| 1. |
- Aljaradin, Mohammad, et al.
(författare)
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Current situation of municipal solid waste landfills in Jordan
- 2011
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 31:8, s. 1897-1898
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Jordan has seen a large increase in inhabitants over the past five decades as a result of a high population growth rate and forced migrations. Economic and cultural development has improved the standard of living and changed consumer habits, resulting in an increase in the volume of municipal solid waste (MSW) over time. The rate of production of MSW has been estimated at about 1,964,284 ton annually with an average generation rate of 0.95 kg/ cap/day in urban and 0.85 kg/cap/day in rural areas (SWEEP, 2010) and is expected to reach 2.5 million ton by 2015. The major fraction of MSW composition is organic (Fig. 1), which implies a high moisture content value, as expected in a developing country where food is the major component of the solid waste stream (Abu Qdais, 2007). About 86% of the MSW is decomposable and recyclable, while the remainder is inert matter. The solid waste volume is still increasing at high rates due to the rapid population increase as well as the change in living standards and consumption patterns.
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| 2. |
- Andersson, S., et al.
(författare)
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Sulfur recirculation for increased electricity production in Waste-to-Energy plants
- 2014
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 34:1, s. 67-78
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Goteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 degrees C and 525 degrees C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 degrees C with sulfur recirculation in operation were similar or lower compared to those measured at 450 degrees C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion.
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| 3. |
- Andreas, Lale, et al.
(författare)
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Steel slags in a landfill top cover : Experiences from a full-scale experiment
- 2014
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 34:3, s. 692-701
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Tidskriftsartikel (refereegranskat)abstract
- A full scale field study has been carried out in order to test and evaluate the use of slags from high-alloy steel production as the construction materials for a final cover of an old municipal landfill. Five test areas were built using different slag mixtures within the barrier layer (liner). The cover consisted of a foundation layer, a liner with a thickness of 0.7 m, a drainage layer of 0.3 m, a protection layer of 1.5 m and a vegetation layer of 0.25 m. The infiltration varied depending on the cover design used, mainly the liner recipe but also over time and was related to seasons and precipitation intensity. The test areas with liners composed of 50% electric arc furnace (EAF) slag and 50% cementitious ladle slag (LS) on a weight basis and with a proper consistence of the protection layer were found to meet the Swedish infiltration criteria of ⩽50 l (m2 a)−1 for final covers for landfills for non-hazardous waste: the cumulative infiltration rates to date were 44, 19 and 0.4 l (m2 a)−1 for A1, A4 and A5, respectively. Compared to the precipitation, the portion of leachate was always lower after the summer despite high precipitation from June to August. The main reason for this is evapotranspiration but also the fact that the time delay in the leachate formation following a precipitation event has a stronger effect during the shorter summer sampling periods than the long winter periods. Conventional techniques and equipment can be used but close cooperation between all involved partners is crucial in order to achieve the required performance of the cover. This includes planning, method and equipment testing and quality assurance.
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| 4. |
- Arm, Maria, et al.
(författare)
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Technical environmental long-term properties of industrial residues : summary of field and laboratory investigations
- 2011
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 31:1, s. 101-107
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, use of industrial residues is still hindered by concern for their long-term properties. A three-year research project was therefore initiated aiming to (1) identify the crucial processes of ageing related to the usefulness of residues in roads; (2) investigate the consequences of these processes for technical and environmental properties of the residues, and (3) propose a method for accelerated ageing to predict the long-term properties. This paper gives an overview of the project methodology, a summary of the test results and references to papers where further details are given. The project, running through 2006-2008, compared naturally aged samples of two residues used as sub-bases in existing asphalt paved roads with samples of fresh residues from producers' piles. Steel slag of electric arc furnace (EAF) type and municipal solid waste incinerator (MSWI) bottom ash were chosen. The samples were thoroughly characterised in order to identify which ageing processes had been crucial. The results showed that: - Bottom ash from the pavement edge was more aged than bottom ash from the road centre. However, no difference in pH was found, instead the differences were caused by differences in water exposure. - Steel slag from the pavement edge showed traces of carbonation and leaching processes, whereas slag from the road centre was identical to fresh slag. - Water exposure to the subbase materials after ten years in an asphalt paved road was calculated to less than 0.1–0.5 litres per kg. - Ageing reactions in steel slag and MSWI bottom ash, ready for use, were too small to be verified by laboratory measurement of deformation properties under loaded conditions. An accelerated ageing test for steel slag was set up to achieve the carbonation (decrease in pH) and leaching that was observed in the pavement edge material. An accelerated ageing test for bottom ash was set up to achieve the pozzolan reactions that were observed in SEM analyses of in situ specimens. It is recommended to use uncrushed particles when properties of aged material are studied, in order to preserve the original particle surfaces.
