This work reports on a case of study for the reuse of the process
water of a WtE plant sited in northern Italy in order to reduce fresh
water consumption, with no modification of the plant layout.
Preliminarily to mass balances, physical–chemical characterisation
and flow rate measurement of fresh water and process water flows,
derived from each utility internal to the WtE plant (e.g. cooling,
bottom ash quenching, flue gas wet scrubbing), have been performed.
Then, the potential direct recycle of the various process
water flows has been considered, focusing on the possibility to
simplify the layout and consequently the operation without intermediate
specific water treatments. This reuse scheme implies the
change from a ‘single passage’ to a ‘cascade’ configuration for water
usage, but some constraints must be taken into account: when the
water request is reduced, the concentration of pollutants in the
final discharge increases, since their production depends mainly
on the characteristics of MSW incinerated.