Rainwater harvesting systems reduce detergent use

Unidad de excelencia María de Maeztu MdM-2015-0552Purpose: Due to population growth, urban water demand is expected to increase significantly, as well as the environmental and economic costs required to supply it. Rainwater harvesting (RWH) systems can play a key role in helping cities meet part of their water demand as an alternative to conventional water abstraction and treatment. This paper presents an environmental and economic analysis of RWH systems providing households with water for laundry purposes in a life cycle thinking perspective. Conclusions: LCA and LCC present better results for high-density scenarios. Overall, avoided environmental and economic impacts from detergent reduction clearly surpass environmental impacts (in all categories except terrestrial acidification) and economic cost of the RWHsystem in most cases (except two scenarios). Another important finding is that 80%of the savings are achieved by minimizing detergent and fabric softener by using soft rainwater; and the remaining 20% comes from replacing the use of tap water

Techniques and crops for efficient rooftop gardens in Bologna, Italy

Urban rooftop farming favours local food production. Although rooftop farming is perceived as 33 a sustainable system, there is a lack of quantitative studies on rooftop farming. There we set up 34 experiments in the community rooftop garden of a public housing building in Bologna, Italy, 35 between 2012 and 2014. We grew lettuce, a leafy vegetable, using three techniques: nutrient 36 film, floating hydroponic and soil cultivation. We also grew tomato, chilli pepper, eggplant, 37 melon, watermelon on soils. Data was analysed by life cycle assessment for environmental and 38 economic performance. Results reveal that the best techniques of lettuce cultivation to address 39 global warming were floating in the summer, with 65-85% less environmental impact per kg 40 than nutrient film; and soil production in the winter, with 85-95% less environmental impact. 41 Furthermore, floating production was 25% cheaper in summer and soil was 65% cheaper in 42 winter, compared to the nutrient film technique. For soil production, eggplants and tomatoes 43 showed the best environmental performances of about 74 g CO2 per kg. Eggplant production in 44 soil gave in the cheapest crop of 0.13 € per kg

Aquaponics in the Built Environment

Aquaponics’ potential to transform urban food production has been documented in a rapid increase of academic research and public interest in the field. To translate this publicity into real-world impact, the creation of commercial farms and their relationship to the urban environment have to be further examined. This research has to bridge the gap between existing literature on growing system performance and urban metabolic flows by considering the built form of aquaponic farms. To assess the potential for urban integration of aquaponics, existing case studies are classified by the typology of their building enclosure, with the two main categories being greenhouses and indoor environments. This classification allows for some assumptions about the farms’ performance in their context, but a more in-depth life cycle assessment (LCA) is necessary to evaluate different configurations. The LCA approach is presented as a way to inventory design criteria and respective strategies which can influence the environmental impact of aquaponic systems in the context of urban built environments

Environmental assessment of copper production in Europe: an LCA case study from Sweden conducted using two conventional software-database setups

Purpose This study focuses on the environmental assessment of European copper production. Life cycle assessment is applied to analyse copper cathode production in Sweden, including its mining (an open-pit mine) and refining (pyrometallurgy), and using two combinations of software and databases: SimaPro software with ecoinvent database and GaBi software with GaBi database. The results are compared with results from other case studies from literature.Methods A cradle-to-gate LCA was conducted considering 1 tonne of copper as functional unit. The inventory for the foreground system was elaborated using primary data gathered by the staff from the mine, the concentrator and the smelter. For the background data, LCA databases are used considering datasets for the Swedish market whenever possible. As the smelter has multiple useful outputs, economic allocation was applied at the inventory level. The calculation method CMLIA baseline 3.5 was considered for both combinations of software and database, reporting all the impact categories of the method plus the Cumulative Energy Demand.Results and discussion The inventory of the system and the main environmental hotspots were presented, such as the explosives for blasting (due to their supply chain) or the electricity used in the concentrator. The results obtained with the two combinations of LCA software and databases yield large differences for categories such as abiotic depletion (7.5 times higher for SimaPro and ecoinvent), possibly due to differences in the system boundaries of the databases and the characterisation factors of the method. Although the case study has a relatively high cumulative energy demand (140/168 kMJ/tonne Cu) compared to other mines, its performance in global warming (3.5/4.7 tonne  CO2eq/tonne Cu) is much better due to the low greenhouse gas emissions from electricity, which shows that the electricity mix is a key aspect.Conclusions The environmental performance of mining depends partially on the specific conditions of the deposit, e.g., the ore grade and the mining type. LCA practitioners should consider the potential different results that can be obtained using different combinations of software and database and exert caution when comparing cases, especially for abiotic depletion, human toxicity and ecotoxicity categories. Finally, the use of renewable energies can be key to improve the environmental sustainability of copper production.</p