Laboratory Scale Evaluation of Fertiliser Factory Wastewater Treatment through Membrane Distillation and Reverse Osmosis.

The incumbent water stress scenario imposes wastewater valorisation to freshwater, promoting technology for its effective treatment. Wastewater from fertiliser factories is quite problematic because of its relevant acidity and solute content. Its treatment through vacuum membrane distillation (VMD) was evaluated through laboratory scale tests at 40 °C and 25 mbar vacuum pressure with polytetrafluoroethylene and polypropylene flat-sheet porous membranes. The wastewater from a partially disused Italian industrial site was considered. VMD distillate fluxes between 22 and 57.4 L m-2 h-1 (LMH), depending on the pore size of the membranes, along with very high retention (R > 99%) for anions (Cl-, NO3-, SO42-, PO43-), NH4+, and chemical oxygen demand (COD) were observed. Laboratory scale reverse osmosis (RO) tests at 25 °C and increasing of the operating pressure (from 20 bar to 40 bar) were carried out with a seawater desalination membrane for comparison purposes. Permeability values around 1.1 LMH/bar almost independently of the operating pressure were observed. Lower retentions than those measured from VMD tests were found. Finally, for any given RO operating pressure, the flux recovery ratio (FRR) calculated from permeate fluxes measured with pure water before and after wastewater treatment was always much lower that evaluated for VMD membranes.

[Diagnosis in related pathologic asbestosis, clinical case of a suspected occupational neoplasm]. / Iter diagnostico nelle patologie asbesto correlate, considerazioni a margine di un caso clinico di sospetta neoplasia professionale.

In our country the rate of asbestos-related neoplasia, in particular pleural mesothelioma and lung cancer, is increasing; the data provided by INAIL concerning the complaints for occupational diseases filed in 2006 ex table D.P.R. 336/1994 (neoplastic diseases caused by asbestos: pleural, pericardial and peritoneal mesothelioma; lung cancer) are significant. The total number of such complaints in our country amounts to 753 (135 in Liguria and 384 in the north-western regions). As the issue of health following up of former exposed workers is actually an important concern of occupational medicine, some protocols have recently been proposed with the aim to early diagnose asbestos related neoplasia, thus getting a better prognosis. Under the medico-legal aspect, the need for fixing the proper criteria for aetiological attribution to asbestos of lung cancer in subjects previously exposed to that substance is a controversial issue, being the various approaches quite different; the incidental finding of a lung "coin lesion" in a subject who had been holding an annuity for years, as an indemnity granted by INAIL for asbestosis, has prompted the authors both to go over such a clinical case and to review the literature on the topic, in particular as to the complex medico-legal implications.

Ozone treatment of textile wastewaters for reuse.

Treatment of textile wastewaters by means of an ozonation pilot plant are described. Wastewaters used were produced by a dyeing and finishing factory and were first treated in an active sludge plant and filtrated through sand. In the appropriate conditions very high colour removal (95-99%) was achieved and the effluent could be reused in production processes requiring water of high quality as dyeing yarns or light colorations. Even if the chemical oxygen demand of treated waters was still in a range (75-120 mg/l, a decrease of up to 60%) that was usually considered to be too high for recycling purposes, recycling experiments were successful. The economical viability of the techniques implementation was also demonstrated and the industrial plant is currently under realisation under an EU financed project. The paper considers also the possible improvement of ozone diffusion by means of membrane contactors realised in a second pilot plant, in order to further reduce operating costs of the technique. With respect to traditional systems, the gas/liquid contact surface is much higher being that of the membrane. Ozone at the interface is therefore immediately solubilized and potentially consumed with no additional resistance to the mass transfer.