The fifth and final step allows to obtain

The upgrading actions may concern the following critical UOPs: (i) process for BOD5 removal; (ii) processes for N and P removal; (iii) solid/liquid LY335979 after the secondary or tertiary treatments (where present); (iv) fining treatment; and (v) disinfection. On the basis of the specific plant characteristics (i.e., overloaded/not overloaded, UOP presence/absence) (see Table 2), two types of upgrading actions were considered. The first type (A1) optimizes the management of a process identified as critical. While the second type (A2) represents a structural action carried out by means of the construction of new treatment basins.