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  • 251.
    Ekelund, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Barandka, Saioa Ibarrola
    SWECO.
    Kreativ snöhantering2014Report (Other academic)
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  • 252.
    Ekka, Sujit A.
    et al.
    Department of Biological and Agricultural Engineering, North Carolina State University, Box 7625, Raleigh, NC, 27695, USA. Department of Environment-Water Resources, AECOM, 1600 Perimeter Park Dr, Suite 400, Morrisville, NC, 27560, USA.
    Rujner, Hendrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Leonhardt, Günther
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hunt, William F.
    Department of Biological and Agricultural Engineering, North Carolina State University, Box 7625, Raleigh, NC, 27695, USA.
    Next generation swale design for stormwater runoff treatment: A comprehensive approach2021In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 279, article id 111756Article, review/survey (Refereed)
    Abstract [en]

    Swales are the oldest and most common stormwater control measure for conveying and treating roadway runoff worldwide. Swales are also gaining popularity as part of stormwater treatment trains and as crucial elements in green infrastructure to build more resilient cities. To achieve higher pollutant reductions, swale alternatives with engineered media (bioswales) and wetland conditions (wet swales) are being tested. However, the available swale design guidance is primarily focused on hydraulic conveyance, overlooking their function as an important water quality treatment tool. The objective of this article is to provide science-based swale design guidance for treating targeted pollutants in stormwater runoff. This guidance is underpinned by a literature review.

    The results of this review suggest that well-maintained grass swales with check dams or infiltration swales are the best options for runoff volume reduction and removal of sediment and heavy metals. For nitrogen removal, wet swales are the most effective swale alternative. Bioswales are best for phosphorus and bacteria removal; both wet swales and bioswales can also treat heavy metals. Selection of a swale type depends on the site constraints, local climate, and available funding for design, construction, and operation. Appropriate siting, pre-design site investigations, and consideration of future maintenance during design are critical to successful long-term swale performance. Swale design recommendations based on a synthesis of the available research are provided, but actual design standards should be developed using local empirical data. Future research is necessary to identify optimal design parameters for all swale types, especially for wet swales.

  • 253.
    Elhammeli, Alaaeddin A.
    et al.
    Mechanical Engineering Faculty of Engineering and Applied Science, Memorial Univ of Newfoundland, St. John's, NF.
    Muntasser, Mohamed A.
    Mechanical and Industrial Engineering Faculty of Engineering, Tripoli University.
    Lindblom, Jenny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Producing water by condensation of humid air in buried pipe2017In: Proceedings of the International Conference on Industrial Engineering and Operations Management: Rabat, Morocco, April 11-13, 2017, IEOM Society , 2017, p. 2270-2281Conference paper (Refereed)
    Abstract [en]

    This study investigates the possibility of using warm humid air for irrigation and drinking water production, by flowing air over the water surface in a solar still with saline or polluted water. Vapor will be saturated during mixing with the warm air in buried pipe. Finite difference method is employed to simulate the flow of the air long the pipe. The amount of water produced and buried pipe length depends upon the flow velocity, humid air properties and buried pipe diameter. The amount of water produced is 0.02525kg/s (0.0909m3/h). The length of the buried pipe needed in this study is 77.36m for a selected air flow velocity 5m/s with the properties of 70°C, 100% relative humidity at pipe inlet, 40°C and 100% relative humidity at pipe outlet of 0.2m pipe diameter. The results agree with a previous study (Gustafsson & Lindblom, 2001) with -4.0% deviation in water production and 7% of required pipe length

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  • 254.
    Elhammeli, Alaaeddin A.
    et al.
    Mechanical Engineering Faculty of Engineering and Applied Science, Memorial Univ of Newfoundland, St. John's, NF.
    Muntasser, Mohamed A.
    Mechanical and Industrial Engineering Faculty of Engineering, Tripoli University.
    Lindblom, Jenny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Producing water by condensation of humid air in buried pipe2017In: Proceedings of the International Conference on Industrial Engineering and Operations Management, IEOM Society , 2017, p. 2270-2281Conference paper (Refereed)
    Abstract [en]

