (or 99%). In other words, the acid recycling design is closely related to the water circular design, but not in linear way. As most of the energy is consumed in the water evaporation step, the circulated water can be almost linearly proportional to electricity consumption: 80% (or 99%) acid recovery circulates 29% (or 94%) of the process water, requiring 5 times (or 15 times) the electricity of the design without acid recycling.