The only phase which could prove critical in terms of capital
investment is pre-treatments, which is also the one with the
smallest number of BATs implemented. The measures documented
in this process phase are generally the introduction
of micro-filtering systems for the cleaning fluids. These are
very expensive with relatively long pay-back times (2.97
years).
The most accessible investments are those common to all
phases, which in general involve new operational practices
or new process control tools. Fig. 3 summarises the economic
criticality in the implementation of various types of BATs.