Table shows that the circular design can affect purity of CNC. The main impurity of CNC61 is Na2SO4, which comes from neutralization of (i) sulfate esters on CNC surfaces (expressed as 'fixed acid') and (ii) residual acid in suspension (expressed as 'free acid') after UF. Different circular designs do not affect the 'fixed' acid, as it corresponds to 3% DS. By contrast, 'free acid' can be affected: the circulated water from the evaporator contains ~0.02 wt.% acid, so more circulated water can unavoidably increase the amount of 'free acid' and then decrease the purity of CNC61. When no acid recycling is carried out and water is not reused, the purity of CNC is 97%. Partial acid recycling results in small decrease in CNC purity, while full acid recycling make purity of CNC fall to 95%. This section shows that circulating acid and water is at the cost of increase in energy use. In this sense, full acid recycling design can be an extreme process design. On the one hand, acid The hotspot of AP, as shown in Figure , is similar to that of CC, and similar regional recommendations can be made. Figure shows that pulp and electricity are the main contributors to LU. Pulp contribution comes from the required land for woody biomass cultivation. As pulp is one of the major CNC production inputs and is independent from acid recycling, the LU impact from pulp production is similar regardless of acid recycling design and regions. Electricity is the second contributor to LU in all regions, and strongly depends on regional energy profiles. All of the power generation technologies require LU for its infrastructure: hydroelectric dams can result in the area being flooded by the reservoir; wind power requires area for a wind farm; solar photovoltaics (PV) require land for panels and ancillary facilities; coal/gas impacts the area for power plant infrastructure, mining/drilling and transportation infrastructure . Therefore the design without acid recycling, which corresponds to a lower electricity requirement, demonstrates lower LU values.