    This study investigates the possibility of using warm humid air for irrigation and drinking water production, by flowing air over the water surface in a solar still with saline or polluted water. Vapor will be saturated during mixing with the warm air in buried pipe. Finite difference method is employed to simulate the flow of the air long the pipe. The amount of water produced and buried pipe length depends upon the flow velocity, humid air properties and buried pipe diameter. The amount of water produced is 0.02525kg/s (0.0909m3/h). The length of the buried pipe needed in this study is 77.36m for a selected air flow velocity 5m/s with the properties of 70°C, 100% relative humidity at pipe inlet, 40°C and 100% relative humidity at pipe outlet of 0.2m pipe diameter. The results agree with a previous study (Gustafsson & Lindblom, 2001) with -4.0% deviation in water production and 7% of required pipe length

  • 255.
    Elmozughi, A.F.
    et al.
    Al-Fateh University, Tripoli.
    Muntasser, M.A.
    Al-Fateh University, Tripoli.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Simulation of vertical U tube heat exchanger2009In: Effstock 2009, Thermal Energy Storage for Efficiency and Sustainability : / [ed] Signild Gehlin, Stockholm: Energi- och Miljötekniska Föreningen / EMTF Förlag , 2009Conference paper (Refereed)
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  • 256.
    Elmén Berg, Anna
    et al.
    Piteå museum. Kungliga Skytteanska samfundet.
    Sjöholm, Jennie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Trästaden Piteå — Riksintresset som (nästan) försvann2020In: Piteå museum årsbok 2020 / [ed] Morgan Stenberg, Piteå: Piteå museums förlag , 2020, p. 52-75Chapter in book (Other (popular science, discussion, etc.))
  • 257.
    Emil, Iversen
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Samhällsekonomisk analys av investerings- och driftåtgärder för cykling på landsbygd i kallt klimat: Fallstudie sträckan Umeå-Vännäs och utvärdering av GC-kalk 1.22020Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The Swedish Traffic Administration Region North requested an examination the conditions for a fast-cycling connection between Umeå and Vännäs in Västerbotten County. The distance between the locations is about 35 km. The towns are now linked by the road E12 which is not suitable for cycling, but along the E-road there remains parts of the old country road that runs through several small towns. These country roads have very low traffic flows and should be suitable for commuter cycling for adults, but in a few locations crossing of, or cycling along, the E12 is required. This study has focused on the following issues:

    • Is there a potential for bicycle commuting up to 35 km?
    • Is the tool GC-kalk and its methodology for socio-economic calculations suitable for cases of cycling commuting in rural areas and subarctic climate?
    • What level of investment measures in rural areas in a subarctic climate are viable from a cost-benefit analysis perspective?
    • How much can the benefits be increased through maintenance measures which extend the cycling season?

    This is a case study, centred on socio-economic calculations made with the Swedish Transport Administration's calculation tool GC-kalk, version 1.2. This is a qualitative analysis of quantified aspects: socio-economic calculations have been carried out using the Swedish Transport Administration's tools partly based on the Swedish Transport Administration's data and templates for calculations, and partly with other values ​​based on literature studies and from publications of the municipalities concerned. Travel patterns were obtained as secondary data from Statistics Sweden via the Municipality of Umeå. To test the influence of alternative values ​​in addition to main analyses according to the Swedish Transport Administration's normal methods for GC-kalk, other sensitivity analyses have been performed where specific parameters have been adjusted one by one. The results of the calculations are analysed partly to assess the cost-benefit viability of the measures, but also to assess the validity of the calculation tool and the calculation methods.

    The study was conducted mainly during the spring of 2015. Some revisions were made prior to the approval in 2019, but the study is based on the conditions in the spring of 2015. In this study, only the benefit of increased commuting cycling is considered. Cycling for exercise or recreation is not taken into account. Also, no potential benefit to pedestrians is considered. Geographically, the study is delimited to the countryside between Umeå and Vännäsby. Also, a new bridge over the river Vindelälven is not included in the cost as a separate project for that was already underway. Costs for land acquisition and planning have also been omitted.

