| 1. |
- Alvarez, Rene, et al.
(author)
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Anaerobic co-digestion of aquatic flora and quinoa with manures from Bolivian Altiplano
- 2008
-
In: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 28:10, s. 1933-1940
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Journal article (peer-reviewed)abstract
- Quinoa stalk (Chenopodium quinoa Willd.) from agricultural crop residue, totora (Schoenoplectus tatora) and o-macrophytes (aquatic flora) from Lake Titicaca (on the Bolivian Altiplano) were studied in a wet anaerobic co-digestion process together with manure front llama, cow and sheep. Anaerobic semi-continuous experiments were performed in (10) 2-1 reactors at a temperature of 25 degrees C with 30 days of hydraulic retention time (HRT) and ail organic loading rate (OLR) of 1.8 kg VS m(-3) d(-1). Totora was found to be the best co-substrate. In mixture ratios of 1:1 (VS basis), it increased the biogas productivity by 130% for llama manure, 60% for cow manure, and 40% for sheep manure. It was possible to use up to 58% (VS basis) of totora in the substrate. Higher concentrations (including pure totora) could not be digested, as that caused acidification problems similar to those caused by other lignocellulosic materials. When quinoa and o-macrophytes were used as co-substrates, the increase in biogas productivity was slightly less. However, these co-substrates did not cause any operational problems. An additional advantage of quinoa and o-macrophytes was that they could be used in any proportion (even in pure form) without causing any destabilization problems in the anaerobic digestion process. (C) 2007 Elsevier Ltd. All rights reserved.
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| 2. |
- Björklund, Anna, et al.
(author)
-
Life cycle assessment of a national policy proposal - The case of a Swedish waste incineration tax
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:8, s. 1046-1058
-
Journal article (peer-reviewed)abstract
- At the core of EU and Swedish waste policy is the so-called waste hierarchy, according to which waste should first be prevented, but should otherwise be treated in the following order of prioritisation: reuse, recycling when environmentally motivated, energy recovery, and last landfilling. Some recent policy decisions in Sweden aim to influence waste management in the direction of the waste hierarchy. In 2001 a governmental commission assessed the economic and environmental impacts of introducing a weight-based tax on waste incineration, the purpose of which would be to encourage waste reduction and increase materials recycling and biological treatments This paper presents the results of a life cycle assessment (LCA) of the waste incineration tax proposal. It was done in the context of a larger research project concerning the development and testing of a framework for Strategic Environmental Assessment (SEA). The aim of this paper is to assess the life cycle environmental impacts of the waste incineration tax proposal, and to investigate whether there are any possibilities of more optimal design of such a tax. The proposed design of the waste incineration tax results in increased recycling, but only in small environmental improvements. A more elaborate tax design is suggested, in which the tax level would partly be related to the fossil carbon content of the waste.
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| 3. |
- Cui, Jirang, et al.
(author)
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Characterization of shredded television scrap and implications for materials recovery
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:3, s. 415-424
-
Journal article (peer-reviewed)abstract
- Characterization of TV scrap was carried out by using a variety of methods, such as chemical analysis, particle size and shape analysis, liberation degree analysis, thermogravimetric analysis, sink-float test, and IR spectrometry. A comparison of TV scrap, personal computer scrap, and printed circuit board scrap shows that the content of non-ferrous metals and precious metals in TV scrap is much lower than that in personal computer scrap or printed circuit board scrap. It is expected that recycling of TV scrap will not be cost-effective by utilizing conventional manual disassembly. The result of particle shape analysis indicates that the non-ferrous metal particles in TV scrap formed as a variety of shapes; it is much more heterogeneous than that of plastics and printed circuit boards. Furthermore, the separability of TV scrap using density-based techniques was evaluated by the sink-float test. The result demonstrates that a high recovery of copper could be obtained by using an effective gravity separation process. Identification of plastics shows that the major plastic in TV scrap is high impact polystyrene. Gravity separation of plastics may encounter some challenges in separation of plastics from TV scrap because of specific density variations.
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| 4. |
- Dahlén, Lisa, et al.
(author)
-
Comparison of different collection systems for sorted household waste in Sweden
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:10, s. 1298-1305
-
Journal article (peer-reviewed)abstract
- Composition and quantity per person of municipal solid waste (MSW) have been analyzed in six municipalities in southern Sweden with similar socio-economic conditions but with different collection systems. Samples of residual waste have been sorted, classified and weighed in 21 categories during 26 analyses that took place from 1998-2004. Collection data of the total waste flow, including source sorted recycling materials, in the same area have been compiled and compared. Multivariate data analyses have been applied. Weight-based billing reduced delivered amounts of residual household waste by 50%, but it is unknown to what extent improper material paths had developed. With curbside collection more metal, plastic and paper packaging was separated and left to recycling. When separate collection of biodegradables was included in the curbside system, the overall sorting of dry recyclables increased. The large uncertainty associated with waste composition analyses makes it difficult to draw strong conclusions regarding the effects on specific recyclables or the changes in the composition of the residual waste.
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| 5. |
- Dahlén, Lisa, et al.
(author)
-
Inconsistent pathways of household waste
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29:6, s. 1798-1806
-
Journal article (peer-reviewed)abstract
- The aim of this study was to provide policy-makers and waste management planners with information about how recycling programs affect the quantities of specific materials recycled and disposed of. Two questions were addressed: which factors influence household waste generation and pathways? and how reliable are official waste data? Household waste flows were studied in 35 Swedish municipalities, and a wide variation in the amount of waste per capita was observed. When evaluating the effect of different waste collection policies, it was found to be important to identify site-specific factors influencing waste generation. Eleven municipal variables were investigated in an attempt to explain the variation. The amount of household waste per resident was higher in populous municipalities and when net commuting was positive. Property-close collection of dry recyclables led to increased delivery of sorted metal, plastic and paper packaging. No difference was seen in the amount of separated recyclables per capita when weight-based billing for the collection of residual waste was applied, but the amount of residual waste was lower. Sixteen sources of error in official waste statistics were identified and the results of the study emphasize the importance of reliable waste generation and composition data to underpin waste management policies.
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| 6. |
- Dahlén, Lisa, et al.
(author)
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Methods for household waste composition studies
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:7, s. 1100-1112
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Journal article (peer-reviewed)abstract
- The question is how to conduct household waste composition studies. The review is divided into three parts: overview of known methods, sampling theory, and the waste components. Twenty methods are listed and commented on. There is no adopted, working international standard. In accordance with Pierre Gy’s Theory of Sampling, the seven types of sampling errors, when collecting and splitting solid samples, are described and commented on in relation to sampling of household solid waste. It is concluded that the most crucial choices in household waste composition studies are: to divide the investigation into relevant number and types of strata; to decide the required sample size and number of samples; to choose the sampling location, i.e., sampling at household level or sampling from loads of waste collection vehicles; and to choose the type and number of waste component categories to be investigated. Various classifications of household waste components used in composition studies are listed and discussed. Difficulties and weaknesses of the reviewed methods are discussed and concluded in suggested questions for further research.
