These results are in accordance with other studies that report higher emission from the separated fractions during storage (Fangueiro et al., 2008; Dinuccio et al., 2008). These mechanisms can also explain the difference in losses between the P and C slurries. The lower losses from C_UN compared with P_UN may be explained by the higher TS content and the lower TAN/TKN ratio. After separation, the two liquid fractions (P_LF and C_LF) have similar TS content and TAN/TKN ratio (Table 1) and similar losses were observed.