| 1. |
- Sundell, Jonas, 1984, et al.
(författare)
-
Comprehensive risk assessment of groundwater drawdown induced subsidence
- 2019
-
Ingår i: Stochastic Environmental Research and Risk Assessment. - : Springer Science and Business Media LLC. - 1436-3240 .- 1436-3259. ; 33:2, s. 427-449
-
Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s). We present a method for risk assessment of groundwater drawdown induced land subsidence when planning for sub-surface infrastructure. Since groundwater drawdown and related subsidence can occur at large distances from the points of inflow, the large spatial extent often implies heterogeneous geological conditions that cannot be described in complete detail. This calls for estimation of uncertainties in all components of the cause-effect chain with probabilistic methods. In this study, we couple four probabilistic methods into a comprehensive model for economic risk quantification: a geostatistical soil-stratification model, an inverse calibrated groundwater model, an elasto-plastic subsidence model, and a model describing the resulting damages and costs on individual buildings and constructions. Groundwater head measurements, hydraulic tests, statistical analyses of stratification and soil properties and an inventory of buildings are inputs to the models. In the coupled method, different design alternatives for risk reduction measures are evaluated. Integration of probabilities and damage costs result in an economic risk estimate for each alternative. Compared with the risk for a reference alternative, the best prior alternative is identified as the alternative with the highest expected net benefit. The results include spatial probabilistic risk estimates for each alternative where areas with significant risk are distinguished from low-risk areas. The efficiency and usefulness of this modelling approach as a tool for communication to stakeholders, decision support for prioritization of risk reducing measures, and identification of the need for further investigations and monitoring are demonstrated with a case study of a planned railway tunnel in Varberg, Sweden.
|
|
| 2. |
- Sundell, Jonas, 1984, et al.
(författare)
-
Economic valuation of hydrogeological information when managing groundwater drawdown
- 2019
-
Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 27:4, s. 1111-1130
-
Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s). A procedure is presented for valuation of information analysis (VOIA) to determine the need for additional information when assessing the effect of several design alternatives to manage future disturbances in hydrogeological systems. When planning for groundwater extraction and drawdown in areas where risks—such as land subsidence, wells running dry and drainage of streams and wetlands—are present, the need for risk-reducing safety measures must be carefully evaluated and managed. The heterogeneity of the subsurface calls for an assessment of trade-offs between the benefits of additional information to reduce the risk of erroneous decisions and the cost of collecting this information. A method is suggested that combines existing procedures for inverse probabilistic groundwater modelling with a novel method for VOIA. The method results in (1) a prior analysis where uncertainties regarding the efficiency of safety measures are estimated, and (2) a pre-posterior analysis, where the benefits of expected uncertainty reduction deriving from additional information are compared with the costs for obtaining this information. In comparison with existing approaches for VOIA, the method can assess multiple design alternatives, use hydrogeological parameters as proxies for failure, and produce spatially distributed VOIA maps. The method is demonstrated for a case study of a planned tunnel in Stockholm, Sweden, where additional investigations produce a low number of benefits as a result of low failure rates for the studied alternatives and a cause-effect chain where the resulting failure probability is more dependent on interactions within the whole system rather than on specific features.
|
|
| 3. |
- Dymitrow, Mirek, et al.
(författare)
-
Crossing dichotomies and breaking mental patterns: Green business development when all else fails?
- 2017
-
Ingår i: 8th International Scientific Conference “Rural Development 2017: Bioeconomy Challenges”, 23–24 November, 2017 Kaunas, Lithuania.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Obtaining sustainable and inclusive societal organization is not merely a simple matter of ‘doing it’ by subscribing to some winning formula. Given that conceptual frameworks always guide our thoughts, judgments and actions (Latour, 2013; Harvey, 1996; Dennett, 1993), the ways in which we relate to concepts chosen to serve as guiding forces for future development will eventually determine its outcome. As scholarly evidence continuously suggests the concepts ‘rural’ and ‘urban’ are increasingly recognized as artificial barriers for conducting sound and integrated development endeavors in a globalized reality of interconnectedness. In line with the Sustainable Development Goals, which aim to eradicate poverty, shield the planet and safeguard prosperity for all, commitment to universal access to healthy food year round has become an important agenda point. This, however, has been exacerbated by binary thinking and separate ways of doing policy. This paper aims to share experiences from a unique project launched in the northern parts of Gothenburg, Sweden’s second largest city. While the area offers ample resources and immense opportunities for areal economies, it at the same time remains one of Gothenburg’s most segregated, with high levels of unemployment, ill health and crime. The uniqueness of the project lies not only in its way of abridging the rural-urban divide, but also by consciously deferring from the debilitating rhetoric of previous ‘immigrant policies’, and instead focusing on agricultural productivity, small-scale food producers and sustainable food strategies. Such exhortations to bridge between philosophical and material polarities, however, have not come without conceptual and practical challenges, something this paper aims to subsume and open up to debate.
|
|
| 4. |
|
|
| 5. |
- Hagbert, Pernilla, 1986, et al.
(författare)
-
Reducing water consumption
- 2012
-
Ingår i: 1st RESPONDER Knowledge Brokerage Event on Sustainable Housing, 28-30 March, 2012, Barcelona, Spain.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 6. |
- Kharazmi, Parastou, 1977-
(författare)
-
Experimental evaluation of a rubber-epoxy polymeric system used in the rehabilitation of sewer infrastructure- Dataset
- 2019
-
Annan publikationabstract
- This dataset includes data related to water sorption analyses to support research findings stated in the article:"Experimental evaluation of a rubber-epoxy polymeric system used in the rehabilitation of sewer infrastructure: a case study in Sweden" with the following abstract: One rehabilitation method used mainly for wastewater sewers in residential buildings involves applying a rubber-epoxy composite to the inner surface of the aged pipeline. In order to understand the material’s performance and stability in operation, during which it is constantly exposed to deteriorative factors, the properties of the material were studied in the laboratory under artificial water and air aging conditions. Changes in the material were monitored by means of tests such as thermal analyses, mechanical testing and water absorption assessment.
|
|
| 7. |
- Mangold, Mikael, 1982, et al.
(författare)
-
Who benefits? Effects and perceptions of residential volumetric water billing
- 2012
-
Ingår i: 2nd Nordic Conference on Consumer Research, 29 May-1 June, 2012, Göteborg.
-
Konferensbidrag (refereegranskat)abstract
- What are the effects and perceptions of increased installation of water metering and volumetric billing in residential areas in Sweden? An interview study was undertaken in a low-income suburb of Göteborg to explore residents’ experiences and opinions. Additionally, the interests of water and energy companies, social affairs committee, real estate owner and maintainer were investigated to contrast the added value of reduced water consumption. Stakeholders either benefit or are disadvantaged by the introduced system. Furthermore, the applied tariff structure fails to motivate all segments of the population to reduce water consumption, yet still inequitably burdens the most financially exposed groups.
|
|
| 8. |
- Mc Conville, Jennifer R, 1978, et al.
(författare)
-
Bridging sanitation engineering and planning: theory and practice in Burkina Faso
- 2011
-
Ingår i: Journal of Water Sanitation and Hygiene for Development. - : IWA Publishing. - 2043-9083 .- 2408-9362. ; 1:3, s. 205-212
-
Tidskriftsartikel (refereegranskat)abstract
- The global challenge of providing sanitation services to the un-served underlines a need to change the way in which sanitation planning and service provision is approached. This paper offers a framework for categorizing sanitation projects planning processes based on planning steps and procedural planning theory to help engineers and sanitation planners gain a deeper understanding of the dynamics of these processes. The analysis identifies and discusses trends in both guidelines and actual sanitation programs. The results show that contemporary sanitation planning guidelines and field projects utilize patchwork processes of different planning modes, although the step of designing options is dominated by an expert-driven, rational-comprehensive approach. The use of planning theory can help engineers to ask critical questions about the objectives of the planning process and to develop context-appropriate planning processes that will make a difference for improving sanitation service provision.
|
|
| 9. |
|
|
| 10. |
- Garmabaki, Amir H. Soleimani, et al.