    The study concludes that there is potential for some bicycle commuting at distances up to 35 km. The majority of the population in Sweden would probably not choose to cycle if they have 30 kilometres or more to commute daily, especially not with a traditional safety cycle. But the literature study shows that some few per cent of commuters in Sweden commutes by bike at a distance over 20 km in the summertime. It is also clear that the cycle as a vehicle is constantly evolving and that electric assistance and more aerodynamic and weather-protected bikes drastically increase the range for commuter cycling. Thus, during the snow-free season, there is potential for at least a few percent of commuting trips of 35 km to be made with some form of cycle. In winter, there does not appear to be any commuting at such distances at present, but if roads conditions corresponding to summer roads can be maintained, it is not unlikely that some bicycle commuting can also take place during winter.

    GC-kalk has several shortcomings regarding effects that are directly linked to traffic, among other things that it does not take into account the impact of the climate and that speed is based on urban conditions and only one type of bicycle. The validity of the tool can therefore be considered relatively low for analysis of rural measures in subarctic climate. Reliability is strongly dependent on the reliability of the parameters in the model. Existing manuals and templates promote calculations to be carried out in a consistent manner, but aspects such as waiting times at the intersection lack templates so the calculations are dependent on subjective values to some extent. The lack of a standardized input network also contributes to making the tool less reliable than, for example, the tool EVA that is used for calculations for motor traffic. At present, however, there seems to be no other tool in Sweden than GC-kalk for calculating the benefits of bicycle measures. Therefore, a better model and a better knowledge base, and thus more research, is needed.

    The results of the calculations for the studied route between Umeå and Vännäs indicate that measures that complements the existing road network should be render more benefits than costs. In sparsely populated places in cold climates, it is however usually not likely that separated bike lanes other than in urban areas would be render more benefits than costs.

    The calculated results show that cycling during the snow-free period may be sufficient for cycling measures to render more benefits than costs. But they also show that the benefits can be significantly increased through maintenance measures that extend the cycling season. In the studied case, the benefit of extending the cycling season from 106 days (for which the snow-free season is calculated) to 232 days (the default value in GC-kalk) will be about SEK 40 per meter if it is distributed throughout the entire route. This is significantly higher than both the Swedish Transport Administration's figure of SEK 15 per meter per year for snow removal and the ditto figure from the municipality of Umeå of SEK 33 per meter per year. The Swedish Transport Administration and other road maintainers should thus be able to add significantly more winter road maintenance for cyclists without causing the costs to exceed the benefits.

    The sensitivity analyses of the effect of speed change due to measures also shows that the effect of increasing the average speed by only 1 km / h can amount to several hundred thousand SEK per year. This means that maintenance measures that ensure that cyclists do not need to slow down due to, for example, snow, slippery autumn leaves, or crumbling paving can provide significant benefits.

    A further conclusion in addition to the answers to the posed research questions is that there is a plethora of bicycle types catering to various transportation needs, but current design guidelines for road infrastructure in Sweden only take into account standard cycles. Not even bicycles with trailers, which can be considered a fairly established vehicle combination, are mentioned in the Swedish Transport Administration's main design guidelines, Vägar och Gators Utformning (VGU). There is thus a risk that the infrastructure being built will not be suitable for, for example, wide cargo bikes or aerodynamic recumbent bicycles. This could hinder both families with children from choosing a bicycle instead of a car as well as citizens who want to commute by bicycle at a longer distance. It is therefore important to either redefine the type vehicle bicycle in VGU and other design guidelines to reflect the characteristics of all bicycle types, or to divide bicycles into multiple type vehicles.

