Performance assessment and life cycle analysis of potable water production from harvested rainwater by a decentralized system

© 2017 The Authors Decentralized rainwater harvesting (RWH) from roof runoff can complement the centralized supply of mains (drinking) water for a range of contexts, to assist in alleviating issues of water security. However, treatment to potable standard of harvested rainwater is not widespread. Consequently a comparative life cycle analysis (LCA) of decentralized and centralized potable water supply has not previously been undertaken. In this paper we describe a novel point-of-use (POU) treatment device, which was used to treat harvested rainwater to potable standard. We then provide a performance assessment for this system and an LCA with a comparison to centralized supply. Results of the performance assessment indicate a water saving efficiency (ET) of between 0.6 and 100%, depending on rainfall (0.6 from April when rainfall was significantly below average). This highlights that the POU device was able to deal with the scale of roof runoff supply originating from a RWH system at a commercial building scale. The LCA results suggest that potable water produced from this decentralized RWH POU system currently performs more poorly than centralized water from an environmental perspective. Its impacts in most categories would be significantly reduced if the electricity consumed by the system were supplied from a renewable source such as solar PV or wind turbines instead of the UK grid. Priority should be given to optimizing the energy efficiency and exploring opportunities for combined use with renewable energy technologies in order to improve the environmental performance of POU treatment devices

Emissions down the drain: Balancing life cycle energy and greenhouse gas savings with resource use for heat recovery from kitchen drains

peer-reviewedThe full text of this article will not be available in ULIR until the embargo expires on the 26/06/2022Although the food service sector is a major user of water, the potential for heat recovery from commercial kitchens’ drain water remains largely unexplored. For the first time, we compare the life cycle environmental burdens of producing and installing a heat recovery system with the environmental credits arising from energy savings for a restaurant case study, and for the entire UK food service sector. Life Cycle Assessment was applied to determine the impacts of heat recovery systems made from different materials and comprising a heat exchanger in the shape of a concentric double-walled pipe, pipework and fittings. The design option with the smallest environmental footprint combined a heat exchanger made out of polypropylene-graphite (PP-GR) with polyethylene pipework, exhibiting 80–99% less environmental impact compared with components made out of (35% recycled) copper. Contrasting the environmental impacts of two heat recovery set-ups with energy savings shows that a PP-GR based system pays back all burdens of the seven assessed environmental impact categories, within two years, while payback times for the copper-based system vary depending on the replaced energy source, and can exceed the 10 year operational lifetime of the system. When looking at typical flow-rates in UK food outlets, net environmental savings can be realised across all analysed impact categories above a threshold water consumption of 555 L/day, using current technology. Extrapolation to the UK food service sector indicates annual greenhouse gas emission mitigation potential of about 500 Gg CO2 equivalent

Environmental impact of heavy pig production in a sample of Italian farms. A cradle to farm-gate analysis

Four breeding piggeries and eight growing-fattening piggerieswere analyzed to estimate potential environmental impacts of heavy pig production (N160 kg of live height at slaughtering). Life Cycle Assessment methodology was adopted in the study, considering a system from breeding phase to growing fattening phase. Environmental impacts of breeding phase and growing-fattening phasewere accounted separately and then combined to obtain the impacts of heavy pig production. The functional unit was 1 kg of live weight gain. Impact categories investigated were global warming (GW), acidification (AC), eutrophication (EU), abiotic depletion (AD), and photochemical ozone formation (PO). The total environmental impact of 1 kg of live weight gain was 3.3 kg CO2eq, 4.9 E−2 kg SO2eq, 3.1 E−2 kg PO4 3−eq, 3.7 E−3 kg Sbeq, 1.7 E−3 kg C2H4eq for GW, AC, EU, AD, and PO respectively. Feed production was the main hotspot in all impact categories. Greenhouse gases responsible for GWwere mainly CH4, N2O, and CO2. Ammonia was the most important source of AC, sharing about 90%. Nitrate and NH3 were the main emissions responsible for EU, whereas P and NOx showed minor contributions. Crude oil and natural gas consumption was the main source of AD. A large spectrum of pollutants had a significant impact on PO: they comprised CH4 from manure fermentation, CO2 caused by fossil fuel combustion in agricultural operations and industrial processes, ethane and propene emitted during oil extraction and refining, and hexane used in soybean oil extraction. The farm characteristics that best explained the results were fundamentally connected with performance indicators Farms showed a wide variability of results, meaning that there was wide margin for improving the environmental performance of either breeding or growing-fattening farms. The effectiveness of some mitigation measures was evaluated and the results that could be obtained by their introduction have been presented

A life cycle analysis of ionizing radiation shielding construction systems in healthcare buildings

Optimization of material resources, energy efficiency and reduction of environmental impact are basic aspects in selection of a construction system. The aim of this study is to evaluate the environmental impact generated by different shielding systems for walls of an X-ray room in healthcare buildings. Eight commercial construction systems for anti-X shielding were analysed. A Life Cycle Assessment (LCA) was performed by SimaPro using the Ecoinvent database, and a single-score damage category analysis was performed for midpoint and endpoint levels. Prices of installation and working time employed in the construction of a functional unit of each system were obtained. Solutions with clay brick, cast-in-place reinforced concrete and sprayed concrete were the most favourable for the different categories. Sprayed concrete obtained 6.739 points/m² of against 165.12 points/m² of rolled steel option. The damage to human health occupies between 41% and 87% of the total impact in the protection areas. The impact category of human toxicity is also the broadest in the midpoint approach. Considering time and cost of implementation, clay brick solutions proved to be the most favourable, along with cast-in-place reinforced concrete and barite concrete. System #6 is the most environmentally friendly, 1.6 times less than the next one (which is #4), although its unit price is 1.94 times the cheapest (which is #2) and its execution time is 1.89 times the lowest (which is #2 again). The knowledge generated in this study will improve investment decision making for the planning departments of the Sanitary Systems, obtaining an economic, social and environmental benefit. The main novelty of the work lies in the object of the study (X-ray room) as well as in the integration of LCA and economic aspects