(författare)
-
A Survey on Underground Pipelines and Railway Infrastructure at Cross-Sections
- 2019
-
Ingår i: Proceedings of the 29th European Safety and Reliability Conference (ESREL 2019). - Singapore : Research Publishing Services. ; , s. 1094-1101
-
Konferensbidrag (refereegranskat)abstract
- Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures are critical for society and industry resulting in direct and indirect costs for all the related stakeholders. Pipeline failures are complex processes, which are affected by many factors, both static (e.g., pipe material, size, age, and soil type) and dynamic (e.g., traffic load, pressure zone changes, and environmental impacts). These failures have serious impacts on public due to safety, disruption of traffic, inconvenience to society, environmental impacts and shortage of resources. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within transportation infrastructure. The aim of this study is to identify failure modes and consequences related to the crossing of pipelines in railway corridors. Expert opinion have been collected through two set of questionnaires which have been distributed to the 291 municipalities in the whole Sweden. The failure analysis revealed that pipe deformation has higher impact followed by pipe rupture at cross-section with railway infrastructure. For underground pipeline under railway infrastructure, aging and external load gets higher ranks among different potential failure causes to the pipeline.
|
|
| 11. |
- Lanau, Maud, 1989, et al.
(författare)
-
The Industrial Ecology of the Göteborg City Region — a first appraisal
- 2015
-
Ingår i: International Society for Industrial Ecology 2015.
-
Konferensbidrag (refereegranskat)abstract
- An infrastructure system – here, the industrial ecology of Gothenburg — is more important for society than we usually credit it for (cf. Technology is society made durable, Latour 1990) and is taken for granted by most inhabitants. Gothenburg is an unusually well-developed and interconnected infrastructure system. The first district heating facility was put in operation in 1952. Soon enough, waste was re-used and recycled into energy, into both electricity and heat. With time, more varied materials and sources became integrated into the system to also produce biogas and compost. The project makes a historiographic description of how the industrial ecology of the Gothenburg city region developed since the Gothenburg technical environmental flow system is unique in size, age, diversity of flows and functions. The study describes environmental flows and their actors in a networked organization. The focus on interconnectivity of the different actors, flows and sectors of Gothenburg requires the combination of several theoretical fields. Such theoretical fields include Networked Learning, which takes a relational stance in which learning takes place both in relation to others, and in relation to learning resources (Dirckinck-Homfeld et al., 2009); STS (Science Technology and Society), which study how technical innovation are affected by social, political and cultural values, and how these innovation affect, in turn, political, social and cultural values; (Joerges & Novotny, 2003); and Urban Metabolism, which uses models to facilitate the description and analysis of the flows of the energy and materials within cities, such as Material Flow Analysis of a city, and provides a metaphorical framework to study the interactions of natural and human systems in specific regions. Preliminary findings will be presented.
|
|
| 12. |
- Mangold, Mikael, 1982
(författare)
-
The effect of resource sustainability interventions on social sustainable development in the built environment
- 2013
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There are several sustainable development targets for the Swedish housing market. The sector as a whole is expected to contribute to the reduction of greenhouse gases. Housing prices should increase and not inflate. Meanwhile, the development of the built environment should contribute to well being and decrease segregation. Prioritization amongst these targets is often done through policy and by actors in the housing market. This thesis focuses on the trade-offs between environmental and social sustainable development targets. The thesis builds on two studies of development in the built environment. The main study describes an environmental upgrade of housing in a disadvantaged area of Gothenburg, and the second investigates a redevelopment area with high environmental ambitions. Environmental targets, such as CO2 reduction, have in some cases been profitably achieved in housing projects in Sweden. The principal study of this thesis describes the implementation of volumetric billing of water at Bredfjällsgatan which successfully reduced water usage and was profitable for the implementing real estate company. However, the system’s change also increased the average monthly costs for the households, and the average monthly costs increased even more in households where the inhabitants were unemployed. The lock-in effect of welfare dependency is increased by rising monthly expenses. This group lacks economic incentive to save water since welfare pays for water usage. The analyses of water consumption data show that while economic incentives account for some reduction of water consumption, other parameters such as household size, crowdedness of apartments, and household level of education are also important factors. Households receiving welfare are not economically affected by the implementation of volumetric billing of water but are further socially excluded from society when trapped in welfare dependence. The real estate owner states economic and environmental aspects as motivators for the system’s change. Social sustainable development targets on a societal level are not an outspoken priority to the same extent. The real estate owners in disadvantaged housing areas should be recognized as important actors in the development to tackle segregation of the housing market.The second study presents empirical insights from a housing area that is being built with high environmental ambitions. Perspectives of sustainable development amongst developers in the area differ, but it is apparent that social dimensions of sustainable development receive less attention. The complexity of social dimensions is not fully addressed. Social sustainable development is for example thought of as comfortable outdoor environments in the area, while the larger societal impacts of the housing project were not considered to the same extent. Integration, affordability, and equity were given direct focus; instead these targets are often assumed to be reached by varying apartment sizes and mixing tenure in the area.
|
|
| 13. |
- Pettersson, Kaj, 1990
(författare)
-
Modeling stormwater transport through unsaturated green roof substrates
- 2018
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent decades there has been an increase in research regarding green roofs and similar technologies. This increased interest is driven by the requirements of urban development and its effects both on humans and the environment. Additionally, the predicted increase in weather severity in the future is raising concerns on the capabilities of urban environments and their stormwater management systems to cope with the increase. Green roofs can be used as a space-conscious solution for improving stormwater management in urban areas as well as contributing to, for example, building protection and pollution and noise reduction. In order to fully utilize them effectively for stormwater runoff reduction it is necessary to quantify their effect and optimize their performance in a given climate. This optimization can take the form of placement on structures or by design within the green roof construction itself. This work focuses on optimization of design by applying computational fluid dynamics and lattice Boltzmann theory to the soil growth substrate. Computational fluid dynamics is used for modeling the flow through the green roof growth substrate (soil layer) at the macrososcopic scale while a lattice Boltzmann model is applied to the mesoscopic (soil particle) scale. Using these methods, the efficacy at water retention and drainage of given soil particles and full-sized green roofs can be determined. This work covers the framework covering both scales however the methodology is applied only to the mesoscopic scale. The focus within the mesoscopic scale is primarily on the hydrophilicity of the particles in the soil and its impact on liquid imbibition. Also included is an exploration on the liquid-air interfacial area and liquid penetration depth to aid in the analysis of the results. The findings of the study suggest particle hydrophilicity plays an important role in the imbibition process, particularly under light to medium rainfall conditions. In addition a pore blocking phenomenon is identified which requires further analysis. Finally, plans for future work and the closure of the two-framework methodology proposed in this work is discussed.
|
|
| 14. |
- Haghighatafshar, Salar, et al.
(författare)
-
Hydroeconomic optimization of mesoscale blue-green stormwater systems at the city level
- 2019
-
Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 578
-
Tidskriftsartikel (refereegranskat)abstract
- The development of tools to help cities and water utility authorities communicate and plan for long-term sustainable solutions is of utmost importance in the era of a changing and uncertain climate. This study introduces a hybrid modeling concept for the cosimulation of mesoscale blue-green stormwater systems and conventional urban sewer networks. The hybrid model successfully introduces the retention/detention effects of mesoscale blue-green stormwater systems to the hydraulic dynamics of the sewer network. The cosimulation package was further facilitated with a cost-oriented multiobjective optimization algorithm. The aim of the scalar multiobjective optimization was to minimize the total cost comprising both flooding costs and action costs – both parameters solely representing the financial components of cost – through optimal placement of mesoscale blue-green systems of optimal size. The suggested methodology provides a useful platform for sustainable management of the existing sewer networks in cities from a hydroeconomic perspective.
|
|
| 15. |
- Schade, Jutta, et al.
(författare)
-
Sjunde huset i Kiruna
- 2016
-
Ingår i: Husbyggaren. - Stockholm. - 0018-7968. ; :4, s. 29-31
-
Tidskriftsartikel (populärvet., debatt m.m.)
|
|
| 16. |
- Jönsson, Håkan, et al.
