In the present paper, the performance of a pilot plant for domestic use was investigated, able
to operate continuously, and in which tap water was fed (inorganic carbon IC: 81.6±0.5 ppm; total organic
carbon TOC content: 1.52±0.02 ppm). This plant produced 130 L/d of purified water. The tap water was first
subjected to a prefiltration by a membrane microfiltration unit, followed by filtration through a membrane
immobilising activated carbon, then through a reverse osmosis membrane, at a transmembrane pressure of
4 bar, and finally through a photocatalytic membrane unit, constituted by a metallic membrane, onto which
the semiconductor and its photopromoters were present as a 3–4 μm thick surface layer, directly produced
on the nanotechnologically treated surface of this membrane, irradiated at a power of 9.6 W in the range of
optical absorption by semiconductor. Efficiency of these operations was compared by carrying out parallel
experiments, using two other commercial plants (I and II), in which the photocatalytic treatment was not
provided for. All the three plants were able to soften the tap water down to 6–8ppm IC, but, as regards TOC,
(I) yielded a purified water still containing 1.12±0.05 ppm of organic carbon, and (II) 0.908±0.0095 ppm, while the TOC content of water purified in the pilot plant of present work was lowered down to 0.06±0.02 ppm. In order to compare further efficiency of these plants, a simulated feed solution was treated, containing
3.05 ppm of humic acids, or 2.16 ppm of atrazine, or 4.23 ppm of symazine. Reverse osmosis, which was
present in all the three kind of plants examined, even if coupled with active carbon adsorption, was not able
to remove entirely contamination due to organic micropollutants. This goal, on the contrary, was successfully
achieved by the plant fitted with the photocatalytic membrane unit, particularly by considering that this
plant showed substantially the same abatement efficiencies of plants (I) and (II), if the photocatalytic unit
was switched off.