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| 7. |
- Davidsson, Åsa, et al.
(author)
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Co-digestion of grease trap sludge and sewage sludge.
- 2008
-
In: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 28:6, s. 986-992
-
Journal article (peer-reviewed)abstract
- Redirection of organic waste, from landfilling or incineration, to biological treatment such as anaerobic digestion is of current interest in the Malmö-Copenhagen region. One type of waste that is expected to be suitable for anaerobic digestion is sludge from grease traps. Separate anaerobic digestion of this waste type and co-digestion with sewage sludge were evaluated. The methane potential was measured in batch laboratory tests, and the methane yield was determined in continuous pilot-scale digestion. Co-digestion of sludge from grease traps and sewage sludge was successfully performed both in laboratory batch and continuous pilot-scale digestion tests. The addition of grease trap sludge to sewage sludge digesters was seen to increase the methane yield of 9-27% when 10-30% of sludge from grease traps (on VS-basis) was added. It was also seen that the grease trap sludge increases the methane yield without increasing the sludge production. Single-substrate digestion of grease trap sludge gave high methane potentials in batch tests, but could not reach stable methane production in continuous digestion.
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| 8. |
- Davidsson, Åsa, et al.
(author)
-
Methane yield in source-sorted organic fraction of municipal solid waste
- 2007
-
In: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 27:3, s. 406-414
-
Journal article (peer-reviewed)abstract
- Treating the source-separated organic fraction of municipal solid waste (SS-OFMSW) by anaerobic digestion is considered by many municipalities in Europe as an environmentally friendly means of treating organic waste and simultaneously producing methane gas. Methane yield can be used as a parameter for evaluation of the many different systems that exist for sorting and pre-treating waste. Methane yield from the thermophilic pilot scale digestion of 17 types of domestically SS-OFMSW originating from seven full-scale sorting systems was found. The samples were collected during I year using worked-out procedures tested statistically to ensure representative samples. Each waste type was identified by its origin and by pre-sorting, collection and pre-treatment methods. In addition to the pilot scale digestion, all samples were examined by chemical analyses and methane potential measurements. A VS-degradation rate of around 80% and a methane yield of 300-400 Nm(3) CH4/ton VSin were achieved with a retention time of 15 days, corresponding to similar to 70% of the methane potential. The different waste samples gave minor variation in chemical composition and thus also in methane yield and methane potential. This indicates that sorting and collection systems in the present study do not significantly affect the amount of methane produced per VS treated.
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| 9. |
- Ecke, Holger, et al.
(author)
-
Mobility of organic carbon from incineration residues
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:8, s. 1301-1309
-
Journal article (peer-reviewed)abstract
- Dissolved organic carbon (DOC) may affect the transport of pollutants from incineration residues when landfilled or used in geotechnical construction. The leaching of dissolved organic carbon (DOC) from municipal solid waste incineration (MSWI) bottom ash and air pollution control residue (APC) from the incineration of waste wood was investigated. Factors affecting the mobility of DOC were studied in a reduced 26-1 experimental design. Controlled factors were treatment with ultrasonic radiation, full carbonation (addition of CO2 until the pH was stable for 2.5 h), liquid-to-solid (L/S) ratio, pH, leaching temperature and time. Full carbonation, pH and the L/S ratio were the main factors controlling the mobility of DOC in the bottom ash. Approximately 60 weight-% of the total organic carbon (TOC) in the bottom ash was available for leaching in aqueous solutions. The L/S ratio and pH mainly controlled the mobilization of DOC from the APC residue. About 93 weight-% of TOC in the APC residue was, however, not mobilized at all, which might be due to a high content of elemental carbon. Using the European standard EN 13 137 for determination of total organic carbon (TOC) in MSWI residues is inappropriate. The results might be biased due to elemental carbon. It is recommended to develop a TOC method distinguishing between organic and elemental carbon.
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| 10. |
- Ekvall, Tomas, et al.
(author)
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What life-cycle assessment does and does not do in assessments of waste management
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:8, s. 989-996
-
Journal article (peer-reviewed)abstract
- In assessments of the environmental impacts of waste management, life-cycle assessment (LCA) helps expanding the perspective beyond the waste management system. This is important, since the indirect environmental impacts caused by surrounding systems, such as energy and material production, often override the direct impacts of the waste management system itself. However, the applicability of LCA for waste management planning and policy-making is restricted by certain limitations, some of which are characteristics inherent to LCA methodology as such, and some of which are relevant specifically in the context of waste management. Several of them are relevant also for other types of systems analysis. We have identified and discussed such characteristics with regard to how they may restrict the applicability of LCA in the context of waste management. Efforts to improve LCA with regard to these aspects are also described. We also identify what other tools are available for investigating issues that cannot be adequately dealt with by traditional LCA models, and discuss whether LCA methodology should be expanded rather than complemented by other tools to increase its scope and applicability.
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| 11. |
- Finnveden, Göran, et al.
(author)
-
Flexible and robust strategies for waste management in Sweden
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:8, s. s1-S8
-
Journal article (peer-reviewed)abstract
- Treatment of solid waste continues to be on the political agenda. Waste disposal issues are often viewed from an environmental perspective, but economic and social aspects also need to be considered when deciding on waste strategies and policy instruments. The aim of this paper is to suggest flexible and robust strategies for waste management in Sweden, and to discuss different policy instruments. Emphasis is on environmental aspects, but social and economic aspects are also considered. The results show that most waste treatment methods have a role to play in a robust and flexible integrated waste management system, and that the waste hierarchy is valid as a rule of thumb from an environmental perspective. A review of social aspects shows that there is a general willingness among people to source separate wastes. A package of policy instruments can include landfill tax, an incineration tax which is differentiated with respect to the content of fossil fuels and a weight based incineration tax, as well as support to the use of biogas and recycled materials.
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| 12. |
- Furtenback, Örjan
(author)
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Demand for waste as fuel in the swedish district heating sector: A production function approach
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29, s. 285-292
-
Journal article (peer-reviewed)abstract
- This paper evaluates inter-fuel substitution in the Swedish district heating industry by analyzing almost all the district heating plants in Sweden in the period 1989-2003, specifically those plants incinerating waste. A multi-output plant-specific production function is estimated using panel data methods. A procedure for weighting the elasticities of factor demand to produce a single matrix for the whole industry is introduced. The price of waste is assumed to increase in response to the energy and CO(2) tax on waste-to-energy incineration that was introduced in Sweden on 1 July 2006. Analysis of the plants involved in waste incineration indicates that an increase in the net price of waste by 10% is likely to reduce the demand for waste by 4.2%, and increase the demand for bio-fuels, fossil fuels. other fuels and electricity by 5.5%, 6.0%, 6.0% and 6.0%, respectively. (C) 2008 Elsevier Ltd. All rights reserved.
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| 13. |
- Gunnarsson, Carina C., et al.
