56 research outputs found
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The use of virtual reality technology in teaching environmental engineering
The Open University (OU) provides a Diploma in Pollution control as part of its undergraduate degree programme. The courses that make up the Diploma are presented in distance learning format using the OU's supported open learning system that has been developed over several decades. Teaching environmental engineering by distance learning presents several challenges in terms of ensuring that students gain an appreciation of the technology in action and receive the motivation and support more-readily available to students taught in a campus setting. The OU has developed a multi-media resources DVD to help meet these challenges for students undertaking an environmental impact assessment project. The DVD contains virtual reality views of the proposed site, maps of the region, supporting technical data, interviews with experts and advice from a virtual tutor. A survey of students using the DVD found that the overwhelming majority found the DVD to be 'very useful' or 'useful'. Understandably, the material that is essential for completing the project received the highest rating, but the background material was still considered to be useful by most students. Similar resources could benefit all students in many areas of engineering and technology
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The environmental and financial benefits of recovering plastics From residual municipal waste before energy recovery
A life cycle assessment was carried out to investigate the environmental benefits of removing dense plastics from household waste before burning the waste in an energy from waste (EfW) facility. Such a process was found to improve the climate change and non-renewable resource depletion impacts of the waste management system.
A preliminary financial assessment suggests that the value of the plastics recovered in this way would be less than the reduction in electricity income for the EfW. However, if the plastics were separated by the householders and collected in a kerbside recycling scheme, the greater price commanded by the higher-quality reclaimed plastics means that the operation would financially viable Further work is required to assess the effectiveness of using both kerbside collections and mechanical recovery to reduce the plastics content and carbon intensity of EfW feeds
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A Life Cycle Assessment Of Energy From Waste And Recycling In A Post Carbon Future
Life cycle assessment was used to investigate the environmental impacts and benefits of managing residual municipal solid waste, waste newspapers, and organic waste for two energy supply scenarios. In the first scenario, gas-fired electricity is replaced by energy from waste and landfill gas use and gas is also used to provide the electricity and process heat used in recycling and primary material production processes. In the second scenario, wind power is the marginal electricity source displaced by energy from waste and landfill gas use and wind and biomass are used to provide process electricity and heat respectively. The results show that, under both energy scenarios, treating the residual non-recyclable municipal solid waste in energy from waste facilities is preferable to landfill. For waste paper and organic waste, recycling/composting is the better option in some LCA impact categories while energy from waste is the better option in other impact categories. These results suggest that moving from gas to wind-powered electricity does not suggest that any changes should be made in the way these wastes are managed
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A life cycle assessment of energy from waste and recycling in a post-carbon future
Life cycle assessment was used to investigate the environmental impacts and benefits of managing residual municipal solid waste, waste newspapers and organic waste for two energy supply scenarios. In the first scenario, the electricity generated by energy from waste and landfill gas combustion displaces grid electricity generated from natural gas. The electricity and process heat used in the recycling and primary material production processes are also generated from gas. In the second scenario, wind power is the marginal electricity source displaced by energy from waste (EfW) and landfill gas use and wind and biomass are used to provide process electricity and heat respectively. The results show that, under both energy supply scenarios, treating the residual non-recyclable municipal solid waste in EfW facilities is preferable to landfill. Comparing the recycling of waste paper with EfW shows that neither option can be regarded as the better environment option and this is the case regardless of the energy supply scenario. The environmental burdens of treating organic waste by EfW increase with a move to wind power and, in this case, the results suggest that composting has environmental advantages over EfW. Normalising the LCA results demonstrates that waste management represents a low proportion (-1.5% to 1.5%) of an individual’s contribution to their overall LCA impacts
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Developing Integrated Waste Management Systems: Information Needs and the Role of Locally Based Data
No abstract available
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Using Life Cycle Assessment in environmental engineering education