(författare)
-
Potential of productive waste management systems in low- income countries
- 2014
-
Ingår i: Urban and peri-urban farming in low income countries – challenges and knowledge gaps. - 9789157692306 ; :2014:4, s. 22-26
-
Bokkapitel (refereegranskat)abstract
- In low- and middle-income countries, often neither waste nor wastewater are fully collected and treated, resulting in major impacts on the environment and health. Urban and peri-urban agriculture provides both food and income to many urban poor, but productivity of land is decreasing. Tackling these problems simultaneously enables solutions for both issues by introducing systems where organic waste is turned into high-value products and safe fertilisers.
|
|
| 17. |
- Niwagaba, Charles, et al.
(författare)
-
Experiences on the implementation of a pilot grey water treatment and reuse based system at a household in the slum of Kyebando-Kisalosalo, Kampala
- 2014
-
Ingår i: Journal of Water Reuse and Desalination. - : IWA Publishing. - 2220-1319 .- 2408-9370. ; 4, s. 294-307
-
Tidskriftsartikel (refereegranskat)abstract
- Grey water constitutes the largest fraction of domestic wastewater. It causes environmental sanitation and pollution problems if it is not managed well. If treated, grey water can be a resource for a variety of uses. A pilot system was constructed in February 2013 to treat grey water from a four-member household for sub-surface irrigation of local vegetables. A hydraulic loading rate (HLR) of 60 L m(-2)d(-1) and an organic loading rate (OLR) of 519-1,580 g BOD(5)m(-2)d(-1) were implemented on a multi-media filter of gravel, charcoal, geotextile and mulch (charcoal being the predominant layer) operated as a batched type-system, with a 36-hour retention time. The system was operated for 3 months, during which it showed remarkable removal efficiencies of 90.8 +/- 5.4 and 96.1 +/- 3.0% after 36 hours for chemical oxygen demand (COD) and biochemical oxygen demand (BOD), respectively, and 95 +/- 3.1% for faecal coliforms (FC). The removal efficiencies at 36 hours, of total nitrogen (TN), total phosphorus (Tot-P), total suspended solids (TSS) and total dissolved solids (TDS) were 39.0, 30.1, 85.2 and 78.6%, respectively. Plant response to sub-surface irrigation with treated grey water was largely masked by rainy season and the effluent had a limited effect on the soil.
|
|
| 18. |
-
Proceedings of the 14th ICOLD International Benchmark Workshop on Numerical Analysis of Dams
- 2017
-
Proceedings (redaktörskap) (refereegranskat)abstract
- Every second year, the Technical Committee A (Computational Aspects of Dam Analysis and Design) of ICOLD organizes an international benchmark workshop on numerical analysis of dams. The purpose is to share knowledge and experience regarding numerical modelling within the fields of dam safety, planning, design, construction as well as operation and maintenance of dams. The Terms of Reference for Committee A state; ”BenchmarkWorkshops are organised to compare numerical models between one another and/or with reference solutions, including the dissemination and publication of results”. The 14th ICOLD International Benchmark Workshop on Numerical Analysis of Dams was held from the 6th to the 8th September 2017 in Stockholm, the capital of Sweden. It was organized by the Local Organizing Committee, on behalf of the Swedish National Committee of ICOLD (SwedCold) and the ICOLD Technical Committee A. It was hosted by KTH Royal Institute of Technology, Sweden’s largest technical research and learning institution and one of Europe’s leading technical universities. With respect to hydropower and dam engineering, KTH has for many years been active within of the Swedish hydropower Center (SVC), a key centre for research and educational activities in Sweden. SwedCOLD established in 1931, and is one of the oldest members of the International Commission On Large Dams, ICOLD. The development of hydro power for electricity production was initiated in the late 19th century and made the large scale industrialisation in Sweden possible. About 2000 hydropower plants are in operation in Sweden today, producing almost half of the total electricity supply. Considering the many and relatively old dams in Sweden, organizing the benchmark workshop was important to increase the knowledge regarding managing aging hydropower structures.The 14th ICOLD International Benchmark Workshop has addressed current challenges regarding design and maintenance of existing dams and improved the understanding of these by exchange of experience on the use of numerical modelling for design, performance evaluation and safety assessment of dams. On behalf of the organizing committee, I would like to express my sincere appreciation to the formulators/moderators of each theme for their outstanding work to prepare the themes, reviewing the papers and evaluating the results. I also want to thank all participants to the benchmark workshop for their contributions and their presence to this benchmark workshop. Finally, the support from the Technical Committee A and the support from the companies and organizations that sponsored this benchmark workshop is gratefully acknowledged.
|
|
| 19. |
|
|
| 20. |
- Jönsson, Håkan, et al.
(författare)
-
Återvinn fler näringsämnen än fosfor i avloppsvatten
- 2012
-
Ingår i: Dagens nyheter. - 1101-2447. ; ?, s. 6-
-
Annan publikation (populärvet., debatt m.m.)abstract
- För att minska utsläppen av växthusgaser bör vi återvinna fler växtnäringsämnen ur avloppsslammet. Regeringens ensidiga fokus på fosfor i detta avseende riskerar att skada det långsiktiga miljöarbetet. Vi vill skärpa miljömålen och inkludera även ämnen som kväve, kalium och svavel, skriver professorer och forskare från SLU.
|
|
| 21. |
- Bundschuh, Jochen, et al.
(författare)
-
Emerging mitigation needs and sustainable options for solving the arsenic problems of rural and isolated urban areas in Latin America : A critical analysis
- 2010
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 44:19, s. 5828-5845
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, current information about the contamination of ground- and surface-water resources by arsenic from geogenic sources in Latin America is presented together with possible emerging mitigation solutions. The problem is of the same order of magnitude as other world regions, such as SE Asia, but it is often not described in English. Despite the studies undertaken by numerous local researchers, and the identification of proven treatment methods for the specific water conditions encountered, no technologies have been commercialized due to a current lack of funding and technical assistance. Emerging, low-cost technologies to mitigate the problem of arsenic in drinking water resources that are suitable for rural and urban areas lacking centralized water supplies have been evaluated. The technologies generally use simple and low-cost equipment that can easily be handled and maintained by the local population. Experiences comprise (i) coagulation/filtration with iron and aluminum salts, scaled-down for small community-and household-scale-applications, (ii) adsorption techniques using low-cost arsenic sorbents, such as geological materials (clays, laterites, soils, limestones), natural organic-based sorbents (natural biomass), and synthetic materials. TiO2-heterogeneous photocatalysis and zerovalent iron, especially using nanoscale particles, appear to be promising emergent technologies. Another promising innovative method for rural communities is the use of constructed wetlands using native perennial plants for arsenic rhizofiltration. Smallscale simple reverse osmosis equipment (which can be powered by wind or solar energy) that is suitable for small communities can also be utilized. The individual benefits of the different methods have been evaluated in terms of (i) size of the treatment device, (ii) arsenic concentration and distribution of species, chemical composition and grade of mineralization in the raw water, (iii) guidelines for the remaining As concentration, (iv) economical constrains, (v) complexity of installation and maintenance, and infrastructure constraints (e.g. electricity needs). (c) 2010 Elsevier Ltd. All rights reserved.
|
|
| 22. |
- Flyborg, Lena, et al.
