Challenges and opportunities for more efficient water use and circular wastewater management. The case of Campania Region, Italy.

By 2050, global demand for water is expected to increase by some 55% due to population growth and urbanization. The utilization of large amounts of freshwater in the world, generate huge volumes of wastewater of which, globally, more than 80% is discharged without treatment, thus causing impacts on aquatic ecosystems, human health and economic productivity. More sustainable practices of wastewater management are expected as a way towards circular bioeconomy (CBE) processes, whose goal is to implement closed systems promoting the systematic use of recycling, reuse and recovery of bioproducts and by-products and the reduction of waste generation. This approach, if adopted in the water and wastewater sector, can ensure environmental, economic and social benefits. The reuse of wastewater, on the one hand, reduces the volume of wastewater and the pressure on water bodies; on the other hand, the recovery of nutrients (P or N) and/or other high value bioproducts (biogas, cellulose, biopolymers) from wastewater offers numerous advantages in terms of supplying new raw bio-based materials that can be refed back to supply chains (thus substituting fossil resources) and, at the same time, producing cleaner water to be reused. Nevertheless, while in Europe many industries have demonstrated the ability to recycle and reuse water, in many regions of Italy the sustainable management of water and wastewater is not yet consolidated. In this study we explore the available technological, economic and environmental options concerning water use and wastewater treatment and we apply them to design appropriate scenarios for improved use efficiency and circular management. A comprehensive literature review of the most promising wastewater treatment processes for resources and energy valorization was conducted. The recovery of PHAs, struvite, nitrogen and algal biomass, as potential substitutes for conventional PET, phosphate and nitrogen chemical fertilizers and electricity, respectively, in addition to reusable treated water, were hypothesized and carefully discussed. Resulting scenarios are tested against the present situation of Campania Region (situated in Southern Italy) based on population and demand statistics, in order to develop strategies and policies potentially applicable locally and elsewhere.

Bio-products from algae-based biorefinery on wastewater: A review.

Increasing resource demand, predicted fossil resources shortage in the near future, and environmental concerns due to the production of greenhouse gas carbon dioxide have motivated the search for alternative 'circular' pathways. Among many options, microalgae have been recently 'revised' as one of the most promising due to their high growth rate (with low land use and without competing with food crops), high tolerance to nutrients and salts stresses and their variability in biochemical composition, in so allowing the supply of a plethora of possible bio-based products such as animal feeds, chemicals and biofuels. The recent raising popularity of Circular Bio-Economy (CBE) further prompted investment in microalgae, especially in combination with wastewater treatment, under the twofold aim of allowing the production of a wide range of bio-based products while bioremediating wastewater. With the aim of discussing the potential bio-products that may be gained from microalgae grown on urban wastewater, this paper presents an overview on microalgae production with particular emphasis on the main microalgae species suitable for growth on wastewater and the obtainable bio-based products from them. By selecting and reviewing 76 articles published in Scopus between 1992 and 2020, a number of interesting aspects, including the selection of algal species suitable for growing on urban wastewater, wastewater pretreatment and algal-bacterial cooperation, were carefully reviewed and discussed in this work. In this review, particular emphasis is placed on understanding of the main mechanisms driving formation of microalgal products (such as biofuels, biogas, etc.) and how they are affected by different environmental factors in selected species. Lastly, the quantitative information gathered from the articles were used to estimate the potential benefits gained from microalgae grown on urban wastewater in Campania Region, a region sometimes criticized for poor wastewater management.

Upgrading wineries to biorefineries within a Circular Economy perspective: An Italian case study.

In the challenge of transforming waste into useful products that can be re-used in a circular perspective, Italian wine industry can represent a suitable model for the application of the bioeconomy principles, including the valorisation of the agricultural and food waste. In the present study, a comprehensive environmental assessment of the traditional production of wine was performed and the potentiality of a biorefinery system, based on winery waste and aimed at recovering useful bio-based products, such as grapeseed oil and calcium tartrate, was examined through Life Cycle Assessment (LCA). The wine company "I Borboni", producing Asprinio wine in the Campania Region (Italy), was proposed as a case study. The hotspots of the linear production system were identified and the bottling phase, in particular the production of packaging glass, resulted to contribute to the generation of impacts at 63%, on average, versus 14.3% of the agricultural phase and 22.7% of the vinification phase. The LCA results indicated human carcinogenic toxicity, freshwater eutrophication and fossil resource scarcity impact categories as the most affected ones, with normalized impacts amounting to 9.22E-03, 3.89E-04 and 2.64E-04, respectively. Two side production chains (grapeseed oil and tartrate production) were included and circular patterns were designed and introduced in the traditional production chain with the aim of valorising the winery residues and improving the overall environmental performance. By implementing the circular approach, environmental impacts in the global warming, freshwater eutrophication and mineral resource scarcity impact categories, in particular, resulted three times lower than in the linear system. The results achieved demonstrated that closing the loops in the wine industry, through the reuse of bio-based residues alternatively to fossil-based inputs within the production process, and integrating the traditional production system with new side production chains led to an upgrade of the wineries to biorefineries, towards more sustainable production patterns.