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| 5. |
- Bernstad, Anna, et al.
(författare)
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A life cycle approach to the management of household food waste - A Swedish full-scale case study.
- 2011
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 31, s. 1879-1896
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Tidskriftsartikel (refereegranskat)abstract
- Environmental impacts from incineration, decentralised composting and centralised anaerobic digestion of solid organic household waste are compared using the EASEWASTE LCA-tool. The comparison is based on a full scale case study in southern Sweden and used input-data related to aspects such as source-separation behaviour, transport distances, etc. are site-specific. Results show that biological treatment methods - both anaerobic and aerobic, result in net avoidance of GHG-emissions, but give a larger contribution both to nutrient enrichment and acidification when compared to incineration. Results are to a high degree dependent on energy substitution and emissions during biological processes. It was seen that if it is assumed that produced biogas substitute electricity based on Danish coal power, this is preferable before use of biogas as car fuel. Use of biogas for Danish electricity substitution was also determined to be more beneficial compared to incineration of organic household waste. This is a result mainly of the use of plastic bags in the incineration alternative (compared to paper bags in the anaerobic) and the use of biofertiliser (digestate) from anaerobic treatment as substitution of chemical fertilisers used in an incineration alternative. Net impact related to GWP from the management chain varies from a contribution of 2.6kg CO(2)-eq/household and year if incineration is utilised, to an avoidance of 5.6kg CO(2)-eq/household and year if choosing anaerobic digestion and using produced biogas as car fuel. Impacts are often dependent on processes allocated far from the control of local decision-makers, indicating the importance of a holistic approach and extended collaboration between agents in the waste management chain.
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| 6. |
- Bernstad, Anna
(författare)
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Household food waste separation behavior and the importance of convenience.
- 2014
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 34:7, s. 1317-1323
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Tidskriftsartikel (refereegranskat)abstract
- Two different strategies aiming at increasing household source-separation of food waste were assessed through a case-study in a Swedish residential area (a) use of written information, distributed as leaflets amongst households and (b) installation of equipment for source-segregation of waste with the aim of increasing convenience food waste sorting in kitchens. Weightings of separately collected food waste before and after distribution of written information suggest that this resulted in neither a significant increased amount of separately collected food waste, nor an increased source-separation ratio. After installation of sorting equipment in households, both the amount of separately collected food waste as well as the source-separation ratio increased vastly. Long-term monitoring shows that results where longstanding. Results emphasize the importance of convenience and existence of infrastructure necessary for source-segregation of waste as important factors for household waste recycling, but also highlight the need of addressing these aspects where waste is generated, i.e. already inside the household.
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| 7. |
- Bernstad, Anna, et al.
(författare)
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Need for improvements in physical pretreatment of source-separated household food waste.
- 2013
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 33:3, s. 746-754
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to investigate the efficiency in physical pretreatment processes of source-separated solid organic household waste. The investigation of seventeen Swedish full-scale pretreatment facilities, currently receiving separately collected food waste from household for subsequent anaerobic digestion, shows that problems with the quality of produced biomass and high maintenance costs are common. Four full-scale physical pretreatment plants, three using screwpress technology and one using dispergation technology, were compared in relation to resource efficiency, losses of nitrogen and potential methane production from biodegradable matter as well as the ratio of unwanted materials in produced biomass intended for wet anaerobic digestion. Refuse generated in the processes represent 13-39% of TS in incoming wet waste. The methane yield from these fractions corresponds to 14-36Nm(3)/ton separately collected solid organic household waste. Also, 13-32% of N-tot in incoming food waste is found in refuse. Losses of both biodegradable material and nutrients were larger in the three facilities using screwpress technology compared to the facility using dispersion technology.(1) Thus, there are large potentials for increase of both the methane yield and nutrient recovery from separately collected solid organic household waste through increased efficiency in facilities for physical pretreatment. Improved pretreatment processes could thereby increase the overall environmental benefits from anaerobic digestion as a treatment alternative for solid organic household waste.