(författare)
-
A PLS model for predicting rejection of trace organic compounds by nanofiltration using treated wastewater as feed
- 2017
-
Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 174, s. 212-221
-
Tidskriftsartikel (refereegranskat)abstract
- In this study a Partial Least Squares Projection of Latent Structures (PLS) model has been developed for predicting the rejection of pharmaceutical residuals by nanofiltration (NF) using treated municipal wastewater as feed. The objective was to provide a practical tool for wastewater reuse facilities for estimating the rejection of emerging organic contaminants based on their physiochemical characteristics. The model was developed by identifying the important physiochemical properties of pharmaceutical residuals for rejection by NF. The investigated pharmaceuticals were those present in the effluent from Henriksdal wastewater treatment plant (WWTP), Sweden. The rejection, at volume reduction factors (VRF) ranging from 2 to 20, was examined in a NF pilot plant at two occasions. The important variables for rejection by NF were, in descending order: polarizability, globularity, ratio hydrophobic to polar water accessible surface area and compound charge. Two studies were performed with a time interval of about a year with different wastewater matrices and age of membranes. For different VRFs, but in the same study, the model produced consistent predicted rejections. For the same VRF, but in the different studies, the regression lines were almost parallel, but with a deviation of about 7% for the predicted values. Most of the compounds were within the 95% prediction interval. The model also proved to be able to predict rejection using data from the literature. This confirms that the predictive PLS model can estimate the rejection albeit, with limitations. Generally the proposed predictive rejection model is most likely valid but the model coefficients need to be determined for each individual WWTP or wastewater reuse facility.
|
|
| 23. |
- Kordi, Maryam, 1979-, et al.
(författare)
-
Effects of increasing fuzziness on analytic hierarchy process for spatial multicriteria decision analysis
- 2012
-
Ingår i: Computers, Environment and Urban Systems. - : Elsevier. - 0198-9715 .- 1873-7587. ; 36:1, s. 43-53
-
Tidskriftsartikel (refereegranskat)abstract
- Multicriteria decision analysis (MCDA) involves techniques which relatively recently have received great increase in interest for their capabilities of solving spatial decision problems. One of the most frequently used techniques of MCDA is Analytic Hierarchy Process (AHP). In the AHP, decision-makers make pairwise comparisons between different criteria to obtain values of their relative importance. The AHP initially only dealt with crisp numbers or exact values in the pairwise comparisons, but later it has been modified and adapted to also consider fuzzy values. It is necessary to empirically validate the ability of the fuzzified AHP for solving spatial problems. Further, the effects of different levels of fuzzification on the method have to be studied. In the context of a hypothetical GIS-based decision-making problem of locating a dam in Costa Rica using real-world data, this paper illustrates and compares the effects of increasing levels of uncertainty exemplified through different levels of fuzzification of the AHP. Practical comparison of the methods in this work, in accordance with the theoretical research, revealed that by increasing the level of uncertainty or fuzziness in the fuzzy AHP, differences between results of the conventional and fuzzy AHPs become more significant. These differences in the results of the methods may affect the final decisions in decision-making processes. This study concludes that the AHP is sensitive to the level of fuzzification and decision-makers should be aware of this sensitivity while using the fuzzy AHP. Furthermore, the methodology described may serve as a guideline on how to perform a sensitivity analysis in spatial MCDA. Depending on the character of criteria weights, i.e. the degree of fuzzification, and its impact on the results of a selected decision rule (e.g. AHP), the results from a fuzzy analysis may be used to produce sensitivity estimates for crisp AHP MCDA methods.
|
|
| 24. |
|
|
| 25. |
- Lindhe, Andreas, 1981
(författare)
-
Risk Assessment and Decision Support for Managing Drinking Water Systems
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The vital importance of a reliable and safe drinking water supply makes efficient risk management necessary for water utilities. Risks must be assessed and possible risk-reduction measures evaluated to provide relevant decision support. The World Health Organization emphasises the use of an integrated approach where the entire drinking water system, from source to tap, is considered when assessing and managing risks. Integrated risk assessments are important in order to avoid overlooking interactions between subsystems and events and to minimise sub-optimisation of risk-reduction measures. Methods for integrated risk assessment are, however, limited. A dynamic fault tree method is presented that enables quantitative, integrated risk assessment of drinking water systems. An approach for approximate dynamic fault tree calculations has been developed to minimise computational demand. It is shown how the method can be used to evaluate uncertainties and provide information on risk levels, failure probabilities, failure rates and downtimes of the entire system and its subsystems. The fault tree method identifies where risk-reduction measures are needed most and different risk-reduction alternatives can be modelled, evaluated and compared. The method is combined with economic analysis to identify the most cost-effective risk-reduction alternative. Integrated risk assessments of drinking water systems are commonly performed using risk ranking, where the probability and consequence of undesired events are assessed using discretised scales. There is, however, no common, structured way of using risk ranking to prioritise risk-reduction measures. Two alternative models for risk-based, multi-criteria decision analysis (MCDA) for evaluating and comparing risk-reduction measures have therefore been developed. The MCDA models are based on risk ranking, they can consider uncertainty in estimates and include criteria related to, for example, different risk types and economic aspects. In summary, this thesis provides methods for integrated risk assessment that make it possible to prioritise risk-reduction measures. It is concluded that the methods provide relevant decision support for efficient risk management in water utilities.
|
|
| 26. |
- Lindhe, Andreas, 1981
(författare)
-
Riskanalys från råvatten till tappkran
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Dricksvattenförsörjningen har en central funktion i samhället och är samtidigt utsatt för ett stort antal risker. För att analysera och hantera dessa risker krävs både lämpliga metoder och en förståelse för de arbetsmoment och aspekter som behöver beaktas. Denna rapport utgör en sammanfattning av licentiatuppsatsen med titeln Integrated and probabilistic risk analysis of drinking water systems, som Andreas Lindhe presenterade vid Chalmers i oktober 2008. För ytterligare redogörelse av det som behandlas i denna rapport hänvisas således till licentiatuppsatsen.Världshälsoorganisationen WHO framhåller att en säker dricksvattenförsörjningen inte uteslutande kan baseras på analyser av färdigproducerat dricksvatten. I stället krävs ett riskbaserat arbetssätt som inkluderar hela försörjningskedjan, från råvatten till tappkran. WHO förespråkar framtagandet av vattensäkerhetsplaner (Water Safety Plans) där bland annat risker skall analyseras och åtgärder föreslås. Vattensäkerhetsplanerna bidrar till en viktig ökad fokus på riskfrågor kopplat till dricksvatten och förväntas bli del av EU:s dricksvattendirektiv. För att möjliggöra det som WHO förespråkar krävs dock lämpliga metoder och verktyg.Tillgången till metoder för att genomföra integrerade riskanalyser av dricksvattensystemet är begränsad. Med integrerad avses att hela systemet, från råvatten till tappkran, inkluderas. En metod baserad på felträdsteknik har utvecklats för att visa hur så kallade integrerade riskanalyser kan genomföras och vilka möjligheter det ger. Ett felträd är en modell som beskriver hur olika händelser förhåller sig till varandra och vad som måste hända för att problem skall uppstå. Med hjälp av metoden kan risken beräknas för hela systemet samt för delar av systemet. Detta ger möjlighet att se hur olika delar av systemet bidrar till den totala risken. Både en kvantitets- och en kvalitetsrelaterad risk beräknas, och de uttrycks som antalet minuter per år den genomsnittlige brukaren (i) blir utan vatten och (ii) får vatten som inte uppfyller kvalitetskraven. Utöver risknivåerna ger modellen information om hur ofta händelser inträffar och hur varaktiga de är.Den framtagna metoden är ett bidrag till den verktygslåda som dricksvattenproducenter världen över bör ha tillgång till för att underlätta arbetet med vattensäkerhetsplaner och riskhantering i stort.
|
|
| 27. |
- Lindhe, Andreas, 1981, et al.