(author)
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Water hyacinths as a resource in agriculture and energy production : a literature review
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:1, s. 117-129
-
Research review (peer-reviewed)abstract
- Water hyacinths are becoming a problem in lakes, ponds and waterways in many parts of the world. This paper contains a literature study of different ways to use water hyacinths, mainly in agricultural or alternative energy systems. The literature review indicated that water hyacinths can be rich in nitrogen, up to 3.2% of DM and have a C/N ratio around 15. The water hyacinth can be used as a substrate for compost or biogas production. The sludge from the biogas process contains almost all of the nutrients of the substrate and can be used as a fertiliser. The use of water hyacinth compost on different crops has resulted in improved yields. The high protein content makes the water hyacinth possible to use as fodder for cows, goats, sheep and chickens. Water hyacinth, due to its abundant growth and high concentrations of nutrients, has a great potential as fertiliser for the nutrient deficient soils of Africa and as feed for livestock. Applying the water hyacinths directly without any other processing than sun drying, seems to be the best alternative in small-scale use due to the relatively small losses of nutrients and workload required. To meet the ever-growing energy demand, biogas production could be one option but it requires investments and technological skills that would impose great problems in developing countries where the water hyacinth is often found. Composting as an alternative treatment has the advantage of a product that is easy to work into the soil compared with dried water hyacinths, because of the decomposed structure. Harvesting and transport of water hyacinths can be conducted manually on a small scale and does not require a new harvesting technique to be introduced. Transporting of fresh water hyacinths means, if used as fertiliser in amounts large enough to enhance or effect crop growth, an unreasonably large labour requirement. Based on the labour need and the limited access to technology, using dried water hyacinths, as green manure is a feasible alternative in many developing countries. (c) 2006 Elsevier Ltd. All rights reserved.
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| 14. |
- Hage, Olle, et al.
(author)
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An econometric analysis of regional differences in household waste collection : the case of plastic packaging waste in Sweden
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:10, s. 1720-1731
-
Journal article (peer-reviewed)abstract
- The Swedish producer responsibility ordinance mandates producers to collect and recycle packaging materials. This paper investigates the main determinants of collection rates of household plastic packaging waste in Swedish municipalities. This is done by the use of a regression analysis based on cross-sectional data for 252 Swedish municipalities. The results suggest that local policies, geographic/demographic variables, socio-economic factors and environmental preferences all help explain inter-municipality collection rates. For instance, the collection rate appears to be positively affected by increases in the unemployment rate, the share of private houses, and the presence of immigrants (unless newly arrived) in the municipality. The impacts of distance to recycling industry, urbanization rate and population density on collection outcomes turn out, though, to be both statistically and economically insignificant. A reasonable explanation for this is that the monetary compensation from the material companies to the collection entrepreneurs vary depending on region and is typically higher in high-cost regions. This implies that the plastic packaging collection in Sweden may be cost ineffective. Finally, the analysis also shows that municipalities that employ weight-based waste management fees generally experience higher collection rates than those municipalities in which flat and/or volume-based fees are used.
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| 15. |
- Hansen, Trine Lund, et al.
(author)
-
Composition of source-sorted municipal organic waste collected in Danish cities
- 2007
-
In: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 27:4, s. 510-518
-
Journal article (peer-reviewed)abstract
- Source-sorted municipal organic waste from different dwelling types in five Danish cities was sampled during one year. The samples were from permanent, full-scale systems or temporary, experimental systems for collection of source-sorted municipal organic waste. Pre-treatment of the organic waste prior to biological treatment was used in all cities to remove foreign objects and provide size reduction. All sampling was performed after pre-treatment in order to obtain more homogeneous and representative samples. The sampling included both the pre-treated waste and the reject from the pre-treatment allowing for estimation of the composition of the original waste. A total of 40 waste samples were chemically characterised with respect to 15 parameters. The waste generally consisted of around 88% VS of which an average of 80% was easily degradable. The average content of N, P and K in the dry matter of the organic waste was 2.5%, 0.4% and 0.9%, respectively. A general analysis of variance was applied to show the influence of the collection system, dwelling type and annual season on the waste composition. The content of plastic and crude fibres in the waste differed the most among the samples, probably due to use of different bag types (plastic and paper) in the different collection systems. Variations in the ash content and the calorific value might be explained by differences in the sorting instructions (whether soil and cat litter are allowed in the organic fraction). Significant seasonal variations were seen for ash, S and Cl. Dwelling type showed no statistically significant influence on any waste components. A test for uniform distribution of the p-values from the analysis of variance (Kolmogorov-Smirnov test) showed that the overall composition of the collected waste was strongly affected by the collection system (city) and season, while dwelling type had no significant influence. (c) 2006 Elsevier Ltd. All rights reserved.
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| 16. |
- Hansen, Trine Lund, et al.
(author)
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Effects of pre-treatment technologies on quantity and quality of source-sorted municipal organic waste for biogas recovery
- 2007
-
In: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 27:3, s. 398-405
-
Journal article (peer-reviewed)abstract
- Source-sorted municipal organic waste collected from different dwelling types in five Danish cities and pre-treated at three different plants was sampled and characterized several times during one year to investigate the origin of any differences in composition of the pre-treated waste introduced by city, pre-treatment technology, dwelling type or annual season. The investigated pre-treatment technologies were screw press, disc screen and shredder + magnet. The average quantity of pre-treated organic waste (biomass) produced from the incoming waste varied between the investigated pre-treatment technologies: 59%, 66% and 98% wet weight, respectively (41%, 34% and 2% reject, respectively). The pre-treatment technologies showed differences with respect to distribution of the chemical components in the waste between the biomass and the rejected material (reject), especially for dry matter, ash, collection bag material (plastic or paper) and easily degradable organic matter. Furthermore, the particle size of the biomass was related to the pre-treatment technology. The content of plastic in the biomass depended both on the actual collection bag material used in the system and the pre-treatment technology. The sampled reject consisted mostly of organic matter. For cities using plastic bags for the source-separated organic waste, the expected content of plastic in the reject was up to 10% wet weight (in some cases up to 20%). Batch tests for methane potential of the biomass samples showed only minor variations caused by the factors city, pre-treatment technology, dwelling type and season when based on the VS content of the waste (overall average 459 STP m(3)/t VS). The amount of methane generated from 1 t of collected waste was therefore mainly determined by the efficiency of the chosen pre-treatment technology described by the mass distribution of the incoming waste between biomass and reject. (c) 2006 Elsevier Ltd. All rights reserved.
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| 17. |
- Hedman, Björn, et al.
(author)
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Emissions from small-scale energy production using co-combustion of biofuel and the dry fraction of household waste
- 2005
-
In: Waste Management. - New York, N.Y. : Pergamon. - 0956-053X .- 1879-2456. ; 25:3, s. 311-321
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Journal article (peer-reviewed)abstract
- In sparsely populated rural areas, recycling of household waste might not always be the most environmentally advantageous solution due to the total amount of transport involved. In this study, an alternative approach to recycling has been tested using efficient small-scale biofuel boilers for co-combustion of biofuel and high-energy waste. The dry combustible fraction of source-sorted household waste was mixed with the energy crop reed canary-grass (Phalaris Arundinacea L.), and combusted in both a 5-kW pilot scale reactor and a biofuel boiler with 140–180 kW output capacity, in the form of pellets and briquettes, respectively. The chlorine content of the waste fraction was 0.2%, most of which originated from plastics. The HCl emissions exceeded levels stipulated in new EU-directives, but levels of equal magnitude were also generated from combustion of the pure biofuel. Addition of waste to the biofuel did not give any apparent increase in emissions of organic compounds. Dioxin levels were close to stipulated limits. With further refinement of combustion equipment, small-scale co-combustion systems have the potential to comply with emission regulations.