  • 258. Engman, M.
    et al.
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Sundqvist, A.
    Goldkuhl, I.
    Wennberg, T.
    Some design considerations of high density base metal tailings handling systems2004In: Proceedings of the 12th international conference on Transport & sedimentation of solid particles joined with 12th international symposium on Freight pipelines: 20-24 September 2004, Prague, Czech Republic, Prague: Institute of Hydrodynamics, Academy of Sciences of the Czech Republic , 2004, p. 307-318Conference paper (Refereed)
  • 259.
    Engman, M.
    et al.
    LKAB.
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Sundqvist, Å,
    LKAB.
    Wennberg, Thord
    Goldkuhl, I.
    Multiserv.
    Users perspective on the design of high density base metal tailings systems2004In: Tailings and mine waste '04: Proceedings of the Eleventh International Conference on Tailings and Mine Waste, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 2004, p. 45-54Conference paper (Refereed)
  • 260.
    Engström, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Seasonal turnover in groundwater2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This Licentiate Thesis presents a new approach of understanding leakage in agricultural land. Former studies concentrate on long term measurement of different pollutants in nearby watercourses and streams. The new approach is so far only numerically performed, but will soon be complemented by laboratory tests and field measurements. Our hypothesis is that nutrient leakage into groundwater is caused by thermally driven groundwater convection. The maximum density of water occurs at a temperature of near 4oC. Thus, a density increase of the groundwater occurs by heating from about 0oC in the north of Sweden (springtime) and by cooling from about 10oC in the south (autumn). The depth of the convection (leakage) depends on the size of the thermal gradient. This hypothesis consequently explains both why the nutrient leakage occurs during different seasons in the north and south of Sweden and also why the leakage reaches greater depths in the south. The numerical results show that convection is induced by a small horizontal groundwater flow. In the south of Sweden the lowest required permeability for convection to occur was K=6.7∙10-10m2. In this soil the convection cells reached to a maximum depth of 6 meters. The Rayleigh number (Ra) could be as low as 19 for convection to occur, the general critical Ra is 40 in porous media. In northern Sweden a permeability of K=6.1∙10-92 was required. In this soil and climate convection occurred to depths from 0.2 to 0.9 meters. Transient solutions showed that the required time for the convection pattern to fully develop was 22 days. The effect of frost lenses on the groundwater convection was also studied. Small lenses changed the convection rolls slightly, while large obstacles forced the convection rolls to change size and shape. The simulations showed that the required grain size for convection to occur was considerably greater than the grain size in typical agricultural soils. Still vertical groundwater movements exist. Other possible explanations to groundwater convection in agricultural soil in northern Sweden are to be investigated. Unstable groundwater convection or oscillating convection cells, infiltration of rain and melt water, pressure induced convection and the possibility that Coriolis force due to Earth´s rotation could cause secondary currents in groundwater flow.

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  • 261.
    Engström, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. ÅF Industry AB.
    Secondary currents in groundwater2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis concerns the small vertical water movements created by thermal convection and the Coriolis force acting on groundwater flows. These small flows are of importance to vertical transports of temperature, nutrients and contaminants that would not be spread in the way they are. The first part analyzes thermally driven, seasonal groundwater convection by numerical simulation. The second part shows that the Coriolis force also induces secondary currents in groundwater flow through different vertical permeability distributions. Density driven convection occurs during the autumn in southern Sweden when the ambient air temperature cools the mean groundwater temperature from about 10ºC. When the shallow groundwater is cooled by the ambient air its increased density makes this water sink, slowly increasing in temperature, while pressing the warmer water upwards creating a convection cell. The process is ongoing as long as there is a thermal gradient between ground surface and the groundwater. Under favorable conditions convection can reach a depth of 6m. Such density-driven water movements occur most easily in more permeable soil. In northern Sweden, the situation is reversed, since the mean groundwater temperature is below 4ºC, at which water is at its density maximum. So, in springtime when the uppermost groundwater is heated to 4ºC by the warmer air the convection process starts. Here, the sinking groundwater does not reach the same depth, less than one meter. The Coriolis force has been considered too small to have any effect on groundwater flow, though its importance in meteorology and oceanography is well established. These theories have been applied using numerical simulations of groundwater flow. The numerical model has been validated by simulating some earlier studies of Coriolis forces in fluids. Furthermore the model has been extended to include porous media. It has been shown that secondary currents occur in nonlinear vertical permeability distributions. For simulations of constant and linear distributions no secondary currents have been seen. The development is more pronounced in confined aquifers. The structure of the bottom of the aquifer  affects  how the secondary currents arise. It was shown that both temperature gradients and the Coriolis force form secondary currents in groundwater and a general conclusion is that groundwater flow is more complex than previously assumed.

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  • 262.
    Engström, Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Earth’s Rotation Induces Vertical Ground Water Flow2007Conference paper (Other academic)
    Abstract [en]

    It is well established that the Coriolis Force deflects wind and water currents. However, its influence on groundwater flow is neglected. Earth’s rotation causes inertia circles in groundwater that create vortices ending up in different local pressure zones, similar to the high and low pressures in air. High pressure zones in groundwater induce, under certain conditions, a vertical flow up to the surface. This could be the missing link where hydrostatic pressure is not sufficient to explain springs in deserts, mountains and on islands in the sea. Here, simulations on the Coriolis force acting on groundwater flows are presented.