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| 8. |
- Bernstad, Anna, et al.
(författare)
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Property-close source separation of hazardous waste and waste electrical and electronic equipment - A Swedish case study.
- 2011
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 31, s. 536-543
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Tidskriftsartikel (refereegranskat)abstract
- Through an agreement with EEE producers, Swedish municipalities are responsible for collection of hazardous waste and waste electrical and electronic equipment (WEEE). In most Swedish municipalities, collection of these waste fractions is concentrated to waste recycling centres where households can source-separate and deposit hazardous waste and WEEE free of charge. However, the centres are often located on the outskirts of city centres and cars are needed in order to use the facilities in most cases. A full-scale experiment was performed in a residential area in southern Sweden to evaluate effects of a system for property-close source separation of hazardous waste and WEEE. After the system was introduced, results show a clear reduction in the amount of hazardous waste and WEEE disposed of incorrectly amongst residual waste or dry recyclables. The systems resulted in a source separation ratio of 70wt% for hazardous waste and 76wt% in the case of WEEE. Results show that households in the study area were willing to increase source separation of hazardous waste and WEEE when accessibility was improved and that this and similar collection systems can play an important role in building up increasingly sustainable solid waste management systems.
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| 9. |
- Bernstad, Anna, et al.
(författare)
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Review of comparative LCAs of food waste management systems - Current status and potential improvements.
- 2012
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456.
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-five comparative cycle assessments (LCAs) addressing food waste treatment were reviewed, including the treatment alternatives landfill, thermal treatment, compost (small and large scale) and anaerobic digestion. The global warming potential related to these treatment alternatives varies largely amongst the studies. Large differences in relation to setting of system boundaries, methodological choices and variations in used input data were seen between the studies. Also, a number of internal contradictions were identified, many times resulting in biased comparisons between alternatives. Thus, noticed differences in global warming potential are not found to be a result of actual differences in the environmental impacts from studied systems, but rather to differences in the performance of the study. A number of key issues with high impact on the overall global warming potential from different treatment alternatives for food waste were identified through the use of one-way sensitivity analyses in relation to a previously performed LCA of food waste management. Assumptions related to characteristics in treated waste, losses and emissions of carbon, nutrients and other compounds during the collection, storage and pretreatment, potential energy recovery through combustion, emissions from composting, emissions from storage and land use of bio-fertilizers and chemical fertilizers and eco-profiles of substituted goods were all identified as highly relevant for the outcomes of this type of comparisons. As the use of LCA in this area is likely to increase in coming years, it is highly relevant to establish more detailed guidelines within this field in order to increase both the general quality in assessments as well as the potentials for cross-study comparisons.
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| 10. |
- Bernstad, Anna, et al.
(författare)
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Separate collection of household food waste for anaerobic degradation - Comparison of different techniques from a systems perspective.
- 2012
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Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 32:5, s. 806-815
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Tidskriftsartikel (refereegranskat)abstract
- Four systems for household food waste collection are compared in relation the environmental impact categories eutrophication potential, acidification potential, global warming potential as well as energy use. Also, a hotspot analysis is performed in order to suggest improvements in each of the compared collection systems. Separate collection of household food waste in paper bags (with and without drying prior to collection) with use of kitchen grinders and with use of vacuum system in kitchen sinks were compared. In all cases, food waste was used for anaerobic digestion with energy and nutrient recovery in all cases. Compared systems all resulted in net avoidance of assessed environmental impact categories; eutrophication potential (-0.1 to -2.4kg NO(3)(-)eq/ton food waste), acidification potential (-0.4 to -1.0kg SO(2)(-)eq/ton food waste), global warming potential (-790 to -960kg CO(2)(-)eq/ton food waste) and primary energy use (-1.7 to -3.6GJ/ton food waste). Collection with vacuum system results in the largest net avoidence of primary energy use, while disposal of food waste in paper bags for decentralized drying before collection result in a larger net avoidence of global warming, eutrophication and acidification. However, both these systems not have been taken into use in large scale systems yet and further investigations are needed in order to confirm the outcomes from the comparison. Ranking of scenarios differ largely if considering only emissions in the foreground system, indicating the importance of taking also downstream emissions into consideration when comparing different collection systems. The hot spot identification shows that losses of organic matter in mechanical pretreatment as well as tank connected food waste disposal systems and energy in drying and vacuum systems reply to the largest impact on the results in each system respectively.
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