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| 18. |
- Hedman, Björn, et al.
(author)
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PCDD/F in source-sorted waste fractions and emissions from their co-combustion with reed canary-grass
- 2007
-
In: Waste Management. - Oxford : Pergamon Press. - 0956-053X .- 1879-2456. ; 27:11, s. 1580-1592
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Journal article (peer-reviewed)abstract
- The dry combustible fraction of source-sorted household waste, including material that would otherwise be recycled, was mixed with the energy crop reed canary-grass (Phalaris arundinacea L.), and combusted as briquettes in 150 and 600 kW biofuel-boilers without advanced cleaning systems. The source-sorted waste was further sorted and characterized according to its material and chemical contents. The bulk of the waste’s chlorine content came from the non-package plastic fraction, whereas 90–95% of ∑PCDD/F (74–90% of WHO-TEQ) originated from the textile fraction. The sources of the dioxins in the waste fractions are discussed. The balance of dioxin levels was negative, i.e., the amounts of dioxins output in the flue gas were lower than those input in the fuel, except when there were operational disturbances in the combustion. In one of the combustion trials the total levels of dioxins in the flue-gas and ashes were also lower than the input levels. The use of additional cleaning equipment will be needed to ensure that emissions of dioxins and hydrochloric acid will be below legal limits.
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| 19. |
- Krook, Joakim, 1977-, et al.
(author)
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Swedish recovered wood waste: Linking regulation and contamination
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:3, s. 638-648
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Journal article (peer-reviewed)abstract
- In Sweden, large amounts of wood waste are generated annually from construction and demolition activities, but also from other discarded products such as packaging and furniture. A large share of this waste is today recovered and used for heat production. However, previous research has found that recovered wood waste (RWW) contains hazardous substances, which has significant implications for the environmental performance of recycling. Improved sorting is often suggested as a proper strategy to decrease such implications. In this study, we aim to analyse the impacts of waste regulation on the contamination of RWW. The occurrence of industrial preservative-treated wood, which contains several hazardous substances, was used as an indicator for contamination. First the management of RWW during 1995–2004 was studied through interviews with involved actors. We then determined the occurrence of industrial preservative-treated wood in RWW for that time period for each supplier (actor). From the results, it can be concluded that a substantially less contaminated RWW today relies on extensive source separation. The good news is that some actors, despite several obstacles for such upstream efforts, have already today proved capable of achieving relatively efficient separation. In most cases, however, the existing waste regulation has not succeeded in establishing strong enough incentives for less contaminated waste in general, nor for extensive source separation in particular. One important factor for this outcome is that the current market forces encourage involved actors to practice weak quality requirements and to rely on end-of-pipe solutions, rather than put pressure for improvements on upstream actors. Another important reason is that there is a lack of communication and oversight of existing waste regulations. Without such steering mechanisms, the inherent pressure from regulations becomes neutralized.
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| 20. |
- Kumpiene, Jurate, et al.
(author)
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Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments : a review
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:1, s. 215-225
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Journal article (peer-reviewed)abstract
- The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxyhydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays.
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| 21. |
- Lagerkvist, Anders
(author)
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Academic research on solid waste in Sweden 1994-2003
- 2006
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 26:3, s. 277-283
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Journal article (other academic/artistic)abstract
- A small desk survey was conducted in the spring of 2004 to get an overview on the development of waste research. The survey targeted the last 10 years of waste research at Swedish academic institutions trying to identify the total amount of research and trends over time with regard to issues, volume and distribution over academic disciplines. In the survey, only the theses written at major Swedish universities were considered. All post-graduate theses from major Swedish universities were reviewed. Data were obtained from the homepages and search engines of the various libraries as of May 13 2004. Altogether 90 theses were identified from nine universities, i.e., an average of 1 thesis per University per year. The results of the survey indicate that: (1) the academic waste research is very small in comparison to the R&D performed by the industry; there seems to be a lack of interaction between industry and academia; (2) waste research is slowly getting into established academic environments and gains in quantity and diversion over time; (3) in addition to being driven by environmental protection legislation, there also seems to be emerging more industry interest from a production perspective.
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| 22. |
- Lidelöw, Sofia, et al.
(author)
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Evaluation of leachate emissions from crushed rock and municipal solid waste incineration bottom ash used in road construction
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:10, s. 1356-1365
-
Journal article (peer-reviewed)abstract
- Three years of leachate emissions from municipal solid waste incineration bottom ash and crushed rock in a full-scale test road were evaluated. The impact of time, construction design, and climate on the emissions was studied, and the predicted release from standard leaching tests was compared with the measured release from the road. The main pollutants and their respective concentrations in leachate from the roadside slope were Al (12.8-85.3 mg l-1), Cr (2-125 μg l-1), and Cu (0.15-1.9 mg l-1) in ash leachate and Zn (1-780 μg l-1) in crushed rock leachate. From the ash, the initial Cl- release was high (≈20 g l-1). After three years, the amount of Cu and Cl- was in the same range in both leachates, while that of Al and Cr still was more than one order of magnitude higher in ash leachate. Generally, the release was faster from material in the uncovered slopes than below the pavement. Whether the road was asphalted or not, however, had minor impacts on the leachate quality. During rain events, diluted leachates with respect to, e.g., salts were observed. The leaching tests failed to simulate field leaching from the crushed rock, whereas better agreement was observed for the ash. Comparisons of constituent release from bottom ash and conventional materials solely based on such tests should be avoided.
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| 23. |
- Mahmoudkhani, Maryam, 1971, et al.
(author)
-
Evaluating two test methods used for characterizing leaching properties
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:1, s. 133-141
-
Journal article (peer-reviewed)abstract
- A standard leaching test method (EN 12457-3) was compared with a modified pHstat-column leaching test method with respect to leaching information obtained for aggregates composed of different alkaline solid wastes. In addition to a different experimental set-up, the major dissimilarity between the two test methods was the chemical equilibrium condition, i.e., in the first test the system approaches equilibrium while in the second test the system is far from equilibrium conditions. The leaching trends of sodium, calcium, chloride, sulfate and cadmium were studied. Results showed that these two test methods were comparable in respect to the total amount sodium and sulfate leached. It was also concluded that the two test methods provide different information for the constituents for which dissolution reaction is highly dependent on pH and other experimental conditions, e.g., flow rate. It was found that a batch test can be used in order to investigate the total amount leached, while a modified column-pHstat test generates more detailed results on leaching trends of some constituents.
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| 24. |
- Mellbo, Peter, et al.
