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| 2. |
- Bertanza, Giorgio, et al.
(författare)
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A comparison between two full-scale MBR and CAS municipal wastewater treatment plants: techno-economic-environmental assessment
- 2017
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 24:21, s. 17383-17393
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Tidskriftsartikel (refereegranskat)abstract
- A holistic assessment procedure has been used in this study for comparing conventional activated sludge (CAS) and membrane bioreactor (MBR) processes for the treatment of municipal wastewater. Technical, social, administrative, economic and environmental impacts have been evaluated based on 1 year of operational data from three full-scale lines (one MBR and two CAS) working in parallel in a large municipal treatment plant. The comparative assessment evidences a slight advantage of the conventional process in the studied case, essentially due to lower costs, complexity and energy consumption. On the other hand, the MBR technology has a better social acceptance and similar overall environmental footprint. Although these results are influenced by site-specific parameters and cannot be generalized, the assessment procedure allowed identifying the most important factors affecting the final scores for each technology and the main differences between the compared technologies. Local conditions can affect the relative importance of the assessed impacts, and the use of weighting factors is proposed for better tailoring the comparative assessment to the local needs and circumstances. A sensitivity analysis on the weighted final scores demonstrated how local factors are very important and must be carefully evaluated in the decision making process.
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| 3. |
- Bertanza, Giorgio, et al.
(författare)
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Techno-economic and environmental assessment of sewage sludge wet oxidation
- 2015
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 22:10, s. 7327-38
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Tidskriftsartikel (refereegranskat)abstract
- Today, several technologies and management strategies are proposed and applied in wastewater treatment plants (WWTPs) to minimise sludge production and contamination. In order to avoid a shifting of burdens between different areas, their techno-economic and environmental performance has to be carefully evaluated. Wet oxidation (WO) is an alternative solution to incineration for recovering energy in sewage sludge while converting it to mostly inorganic residues. This paper deals with an experimentation carried out within the EU project “ROUTES”. A mass balance was made for a WWTP (500,000 person equivalents) in which a WO stage for sludge minimisation was considered to be installed. Both bench- and full-scale test results were used. Design of treatment units and estimation of capital and operational costs were then performed. Subsequently, technical and economic aspects were evaluated by means of a detailed methodology which was developed within the ROUTES project. Finally, an assessment of environmental impacts from a life cycle perspective was performed. The integrated assessment showed that for the specific upgrade considered in this study, WO technology, although requiring a certain increase of technical complexity at theWWTP, may contribute to environmental and economic advantages. The paper provides guidance in terms of which aspects need a more thorough evaluation in relation to the specific case in which an upgrade with WO is considered.
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| 4. |
- Di Iaconi, C., et al.
(författare)
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Upgrading small wastewater treatment plants with the sequencing batch biofilter granular reactor technology: Techno-economic and environmental assessment
- 2017
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 148, s. 606-615
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Tidskriftsartikel (refereegranskat)abstract
- This paper is aimed at evaluating, from a techno-economic and environmental point of view, the performance of an existing wastewater treatment plant in which the traditional biological section is upgraded with an innovative Sequencing Batch Biofilter Granular Reactor. Two scenarios were simulated in order to model and assess the performances of conventional (CAS, Conventional Activated Sludge) and innovative solutions, based on mass balances, techno-economic evaluation and environmental assessment. The results showed that converting the activated sludge process into an SBBGR allows to achieve a drastic reduction in sludge production (up to 75% as volatile suspended solids). Furthermore, the secondary sedimentation and sludge stabilization units can be dismissed, reducing the area requirement (up to 50%). The technical assessment is mainly positive, with the electric energy consumption being the only critical item. The higher energy demand of the upgraded plant (about 25% more than the conventional treatment) is mainly associated with the recycle flow in the SBBGR system. Although the economic sustainability of the upgraded plant depends on local conditions, it can be considered to be likely favourable: sludge disposal and materials & reagents costs, together with the investment for plant reconstruction are those items that should be carefully evaluated before upgrading the CAS plant with SBBGR technology. The environmental assessment shows also mostly positive results, although it points to the increased phosphorus concentration in the effluent as a potentially critical issue and it highlights the electricity use and the increased nitrous oxide generation as other matters that need to be carefully checked in real case application.
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| 5. |
- Gianico, A., et al.
(författare)
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Upgrading a wastewater treatment plant with thermophilic digestion of thermally pre-treated secondary sludge: techno-economic and environmental assessment
- 2015
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 102, s. 353-361
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, several technologies and management strategies are proposed for upgrading wastewater treatment plants (WWTPs) in order to improve sludge stabilization or minimize sludge production. In order to make sure that this leads to overall improvements, their techno-economic and environmental performance has to be carefully evaluated. In response to this, the techno-economic and environmental performance was assessed for a considered model reference WWTP upgraded with separate treatment and disposal for primary and secondary sludge to provide guidance to research, policy and investment efforts. This paper departs in an experimental campaign carried out within the EU project "ROUTES" and describes an assessment of an upgrade of a WWTP, involving wet oxidation of primary sludge and thermophilic anaerobic digestion (integrated with thermal hydrolysis pre-treatment) for secondary sludge. The reference plant and the upgrade implied different disposal routes for the resulting sludges: incineration for the stabilized sludge deriving from the reference WWTP; agricultural land application for the secondary stabilized sludge from the upgraded plant and landfilling for the solid residue deriving from the wet oxidation process (as non-hazardous waste). The mass balance carried out for both reference and upgraded WWTPs showed a reduction of total sludge production (up to 45%) for the upgraded WWTP. The additional energy demand of the upgraded solution (+22.4 Wh/(PE d), PE: population equivalent) was partially balanced by the electric energy produced by combined heat and power unit installed in the upgraded WWTP (-18.08 Wh/(PE d)). The integrated assessment showed that the upgraded solution, although resulting in an increase of WWTP technical complexity, may contribute to environmental and economic advantages. The paper provides guidance in terms of which aspects need a more thorough evaluation when this upgrade is considered in real cases.
