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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]

Water supply and reuse through non-conventional water resources can significantly decrease the stress on natural water resources. Decentralized systems can help not only to alleviate issues of water security in arid areas, but also to create a sustainable framework within a circular economy. Although these small-scale innovative technologies are able to achieve ready-to-use, high quality of recovered/treated water on-site, the loop cannot be closed in most cases due to legislative barriers. Similarly, the end-use of sewage sludge after treatment in decentralized systems still lacks specific regulations that limit its valorization. This work analyzes the current policy and legislations related to water supply, wastewater treatment, water reuse and resource valorization within the context of decentralized state-of-the-art technologies applied in rural areas. The drawbacks in the current EU legislation that set barriers to close water-related loops in European countries are highlighted. A regulatory fitness check was applied to each type of loop to identify the key factors to accomplish the legislative compliance, and financing pathways were further evaluated at the EU level. As a possible solution, further development of an innovation deal approach is recommended to address the environmental, regulatory and financial gaps in water management through an integrated framework, providing ad-hoc policies and prescriptions for sustainable reuse of all water resources. • Regulatory fitness check was applied to closed water loops to identify legislative and financing barriers. • Current EU legislatives do not provide ad-hoc guidelines to decentralized systems. • No general barriers were detected for the reuse of reclaimed water in the EU legislation. • Serious limitations exist on drinking water production from non-conventional water resources. • Major constraints were determined for EC-marked compost for organic farming. [ABSTRACT FROM AUTHOR]

Italy is among the top biowaste-generating countries in Europe, and has a well-structured waste management framework with quite a number of centralized composting facilities. In recent years, there has also been huge interest from local communities in decentralized composting. Although decentralized community composting is common in some countries, there is still a lack of information on the operative environment together with its potential logistical, environmental, economic, and social impacts. Considering the national Italian legislation on community composting as well as successfully implemented projects at EU level, Italy can set a model especially for Mediterranean countries that intend to build decentralized composting programs. Therefore, in the context of this review paper, a brief overview of the composting process was presented together with main applications in centralized and especially in decentralized composting, while the main focus was kept on the operative and legislative information gathered from Italian community composting. There is a huge difference in the number of composting plants between the regions, and the lack of centralized facilities in the central and southern regions can be supported by decentralized solutions. Decentralizing waste treatment facilities and thus creating local solutions to urban waste management strategies will help to achieve the resource recovery and valorization targets in line with the circular economy. [ABSTRACT FROM AUTHOR]

Cost benefit analysis (CBA) and social impact assessment are well established methodologies to systematically estimate the viability of investments on technologies as well as the benefits for the society. However, there is a limited application of these assessment methods in the wastewater sector especially for resource recovery to deliver circularity objectives within urban water cycle management. In this regard, the Horizon 2020 SMART-Plant Innovation Action aimed to evaluate holistic impacts of wastewater-based resource recovery by applying and adapting cost benefit and social analysis on innovative technologies (SMARTechs). The SMARTechs were implemented and validated in real wastewater treatment plants (WWTPs) across Europe and Mediterranean basin where potential impacts in terms of carbon, material and energy efficiency, recovery and safe reuse were defined. Sixteen bottom-up SMARTech scenarios were analysed for the estimation of technical, economic and social impacts using CBA, social life cycle assessment (S-LCA) and social readiness level (SRL) methods. Overall, the SMARTechs created benefits both from an environmental and social point of view, with a maximum relative total economic value up to +23% compared to baseline scenario (without any SMARTech implementation). In terms of social benefits, the S-LCA highlighted a global positive impact of all the SMARTechs in terms of technical characteristics and social acceptance. Specifically, SMARTech 1 (cellulose recovery) was the most socially accepted solution thanks to its high performance and simplicity. Finally, based on the SRL assessment, most of the SMARTechs were positioned within the SRL range of 6–7, which implies a good societal acceptance and adaptation potential. • Socio-economic impacts of wastewater-based resource recovery were determined. • Nine different technologies were evaluated in sixteen bottom-up scenarios. • CBA and S-LCA were carried out leading to TEV and SRL. • Cellulose recovery scored the highest relative TEV and social acceptance. • Most of the technologies fell within a SRL range of 6–7. [ABSTRACT FROM AUTHOR]