(författare)
-
Uncertainty modelling in multi-criteria analysis of water safety measures
- 2013
-
Ingår i: Environment Systems & Decisions. - : Springer Science and Business Media LLC. - 2194-5403 .- 2194-5411. ; 33:2, s. 195-208
-
Tidskriftsartikel (refereegranskat)abstract
- Water utilities must assess risks and make decisions on safety measures in order to obtain a safe and sustainable drinking water supply. The World Health Organization emphasises preparation of Water Safety Plans, in which risk ranking by means of risk matrices with discretised probability and consequence scales is commonly used. Risk ranking enables prioritisation of risks but there is currently no common and structured way of performing uncertainty analysis and using risk ranking for evaluating and comparing water safety measures. To enable a proper prioritisation of safety measures and an efficient use of available resources for risk reduction, two alternative models linking risk ranking and multi-criteria decision analysis (MCDA) are presented and evaluated. The two models specifically enable uncertainty modelling in MCDA and they differ in terms of how uncertainties in risk levels are considered. The need of formal handling of risk and uncertainty in MCDA is emphasised in the literature and the suggested models provide innovations that are not dependent on the application domain. In the case study application presented here, possible safety measures are evaluated based on the benefit of estimated risk reduction, the cost of implementation and the probability of not achieving an acceptable risk level. Additional criteria such as environmental impact and consumer trust may also be included when applying the models. The case study shows how safety measures can be ranked based on preference scores or cost-effectiveness and how measures not reducing the risk enough can be identified and disqualified. Furthermore, the probability of each safety measure being ranked highest can be calculated. The two models provide a stepwise procedure for prioritising safety measures and enable a formalised handling of uncertainties in input data and results.
|
|
| 28. |
- Lindhe, Andreas, 1981, et al.
(författare)
-
Verktyg för kvantitativ mikrobiologisk riskbedömning (QMRA) av små avloppsanläggningar nära dricksvattenbrunnar – Manual 2016-03-31
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna manual är avsedd att ge vägledning för att använda ett nyutvecklat verktyg för kvantitativ mikrobiologisk riskbedömning (QMRA) av små avloppsanläggningar nära dricksvattenbrunnar. Som grund för verktyget ligger projektet Verktyg för mikrobiell riskanalys av små avloppsanläggningar nära dricksvattenbrunnar, finansierat av Havs- och vattenmyndigheten inom ramen för anslag 1:12 Åtgärder för havs- och vattenmiljöer. Den teoretiska bakgrunden till detta verktyg (QMRA-verktyget) med redogörelse för antaganden, men även en kortfattad manual, har tidigare redovisats tillsammans med ett fältförsök med bakteriofager i markens mättade grundvattenzon. QMRA-verktyget ska kunna användas av tillsynsmyndigheten för att analysera risken för smittspridning från befintliga avloppsanläggningar men också i planeringssyfte vid bedömning av rimliga säkerhetsavstånd och placering av nya små avlopp och dricksvattenbrunnar. Verktyget är utformat enligt grunderna för kvantitativ mikrobiologisk riskbedömning som inkluderar fyra huvudsteg: faroidentifiering, exponeringsbedömning, dos-respons-bedömning och riskkarakterisering. Modellutvecklingen har framförallt varit inriktad på exponeringsbedömningen och att ta fram en modell som beaktar den barriäreffekt som uppnås via slamavskiljaren, biohuden, transport i markens omättade zon samt transport i markens mättade grundvattenzon. Speciellt fokus har riktats mot transporten och avskiljningen i mättad grundvattenzon. Modellen är fritt tillgänglig som en webb-länk och kräver ingen installation på den egna datorn, även om möjlighet finns till detta.I denna manual beskrivs indata och hur en modellering genomförs, steg för steg. QMRA-verktyget kan ses som ett komplement och fördjupande verktyg i arbetet med att bedöma den smittorisk som små avloppsanläggningar medför. Under hösten 2015 genomfördes utbildningsseminarier under en dag i Uddevalla, Alingsås respektive Norrtälje kommun riktade till miljö- och hälsoskyddsinspektörerna. Under dessa seminarier fick deltagarna dels föreläsningar inom mikrobiologi, riskbedömning och hydrogeologi, dels en presentation av modellverktyget. Deltagarna fick själva testa verktyget på medhavda exempel. Utöver att sprida kunskap om verktyget syftade seminarierna till att generera erfarenhet och underlag för att förbättra verktyget. Den version av QMRA-verktyget som beskrivs i denna manual är en produkt av genomförda seminarier. I ett avslutande kapitel redovisas modelljusteringar samt några av de viktigaste aspekterna som diskuterades vid seminarierna.
|
|
| 29. |
- Lindhe, Andreas, 1981, et al.
(författare)
-
Verktyg för mikrobiell riskanalys (MRA) av små avloppsanläggningar nära dricksvattenbrunnar – Modellutveckling och fältförsök
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Föreliggande rapport utgör slutredovisningen av projektet Verktyg för mikrobiell riskanalys av små avloppsanläggningar nära dricksvattenbrunnar, som finansierats av Havs- och vattenmyndigheten inom ramen för anslag 1:12 Åtgärder för havs- och vattenmiljöer. I utlysningen konstateras att små avlopp utgör ett betydande problem och att det därför är viktigt att stimulera fortsatt utveckling inom verksamhetsområdet.Projektet som redovisas i denna rapport fokuserade på smittspridning från små avlopp till närliggande dricksvattenbrunnar. Ett verktyg i form av en datormodell för mikrobiell riskanalys (MRA) anpassad till enskilda avlopp har utvecklats och ett fältförsök har genomförts för att få ökad kunskap om virustransport i grundvatten. Projektet har genomförts i samarbete mellan Chalmers tekniska högskola (DRICKS – Centrum för dricksvattenforskning), Tyréns AB och Sveriges geologiska undersökning. Folkhälsomyndigheten och Norges miljø- og biovitenskapelige universitet (NMBU) har genomfört vattenanalyser. Representanter från Uddevalla kommun, Trollhättans Stad och Alingsås kommun har tillhandahållit synpunkter på den MRA-modell som utvecklats.Författarna vill rikta ett stort tack till Uddevalla kommun och speciellt Tony Grantz som medverkat i projektet och praktiskt bistått i fältförsökets genomförande. Ett stort tack riktas också till Stiftelsen Backamo Lägerplats som upplåtit det aktuella fallstudieområdet.Projektet som presenteras i denna rapport har varit nära knutet till andra pågående projekt vid Chalmers som behandlar mikrobiella risker och grundvattenfrågor, men då med fokus på kommunala grundvattentäkter. Författarna är mycket tacksamma för finansieringen från Havs- och vattenmyndigheten, vilket möjliggjort detta projekt och därmed också en fortsatt utveckling inom området. Förhoppningen är att den utvecklade MRA-modellen, trots kvarstående förbättringsmöjligheter, ska komma till praktisk nytta och underlätta bedömningen av den hälsorisk enskilda avlopp kan utgöra.
|
|
| 30. |
- Rosen, Lars, 1962, et al.
(författare)
-
Comparing risk-reduction measures to reach water safety targets using an integrated fault tree model
- 2010
-
Ingår i: Water Science and Technology: Water Supply. - : IWA Publishing. - 1606-9749. ; 10:3, s. 428-436
-
Tidskriftsartikel (refereegranskat)abstract
- In the third edition of the Guidelines for Drinking-water Quality, the World Health Organization concludes that an integrated management of risks in source waters, treatment systems and distribution networks is the most effective way to guarantee safe drinking water to consumers. The integrated approach is fundamental to avoid sub-optimisation of risk-reduction measures. This paper presents an application of an integrated and quantitative risk model for comparing risk-reduction measures to support decisions for reaching specified water safety targets. A fault tree approach is used for structuring the risk analysis and for estimating the risk, expressed as Customer Minutes Lost (CML). Input information is a combination of hard data and expert judgements. Uncertainties in input information are considerable and modelled by a Bayesianstatistical approach. A drinking water system in Sweden is used to exemplify model application. Quantitative safety targets have been confirmed at the political level as a basis for long-term planning of investments and reinvestments. One target defines an acceptable risk level of 144 annual CML for the average consumer. For the current system structure an estimated risk of 612CML was obtained. Four risk-reduction alternatives were compared and they reduce the risk to between 50 and 81 CML, i.e. below the acceptable level. The paper describes how a structuredand thorough analysis of risk-reduction measures can facilitate transparency and long-term planning of drinking water systems.
|
|
| 31. |
- Schooneveldt, Gerben, et al.
