| 1. |
- Davidsson, Åsa, et al.
(författare)
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Effect of anaerobic digestion at 35, 55 and 60 °C ON pharmaceuticals and organic pollutants
- 2013
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Ingår i: Presented at the 1st International IWA Conference on Holistic Sludge Management, Västerås, Sweden, May 6-8, 2013. ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- The application of treated sewage sludge on farmland is a suggested method for recycling nutrients and reducing demand for commercial fertilizer. However sludge needs to be rendered safe from possible contaminants which can cause acute and long-term health and environmental problems. Residual pharmaceuticals and organic contaminants in sludge are mentioned as emerging threats since wastewater treatment plants are not designed to degrade these substances thus yielding an accumulation in sludge. The aim of this study was to evaluate the presence, and reduction, of pharmaceuticals and polycyclic aromatic hydrocarbons (PAHs) during anaerobic digestion at 35, 55 and 60ºC and during pasteurization at 70°C. The substrate used was mixed primary and secondary sludge from a 300 000 person-equivalents municipal wastewater treatment plant in southern Sweden. In general no reduction of pharmaceuticals could be observed at any temperature or minimum exposure time, except for the beta-blocker Irbesartan and the antibiotic Trimethoprim. The results from pharmaceuticals in mesophilic sludge agreed with results in recent Swedish studies. Also, no reduction of PAHs during digestion or pasteurization (70°C – 1 hour) was seen, but for single PAHs digestion could lead to reduction.
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| 2. |
- 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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| 3. |
- Bernstad, Anna, et al.
(författare)
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Collaboration Outcomes
- 2013
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Ingår i: Modern Solid Waste Management in Practice: the City of Malmo Experience. - London : Springer London. - 2191-530X. ; , s. 69-74
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Bokkapitel (refereegranskat)
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| 4. |
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| 5. |
- Bernstad, Anna, et al.
(författare)
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Door-stepping as a strategy for improved food waste recycling behaviour Evaluation of a full-scale experiment
- 2013
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Ingår i: Resources, Conservation & Recycling. - : Elsevier BV. - 0921-3449. ; 73, s. 94-103
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Tidskriftsartikel (refereegranskat)abstract
- Comparisons were made between two groups of households in a multi-family residential area in order to investigate how oral information through a door-stepping campaign can influence household food waste recycling behaviour from a quantitative as well as qualitative perspective. Source-separation behaviour was assessed both through weakly weighting of all source-separated food waste and dry recyclables as well as residual waste generated over a period of 104 weeks, as well as repeated waste composition analyses. Introduction of source-separation of food waste for biogas production significantly decreased the generation of residual waste in the whole case-study area. An average generation of 0.72 and 0.71 kg, household(-1), week(-1) of separately collected food waste was found amongst households receiving and not contacted through the door-stepping campaign respectively. The difference between the groups was not statistically significant. Four waste composition analyses show that the average source-separation ratio of food waste was higher and the ratio of incorrectly sorter material lower in the food waste fraction amongst households where oral information had been provided. A decrease over time in the source-separation ratio of food waste amongst households receiving oral information suggests a low durability of the door-stepping campaign. No signs were seen of increased source-separation ratio or decreased ratio of incorrectly sorted material amongst dry recyclables. The study supports previous findings pointing at accessibility as a key factor for increased recycling behaviour. However, results also suggest that such systems must address convenience also in the household interior. (C) 2012 Elsevier B.V. All rights reserved.
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| 6. |
- Bernstad, Anna, et al.
(författare)
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From Idea to Reality: The City as a Test Bed
- 2013
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Ingår i: Modern Solid Waste Management in Practice: the City of Malmo Experience. - London : Springer London. - 2191-530X. ; , s. 21-67
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Bokkapitel (refereegranskat)
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| 7. |
- Bernstad, Anna, et al.
(författare)
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Future Challenges
- 2013
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Ingår i: Modern Solid Waste Management in Practice: the City of Malmo Experience. - London : Springer London. - 2191-530X. ; , s. 85-93
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Bokkapitel (refereegranskat)
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| 8. |
- Bernstad, Anna, et al.
(författare)
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Life cycle assessment of a household solid waste source separation programme: a Swedish case study.
- 2011
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Ingår i: Waste Management & Research. - 1096-3669. ; 29, s. 1027-1042
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Tidskriftsartikel (refereegranskat)abstract
- The environmental impact of an extended property close source-separation system for solid household waste (i.e. a systems for collection of recyclables from domestic properties) is investigated in a residential area in southern Sweden. Since 2001, households have been able to source-separate waste into six fractions of dry recyclables and food waste sorting. The current system was evaluated using the EASEWASTE life cycle assessment tool. Current status is compared with an ideal scenario in which households display perfect source-separation behaviour and a scenario without any material recycling. Results show that current recycling provides substantial environmental benefits compared to a non-recycling alternative. The environmental benefit varies greatly between recyclable fractions, and the recyclables currently most frequently source-separated by households are often not the most beneficial from an environmental perspective. With optimal source-separation of all recyclables, the current net contribution to global warming could be changed to a net-avoidance while current avoidance of nutrient enrichment, acidification and photochemical ozone formation could be doubled. Sensitivity analyses show that thetype of energy substituted by incineration of non-recycled waste, as well as energy used in recycling processes and in the production of materials substituted by waste recycling, is of high relevance for the attained results.
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| 9. |
- Bernstad, Anna, et al.
(författare)
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Local strategies for efficient management of solid household waste - the full-scale Augustenborg experiment.
- 2012
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Ingår i: Waste Management & Research. - 1096-3669. ; 30, s. 200-212
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Tidskriftsartikel (refereegranskat)abstract
- A system with property-close source-separation of thirteen different solid household waste fractions in a residential area in southern Sweden, including the implementation of new systems for source-separation of food waste, waste electric and electronic equipment, hazardous waste and fat, oils and grease was monitored over a 2-year period. Continuous weighing of disposed waste and repeated waste composting analyses were used to investigate recycling behaviour of households in the area and to monitor the composition of disposed waste. Results show that 34% of the total amount of generated waste was currently diverted to material recycling. The removal of recyclables from residual waste could be significantly increased, as more than 80% of all waste in the area (bulky waste excluded) was either covered by the Producer Responsibility Ordinances on packaging and newspaper or constitutes food waste suitable for biogas production. Food waste still represented almost 30% of all residual waste in the study area and was thus the fraction with the greatest potential (on weight basis) for increased source-separation.
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| 10. |
- 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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