An external ceramic membrane bioreactor was used to carry out an experimental study of process stability and fouling aspects for olive mill wastewater (OMW) treatment. Three diluted OMW solutions were used to continuously feed the reactor. An acclimated biomass was employed and the process stability was followed on the basis of the permeate quality and some operating parameters (pressure, temperature, mass flow and dissolved oxygen). Several backpulse combinations were tested to determine the best filtration and backwash time. It appeared that a short backpulse duration was sufficient and that the behaviour, in terms of the permeate flux versus time, stabilized. In terms of increased permeate flux, the effect of the backpulsing depended on the nature of the solution. This improvement was limited, but, in the long-term, backpulsing makes it possible to maintain a constant permeate flux over a period of several days.

The title new compound, (C2H6N5+)2, 2Cl−.H2O, contains two 3,5-diamino-4H-1,2,4-triazol-1-ium cations, two chloride anions and one water molecule. The crystal structure is stabilized by O - H···Cl, N - H···Cl, N - H···O and N - H···N hydrogen bonds, one of them being a three-center interaction. Strong π - π stacking interactions between neighboring triazolium rings are present, with a centroid - centroid distance of 3.338 (7) Å. The exocyclic N atoms are sp2 hybridized, as evidenced by bond lengths and angles, in agreement with an enamine-imine tautomerism. A dielectric spectroscopic study of the title compound was performed. The 13C CP-MAS NMR spectrum is in agreement with crystallographic data. The infrared spectrum has been recorded at ambient temperature and interpreted on the basis of literature data. The temperature dependence of the imaginary part of the permittivity constant was analyzed with the Cole - Cole formalism in the temperature range 325 - 375 K.