(författare)
-
Hyperthermia treatment planning including convective flow in cerebrospinal fluid for brain tumour hyperthermia treatment using a novel dedicated paediatric brain applicator
- 2019
-
Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 11:8
-
Tidskriftsartikel (refereegranskat)abstract
- Hyperthermia therapy (40–44 °C) is a promising option to increase efficacy of radiotherapy/chemotherapy for brain tumours, in particular paediatric brain tumours. The Chalmers Hyperthermia Helmet is developed for this purpose. Hyperthermia treatment planning is required for treatment optimisation, but current planning systems do not involve a physically correct model of cerebrospinal fluid (CSF). This study investigates the necessity of fluid modelling for treatment planning. We made treatments plans using the Helmet for both pre-operative and post-operative cases, comparing temperature distributions predicted with three CSF models: A convective “fluid” model, a non-convective “solid” CSF model, and CSF models with increased effective thermal conductivity (“high-k”). Treatment plans were evaluated by T90, T50 and T10 target temperatures and treatment-limiting hot spots. Adequate heating is possible with the helmet. In the pre-operative case, treatment plan quality was comparable for all three models. In the post-operative case, the high-k models were more accurate than the solid model. Predictions to within ±1 °C were obtained by a 10–20-fold increased effective thermal conductivity. Accurate modelling of the temperature in CSF requires fluid dynamics, but modelling CSF as a solid with enhanced effective thermal conductivity might be a practical alternative for a convective fluid model for many applications.
|
|
| 32. |
- Sun, Siao, et al.
(författare)
-
A Bayesian method for missing rainfall estimation using a conceptual rainfall–runoff model
- 2017
-
Ingår i: Hydrological Sciences Journal. - : Taylor & Francis. - 0262-6667 .- 2150-3435. ; 62:15, s. 2456-2468
-
Tidskriftsartikel (refereegranskat)abstract
- The estimation of missing rainfall data is an important problem for data analysis and modelling studies in hydrology. This paper develops a Bayesian method to address missing rainfall estimation from runoff measurements based on a pre-calibrated conceptual rainfall–runoff model. The Bayesian method assigns posterior probability of rainfall estimates proportional to the likelihood function of measured runoff flows and prior rainfall information, which is presented by uniform distributions in the absence of rainfall data. The likelihood function of measured runoff can be determined via the test of different residual error models in the calibration phase. The application of this method to a French urban catchment indicates that the proposed Bayesian method is able to assess missing rainfall and its uncertainty based only on runoff measurements, which provides an alternative to the reverse model for missing rainfall estimates.
|
|
| 33. |
- Andersson Chan, Anneli, 1971-, et al.
(författare)
-
Increased nitrogen removal in existing volumes at Sundet wastewater treatment plant, Växjö
- 2014
-
Ingår i: Water practice and technology. - : IWA Publishing. - 1751-231X. ; 9:2, s. 215-224
-
Tidskriftsartikel (refereegranskat)abstract
- Many wastewater treatment plants need to improve their nitrogen removal due to stricter requirements and increasing loads. This often means larger bioreactor volumes, which can be very expensive and is sometimes impossible if space is limited. Therefore, there is a need for compact hybrid solutions that can increase capacity within existing volumes. Two full-scale demonstration projects using moving bed biofilm reactor (MBBR) technology has proven to be an efficient way to treat nitrogen in existing volumes at Sundet wastewater treatment plant in Växjö. Increased nitrification and denitrification capacity in parts of the main stream were demonstrated through the Hybas™ process, a combination of MBBR and activated sludge using the integrated fixed-film activated sludge technology. The ANITA™ Mox process, using autotrophic N-removal through anaerobic ammonium oxidation (anammox), provided high nitrogen removal for the sludge liquor. Data collected on-site for over a year are analyzed and compared with the performance of conventional treatment systems. These two full-scale demonstration projects have been a successful learning experience in identifying and correcting both process and operational issues, which may not have arisen at pilot scale. The set objectives in terms of nitrogen removal were met for both processes and design modifications have been identified that will improve future operation at Sundet WWTP.
|
|
| 34. |
- Annaduzzaman, Md, 1986-
(författare)
-
Chitosan biopolymer as an adsorbent for drinking water treatment : Investigation on Arsenic and Uranium
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In many countries over the world (including Sweden), metal toxicity in freshwater resources causes a severe drinking water quality problem and poses a threat to the environment and human health. Among the different toxic metals in the water resources of Sweden, arsenic and uranium are the biggest threats to health. These elements, over long time consumption, may even lead to cancer and/or neurological disorder. Most of the wells are installed in crystalline and sedimentary bedrock and the received water comes from water bearing fractures in the bedrock. The handling of such water is an issue and there is a need to reduce the arsenic and uranium exposure by improving processes and technologies. It is a very serious problem demanding a safe, sustainable and eco-friendly arsenic and uranium removal technology prior to drinking water supply. Different treatment systems are available, but many of them are not suitable due to their high cost, operation complexity and waste management issues. Through this study, chitosan biopolymer the second largest abundant polysaccharide on earth after cellulose, was verified as a potential adsorbent for arsenic(V) and uranium(VI) removal from water solution. Adsorbent characterizations were also conducted by XRD, FTIR, SEM, UV-visible spectrum and TGA/DTA investigations. Bench-scale batch experiments were conducted using chitosan biopolymer (DDA-85%) as an adsorbent to determine the arsenic(V) and uranium(VI) removal efficiency, by allowing four important effective parameters e.g. chitosan dosages, pH, contact time and contaminant concentration. The adsorption data at optimum conditions were fitted with Langmuir, Freundlich and Dubinin-Radushkhevic (D-R) isotherm and Lagergren pseudo-first-order and pseudo-second-order kinetic model to investigate the adsorption process. The characterization of materials assured the presence of effective amino, hydroxyl, and carboxyl groups of chitosan. Another advanntage is that the materials are bio-degradable. The results show that the arsenic(V) and uranium(VI) removal efficiency was 100% and 97.45% after 300 minutes with optimum pH of 6.0 and 7.0 respectively. The optimum adsorbent dosages and initial concentration were 60 and 80g/L and 100 and 250 µg/L respectively. The adsorption process was suitably described by Freundlich isotherm (R2 = 0.9933) and Langmuir isotherm (R2 = 0.9858) correspondingly for arsenic(V) uranium(VI) compared to other isotherms. This is an important indicator of homogeneous monolayer adsorption of metals. For both of arsenic(V) and uranium(VI), pseudo-second-order explained the adsorption kinetics better than pseudo-first-order and the second-order kinetic regression coefficient (R2) were 0.9959 and 0.9672 correspondingly. Connecting to the above mentioned results, it can be summed up that the chitosan biopolymer (DDA 85%) can be used as an inexpensive, sustainable and environment-friendly treatment option for arsenic(V) and uranium(VI) contaminated drinking water.
|
|
| 35. |
- Bergion, Viktor, 1986
(författare)
-
Development of a Risk-Based Decision Model for Prioritizing Microbial Risk Mitigation Measures in Drinking Water Systems
- 2017
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Risk management of drinking water systems is crucial since our society relies on these systems to be robust and sustainable to supply safe drinking water now and to future generations. Pathogens may spread in drinking water systems and cause waterborne outbreaks resulting in human suffering and large costs to the society. Thus, mitigating microbial risks is of great importance for provision of safe drinking water in a changing world. Since risk mitigation measures can be costly, there is a need for a transparent and holistic decision support to enable a sound and efficient use of available resources. In this thesis, a risk-based decision model that facilitates evaluation and comparison of microbial risk mitigation measures is presented. The model was developed by combining source characterisation, water quality modelling, quantitative microbial risk assessment and cost-benefit analysis. Uncertainties associated with input variables and output results were analysed by means of Monte Carlo simulations. The decision model puts emphasis on health benefits obtained from reduced microbial risks in drinking water systems and the monetisation of these effects. In addition, the approach also accounts for non-health benefits that occur because of implemented mitigation measures. Such benefits, also if they cannot be monetised, are important to include and carefully consider in the cost-benefit analysis. The probabilistic approach provides an analysis of uncertainties that need to be considered by decision makers. To conclude, this thesis underlines and illustrates the strength of combining methods from several disciplines to create a robust decision support in order to optimise societal benefits.