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  • 263.
    Engström, Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Seasonal groundwater turnover in the north and south of Sweden2007Conference paper (Other academic)
    Abstract [en]

    Nutrient leakage from agricultural areas in Sweden mainly occurs during the autumn in the south and during the spring in the north. The infiltration of nutrients also reaches greater depths in the south. An occurring “seasonal groundwater turnover” similar to that in lakes is the suggested mechanism. This thermal convection results from changing temperatures (densities). The 10oC groundwater in southern Sweden becomes denser as it is cooled from the surface in the autumn, while the corresponding convection in the North occurs during the spring. Performed simulations show how seasonal temperature variations, under certain conditions, initiate and drive thermal convection.

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  • 264.
    Engström, Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Temperature-driven groundwater convection in cold climates2016In: Hydrogeology Journal, ISSN 1431-2174, E-ISSN 1435-0157, Vol. 24, no 5, p. 1245-1253Article in journal (Refereed)
    Abstract [en]

    The aim was to study density-driven groundwater flow and analyse groundwater mixing because of seasonal changes in groundwater temperature. Here, density-driven convection in groundwater was studied by numerical simulations in a subarctic climate, i.e. where the water temperature was < 4 A degrees C. The effects of soil permeability and groundwater temperature (i.e. viscosity and density) were determined. The influence of impermeable obstacles in otherwise homogeneous ground was also studied. An initial disturbance in the form of a horizontal groundwater flow was necessary to start the convection. Transient solutions describe the development of convective cells in the groundwater and it took 22 days before fully developed convection patterns were formed. The thermal convection reached a maximum depth of 1.0 m in soil of low permeability (2.71 center dot 10(-9) m(2)). At groundwater temperature close to its density maximum (4 A degrees C), the physical size (in m) of the convection cells was reduced. Small stones or frost lenses in the ground slightly affect the convective flow, while larger obstacles change the size and shape of the convection cells. Performed simulations show that "seasonal groundwater turnover" occurs. This knowledge may be useful in the prevention of nutrient leakage to underlying groundwater from soils, especially in agricultural areas where no natural vertical groundwater flow is evident. An application in northern Sweden is discussed.

  • 265. Eriksson, B.
    et al.
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Development of slurry transportation technology in Sweden1978In: Pipes and Pipelines International, ISSN 0370-1204, Vol. 23, no 6, p. 10-13Article in journal (Refereed)
    Abstract [en]

    A system-oriented development project has been started by the LKAB mining company and Chalmers University of Technology (CTH), in co-operation with manufacturers and inventors. The development work has concentrated on improvements of some components and better understanding of specific problems, which, seen together, are believed to be of great interest in slurry transportation applications. So far, a rubber-lined plastic pipe for high-pressure applications has been developed, and a high-pressure pump without large external devices and with a minimum of moving parts is to be patented. Simultaneous laboratory and in-plant tests of the new components have been started, and studies on freezing problems, chemical additives, and secondary flow have also been carried out. A pilot-plant investigation on hydraulic hoisting of heavy ore by centrifugal pumps has been completed at CTH.

  • 266.
    Eswias, Adel A.
    et al.
    Al-Fateh University, Tripoli.
    Muntasser, M.A.
    Al-Fateh University, Tripoli.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    First thermal response test in Libya2009In: Abstract book and proceedings Effstock 2009: 11th International conference on Thermal Energy Storage for Energy Efficiency and Sustainability / [ed] Signhild Gehlin, Stockholm: Energi- och Miljötekniska Föreningen / EMTF Förlag , 2009Conference paper (Refereed)
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  • 267.
    Fahlbeck Carlsson, Sofia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Evaluation of a gross pollutant trap-biofilter stormwater treatment train: The Role Of Calcium Carbonate, Vegetation And Pre-Treatment Facility2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Development of cities, new buildings and other impervious surfaces entails increased stormwater flows, volumes and pollutant loads. Heavy metals, nutrients, sediments and salt are common pollutants in stormwater. The conventional way to manage stormwater, which is by discharge to the receiving water body via a sewage network, will not be sufficient for mitigating high flows, flood risks and pollution export. Thus, Low Impact Development (LID) stormwater facilities, such as stormwater biofilters, are built in an increasing rate in Sweden and worldwide. The main function of a stormwater biofilter is water quality treatment, which is achieved when stormwater percolates through a vegetated filter media. Sometimes a pre-treatment facility is installed before the biofilter to reduce the sediment load on the biofilter and extend its life-length. However, there are knowledge gaps regarding pollutant removal in biofilters and the role of associated pre-treatment facilities.