Reuse of treated wastewater for irrigation purposes is a measure to reduce water stress and overexploitation of freshwater resources. This study aims to investigate the environmental and economic impacts of a current conventional wastewater treatment plant (WWTP) in Peschiera Borromeo (Milan, Italy), and compare possible scenarios to enable reclaimed water reuse for agriculture. Accordingly, we propose alternative disinfection methods (i.e. enhanced UV, peracetic acid) and replace conventional activated sludge (CAS) with upflow anaerobic sludge blanket (UASB) for biological treatment and use anaerobic membrane bioreactor (AnMBR) as the tertiary treatment. Life cycle assessment (LCA) and life cycle costing (LCC) were implemented on the existing full-scale wastewater treatment line and the hypothetical scenarios. In most cases, the impact categories are primarily influenced by fertilizer application and direct emissions to water (i.e. nutrients and heavy metals). The baseline scenario appears to have the largest environmental impact, except for freshwater eutrophication, human ecotoxicity and terrestrial ecotoxicity. As expected, water depletion is the most apparent impact category between the baseline and proposed scenarios. The UASB + AnMBR scenario gives relatively higher environmental benefits than the other proposed scenarios in climate change (−28%), fossil fuel depletion (−31%), mineral resource depletion (−52%), and terrestrial ecotoxicity compared to the baseline. On the other hand, the highest impact on freshwater eutrophication is also obtained by this scenario since the effluent from the anaerobic processes is rich in nutrients. Moreover, investment and operational costs vary remarkably between the scenarios, and the highest overall costs are obtained for the UASB + AnMBR line mostly due to the replacement of membrane modules (24% of the total cost). The results highlighted the importance of the life cycle approach to support decision making when considering possible upgrading scenarios in WWTPs for water reuse. • Different technologies for tertiary wastewater treatment are compared using LCA and LCC. • The proposed scenarios with water reuse provide benefits in most impact categories. • There were no significant differences observed between the disinfection by PAA or UV. • Higher environmental benefits are obtained by the UASB + AnMBR, except freshwater eutrophication. • The highest overall costs are obtained for the AnMBR process. [ABSTRACT FROM AUTHOR]

The occurrence, fate and removal of microplastics (MPs) in a wastewater treatment plant (WWTP) in Central Italy were investigated together with their potential adverse effects on anaerobic processes. In the influent of the WWTP, 3.6 MPs.L−1 were detected that mostly comprised polyester fibers and particles in the shape of films, ranging 0.1–0.5 mm and made of polyethylene and polypropylene (PP). The full-scale conventional activated sludge scheme removed 86% of MPs, with the main reduction in the primary and secondary settling. MPs particles bigger than 1 mm were not detected in the final effluent and some loss of polymers types were observed. In comparison, the pilot-scale upflow granular anaerobic sludge blanket (UASB) + anaerobic membrane bioreactor (AnMBR) configuration achieved 94% MPs removal with the abatement of 87% of fibers and 100% of particles. The results highlighted an accumulation phenomenon of MPs in the sludge and suggested the need to further investigate the effects of MPs on anaerobic processes. Accordingly, PP-MPs at concentrations from 5 PP-MPs.gTS−1 to 50 PP-MPs.gTS−1 were spiked in the pilot-scale UASB reactor that was fed with real municipal wastewater, where up to 58% decrease in methanogenic activity was observed at the exposure of 50 PP-MPs.gTS−1. To the best of our knowledge, the presented results are the first to report of PP-MPs inhibition on anaerobic processes. • Characterization of MPs in full-scale CAS and pilot-scale UASB + AnMBR configurations. • Overall greater removal of MPs by UASB + AnMBR (94%) compared to CAS (86%). • MPs retain and accumulate in the sludge line, mainly PE and PP. • PP-MPs inhibition on anaerobic processes is reported for the first time. • UASB tolerated up to 18 PP-MPs.gTS−1 but was inhibited by 58% at 50 PP-MPs.gTS−1. [ABSTRACT FROM AUTHOR]