Life cycle assessment (LCA) is a method of assessing the environmental impacts of the manufacture and use of a product or provision of a service such as waste management. LCAs are based on quantitative science, but softer skills are also required in interpreting the results. Therefore, LCA provides an ideal opportunity for students to develop and apply both quantitative and qualitative skills in order to address complex real-world problems. In this research a simplified spreadsheet LCA tool was produced for students to assess the environmental impacts of a waste management system. Detailed feedback from face to face and distance-learning students were positive about the tool, with students welcoming the detail provided in the results and the use of a practical example to help their learning. In conclusion, LCA is an effective way of encouraging environmental and engineering students to develop and apply a wide range of transferable skills
‘Priming’ exercise and O2 uptake kinetics during treadmill running
We tested the hypothesis that priming exercise would speed kinetics during treadmill running. Eight subjects completed a square-wave protocol, involving two bouts of treadmill running at 70% of the difference between the running speeds at lactate threshold (LT) and max, separated by 6-min of walking at 4 km h−1, on two occasions. Oxygen uptake was measured breath-by-breath and subsequently modelled using non-linear regression techniques. Heart rate and blood lactate concentration were significantly elevated prior to the second exercise bout compared to the first. However, kinetics was not significantly different between the first and second exercise bouts (mean ± S.D., phase II time constant, Bout 1: 16 ± 3 s vs. Bout 2: 16 ± 4 s; slow component amplitude, Bout 1: 0.24 ± 0.10 L min−1vs. Bout 2: 0.20 ± 0.12 L min−1; mean response time, Bout 1: 34 ± 4 s vs. Bout 2: 34 ± 6 s; P > 0.05 for all comparisons). These results indicate that, contrary to previous findings with other exercise modalities, priming exercise does not alter kinetics during high-intensity treadmill running, at least in physically active young subjects. We speculate that the relatively fast kinetics and the relatively small slow component in the control (‘un-primed’) condition negated any enhancement of kinetics by priming exercise in this exercise modality
Factors influencing the life cycle burdens of the recovery of energy from residual municipal waste
A life cycle assessment was carried out to assess a selection of the factors influencing the environmental impacts and benefits of incinerating the fraction of municipal waste remaining after source-separation for reuse, recycling, composting or anaerobic digestion. The factors investigated were the extent of any metal and aggregate recovery from the bottom ash, the thermal efficiency of the process, and the conventional fuel for electricity generation displaced by the power generated. The results demonstrate that incineration has significant advantages over landfill with lower impacts from climate change, resource depletion, acidification, eutrophication human toxicity and aquatic ecotoxicity. To maximise the benefits of energy recovery, metals, particularly aluminium, should be reclaimed from the residual bottom ash and the energy recovery stage of the process should be as efficient as possible. The overall environmental benefits/burdens of energy from waste also strongly depend on the source of the power displaced by the energy from waste, with coal giving the greatest benefits and combined cycle turbines fuelled by natural gas the lowest of those considered. Regardless of the conventional power displaced incineration presents a lower environmental burden than landfill
Methane emissions from trees planted on a closed landfill site
Trees have morphological adaptations that allow methane (CH4) generated below ground to bypass oxidation in aerobic surface soils. This natural phenomenon however has not been measured in a landfill context where planted trees may alter the composition and magnitude of CH4 fluxes from the surface. To address this research gap, we measured tree stem and soil greenhouse gas (GHG) emissions (CH4 and CO2) from a closed UK landfill and comparable natural site, using an off-axis integrated cavity output spectroscopy analyser and flux chambers. Analyses showed average CH4 stem fluxes from the landfill and non-landfill sites were 31.8 ± 24.4 µg m–2 h–1 and –0.3 ± 0.2 µg m–2 h–1, respectively. The landfill site showed seasonal patterns in CH4 and CO2 stem emissions, but no significant patterns were observed in CH4 and CO2 fluxes at different stem heights or between tree species. Tree stem emissions accounted for 39% of the total CH4 surface flux (7% of the CO2); a previously unknown contribution that should be included in future carbon assessments
Nitrous oxide emissions from trees planted on a closed landfill site
Trees growing in natural and managed environments have the capacity to act as conduits for the transport of greenhouse gases produced belowground to the atmosphere. Nitrous oxide (N2O) emissions have been observed from tree stems in natural ecosystems but have not yet been measured in the context of forested former landfill sites. This research gap was addressed by an investigation quantifying stem and soil N2O emissions from a closed UK landfill and a comparable natural site. Measurements were made by using flux chambers and gas chromatography over a four-month period. Analyses showed that the average N2O stem fluxes from the landfill and non-landfill sites were 0.63 ± 0.06 μg –2 h–1 and 0.26 ± 0.05 μg m–2 h–1, respectively. The former landfill site showed seasonal patterns in N2O stem emissions and decreasing N2O fluxes with increased stem sampling position above the forest floor. Tree stem emissions accounted for 1% of the total landfill N2O surface flux, which is lower than the contribution of stem fluxes to the total surface flux in dry and flooded boreal forests
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