The membrane hydraulic permeability measured
immediately after this set of experiments was
5.8 l/(m*.h*bar), and it was impossible to restore
its initial value simply by water washing at 1 bar
and 4 m/s for 2 h. This fact shows that the severe
permeate flux drop (with respect to the pure water
permeation flux) observed during these experiments,
which lasted for 2.3 h approximately, was
mainly due to fouling. Only after a complete basicacid
washing cycle, as follows: