In many countries of the Mediterranean region, characterized by frequent drought periods, agricultural production often occurs under water deficiency or conditions that cause the depletion of the existing water resources. In these areas, the reuse of reclaimed wastewater for crop irrigation could contribute to mitigate/decrease water shortage, support the agriculture sector and protect groundwater resources. In 1.5-year field experiments in Southern Italy (Apulia Region), the effects of irrigation with treated agro-industrial wastewater on soil properties, crops yield and qualitative traits of crop products, including their microbiological safety, were assessed. Groundwater (GW), secondary treated wastewater (SW) and tertiary treated wastewater (TW) from an innovative "on-demand" UV disinfection system were used to irrigate tomato and broccoli, cultivated in succession. The three irrigation water sources and the corresponding irrigated soils, plants and crop products were analyzed for the main physico-chemical characteristics, quali-quantitative parameters and fecal indicators. SW and TW showed higher values of the main physico-chemical parameters than GW. SW irrigated soil resulted in a significant increase of NH4-N, Na+, SAR, EC (below the threshold value beyond which a soil is defined as saline) during the first tomato crop cycle, and of pH during the broccoli growing season. Irrigation with treated wastewater did not significantly affect the marketable yield nor the qualitative traits of tomato and broccoli crops, except for the Na+ and NO3- content (below the threshold levels defined by the European guidelines for vegetables). High levels of E. coli (above the Italian limit for reuse), Fecal coliforms and Fecal enterococci (up to 10 4 CFU 100 ml-1) were observed in the SW and, when chlorination was not done, in the TW. Nevertheless, E. coli was not isolated from any sample of soil, plant and crop product, probably due to its rapid die-off. Moreover, low concentrations of Fecal coliforms and Total heterotrophic count were found in plant and crop product. The drip irrigation system used, which avoided the close contact between water and plant, may have contributed to this. Under the conditions applied in this study, the reuse of treated agro-industrial wastewater for irrigation can be considered an effective way to cope with agricultural water shortage in the Mediterranean area.

Wastewater reclamation and reuse is becoming a widespread practice for irrigation purposes, owing to new devices and techniques that have been decreasing the overall cost of water recycling in the agro-industry. Recently, the introduction of an ultrafiltration stage improved significantly the effectiveness of wastewater treatment schemes, thus contributing to reach higher sustainable productivities.In this study, we aimed at monitoring the performances of advanced treatment processes, recently introduced within a traditional activated-sludge wastewater treatment plant of a vegetable processing industry. The added tertiary treatments included sand filtration, membrane ultrafiltration (nominal pore size 0.05 µm) and UV disinfection (6x 300W mercury-vapor lamps). The company produced on average 5*104 m3/y of wastewater. At the different treatment stages, water samples were characterized by high electrical conductivity (2.5±0.9 mS/cm), high organic content (1.0±0.3 gCOD/L), low pH (5.6±0.4), and a variable fecal contamination (106-107 CFU/100mL of E. coli). Flow cytometry (FCM) was applied as a diagnostic tool to evaluate the removal of potential microbial contaminants. By quantifying the total and living microorganisms before and after each treatment, we found a moderate effectiveness of disinfection treatments, with a four-time increase of dead cells after UV exposure. Instead, the ultrafiltration stage was highly efficient, with the removal of >99% of the inlet microbial biomass. Whereas microbiological water quality assessment is traditionally based on cultivation methods with substantial manual handling and results only available after 2-5 days, FCM was suited uniquely for this application, due to its speed and potential for automation . Our cytometric outcomes provided a solid information basis for operational decisions concerning the treatment regime and operation, hence contributing to the safety of water reuse.

The biodegradability of different wastewater samples originated from the industrial production of threepharmaceuticals (naproxen, acyclovir, and nalidixic acid) was performed through the standard Zahn-Wellens test. Moreover, the wastewater composition before and during the test was evaluated in termsof parent compounds and main metabolites by LC/MS, and the biodegradability of the parent compoundswas also assessed by performing extra Zahn-Wellens tests on synthetic solutions. The results, besidesshowing the relatively good biodegradability of acyclovir and naproxen, evidenced the masking role ofthe organic matrices, especially in the case of nalidixic acid. The latter compound showed to berecalcitrant and persistent, despite the apparently good performance of the Zahn-Wellens test. Deeperevaluation evidenced that the biodegradation of high concentrations of organic solvents and other biodegradablecompound tended to ''hide" the lack of removal of the target compound.

Reuse of treated wastewater for crop irrigation can contribute to mitigate water stress, especially in Mediterranean countries. The use of reclaimed municipal wastewater for this purpose was demonstrated by numerous studies and full-scale installations. On the other hand, reuse of industrial effluents in irrigation is uncommon and the knowledge in this field is limited. This work aims at assessing the suitability of agro-industrial effluent reuse for irrigation. In the case study presented, a full-scale tertiary treatment based on membrane ultrafiltration and UV disinfection was tested at an agro-industrial site in Apulia (Italy). The wastewater treatment plant processed the stream produced at a vegetable canning factory, and the treated effluents were used for field scale irrigation tests. The variability of wastewater quality and its effects on treatment process performances and reclaimed water quality were investigated. An economic evaluation of the full scale tertiary treatment was also performed. The results showed that the adopted technologies effectively removed suspended solids and the faecal indicator Escherichia coli below the local standards for reuse in irrigation. Furthermore, the use of treated agro-industrial wastewater had no inhibitory effects on the growth of tomato and broccoli, neither resulted in any faecal contamination of crops. In general, the present study shows that reuse of treated wastewater for irrigation is a suitable practice to close the water cycle in the agro-industrial sector. This is very important in areas where the sustainability of agriculture and transformation activities depends on the water available for irrigation. This practice also avoids the discharge of pollutants into water bodies, reducing the environmental impacts of agro-industrial productions. (C) 2017 Elsevier Ltd. All rights reserved.

The enhanced removal of organic compounds from a pharmaceutical wastewater resulting from the productionof an anti-viral drug (acyclovir) was obtained by employing a membrane bioreactor (MBR) and anozonation system. An integrated MBR-ozonation system was set-up by placing the ozonation reactor inthe recirculation stream of the MBR effluent. A conventional treatment set-up (ozonation as polishingstep after MBR) was also used as a reference. The biological treatment alone reached an average CODremoval of 99%, which remained unvaried when the ozonation step was introduced. An acyclovir removalof 99% was also obtained with the MBR step and the ozonation allowed to further remove 99% of theresidual concentration in the MBR effluent. For several of the 28 organics identified in the wastewaterthe efficiency of the MBR treatment improved from 20% to 60% as soon as the ozonation was placed inthe recirculation stream. The benefit of the integrated system, with respect to the conventional treatmentset-up was evident for the removal of a specific ozonation by-product. The latter was efficiently removedin the integrated system, being its abundance in the final effluent 20-fold lower than what obtained whenozonation was used as a polishing step. In addition, if the conventional treatment configuration isemployed, the same performance of the integrated system in terms of by-product removal can only beobtained when the ozonation is operated for longer than 60 min. This demonstrates the effectivenessof the integrated system compared to the conventional polishing configuration.

Treated wastewater reuse is increasing in semi-arid regions as a response to the effects of climate change and increased competition for natural water resources. Investigating the fate of bacterial indicators is relevant to assess their persistence in the environment and possible transfer to groundwater or to the food chain. A long-term field-scale experimental campaign and a soil column test were carried out to evaluate the fate of the fecal indicator Escherichia coli (E. coli) in a cultivated soil when contaminated water resources are used for irrigation. For field experiments, fecal contamination was simulated by dosing the indicator to the effluent of a membrane bioreactor, thus simulating a filtration system's failure, and irrigating a test field where grass was grown. The presence of E. coli on grass and topsoil samples was monitored under different scenarios. For evaluating the fate of the same indicator in the subsoil, a set of soil columns was installed next to the field, operated, and monitored for E. coli concentration over time and along depth. Real municipal wastewater was used in this case as source of fecal contamination. Results showed that short- and medium-term effects on topsoil were strongly dependent on the concentration of E. coli in the irrigation water. Limited persistence and no relevant accumulation of the indicator on the grass and in the topsoil were observed. Watering events performed after fecal contamination did not influence significantly the decay in the topsoil, which followed a log-linear model. The trend of the E. coli concentrations in the leaching of the soil columns followed a log-linear model as well, suggesting bacterial decay as the dominant mechanism affecting the underground indicator's concentration.

Escherichia coli (E. coli) is one of the most commonly adopted indicators for the determination of themicrobiological quality in water and treated wastewater. Two main types of methods are used for theenumeration of this faecal indicator: membrane filtration (MF) and enzyme substrate tests. For bothtypes, several substrates based on the ?-D-glucuronidase activity have been commercialized. Thespecificity of this enzyme for E. coli bacteria has generated considerable use of methods that identifythe ?-D-glucuronidase activity as a definite indication of the presence of E. coli, without any furtherconfirmation. This approach has been recently questioned for the application to wastewater. Thepresent study compares two methods belonging to the above-mentioned types for the enumerationof E. coli in wastewater: MF with Tryptone Bile X-glucuronide agar and the Colilert®-18 test.Confirmation tests showed low average percentages of false positives and false negatives for bothenumeration methods (between 4 and 11%). Moreover, the counting capabilities of these twomethods were compared for a set of 70 samples of wastewater having different origins and degreesof treatment. Statistical analysis showed that the Colilert®-18 test allowed on average for asignificantly higher recovery of E. coli.

The Membrane BioReactor (MBR) is a well-established filtration-based technology for wastewater treatment. Despite the high quality of the effluent produced, one of the main drawbacks of the MBR is membrane fouling. In this context, a possible evolution towards systems having potentially lower installation and operating costs is the Self Forming Dynamic Membrane BioReactor (SFD MBR). Key of this technology is the self-formation of a biological filtering layer on a support of inert material. In this work, a lab-scale aerobic SFD MBR equipped with a nylon mesh was operated at approximately 95 L m-2 h-1. Two mesh pore sizes (20 and 50 ?m) and three air scouring flow rates (150, 250, and 500 mLair min-1) were tested at steady state. Under all the tested conditions, the SFD MBR effectively treated real municipal wastewater. The quality of the produced effluent increased for lower mesh size and lower air scouring intensity.

Squarebop I bacteriorhodopsin is a light-activated proton pump present in the membranes of the archeonHaloquadratum walsbyi, a square-shaped organism representing 50-60% of microbial population in thecrystallizer ponds of the coastal salterns.Here we describe: (1) the operating mode of a bioreactor designed to concentrate the saltern biomassthrough a microfiltration process based on polyethersulfone hollow fibers; (2) the isolation of SquarebopI bacteriorhodopsin from solubilized biomass by means of a single chromatographic step; (3) tightlybound lipids to the isolated and purified protein as revealed by MALDI-TOF/MS analysis; (4) the photoactivityof Squarebop I bacteriorhodopsin isolated from environmental samples by flash spectroscopy.Yield of the isolation process is 150 lg of Squarebop I bacteriorhodopsin from 1 l of 25-fold concentratedbiomass. The possibility of using the concentrated biomass of salterns, as renewable resourcefor the isolation of functional bacteriorhodopsin and possibly other valuable bioproducts, is brieflydiscussed.

Membrane filtration was investigated at field scale in order to assess its effectiveness for reusing municipal effluents in agriculture. The study was started on April 2002 and ended on September 2007, as part of a national R&D project (AQUATEC). Preliminary results, which we already reported elsewhere, concerned the first two project years while this paper refers to the subsequent period. Three different crops (processing tomato, fennel and lettuce) were grown in rotation at a test field located in Apulia (Southern Italy) and irrigated with membrane filtered municipal secondary effluents. The quality of the reclaimed water was monitored chemically and microbiologically, and compared with conventional water pumped from a local well. Both water sources were used in parallel for irrigating two plots of the test field. The results showed that the microbiological quality of the treated wastewater was comparable to or even higher than that of the conventional source. Protozoan (oo)cysts were experimentally identified as effective indicators of possible failures of the filtration system. Moreover, long term heavy metals accumulation trends were monitored in soil and crops, showing that despite some lead and copper accumulation in the soil, no measurable increase of these metals was observed in the edible parts of the crops.

Microbial dynamics and enzymatic activities of activated sludge processes are not completely understood yet. A better understanding about the biology is indispensable for further process optimization. Since proteins play a key role as catalysts in sludge processes, a protocol for protein extraction and analysis by 2-D PAGE was established.

Microbial dynamics and enzymatic activities of activated sludge processes are not completelyunderstood yet. A better understanding about the biology is indispensable for further processoptimization. Since proteins play a key role as catalysts in sludge processes, a protocol forprotein extraction and analysis by 2-D PAGE was established. It is based on phenol extractionof alkaline extracts and on a subsequent precipitation with ammonium sulphate. 2-D proteinpatterns obtained from different sludges collected from membrane bioreactors showed -besides common spots - significant differences. Selected proteins were identified with nano-HPLC-ESI-MS/MS. All membrane biological reactor (MBR) sludge samples investigated inthis study contained elastase 3A, which implies that this human serine protease is a significantconstituent of municipal wastewater. Although the identification of proteins fromammonia-oxidizing bacterium Nitrosomonas europaea was expected, the detection of a proteinwith homology to the marine bacterium Saprospira grandis in MBR1 was surprising.

In biological wastewater treatments, microbial populations of the so-called activated sludge work together in the abatement of pollutants. In this work, the metabolic behavior of the biomass of a lab-scale plant treating industrial pharmaceutical wastewater was investigated through a metaproteomic approach. The complete treatment process included a membrane biological reactor (MBR) coupled with an advanced oxidation process (AOP) for partial breakdown of non-biodegradable molecules. Proteins from biomass samples collected pre- and post-AOP application were investigated by two-dimensional gel electrophoresis (2DE), mass spectrometry (MS), and finally identified by database search. Results showed that most proteins remained constant between pre- and post-AOP. Methanol dehydrogenase (MDH) belonging to Hyphomicrobium zavarzinii appeared as the most constantly expressed protein in the studied consortium. Other identified proteins belonging to Hyphomicrobium spp. revealed a predominant methylotrophic metabolism, and H. zavarzinii appeared as a key actor in the studied microbial community.

Bacteria of activated sludge for wastewater treatment degrade and oxidize the polluting matter. They can also select and adapt to metabolize complex substrates. The knowledge of metabolic pathways for pollutant degradation becomes decisive to manage wastewater treatment plants. These pathways are strongly related to the bacterial enzymatic activity, that can be revealed through protein measurement. The protein set of a cell represents its functional picture in a given situation, and differently from the gene set it may change significantly according to environmental conditions. In biological wastewater treatment plants, metaproteomics can be applied to find the key enzymes or proteins of a process, and can reveal unexpected biochemical pathways. In every case it can show the metabolic dynamics of an entire consortium in different or targeted conditions.In order to evaluate the behavior of microbial consortia under well determined operating conditions, metaproteomics has been applied for the characterization of the biomass of a membrane bioreactor (MBR) treating an industrial wastewater (Salerno et al., 2016).The present work reports on the effects of changes in wastewater composition/supply on the biomass in terms of its functional response as measured through metaproteomics.

Biological processes are considered the conventional treatment for wastewater since almost acentury. Different microbial populations often cooperate in the degradation of pollutants present inwastewater and they represent the biomass of the so-called activated sludge. Several tools weredeveloped for the characterization of these microbial consortia: microscopy, physicaldeterminations, respirometry, molecular tools. Improved understanding of microbial consortia inactivated sludge requires deep investigation including functional analysis. Metagenomics wasrecently applied to wastewater treatment plants. Technical advances in mass spectrometry (MS)enabled the proteome analysis of complex microbial communities in environmental samples suchas those of municipal wastewater treatments. In this work the metabolic behavior of the biomass ofa lab-scale plant treating industrial pharmaceutical wastewater was investigated.

In the framework of the Euro-India project Water4Crops (call FP7 KBBE 2012-6, contract n. 311933) long term pilot scale tests were performed for evaluating the suitability of treated municipal wastewater effluents for irrigation. Two pilot plants were operated in order to evaluate the effectiveness of two different technologies and the quality of produced effluents with respect to national water quality standards for reuse in agriculture. Both the tested technologies were based on the coupling of biological processes and surface filtration, and each of the two pilots was made of: 1) a process based on surface filtration which treated a continuous flow; 2) a UV disinfection system treating only the effluent fraction used for irrigation, and operated on demand. The first plant was based on the technology IFAS-MBR (Integrated Fixed-film Activated Sludge - Membrane BioReactor), and treated raw sewage after preliminary screening. The second pilot was based on the technology FDG (Filtro a Dischi a Gravità, Gravity Disk Filter) and treated the secondary effluent. The effluents produced by the pilots were accumulated into storage tanks and submitted to on-demand UV disinfection (i.e. operated when irrigation was switched on). Results showed the effectiveness of both tested technologies in producing effluents suitable for reuse in agriculture and complying with the local standards.

