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In water scarce areas, like the Mediterranean Region where the lack of irrigation water is already limiting agricultural production, the valorization of non-concventional water resources is utmost important. Accordingly, in this study, we aimed to provide safe and locally sustainable ways of water supply for the Mediterranean agricultural sector by exploiting non-conventional water resources for irrigation purpose. In this context, pilot scale anaerobic reactors treating urban wastewater were operated coupling upflow anaerobıc sludge blanket (UASB) reactor and ultrafiltration anaerobic membrane bioreactor (AnMBR). The resulting permeate is of high quality, accomplishing the EU quality standards for irrigation water reuse, also in terms of E.coli as the main microbial indicator. However, contaminants of emerging concern (CECs) can be a further limitation for safe reuse of the reclaimed water. Hence, molecularly imprinted polymers (MIPs) were further integrated as the final refining step for the selective removal of CECs. Diclofenac was used as the target compound with a removal efficiency up to 50% in the final effluent. In parallel, an intensive pilot system was operated for brine treatment through evaporation, chemical addition and precipitation, and forward osmosis, where up to 77% Mg2+ and 45% Ca2+ recovery rates were achieved. The recovered Mg-salts from the brine treatment were then used as an external source to enhance the struvite precipitation in the N- and P-rich effluent of AnMBR. The preliminary tests showed that only hydroxiapatite salts precipitated without any external P addition. [ABSTRACT FROM AUTHOR]

In European scenario, the potential source for water supply from treated wastewater is actually estimated in 1,100 Mm3/y (EU-ENV, 2015). Anaerobic processes compared with conventional aerobic ones, cause a net reduction of the operative costs and possible reuse for fertigation purposes. The tested anaerobic pilot (HRT 6 h and T 30°C) is constituted from a UASB reactor (16 L). Increment of influent organic loading rate (OLR) was studied for 1 year from 1 to 2 kgCOD/m³/d by feeding raw wastewater (Period 1), methanol (Period 2) and fermented supernatant from cellulosic sludge (Period 3).The biogas production was assessed equal to 0.13 m3biogas/kgCOD (Period 1), to 0.57 m3biogas/kgCOD (Period 2) and to 0.24 m³biogas/kgCOD (Period 3) with methane percentages constant around 33%. UASB effluent has not the final quality to comply limit values for water reuse and fertigation, especially for microbiological parameters. Further treatments could be necessary to achieve the removals of bacteria, such as E.Coli, recalcitrant organic traces and metals. Therefore, some advanced post treatments have been studied in this paper after UASB treatments, like UV disinfection, UV coupled with H2O2 and GAC adsorption. The innovative solution is coupling UASB reactor with anaerobic submerged sidestream AnMBR (UF hollow fiber membrane with 0.03 µm of nominal pore-size and 0.5 m2 of surface area KOCH, Puron single bundle). Membrane cleaning was carried out using sodium hypochlorite solution (400 ppm) each 45 days to remove organic fouling and to recover the initial permeability of the membrane. The average operative flux at process temperature was equal to 8.8±1.9 L/h/m² and operating TMP of 44.6±8.5 mbar was detected. The removal of E.Coli was investigated in the effluent from UASB and in the permeate from AnMBR process. At clean membrane conditions, complete removal of bacteria (99±1%) was found. Furthermore, the determination of microplastics distribution was carried out both in the experimental anaerobic pilot and in the conventional full scale aerobic treatment plant. The effluent microplastics were quantified and the removal role of the different operative units was studied. [ABSTRACT FROM AUTHOR]