Life Cycle Assessment of Mixed Municipal Solid Waste: Multi-input versus multi-output perspective.

This paper analyses four strategies for managing the Mixed Municipal Solid Waste (MMSW) in terms of their environmental impacts and potential advantages by means of Life Cycle Assessment (LCA) methodology. To this aim, both a multi-input and a multi-output approach are applied to evaluate the effect of these perspectives on selected impact categories. The analyzed management options include direct landfilling with energy recovery (S-1), Mechanical-Biological Treatment (MBT) followed by Waste-to-Energy (WtE) conversion (S-2), a combination of an innovative MBT/MARSS (Material Advanced Recovery Sustainable Systems) process and landfill disposal (S-3), and finally a combination of the MBT/MARSS process with WtE conversion (S-4). The MARSS technology, developed within an European LIFE PLUS framework and currently implemented at pilot plant scale, is an innovative MBT plant having the main goal to yield a Renewable Refined Biomass Fuel (RRBF) to be used for combined heat and power production (CHP) under the regulations enforced for biomass-based plants instead of Waste-to-Energy systems, for increased environmental performance. The four scenarios are characterized by different resource investment for plant and infrastructure construction and different quantities of matter, heat and electricity recovery and recycling. Results, calculated per unit mass of waste treated and per unit exergy delivered, under both multi-input and multi-output LCA perspectives, point out improved performance for scenarios characterized by increased matter and energy recovery. Although none of the investigated scenarios is capable to provide the best performance in all the analyzed impact categories, the scenario S-4 shows the best LCA results in the human toxicity and freshwater eutrophication categories, i.e. the ones with highest impacts in all waste management processes.

Emergy evaluation and economic analysis of three wetland fish farming systems in Nansi Lake area, China.

Emergy and economic methods were used to evaluate and compare three fish production models, i.e., cage fish farming system, pond intensive fish rearing system and semi-natural extensive pond fish rearing system, in Nansi Lake area in China in the year 2007. The goal of this study was to understand the benefits and driving forces of selected fish production models from ecological and economic points of view. The study considered input structure, production efficiency, environmental impacts, economic viability and sustainability. Results show that the main difference among the three production systems was the emergy cost for fish feed associated with their feeding system, i.e., feeding on natural biomass such as plankton and grass or on commercial feedstock. As indicated by EYR, ELR and ESI, it can be clearly shown that the intensive production model with commercial feed is not a sustainable pattern. However, the point is that more environmentally sound patterns do not seem able to provide a competitive net profit in the short run. The intensive pond fish farming system had a net profit of 2.57E+03 $/ha, much higher than 1.27E+03 $/ha for cage fish farming system and slightly higher than 2.37E+03 $/ha for semi-natural fish farming system. With regard to the drivers of local farmer's decisions, the accessibility of land for the required use and investment ability determine the farmer's choice of the production model and the scale of operation, while other factors seem to have little effect. Theoretically, the development of environmentally sustainable production patterns, namely water and land conservation measures, greener feed as well as low waste systems is urgently needed, to keep production activities within the carrying capacity of ecosystems. Coupled emergy and economic analyses can provide better insight into the environmental and economic benefits of fish production systems and help solve the problems encountered during policy making.

Environmental aspects of pesticide use in Italian agriculture.

Pesticides used in agriculture accumulate in organisms and reach man through complex metabolic pathways. Accurate analysis of pesticides presence in each step of the food chain is necessary because of the high number of these substances, their potential toxicity and the presence of amplified toxic effects due to synergic interactions. In the same way it is necessary to evaluate the environmental effects of the whole pesticides cycle, from industrial production until final disposal of used containers and residuals. Furthermore recent introduction of new categories of chemicals which are not strictly classifiable as pesticides (photosynthetic activity stimulators, aesthetic aspect enhancers) and not yet sufficiently studied in their metabolic behaviour, increase the problem complexity. Complete studies about these complex problems and about the effects on ecosystems have not yet been carried out in Italy, due to ambiguous laws and regulations, inadequate data collection methods and decisional influence of the chemical industry on agriculture policy.