(author)
-
Leaching of wood ash products aimed for spreading in forest floors : influence of method and L/S ratio
- 2008
-
In: Waste Management. - Elsevier : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:11, s. 2235-2244
-
Journal article (peer-reviewed)abstract
- Use of biofuels in the form of logging residues is increasing in the European countries. This intensive forestry, where entire trees are removed from the felling sites, may contribute to a negative nutrient balance in the forest soil. Recycling of ash from the combustion of clean wood fuel, sometimes in combination with limestone or additives/binders, back into the forest soil could maintain the soil nutrient reservoir intact. Before spreading ash, it is important to determine its contents and, particularly, its decomposition pattern using reliabl laboratory leaching tests. In this study, mineralogy and the leaching of Na, Ca, K, Mg, Mn, Al, Cu, Fe, P, and Zn from wood ash pellets and granules, produced both from green liquor sludge and fly ash, are examined by XRD and by subjecting these substances to three different laboratory leaching tests: upflow percolation (CEN/TS 14405), batch leaching (SS-EN12457), and a new Swedish leaching test using a magnetic stirrer. Mineral phases such as quartz, ettringite, calcite, gehlenite, and aphtitalite were identified in the ash granules and in the ash/green liquor sludge granules, by means of XRD. Six additional minerals were detected in the granules of ash only, and another six in the ash/green liquor sludge granules. At L/S 2, the batch leaching test resulted in the highest amounts of elements leached and the upflow percolation test the lowest. At L/S 10, both the batch leaching test and the upflow percolation test resulted in high amounts of elements leached. The batch leaching test at L/S 10 complies quite well with the percolation test and could be suitable for ash/green liquor sludge granule evaluation in daily practice. The magnetic stirrer test seems to underestimate the release potential of elements from granules. The batch test is simple to perform, and has the ability to dissolve 70–80% of the elements with the highest mobility from the materials under study.
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| 25. |
- Niwagaba, Charles, et al.
(author)
-
Bench-scale composting of source-separated human faeces for sanitation
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29, s. 585-589
-
Journal article (peer-reviewed)abstract
- In urine-diverting toilets, urine and faeces are collected separately so that nutrient content can be recycled unmixed. Faeces should be sanitised before use in agriculture fields due to the presence of possible enteric pathogens. Composting of human faeces with food waste was evaluated as a possible method for this treatment. Temperatures were monitored in three 78-L wooden compost reactors fed with faeces-to-food waste substrates (F:FW) in wet weight ratios of 1:0, 3:1 and 1:1, which were observed for approximately 20 days. To achieve temperatures higher than 15 degrees C above ambient, insulation was required for the reactors. Use of 25-mm thick styrofoam insulation around the entire exterior of the compost reactors and turning of the compost twice a week resulted in sanitising temperatures (>= 50 degrees C) to be maintained for 8 days in the F:FW =1:1 compost and for 4 days in the F:FW = 3:1 compost. In these composts, a reduction of > 3log(10) for E. coli and > 4log(10) for Enterococcus spp. was achieved. The F:FW = 1:0 compost, which did not maintain >= 50 degrees C for a sufficiently long period, was not sanitised, as the counts of E. coli and Enterococcus spp. increased between days 11 and 15. This research provides useful information on the design and operation of family-size compost units for the treatment of source-separated faeces and starchy food residues, most likely available amongst the less affluent rural/urban society in Uganda. (c) 2008 Elsevier Ltd. All rights reserved.
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| 26. |
- Niwagaba, Charles, et al.
(author)
-
Comparing microbial die-off in separately collected faeces with ash and sawdust additives
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29, s. 2214-2219
-
Journal article (peer-reviewed)abstract
- In a urine diversion dry toilet (UDDT), the urine and faeces are collected separately in order to recycle their nutrient content unmixed. In a UDDT, an additive e.g. lime, wood ash, dry soil or sawdust, depending on which one is easily accessed by the users, is usually sprinkled to the faeces after each defecation. The purpose of the additive is primarily to keep away the flies and odours and to contribute to primary treatment of the faeces. In this paper, ash and sawdust were applied separately to source-separated faeces during the collection phase, and then the die-off of indicators and pathogens in the mixtures was studied. The die-off of E. coli in the faeces/ash mixture was faster initially (first 7 days) compared to that achieved in the faeces/sawdust mixture even though the die-off achieved after 30-50 days was nearly similar for both mixtures. E. coli was not detected in faeces/ash after about 2 months, but was detected after 2 months in the faeces/sawdust mixture. Enterococcus spp. did not decrease below detection in faeces/ash or faeces/sawdust mixture but higher numbers (difference of about 2 logs) were detected at all times in faeces/sawdust than in faeces/ash mixture. The difference in the die-off in the mixtures of faeces/ash and faeces/sawdust was attributed to the differences in the characteristics of the additives, namely, high alkaline mineral content (giving high pH) and lower moisture content of ash compared to sawdust. It is recommended to increase use of ash as additive over sawdust in urine diversion dry toilets. (C) 2009 Elsevier Ltd. All rights reserved.
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| 27. |
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| 28. |
- Odlare, Monica, et al.
(author)
-
Changes in soil chemical and microbiological properties during 4 years of application of various organic residues
- 2008
-
In: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 28:7, s. 1246-1253
-
Journal article (peer-reviewed)abstract
- A 4-year field trial was established in eastern Sweden to evaluate the effects of organic waste on soil chemical and microbiological variables. A simple crop rotation with barley and oats was treated with either compost from household waste, biogas residue from household waste, anaerobically treated sewage sludge, pig manure, cow manure or mineral fertilizer. All fertilizers were amended in rates corresponding to 100 kg N ha-1 year-1. The effects of the different types of organic waste were evaluated by subjecting soil samples, taken each autumn 4 weeks after harvest, to an extensive set of soil chemical (pH, Org-C, Tot-N, Tot-P, Tot-S, P-AL, P-Olsen, K-AL, and some metals) and microbiological (B-resp, SIR, μSIR active and dormant microorganisms, PDA, μPDA, PAO, Alk-P and N-min) analyses. Results show that compost increased pH, and that compost as well as sewage sludge increased plant available phosphorus; however, the chemical analysis showed few clear trends over the 4 years and few clear relations to plant yield or soil quality. Biogas residues increased substrate induced respiration (SIR) and, compared to the untreated control amendment of biogas residues as well as compost, led to a higher proportion of active microorganisms. In addition, biogas residues increased potential ammonia oxidation rate (PAO), nitrogen mineralization capacity (N-min) as well as the specific growth rate constant of denitrifiers (μPDA). Despite rather large concentrations of heavy metals in some of the waste products, no negative effects could be seen on either chemical or microbiological soil properties. Changes in soil microbial properties appeared to occur more rapidly than most chemical properties. This suggests that soil microbial processes can function as more sensitive indicators of short-term changes in soil properties due to amendment of organic wastes.
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| 29. |
- Olsson, Susanna, et al.