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| 6. |
- Harder, Robin, 1983, et al.
(författare)
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Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. 1. Estimating the Burden of Disease Associated with Pathogens
- 2014
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:16, s. 9438-9445
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Tidskriftsartikel (refereegranskat)abstract
- The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2–9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28 600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series.
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| 7. |
- Heimersson, Sara, 1984, et al.
(författare)
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Environmental performance of new wastewater and sludge treatment routes compared to conventional approaches
- 2012
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Ingår i: The proceedings of The 6th European Waste Water Conference & Exhibition, 8-10 October 2013.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The value of life cycle assessments depends on their completeness and on how well the assessment answers the question asked. In the EU project ROUTES several case studies have been performed in order to evaluate innovative wastewater and sludge treatment scenarios against baseline scenarios, in order to understand whether the new ones perform better or worse from an environmental systems perspective and identify the hot spots in the studied systems from where the main environmental pressure originates. The performed LCA study assesses five impact categories, Global Warming Potential, Acidification Potential, Eutrophication Potential, Ozone Depletion Potential and Photochemical Ozone Creation Potential. This article discusses the relevance of the obtained results and identifies further assessments needed in order to provide a solid result.The study shows that, at present, although a limited number of impact categories are assessed, the studied energy-demanding technologies, like sequential batch biofilm granular reactor and membrane reactor, have a worse overall environmental performance compared to baseline scenarios, and points out electrical efficiency as the main area to put focus on to decrease the overall environmental impact. It also shows that the technologies aimed at sludge quality improvement exhibit a promising environmental performance, but further assessment, including LCA method development, is needed as the studied impact categories do not model the studied system in a thorough way when it comes to comparing agricultural application of sludge and other disposal options.
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| 8. |
- Heimersson, Sara, 1984, et al.
(författare)
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How uncertainties are handled in LCA – focus on the wastewater and textile sectors
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Life cycle assessment (LCA) relies on large data samples and includes numerous choices and assumptions. This study aimed at reviewing to what extent relevant uncertainties are communicated and considered when interpreting LCA results, looking at current practices in LCAs on wastewater and textile systems. Our review showed that uncertainties are seldom communicated or considered in relation to the conclusions of the study, despite the availability of methods for propagating uncertainties in LCAs. We discuss that uncertainties and variation should at least be qualitatively assessed, and ideally be propagated from the life cycle inventory through the impact assessment.
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| 9. |
- Heimersson, Sara, 1984
(författare)
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Improved life cycle assessment of wastewater and sludge management with resource recovery
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Around the world every day, large amounts of wastewater are treated before release, to avoid impacts on humans and the environment. The treatment requires resources in the form of energy and chemicals, and it generates large amounts of sewage sludge, however, it can also serve as a source of energy, nutrients and carbon. These valuable resources can be recovered in many ways, including in the form of biogas, or through the use of sludge in agriculture or even, potentially, in form of biopolymer raw material.Life cycle assessment (LCA) can be used to quantify the life cycle impact of wastewater and sludge management with resource recovery, on humans and the environment, in order to evaluate their environmental performance and avoid sub-optimisation. LCAs of such systems face different types of methodological problems. This thesis focusses on two such problems.The first research topic concerns how to divide the environmental impact that results from a wastewater treatment process with the simultaneous production of a valuable by-product. Methodologies exist for handling such general situations, however, some properties inherent to wastewater and sludge management may result in complex allocation problems. This research identified the LCA of a system with wastewater treatment and simultaneous polyhydroxyalcanoate (PHA) production as particularly challenging, if PHA was considered as the main product. Three partly new allocation approaches were evaluated, and the choice of approach was found to influence the LCA results.A second research topic concerns the potential importance of assessing the risks of the pathogens that exist in wastewater and sludge management systems, which is not currently done within the LCA framework. This research has found that these risks are potentially important compared to other impacts on human health, both for wastewater and sludge management systems where sludge is incinerated or used for agricultural purposes.
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| 10. |
- Heimersson, Sara, 1984, et al.
(författare)
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Improved life cycle modelling of benefits from sewage sludge anaerobic digestion and land application
- 2017
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 122, s. 126-134
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen, phosphorus and organic matter are valuable resources in sewage sludge. Life cycle assessment (LCA) can be useful for comparing the potential environmental risks of sludge management strategies to their potential environmental benefits. With growing interest in resource recovery from sludge, there is an increasing need to properly account for the benefits that can be achieved, and to handle the multi functionality issues that then arise in LCAs. So far, both of these aspects have often been handled in a generic and seemingly arbitrary way. The study identified and explored several alternative approaches to handle the multi-functionality in the LCA of a sludge handling system that generates both biogas and a sludge that is used on arable land; either through avoiding allocation by substituting for avoided products or services (e.g. fertilisers and natural gas), or by allocating the impact from the studied system between its functions based on economic terms. The choice of approach strongly influenced the overall LCA-result for the studied system, in particular for some of the studied impact categories. Although an attempt was made to apply economic allocation in this article, it can be concluded that no coherent basis for applying allocation was identified. Substitution was more easily applied, however, the results were highly dependent on the product assumed to be replaced by biogas and the modelling of avoided mineral fertiliser use. The previously neglected benefits related to organic matter provided by the sludge to arable land were potentially as important as the benefits of the nitrogen and phosphorus, although the quantification of such effects will need further refinement, and are only relevant for certain soil conditions. (C) 2017 Elsevier B.V. All rights reserved.
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