    In this study the impact of a pre-treatment facility, calcium carbonate as amendment in the filter media and vegetation was investigated regarding treatment of heavy metals (Cd (cadmium), Cu (copper), Pb (lead) and Zn (zinc)), phosphorus and total suspended solids. To do this, influent and effluent stormwater samples from an existing biofilter in Sundsvall were analysed and evaluated regarding removal performance of the above-mentioned pollutants. 

    In general, the stormwater biofilter facility (including pre-treatment) removed total metals well while the removal of the dissolved fraction showed higher variations. Influent concentrations of TP were always higher than effluent concentrations. Leaching of phosphate repeatedly occurred from the filter sections. The mean removal of TSS was high (96.9%).

    CaCO3 as amendment in the filter material had a beneficial effect on the overall metal removal of the stormwater facility. Although leaching of phosphate occurred from all filter sections, the leaching was lowest from the section with CaCO3,indicating possible benefits of CaCO3 as amendment. CaCO3 did not seem to affect the mean total phosphorus removal significantly.

    Removal of total metals seemed to be improved by vegetation, but the removal of dissolved metals, total phosphorus and phosphate did not seem to be enhanced by vegetation. The filter section with vegetation and without CaCO3 amendment contributed with the highest effluent concentrations of total phosphorus and phosphate (leaching), considering that vegetation released more phosphate that it captured.

    The main treatment of the stormwater pollutants occurred within the biofilter and both positive and negative removal of all pollutants was observed by the pre-treatment facility. The result showed that the pre-treatment facility was most beneficial for removal of dissolved metals.

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  • 268.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Att tävla - är det nödvändigt?2007In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, Vol. 11, no 1, p. 42-44Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Alla behöver bekräftelse. Vissa mer än andra, men, alla behöver ett erkännande. Människan har alltid strävat efter att utmärka sig; att överskrida gränser, att nyfiket söka högsta punkten, djupaste dalen... Följaktligen återfinns samma tjusning i att få priset för det bästa huset.

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  • 269.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Betongen är en trogen och anpassbar tjänare2008In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 2, p. 104-105Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Betongen är på intet sätt ett nytt material i människans byggande historia. Romarna utnyttjade den för tryckta konstruktioner och utvecklade en skicklighet i att åstadkomma eleganta konstruktiva resultat. Som material har man länge vetat att uppskatta dess egenskaper.

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  • 270.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Dilemmat med prefab visar behov av paradigmskifte2007In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 2, p. 68-69Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Byggsystem har varit ett hett ämne sedan 1950-talet. Meningarna går isär, omarbetas, omtolkas och återkommer, och frågan om hur ett byggsystem bör utformas kvarstår utan ett enkelt svar. Till detta kommer begreppet det industriella byggandet.

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  • 271.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Glasen i förfallna drivhus är en olöst miljöfråga2007In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 5, p. 58-61Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Drivhus är exempel på energihushållning och tillvaratagande under 1900-talet. Idag innebär växthusen också en miljöfråga - som ännu inte fått sitt svar. Glas kan smältas ner och återanvändas. Rutorna kan också demonteras och användas i nya växthus

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  • 272.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Industrilokal kan spegla vision och vilja2006In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 1, p. 50-51Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Arkitektur kan användas för att skapa något som är mer än summan av delarna. Detta, som kan kallas för mervärde, kan till exempel stärka ett företags budskap. Själva byggnaden kan i sig bli reklam för den produkt som tillverkas.

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  • 273.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ljus är form och känsla - och livsnödvändigt2007In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 6, p. 52-54Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    När modernismen kom till byn på 1920- talet inledde förespråkarna omdaningen av samhället till en hälsosam miljö, fylld av framstegsiver och tilltro till teknikens förlösande effekt på människans oktyngda ohälsosamma tillvaro.