(author)
-
Metal leaching from MSWI bottom ash as affected by salt or dissolved organic matter
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29:2, s. 506-512
-
Journal article (peer-reviewed)abstract
- In order to manage municipal solid waste incineration (MSWI) bottom ash safely, risk assessments, including the prediction of leaching under different field conditions, are necessary. In this study, the influence of salt or dissolved organic matter (DOM) in the influent on metal leaching from MSWI bottom ash was investigated in a column experiment. The presence of salt (0.1 M NaCI) resulted in a small increase of As leaching, whereas no impact on leachate concentration was found when lakewater DOM (35.1 mg/I dissolved organic carbon) was added. Most of the added DOM was retained within the material. Further, X-ray spectroscopy revealed that Cu(II) was the dominating form of Cu and that it probably Occurred as a CuO-type mineral. The CU2+ activity in the MSWI bottom ash leachate was most likely determined by the dissolution of CuO together with the formation of Cu-DOM complexes and possibly also by adsorption to (hydr)oxide minerals. The addition of lake DOM in the influent resulted in lower saturation indices for CuO in the leachates. which may be due to slow CuO dissolution kinetics in combination with strong Cu-DOM complexation.
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| 30. |
- Ore, Solvita, et al.
(author)
-
Toxicity of leachate from bottom ash in a road construction
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:11, s. 1626-1637
-
Journal article (peer-reviewed)abstract
- A test road constructed with municipal solid waste incineration (MSWI) bottom ash was monitored over a period of 36 months. Using chemical and toxicological characterisation, the environmental impact of leachates from bottom ash was evaluated and compared with leachates from gravel used as reference. Initial leaching of Cl, Cu, K, Na, NH4-N and TOC from bottom ash was of major concern. However, the quality of the bottom ash leachate approached that of the gravel leachate with time. Leachates from the two materials were compared regarding the concentration of pollutants using multivariate data analyses (MVDA). A standardized luminescent bacteria assay using Vibrio fischeri did not show any toxicity, most likely because saline contamination can mask the toxic response and stimulate luminescence in these marine bacteria. A mung bean assay using Phaseolus aureus revealed that the toxicity of bottom ash leachate collected at the very beginning of the experimental period (October 2001 and May 2002) might be attributed to the following components and their respective concentrations in mg l-1: Al (34.2-39.2), Cl (2914-16,446), Cu (0.48-1.92), K (197-847), Na (766-4180), NH4-N (1.80-8.47), total-N (12.0-18.5), and TOC (34.0-99.0). The P. aureus assay was judged as a promising environmental tool in assessing the toxicity of bottom ash leachate.
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| 31. |
- Ostman, M., et al.
(author)
-
Leachability and metal-binding capacity in ageing landfill material
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:1, s. 142-150
-
Journal article (peer-reviewed)abstract
- In order to study the stability of landfilled heavy metals, landfill material from a combined household and industrial waste landfill was aerated for 14 months to simulate the natural ageing processes as air slowly begins to penetrate the landfill mass. During aeration, the pH of the landfill material decreased from around 8.6 to 8.1 and the carbon content also decreased. In order to investigate the possible fate of metals in ageing landfills, a four-stage sequential extraction technique was applied. The ability of the materials to bind metal ions by electrostatic attractions and to form stronger complexes was studied separately. The amount of exchangeable cations, the capacity to bind metal ions by electrostatic attraction and the capacity of the landfill material to complex copper ions were increased by the aeration process. However, results from the sequential analysis showed an increased solubility of sulphur and some metals (Cd, Co, Cu, Ni and Zn). Equilibrium speciation models (Medusa) indicated that the organic matter deposit had a significant capacity to bind metal ions provided that pH was sufficiently high. However, as carbonates are consumed over time, the risk for metal mobility increases. Therefore, the landfills can become an environmental risk, depending on variations in the solubility of metal ions due to changes in pH, redox status and the availability of organic material.
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| 32. |
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| 33. |
- Pineau, J.L., et al.
(author)
-
Representativeness of an automobile shredder residue sample for a verification analysis
- 2005
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 25:7, s. 737-746
-
Journal article (peer-reviewed)abstract
- To apply a decision-making scheme using a statistical classification while conforming to the meaning of representativeness as defined by the US EPA, we propose an equation defining the representativeness of a sample. To utilize this equation, the batch must be homogenized. This requires analyzing the constitution and distribution heterogeneities. The equation relates the sample weight ms to its representativeness R either by a statistical approach or by a physical approach using the following equation:ms={4/(1-R)2}·[K+ke(1-2te)/te] In the equation, K and ke are the heterogeneity factors determined from a descriptive analysis. This equation is applicable to solid waste with majority constituents such as automobile shredder residue (ASR) and domestic waste. This analysis was applied to a sample of ASR in the framework of a verification for France. The results of the analysis showed that the sample weight must be at least 140 kg to have a representativeness of 90%.
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| 34. |
- Schnürer, Anna, et al.
(author)
-
Fungal survival during anaerobic digestion of organic household waste
- 2006
-
In: Waste Management. - Oxford, United Kingdom : Elsevier. - 0956-053X .- 1879-2456. ; 26:11, s. 1205-1211
-
Journal article (peer-reviewed)abstract
- Anaerobic digestion of organic waste yields energy rich biogas and retains nutrients (N, P, K, S, etc.) in a stabilised residue. For the residue to be used as a soil fertiliser, it must be free from pollutants and harmful microorganisms. Fungal survival during sanitation and anaerobic treatment of source-separated organic household waste and during aerobic storage of the residue obtained was investigated. Decimal reduction times were determined for inoculated fungi (Aspergillus flavus and Aspergillus fumigatus, Penicillium roqueforti, Rhizomucor pusillus, Thermoascus crustaceus and Thermomyces lanuginosus). Several different fungal species were found after waste sanitation treatment (70 degrees C, 1 h), with Aspergillus species dominating in non-inoculated waste. Anaerobic waste degradation decreased the diversity of fungal species for processes run at both 37 and 55 degrees C, but not total fungal colony forming units. Fungi surviving the mesophilic anaerobic digestion were mainly thermotolerant Talaromyces and Paecilomyces species. T crustaceus and T lanuginosus were the only inoculated fungi to survive the thermophilic anaerobic degradation process. Aerobic storage of both types of anaerobic residues for one month significantly decreased fungal counts.
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| 35. |
- Sundberg, Cecilia, et al.
(author)
-
Higher pH and faster decomposition in biowaste composting by increased aeration
- 2008
-
In: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 28:3, s. 518-526
-
Journal article (peer-reviewed)abstract
- Composting of source separated municipal biowaste has at several plants in Scandinavia been hampered by low pH. In this study the hypothesis that increased aeration would improve the process was tested in full-scale experiments at two large composting plants. The O2 concentrations were high (>15%) even at the low aeration rates, so the prevailing low pH was not due to an anaerobic process environment. In spite of this, increased aeration rates at the start of the process resulted in higher microbial activity, increased pH and a more stable compost product. At one plant the decomposition rate varied in proportion to the aeration rate, to the extent that the temperatures and O2 concentrations were similar during the early processes even though aeration rates varied between 10 and 50 m3/(h, m3 compost). However, increased aeration caused severe drying of the compost, but at one plant the addition of water was adequate to prevent drying. In conclusion, by increasing the aeration rates and adding water to compensate for drying, it was possible to shorten the time needed to produce a stable compost product and thus to increase the efficiency of the composting plants.