The paper reports results of treated wastewater reuse field experiments carried out in Apulia (SouthernItaly). Fennel and lettuce were irrigated with four different water sources: three reclaimed wastewaterstreams, obtained by applying different treatment schemes to the same municipal wastewater, and aconventional source (well water). Differences between the three effluents were significant in terms ofsuspended solids and faecal indicators. Both lettuce and fennel yields were enhanced by the high contentof nutrients in the effluent of one of the treatment plants, which had been operated for partial nitrogenremoval. In particular, fennel productivity was enhanced by replacing chemical fertirrigation with thesupply of nutrients contained in the irrigation water.

Chemical-biological degradation of a widely spread antibacterial (nalidixic acid) was successfully obtained by an integrated membrane bioreactor (MBR)-ozonation process. The composition of the treated solution simulated the wastewater from the production of the target pharmaceutical, featuring high salinity and a relevant concentration of sodium acetate. Aim of treatment integration was to exploit the synergistic effects of chemical oxidation and bioprocesses, by adopting the latter to remove most of the COD and the ozonation biodegradable products. Integration was achieved by placing ozonation in the recirculation stream of the bioreactor effluent. The recirculation flow rate was three-fold the MBR feed. and the performance of the integrated system was compared to the standard polishing configuration (single ozonation step after the MBR). Results showed that the introduction of the ozonation step did not cause relevant drawbacks to both biological and filtration processes. nalidixic acid passed undegraded through the MBR and was completely removed in the ozonation step. Complete degradation of most of the detected ozonation products was better achieved with the integrated MBR-ozonation process than using the sequential treatment configuration, i.e. ozone polishing after MBR, given the same ozone dosage.

The treatment of a pharmaceutical wastewater resulting from the production of an antibacterial drug (nalidixic acid) was investigated employing a membrane bioreactor (MBR) integrated with either ozonation or UV/H2O2 process. This was achieved by placing chemical oxidation in the recirculation stream of the MBR. A conventional configuration with chemical oxidation as polishing for the MER effluent was also tested as a reference. The synergistic effect of MBR when integrated with chemical oxidation was assessed by monitoring (i) the main wastewater characteristics, (ii) the concentration of nalidixic acid, (iii) the 48 organics identified in the raw wastewater and (iv) the 55 degradation products identified during wastewater treatment. Results showed that MBR integration with ozonation or UV/H2O2 did not cause relevant drawbacks to both biological and filtration processes, with COD removal rates in the range 85-95%. Nalidixic acid passed undegraded through the MBR and was completely removed in the chemical oxidation step. Although the polishing configuration appeared to give better performances than the integrated system in removing 15 out of 48 secondary organics while similar removals were obtained for 19 other compounds. The benefit of the integrated system was however evident for the removal of the degradation products. Indeed, the integrated system allowed higher removals for 34 out of 55 degradation products while for only 4 compounds the polishing configuration gave better performance. Overall, results showed the effectiveness of the integrated treatment with both ozone and UV/H2O2.

Results of field experiments of wastewater reuse are presented. Two different crops (fennel and lettuce) were grown in succession on sandy loam soil and drip irrigated with three water sources: the effluent of the local full scale municipal wastewater treatment plant (WWTP), the effluent of a pilot scale non-conventional treatment technology, and a conventional source (well water). In order to evaluate the effects of higher ammonia and nitrate concentrations on crop yields and quality, the pilot plant was operated for partial nitrogen removal (mainly nitrification). Results showed that the pilot plant had better removal performance in terms of suspended solids and faecal indicators with respect to the full scale WWTP. As for the agronomic results, crop yields were significantly higher in plots irrigated with treated wastewater.

The use of non-conventional water resources including treated municipal wastewater has been increasing in the Mediterranean regions over the last decades to cope with water shortages and uneven rainfalls due to climate change. The aim of this paper is to present the first results from two years of experimental field activities carried out in two different demo-places in Southern Italy: the municipal wastewater treatment plants of Noci and Castellana Grotte (Apulia region). In these sites different vegetable crops (cucumber, lettuce, melon, endive in Noci and fennel, lettuce, fennel in Castellana Grotte) were grown in succession and irrigated in parallel with treated wastewater and conventional water pumped from wells, for comparing the effects of the different water sources on soil and vegetables. Reclaimed water quality was monitored for chemical and microbial parameters and compared with conventional water. At harvesting time, microbial indicators were measured on edible part of crops and in soil. Results show that the effluents produced by a full scale membrane bioreactor (MBR) treatment plant (Noci) comply with the stringent Italian standards for reuse in agriculture, and its microbiological quality is higher than the conventional well water. In Castellana Grotte the effluent quality of the two pilot plants was different according to the adopted technologies (MBR and tertiary cloth filtration), and sometimes depended on the quality of incoming wastewater. As for the agronomic results, in both sites crop yields were higher in the plots irrigated with treated wastewater, and the microbial indicators Escherichia coli and Salmonella were never found, at harvesting time, on edible parts of crops and in the soil.