|
|
| 36. |
- Bergion, Viktor, 1986
(författare)
-
Risk-Based Decision Model for Microbial Risk Mitigation in Drinking Water Systems
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Microbial risks in drinking water systems can cause sporadic pathogenic infections and waterborne outbreaks resulting in large costs for society. In 2010 for example, around 27,000 persons were infected with Cryptosporidium in Östersund, Sweden. It is so far the largest waterborne outbreak in Europe, and societal costs were estimated at SEK 220 million (approx. 20 million €). To achieve a safe drinking water supply, assessment of microbial risks and, when needed, implementation of risk mitigation measures is necessary. However, drinking water systems are complex, and risk mitigation measures are expensive. A thorough evaluation of possible mitigation measures is thus essential for identification of the most suitable alternative and efficient use of societal resources. In this thesis, a risk-based decision model for evaluating and comparing microbial risk mitigation measures in drinking water systems is presented and illustrated using two Swedish case studies. The decision model combines quantitative microbial risk assessment and cost-benefit analysis in order to evaluate decision alternatives from the perspective of social profitability. The quantitative microbial risk assessment is complemented with water quality modelling and consideration of unexpected risk events, such as extreme weather events and combined sewer overflows, in order to reflex the complexity of drinking water systems. To facilitate transparent cost-benefit analyses, the effect of different health valuation methods on the output from the decision model is presented. In the decision model, health benefits and other benefits are monetised for each mitigation measure and compared to the costs for implementing the measure. It is possible to combine decision criteria such as tolerable risk levels and maximising the net present value when applying the decision model. The decision model integrates several scientific disciplines, thus constituting a novel approach to evaluate microbial risk mitigation measures in drinking water systems and provides a structured analysis that includes often neglected aspects. The model provides transparent and holistic decision support and facilitates well-founded decisions balancing risks, costs and societal benefits.
|
|
| 37. |
- Björklund, Karin, 1979, et al.
(författare)
-
Hydrodynamic modelling of the influence of stormwater and combined sewer overflows on receiving water quality: Benzo(a)pyrene and copper risks to recreational water
- 2018
-
Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 207, s. 32-42
-
Tidskriftsartikel (refereegranskat)abstract
- The risk from chemical substances in surface waters is often increased during wet weather, due to surface runoff, combined sewer overflows (CSOs) and erosion of contaminated land. There are strong incentives to improve the quality of surface waters affected by human activities, not only from ecotoxicity and ecosystem health perspectives, but also for drinking water and recreational purposes. The aim of this study is to investigate the influence of urban stormwater discharges and CSOs on receiving water in the context of chemical health risks and recreational water quality. Transport of copper (Cu) and benzo[a]pyrene (BaP) in the Göta River (Sweden) was simulated using a hydrodynamic model. Within the 16 km modelled section, 35 CSO and 16 urban stormwater point discharges, as well as the effluent from a major wastewater treatment plant, were included. Pollutant concentrations in the river were simulated for two rain events and investigated at 13 suggested bathing sites. The simulations indicate that water quality guideline values for Cu are exceeded at several sites, and that stormwater discharges generally give rise to higher Cu and BaP concentrations than CSOs. Due to the location of point discharges and the river current inhibiting lateral mixing, the north shore of the river is better suited for bathing. Peak concentrations have a short duration; increased concentrations of the pollutants may however be present for several days after a rain event. Monitoring of river water quality indicates that simulated Cu and BaP concentrations are in the same order of magnitude as measured concentrations. It is concluded that hydrodynamic modelling is a useful tool for identifying suitable bathing sites in urban surface waters and areas of concern where mitigation measures should be implemented to improve water quality.
|
|
| 38. |
|
|
| 39. |
- Christensson, Magnus, et al.
(författare)
-
Experience from start-ups of the first ANITA Mox Plants
- 2013
-
Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 67:12, s. 2677-2684
-
Tidskriftsartikel (refereegranskat)abstract
- ANITA (TM) Mox is a new one-stage deammonification Moving-Bed Biofilm Reactor (MBBR) developed for partial nitrification to nitrite and autotrophic N-removal from N-rich effluents. This deammonification process offers many advantages such as dramatically reduced oxygen requirements, no chemical oxygen demand requirement, lower sludge production, no pre-treatment or requirement of chemicals and thereby being an energy and cost efficient nitrogen removal process. An innovative seeding strategy, the 'BioFarm concept', has been developed in order to decrease the start-up time of new ANITA Moxinstallations. New ANITA Mox installations are started with typically 3-15% of the added carriers being from the 'BioFarm', with already established anammox biofilm, the rest being new carriers. The first ANITA Mox plant, started up in 2010 at Sjolunda wastewater treatment plant (WWTP) in Malmo, Sweden, proved this seeding concept, reaching an ammonium removal rate of 1.2 kgN/m(3) d and approximately 90% ammonia removal within 4 months from start-up. Thisfirst ANITA Mox plant is also the BioFarm used for forthcoming installations. Typical features of this first installation were low energy consumption, 1.5 kW/NH4-N-removed, low N2O emissions, <1% of the reduced nitrogen and a very stable and robust process towards variations in loads and process conditions. The second ANITA Mox plant, started up at Sundets WWTP in Vaxjo, Sweden, reached full capacity with more than 90% ammonia removal within 2 months from start-up. By applying a nitrogen loading strategy to the reactor that matches the capacity of the seeding carriers, more than 80% nitrogen removal could be obtained throughout the start-up period.
|
|
| 40. |
- Engström, Rebecka Ericsdotter, et al.
(författare)
-
Connecting the resource nexus to basic urban service provision – with a focus on water-energy interactions in New York City
- 2017
-
Ingår i: Sustainable cities and society. - : Elsevier. - 2210-6707. ; 31, s. 83-94
-
Tidskriftsartikel (refereegranskat)abstract
- Urban water and energy systems are crucial for sustainably meeting basic service demands in cities. This paper proposes and applies a technology-independent “reference resource-to-service system” framework for concurrent evaluation of urban water and energy system interventions and their ‘nexus’ or ‘interlinkages’. In a concrete application, data that approximate New York City conditions are used to evaluate a limited set of interventions in the residential sector, spanning from low-flow toilet shifts to extensive green roof installations. Results indicate that interventions motivated primarily by water management goals can considerably reduce energy use and contribute to mitigation of greenhouse gas emissions. Similarly, energy efficiency interventions can considerably reduce water use in addition to lowering emissions. However, interventions yielding the greatest reductions in energy use and emissions are not necessarily the most water conserving ones, and vice versa. Useful further research, expanding the present analysis should consider a broader set of resource interactions, towards a full climate, land, energy and water (CLEW) nexus approach. Overall, assessing the impacts, trade-offs and co-benefits from interventions in one urban resource system on others also holds promise as support for increased resource efficiency through integrated decision making.
|
|
| 41. |
- Fredriksson, Johan, 1979, et al.
(författare)
-
Long-term dynamics of the bacterial community in a Swedish full-scale wastewater treatment plant
- 2019
-
Ingår i: Environmental Technology. - : Informa UK Limited. - 0959-3330 .- 1479-487X. ; 40:7, s. 912-928
-
Tidskriftsartikel (refereegranskat)abstract
- The operational efficiency of activated sludge wastewater treatment plants depends to a large extent on the microbial community structure of the activated sludge. The aims of this paper are to describe the composition of the bacterial community in a Swedish full-scale activated sludge wastewater treatment plant, to describe the dynamics of the community and to elucidate possible causes for bacterial community composition changes. The bacterial community composition in the activated sludge was described using 16S rRNA gene libraries and monitored for 15 months by a terminal restriction fragment (T-RF) length polymorphism (T-RFLP) analysis of the 16S rRNA gene. Despite variable environmental conditions, a large fraction of the observed T-RFs were present at all times, making up at least 50% in all samples, possibly representing a relatively stable core fraction of the bacterial community. However, the proportions of the different T-RFs in this fraction as well as the T-RFs in the more variable fraction showed a significant variation over time and temperature. The difference in community composition between summer and winter coincided with observed differences in floc structure. These observations suggest a relationship between floc properties and bacterial community composition, although additional experiments are required to determine causality.
|
|
| 42. |
|
|
| 43. |
|
|
| 44. |
- Helgegren, Ida, 1986, et al.