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| 36. |
- Svensson, Margareta, 1967-, et al.
(author)
-
Leaching of mercury-containing cement monoliths aged for one year
- 2008
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 28:3, s. 597-603
-
Journal article (peer-reviewed)abstract
- A directive from the Swedish Government states that waste containing more than 1% of mercury shall be permanently deposited. The stabilization of mercury by conversion to a sparingly soluble compound like the sulphide is crucial to ensure long-term immobilization in a permanent storage. Immobilization by the solidification/stabilization (S/S) method and possible formation of HgS from mercury oxide or elemental mercury by reaction with a sulphur source (S or FeS) is investigated by a modified version of the NEN 7345 Dutch tank-leaching test. The diffusion of mercury during 11 months from 1-year-old mercury containing monoliths of Portland and slag cement is demonstrated. In a geologic repository under conditions representative of deep granitic bedrock (bicarbonate buffered to pH 8.6), a favourable monolith combination is slag cement with addition of the iron sulphide troilite. The apparent diffusion coefficient of mercury is estimated.
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| 37. |
- Thurdin, Rickard T., et al.
(author)
-
Bio fuel ash in a road construction: Impact on soil solution chemistry
- 2006
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 26:6, s. 599-613
-
Journal article (peer-reviewed)abstract
- Limited natural resources and landfill space and increasing amounts of ash produced from incineration of bio fuel and solid wastes have created a demand for useful applications of ash of which road construction is one. Here the environmental impact of a fly ash layer in a reconstructed road was evaluated by studying the soil solution chemistry in the ash layer, at two depths in the soil below and at two depths in the ditch using a centrifugation drainage technique. The road was situated about 20 km west of Sollefteå, (63˚ 16� 33�N, 17˚12�52�E) in the middle of Sweden. Two years after the application of the ash the concentrations of zinc were increasing in the ash layer solutions while concentrations of cadmium were stabilising. Below the ash layer in the road an initial increase of the pH was observed and the concentrations of potassium, sulphate and cadmium showed an increase while copper and mercury showed decreasing concentrations in the road and the ditch soil solutions. The concentrations in the ditch soil solutions were generally much lower compared to the road. Concentrations of calcium in the ash layer solutions indicated that hardening had taken place.
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| 38. |
- Todorovic, Jelena, et al.
(author)
-
Demobilisation of critical contaminants in four typical waste-to-energy ashes by carbonation
- 2006
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 26:4, s. 430-441
-
Journal article (peer-reviewed)abstract
- Two bottom ashes, one air pollution control (APC) residue and one fly ash from three different Swedish municipal solid waste incineration (MSWI) plants were characterised regarding the leaching of environmentally relevant components. Characterisation was performed using a diffusion tank leaching test. The impact of carbonation on the release of eight critical components, i.e., Cl-, Cr, Cu, Mo, Pb, Sb, Se, and Zn, was assessed at a lab-scale and showed carbonation to have a more pronounced demobilising effect on critical components in bottom ashes than in APC residue and fly ash. From grate type incinerator bottom ash, the release of Cr decreased by 97%, by 63% for Cu and by 45% for Sb. In the investigated APC residue, the releases of Cr, Se and Pb were defined as critical, although they either remained unaffected or increased after carbonation. Cl- and remained mobile after carbonation in all investigated residues.
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| 39. |
- Toller, Susanna, et al.
(author)
-
Environmental assessment of incinerator residue utilisation
- 2009
-
In: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 29:7, s. 2071-2077
-
Journal article (peer-reviewed)abstract
- Incineration ashes may be treated either as a waste to be dumped in landfill, or as a resource that is suit able for re-use. In order to choose the best management scenario, knowledge is needed on the potential environmental impact that may be expected, including not only local, but also regional and global impact. In this study. A life cycle assessment (LCA) based approach Was Outlined for environmental assessment of incinerator residue utilisation, in which leaching of trace elements as well as other emissions to air and water and the use of resources were regarded as constituting the potential environmental impact from the system studied. Case Studies were performed for two selected ash types, bottom ash from municipal solid waste incineration (MSWI) and wood fly ash. The MSWI bottom ash was assumed to be suitable for road construction or as drainage material in landfill, whereas the wood fly ash Was assumed to be suitable for road construction or as a nutrient resource to be recycled oil forest land after biofuel harvesting. Different types of potential environmental impact predominated in the activities of the system and the use of natural resources and the trace element leaching were identified as being relatively important for the scenarios compared. The scenarios differed in use of resources and energy, whereas there is a potential for trace element leaching regardless of how the material is managed. Utilising MSWI bottom ash in road construction and recycling of wood ash on forest land saved more natural resources and energy than when these materials were managed according to the other scenarios investigated, including dumping in landfill.
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| 40. |
- Tossavainen, Mia, et al.
(author)
-
Characteristics of steel slag under different cooling conditions
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:10, s. 1335-1344
-
Journal article (peer-reviewed)abstract
- Four types of steel slags, a ladle slag, a BOF (basic oxygen furnace) slag and two different EAF (electric arc furnace) slags, were characterized and modified by semi-rapid cooling in crucibles and rapid cooling by water granulation. The aim of this work was to investigate the effect of different cooling conditions on the properties of glassy slags with respect to their leaching and volume stability. Optical microscopy, X-ray diffraction, scanning electron microscope and a standard test leaching (prEN 12457-2/3) have been used for the investigation. The results show that the disintegrated ladle slag was made volume stable by water granulation, which consisted of 98% glass. However EAF slag 1, EAF slag 2 and the BOF slag formed 17%, 1% and 1% glass, respectively. The leaching test showed that the glass-containing matrix did not prevent leaching of minor elements from the modified slags. The solubility of chromium, molybdenum and vanadium varied in the different modifications, probably due to their presence in different minerals and their different distributions.
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| 41. |
- Travar, Igor, et al.
(author)
-
Assessing the environmental impact of ashes used in a landfill cover construction
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29:4, s. 1336-1346
-
Journal article (peer-reviewed)abstract
- Large amounts of construction materials will be needed in Europe in anticipation for capping landfills that will be closed due to the tightening up of landfill legislation. This study was conducted to assess the potential environmental impacts of using refuse derived fuel (RDF) and municipal solid waste incineration (MSWI) ashes as substitutes for natural materials in landfill cover designs. The leaching of substances from a full-scale landfill cover test area built with different fly and bottom ashes was evaluated based on laboratory tests and field monitoring. The water that drained off above the liner (drainage) and the water that percolated through the liner into the landfill (leachate) were contaminated with Cl-, nitrogen and several trace elements (e.g., As, Cu, Mo, Ni and Se). The drainage from layers containing ash will probably require pre-treatment before discharge. The leachate quality from the ash cover is expected to have a minor influence on overall landfill leachate quality because the amounts generated from the ash covers were low, <3-30 l (m2 yr)-1. Geochemical modelling indicated that precipitation of clay minerals and other secondary compounds in the ash liner was possible within 3 years after construction, which could contribute to the retention of trace elements in the liner in the long term. Hence, from an environmental view point, the placement of ashes in layers above the liner is more critical than within the liner.