The Membrane BioReactor (MBR) has been widely applied for the treatment of both urban and industrial wastewater. A possible evolution towards systems having potentially lower installation and operating costs is the Self Forming Dynamic Membrane BioReactor (SFD MBR). The main characteristic of this technology is the self-formation of a biological filtering layer on a support (mesh) of inert material. The biological layer, also called "dynamic membrane", has a lower porosity than the mesh itself, so acting as the key player in the filtration processes.

Two lab-scale Self Forming Dynamic Membrane BioReactors (SFD-MBR), equipped with 50 µm nylon meshes were set up and operated for the treatment of real municipal wastewater. Plastic carriers were added in one of the two bioreactors to generate a combination of the Integrated Fixed-film Activated Sludge (IFAS) and the SFD-MBR technologies. Overall, the two systems performed very well, achieving excellent effluent quality under steady state conditions and showing good resilience to extreme organic loading conditions. Continuous air scouring and periodical mesh cleaning by jet rinsing with tap water were effective in maintaining stable and high productivity (membrane flux around 67 L m2 h-1) over a period of 140 days. The application of the IFAS process resulted in lower production of excess sludge and improved denitrification. On the other hand, under the tested conditions the combined IFAS-SFD-MBR showed a higher tendency to mesh clogging with respect to the SFD-MBR.

A lab-scale Membrane BioReactor (MBR) for the treatment of synthetic municipal wastewater was set-up. The functional response of the activated sludge of the plant to a change in the supply of the influent wastewater was investigated. After 60 days at the steady state, the volumetric loading rate (VLR) was suddenly reduced to 65% by reducing the influent flowrate and establishing stress conditions for the biomass.The VLR decrease resulted in a reduction of volatile suspended solids (VSS) in the mixed liquor and in a slight worsening of the chemical oxygen demand (COD) degradation with respect to the previous period. Respirometry results revealed that the autotrophic bacteria more promptly adapted to the organic load perturbation than the heterotrophic ones. More details were provided by the application of metaproteomics. Particularly, several species expressed the same molecular chaperone in different experimental stages, evidencing diverse organic supply stress thresholds by different bacteria. More, coherently with the respirometric approach, some proteins belonging to species based on nitrogen metabolism were found in all samples, confirming the good resistance of autotrophic genera such as Nitrosomonas or Nitrospira to the stress due to VLR decrease. Finally, the expression of 1-butanol dehydrogenase by Thauera butanivorans at the end of the experimentation indicates that some species developed different metabolic pathways such as the degradation of butane, which had not been detected in previous stages.

Results of field experiments of wastewater reuse are presented. Fennel and lettuce were irrigated with four different water sources: three reclaimed wastewater streams, obtained by applying different treatment schemes to the same municipal wastewater, and a conventional source. Differences between the three effluents were significant in terms of suspended solids and faecal indicators. Both lettuce and fennel yields were enhanced by the high content of nutrients in the effluent of one of the treatment plants, which had been operated for partial nitrogen removal. Substituting chemical fertigation with the supplying of nutrients contained in the irrigation water enhanced fennel productivity.

Climate change and a growing population around the Mediterranean Rim are increasing the need for water and, consequently, the pressure on resources in terms of both quantity and quality. High-quality water should be primarily reserved to drinking water while reclaimed water is an alternative for other usages. A review of situations in Tunisia, Jordan, France, and Italy involving the use of reclaimed water highlights the disparity in national regulations governing this alternative water resource and in its management. On the first hand, the use of recycled water for irrigation can have an adverse impact on public health and the environment, depending on treatment and irrigation practices. On the other hand, it may also represent a new source of water: wastewater should no longer be considered as waste but, rather, as a new resource to be handled in a circular economy-type loop. Current scientific knowledge in agronomic and environmental sciences, as well as in the economic and social sciences, can be integrated and used to lower the associated risk through the effective management of irrigation using recycled water and to address the following questions: (i) How can the time-varying nutrient needs of crops be managed to operate safe environmental reuse within an adapted risk assessment framework? (ii) What socio-economic models can render this integrated approach sustainable? (iii) What treatment systems and irrigation technology can be used to support these ideas and with what information? (iv) What changes in the regulations are needed?