(författare)
-
Contextualizing Sustainable Development for Small Scale Water and Sanitation Systems in Cochabamba, Bolivia
- 2013
-
Ingår i: Urban Environment. - 9789400777569 ; , s. 217-225
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Water and sanitation are pressing issues for the urban poor in Bolivia where the lack of safe water and sanitation services contributes to urban poverty. This paper defines sustainable development (SD) in relation to small scale water and sanitation systems in the metropolitan area of Cochabamba, Bolivia. A case study on the water and sanitation systems of two housing cooperatives is performed. By involving all the concerned stakeholders this study aims to identify a contextualized definition of SD, which can be used in order to assess and steer the development of small scale water and sanitation systems in the metropolitan area of Cochabamba. The identified definition consists of the following criteria, referred to as key issues: social context, socio-political factors, target group, freshwater resources, economic obstacles, reproducibility, knowledge, management, reliability, water quality and disposal. Three main challenges are identified to have had major influence on the contextualization of the SD concept: which stakeholders that are included, how the differing opinions among the stakeholders are addressed and how active the stakeholders are in the development process.
|
|
| 45. |
- Liu, Ting, et al.
(författare)
-
Experiments of Air-pocket Movement in an 18.2 degrees downward 240-mm Conduit
- 2012
-
Ingår i: 2012 International Conference On Modern Hydraulic Engineering. - : Elsevier. ; 28, s. 791-795
-
Konferensbidrag (refereegranskat)abstract
- Experiments are carried out in a test rig, consisting of a Plexiglas pipe with an inner diameter of 240 mm and an inclination of 18.2o, to investigate air-water two-phase flows in conjunction with bottom spillways. Results show that the critical velocity, which is the minimal water velocity to start moving an air pocket, in the rough pipe, is independent of the air-pocket volume; in the smooth pipe it doesn't increase with increasing diameter as much as the previous researchers indicated. Pipe roughness doesn't affect the velocity of the air-pocket when it moves upstream in the downward inclined pipe.
|
|
| 46. |
|
|
| 47. |
- PALALANE, JAIME
(författare)
-
Processes of long-term coastal evolution and their mathematical modelling : Application to the Mozambican coast
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Different processes in response to the action of natural driven forces and the human interference on coastal systems act together, contributing to shape the coast. Coastal evolution models have been developed as useful tools to better understand the contribution of different processes on observed coastal changes, and also to anticipate future evolution in response to different actions and interventions taking place along the coast.The predominant practice in coastal modelling is to have models that address separately the evolution as a result of cross-shore sediment transport processes from the ones caused by processes with main effects on the alongshore sediment transport. However, if longer time and spatial scales are to be covered by such models, a combination of cross-shore and longshore processes is crucial. In this context, the thesis explores the possibility of improving the mathematical modelling of long-term coastal evolution by integrating cross-shore evolution processes into a regional coastal evolution model.The developed models were satisfactorily tested against available data, as they could reproduce the observed coastal evolution. The model development stage was followed by its application to simulate the long-term coastal evolution of selected coastal stretches of Mozambique’s 2800-km-long coastline. Based on a literature review of different processes influencing the evolution of the Mozambican coast, the potential contribution of mathematical models to improve the local coastal planning and management was explored.With the model application to the Mozambican coast, it was possible to estimate sediment transport rates, and to reproduce the long-term evolution of the coast, for a period up to nearly two decades. For that reason, mathematical models are considered a valid tool to improve the understanding of the historical long-termcoastal evolution, and to anticipate how it will change in the future. The latter information would be valuable for the improvement of the protection of coastal sensitive systems, reinforcing the integration component, the use of soft approaches in coastal protection projects, and for the definition of setback lines.
|
|
| 48. |
|
|
| 49. |
- Teng, Penghua
(författare)
-
CFD MODELLING AND EXPERIMENTS ON AERATOR FLOW IN CHUTE SPILLWAYS
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A chute spillway is a typical component of large dams for discharging floods. Because of the high water head, the flow velocity in the chute is often in excess of 20 m/s. Consequently, the structure is usually prone to cavitation damages. Flow aeration is evidenced to efficiently eliminate or to mitigate the damages. An aerator is a device that entrains air into the water flows and is an effective technical measure to counter the cavitation damages.Aerator flow includes intense air-water exchange and involves a process of air entrainment, transport, and detrainment. Because of the complex phenomena, it is still a challenge to investigate the behaviors of interaction between air and water. It is fundamental to understand the flow behaviors downstream of the aerator. This thesis investigates the aerator flow features using both the Computational Fluid Dynamics (CFD) and advanced measurement techniques.The CFD method presents three two-phase flow models to describe the aerator flows, namely, the Volume of Fluid Model, the Mixture Model, and the Two-Fluid Model. They are applied and evaluated via practical engineering projects and experimental data. The Volume of Fluid model leads to reasonable results regarding the water flow discharge and flow fields. For predicting the air concentration distribution and air bubble transport processes, the Two-Fluid Model is superior to others because it includes forces acting on the air bubbles. However, the model still overestimates the air content near the chute bottom. Based on the aerator flow from a chute spillway in Sweden, three two-phase flow models are applied and compared.Physical model tests are commonly conducted to investigate aerator flow features. Because of the scale effects, the results may lead to a discrepancy in the flow behaviors compared with the prototype. Thus, CFD modeling becomes an alternative tool when seeking the reason for the difference. Based on the aerator flow in a real spillway, CFD is applied to reproduce the flow; the discrepancy between the model tests and prototype observations is evidenced. The results show similar flow features with the prototype but differ from those of the model tests. An explanation for the discrepancy is discussed in terms of flow features, effect of surface tension in model tests, and the prerequisite for air entrainment of the free-surface flow.Laboratory experiments are conducted to study the aerator flow in a chute. Four image-based measurement techniques－i.e., high-speed particle image velocimetry (HSPIV), shadowgraphic image method (SIM), bubble tracking method (BTM), and bubble image velocimetry (BIV)－are employed. The study focuses on issues of exploring characteristic positions of water-air interfaces, interpreting the evaluation process of air bubbles shed from the tip of the air cavity, identifying the probabilistic means for characteristic positions near the fluctuating free surface, and obtaining the flow field both water flow and air bubbles features of the aerator flow. The application of these techniques leads to a better understanding of two-phase flow characteristics of the chute aerator.
|
|
| 50. |
- Vinas, Victor, 1988, et al.
(författare)
-
Overview of microbial risks in water distribution networks and their health consequences : Quantification, modelling, trends, and future implications
- 2019
-
Ingår i: Canadian journal of civil engineering (Print). - : Canadian Science Publishing. - 0315-1468 .- 1208-6029. ; 46:3, s. 149-159
-
Tidskriftsartikel (refereegranskat)abstract
- The water distribution network (WDN) is usually the final physical barrier preventing contamination of the drinking water before it reaches consumers. Because the WDN is at the end of the supply chain, and often with limited online water quality monitoring, the probability of an incident to be detected and remediated in time is low. Microbial risks that can affect the distribution network are: intrusion, cross-connections and backflows, inadequate management of reservoirs, improper main pipe repair and (or) maintenance work, and biofilms. Epidemiological investigations have proven that these risks have been sources of waterborne outbreaks. Increasingly since the 1990s, studies have also indicated that the contribution of these risks to the endemic level of disease is not negligible. To address the increasing health risks associated to WDNs, researchers have developed tools for risk quantification and risk management. This review aims to present the recent advancements in the field involving epidemiological investigations, use of quantitative microbial risk assessment (QMRA) for modelling, risk mitigation, and decision-support. Increasing the awareness of the progress achieved, but also of the limitations and challenges faced, will aid in accelerating the implementation of QMRA tools for WDN risk management and as a decision-support tool.
|
|