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| 42. |
- van Praagh, Martijn, et al.
(author)
-
Potential emissions from two mechanically-biologically pretreated (MBT) wastes.
- 2009
-
In: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 1879-2456. ; 29:2, s. 859-868
-
Journal article (peer-reviewed)abstract
- The interaction of parameters determining the potential emissions of two different mechanically-biologically pretreated municipal solid wastes (MBT wastes) is elucidated in this work. The origins of the wastes are Germany and Sweden. By means of lab-scale experiments, increased stabilisation through composting is preferably determined by a decrease in respiration activity. Concurrently, the stabilisation is verified for the leachates by a decrease in COD, DOC, and BOD(5). Total organic carbon content reflects stabilisation less accurately. FT-IR and thermal analytical methods add valuable information about the state of degradation, especially when several distinct thermal parameters are taken into account. Mobility of Cr, Ni, Pb, and Zn produced by a batch leaching test with deionized water is reduced by the pretreatment of both materials. Mobility of copper unambiguously increased. A principle component analysis (PCA) of membrane fractionated leachates indicates an affinity of Cu to mobile humic acids or dissolved organic carbon. High Cr, Zn, and Ni contents in the solid co-occur with high contents of solid humic acids. To a lesser extent, this is also true for solid Cd, Cu, and Pb contents. Due to differences in required landfilling conditions, actual emissions and after-care phase length will depend on whether each waste is landfilled in Germany or Sweden.
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| 43. |
- Wilewska-Bien, Magda, 1977, et al.
(author)
-
Treatment process for MSW combustion fly ash, laboratory and pilot plant experiments
- 2007
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:9, s. 1213-1224
-
Journal article (peer-reviewed)abstract
- Fly ash from combustion of municipal solid waste sometimes contains large amounts of soluble salts, such as NaCl, even though the content of soluble toxic metal compounds is relatively low. Removal of the salts by washing with water has been suggested as a method to increase the stability of this type of ash. In the work presented here, a simple washing process was studied and evaluated. The process includes three steps: leaching with water, filtration and displacement washing. Basic data were obtained in laboratory experiments and used in the construction of pilot plant equipment at a full size fluidized bed boiler, where a side-stream of the cyclone ash was treated. The process was designed to minimize the water consumption while obtaining an effective removal of salts and a stable ash residue. In order to achieve this, recirculation of leaching liquor was used and the displacement washing was adjusted to become close to ideal. The results showed that an ash/water slurry with a liquid to solid ratio as low as 3 could be handled without difficulty in the mixing, pumping and filtration units. Washing of the filter cake at a liquid to solid ratio of 0.5 removed the major part of the remaining dissolved salts in the pore liquid. About 90% of the chloride content was removed from the ash, whereas the contents of Na, K, Ca, Cd, Pb and a number of other minor elements were removed by 10-30%. Before treatment, the results of ash leaching tests were sometimes too high for chloride (2003/33/EC), but the treatment reduced the amount of soluble chlorides to far below the limit values. The leachability of most metals was reduced or unaffected by the ash treatment. For Na, K and Cl, it was less than 10% of the value for the untreated ash. However, the results showed that some ash components may be mobilized by the washing. Antimony is the most important due to its toxicity. © 2006 Elsevier Ltd. All rights reserved.
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| 44. |
- Österlund, Helene, et al.
(author)
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Determination of total chlorine and bromine in solid wastes by sintering and inductively coupled plasma-sector field mass spectrometry
- 2009
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 29:4, s. 1258-1264
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Journal article (peer-reviewed)abstract
- A sample preparation method based on sintering, followed by analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) for the simultaneous determination of chloride and bromide in diverse and mixed solid wastes, has been evaluated. Samples and reference materials of known composition were mixed with a sintering agent containing Na2CO3 and ZnO and placed in an oven at 560 °C for 1 h. After cooling, the residues were leached with water prior to a cation-exchange assisted clean-up. Alternatively, a simple microwave-assisted digestion using only nitric acid was applied for comparison. Thereafter the samples were prepared for quantitative analysis by ICP-SFMS. The sintering method was evaluated by analysis of certified reference materials (CRMs) and by comparison with US EPA Method 5050 and ion chromatography with good agreement. Median RSDs for the sintering method were determined to 10% for both chlorine and bromine, and median recovery to 96% and 97%, respectively. Limits of detection (LODs) were 200 mg/kg for chlorine and 20 mg/kg for bromine. It was concluded that the sintering method is suitable for chlorine and bromine determination in several matrices like sewage sludge, plastics, and edible waste, as well as for waste mixtures. The sintering method was also applied for determination of other elements present in anionic forms, such as sulfur, arsenic, selenium and iodine.
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| 45. |
- Östman, M, et al.
(author)
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Metal and organic matter contents in a combined household and industrial landfill
- 2006
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In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 26:1, s. 29-40
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Journal article (peer-reviewed)abstract
- A combined household/industrial landfill in a humid and cold temperate climate was characterised with respect to its chemical composition. Cores taken at three randomly chosen sites on the landfill and at different depths at each site were analysed. Carbon, nitrogen and pH were measured by standard laboratory methods. The chemical elements analysed included metals and the non-metals B, P and S. pH ranged between 8.0 and 8.5. The total carbon content was in the interval 4.5-26.9% and the total nitrogen content in the interval 0.05-0.48%. The C/N ratio was high, indicating that there was not enough nitrogen available to ensure the stabilisation of carbon. The metal contents varied substantially. The water and carbon contents were related to each other as well as to the metal content, which increased with the content of water. Based on the results obtained regarding the chemical composition of the landfill, it is evident that the landfill consists of two layers. This indicates that the landfill body might have different levels of chemical development, due to water content, and different long-term leachability in the future.
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| 46. |
- Krook, Joakim, et al.
(author)
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Sources of heavy metal contamination in Swedish wood waste used for combustion
- 2006
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In: Waste Management. - : Elsevier BV. - 0956-053X. ; 26:2, s. 158-166
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Journal article (peer-reviewed)abstract
- In this paper, wood waste (RWW) recovered for heat production in Sweden was studied. Previous research has concluded that RWW contains elevated amounts of heavy metals, causing environmental problems during waste management. This study extends previous work on RWW by analysing which pollution sources cause this contamination. Using existing data on the metal contents in various materials, and the amounts of these materials in RWW, the share of the elevated amounts of metals in RWW that these materials explain was quantified. Six different materials occurring in RWW were studied and the results show that they explain from 70% to 100% of the amounts of arsenic, chromium, lead, copper and zinc in RWW. The most important materials contributing to contamination of RWW are surface-treated wood, industrial preservative-treated wood, plastic and galvanised fastening systems. These findings enable the development and evaluation of strategies aiming to decrease pollution and resource loss from handling RWW. It is argued that source separation and measures taken further downstream from the generation site, such as treatment, need to be combined to substantially decrease the amount of heavy metals in RWW.
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