In order to mitigate water stress in the Mediterranean area, treated municipal wastewater is among the most readily available alternative water resources. Apulia (Southern Italy) is one of the Mediterranean regions most heavily affected by water shortage, although its economy is strongly based on irrigated agriculture. Nevertheless in Apulia only 1% of treated wastewater potentially available for reuse in agriculture is presently used, mainly because of regulatory constraints and public acceptance. Within the EU funded project Water4Crops different types of treatment schemes are applied at the pilot scale to treat municipal wastewater and polish secondary effluents for reuse in irrigation. In the present study, results from test field experiments carried out at Castellana Grotte (Apulia) are presented. Three different crops (processing tomato, fennel and lettuce) were grown in succession on sandy loam soil and drip irrigated with three water sources: the effluent of the local full scale municipal wastewater treatment plant (WWTP), the effluent of a pilot scale non-conventional treatment technology, and a conventional source (well water). The full scale WWTP is composed of a conventional activated sludge process followed by sand filtration, coagulation-flocculation and chlorination (conventional tertiary treatment). The pilot plant is an integrated process scheme called IFAS/MBR (Integrated Fixed-film Activated Sludge/Membrane BioReactor) followed by UV disinfection. In order to evaluate the effects of higher ammonia and nitrate concentrations on crop yields and quality, the IFAS/MBR pilot plant was operated for partial nitrogen removal (mainly nitrification). Reclaimed water quality was monitored in terms of chemical and microbiological parameters and compared with conventional well water. Microbiological indicators were also measured at harvesting time in soil and on the edible parts of crops. Chemical analyses of soil and crops were also performed in order to assess possible variations across the different water sources adopted. Results showed that the pilot plant had better removal performance in terms of suspended solids and faecal indicators with respect to the full scale WWTP. The effluent of the full scale WWTP compliedwith the Italian standards for reuse in agriculture, except for chlorine and E. Coli, while the effluent of the pilot plant exceeded the limit values only in terms of ammonia and nitrate. As for the agronomic results, crop yields where significantly higher in plots irrigated with treated wastewater. In particular the higher content of nitrates in the pilot plants effluent strongly enhanced the lettuce yield. Microbiological indicators E.Coli and Salmonella were never detected in soil and edible parts at harvesting time.

Nel corso dello lavoro sperimentale effettuato, un bioreattore a membrana in scala pilota è stato realizzato ed operato con un processo di aerazione continua per il trattamento di un'acqua reflua urbana sintetica. L'effluente in uscita dal sistema è stato utilizzato per irrigare una parcella coltivata con prato ed è stata monitorata sia la crescita di questo che la qualità dell'effluente utilizzato. La parcella sperimentale è stata confrontata con una seconda parcella di riferimento irrigata con una fonte convenzionale (acqua di pozzo).L'idea principale del lavoro è di utilizzare a fini irrigui l'effluente di un MBR operato con l'obiettivo di ottenere la rimozione della sostanza organica e la nitrificazione dell'ammoniaca e del nitrito per ottimizzare la produzione di nitrato nell'effluente, che rappresenta un elemento essenziale per la crescita delle piante. Questa attività è stata svolta nell'ambito del progetto PRIN (bando 2008) denominato "Trattamenti innovativi per il riutilizzo a scopo irriguo delle acque reflue".

Mediterranean countries are characterized by semi-arid climate, i.e. lack of natural water resources and scarce or uneven rainfall. Nevertheless, their economy is mainly based on irrigated agriculture. Moreover, in the pastdecades the developmentof local economies, poputatìon increase, and improper water management practiceshave resulted in severe exploitation and/or pollution of natural water resources' Climate change also contributed to reduce water availability. For all these reasons, water shortàge in Mediterranean countries has become a serious and pressing issue' ln particuìar, water stress greatly increases during the warmer season in the coastal areas,because of conflicting requirements due to tourism and agriculture' A recent reportof the EU Joint Reseàrch Centre showed that, during the period 1990-2010'in laige areas of Southern Europe the number of days per year with insufficient water for vegetation growth was higher than 90(JRC ,2012).