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  • 274.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Massiivipuuelementtejä suurille jänneväleille2007In: Puu, ISSN 0357-9484, no 2Article in journal (Other (popular science, discussion, etc.))
  • 275.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    När miljön ber oss sätta stopp2008In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 1, p. 52-53Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Den globala uppvärmningen har varit ett hett debattämne de senaste åren. Larmrapporter kommer från olika håll. Politiker, näringslivsföreträdare och grupper av forskare väljer att antingen bestrida påståendena eller med varierande kraft instämma i dem.

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  • 276.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Olika vägar till betongens form2006In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 2, p. 56-58Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Betong kan som material ges oräkneliga konstruktiva uttryck, vilket väl inte varit alltför uppenbart i de storskaliga miljöerna från 1970-talet. I det följande görs nedslag i olika konstruktionssammanhang i olika delar av världen.

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  • 277.
    Falk, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Vägen mot high tech genom low tech2006In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 6, p. 66-67Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Dagens hjälpmedel för design- och konstruktionsberäkningar är synnerligen avancerade. Som exempel kan nämnas de datorverktyg som berördes i Husbyggaren 2006:02, med beteckningen Computational Morphogenesis, datorstödd utveckling av form.

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  • 278.
    Falk, Andreas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Samuelsson, Sture
    Kungliga tekniska högskolan, KTH.
    Form finding and utility-based optimisation2007In: Proceedings of the IASS Symposium 2007: Structural Architecture - Toward the future looking to the past, International Association for Shell and Spatial Structures , 2007Conference paper (Refereed)
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  • 279.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Chen, Shiwei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Shuo
    Department of Construction Management, Harbin Institute of Technology.
    Yang, Bin
    Department of Applied Physics and Electronics, Umeå University.
    Sun, Chengshuang
    Beijing University of Civil Engineering and Architecture.
    Wang, Yaowu
    Department of Construction Management, Harbin Institute of Technology.
    Embedding Ensemble Learning into Construction Optimisation: A Computational Reduction Approach2020Article in journal (Refereed)
    Abstract [en]

    Simulation-based optimisation (SO), which combines simulation and optimisation technologies, is a popular approach for construction planning optimisation. However, in the framework of SO, the simulation is continuously invoked during the optimisation trajectory, which increases the computing loads to levels that are unrealistic to support the real-time construction decision. This study proposes ensemble learning embedded simulation optimisation (ESO) as an alternative approach for construction optimisation. The ensemble learning (EL) algorithm modifies the SO framework through establishing a connection between the simulation and optimisation technologies. This approach reduces the computing loads associated with the conventional SO framework by accurately learning from simulations and providing efficient fitness evaluations for optimisation. A large-scale project application shows that the proposed approach was able to reduce the computing loads of SO by approximately 90% yet still provide comparable optimisation quality. The proposed method is an alternative approach to SO that can be run on standard computing platforms and supports nearly real-time optimisation decisions.

  • 280.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Wang, Shuo
    Department of Construction Management, Harbin Institute of Technology.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Uncertainty Analysis Approach for Construction under Deep Uncertainty2020In: Journal of construction engineering and management, ISSN 0733-9364, E-ISSN 1943-7862Article in journal (Refereed)
    Abstract [en]

    Construction processes usually occur under uncertain conditions, such as uncertain labour work productivity, equipment failure rate, weather situation and off-site transport condition. These uncertain factors can significantly affect project outcomes. However, for projects lacking a full understanding of uncertain factors, uncertainty analysis approaches relying on prior probability distribution or reasonable range are no longer applicable. Situations in which uncertain factors cannot be fully understood in decision-making are defined as deep uncertainty problems.

    This study proposes an uncertainty analysis approach that integrates process simulation and data mining to be a data-driven method for decision-making in construction projects under deep uncertainty. In process simulation, a Latin Hypercube Sampling (LHS) generates the samples of uncertainty scenario, and Discrete-Event Simulation (DES) quantifies robustness of alternative schemes under uncertain scenarios. In data mining, the Patient Rule Induction Method (PRIM) algorithm reveals the vulnerability of decisions that lead to unacceptable project performance. A real construction case was used to test the presented approach, with the results revealing that the approach is valuable for decision-makers who need to analyse uncertainty without reliable prior probability distributions and reasonable range of certain uncertain factors. It quantified the robustness of various construction schemes, as well as identified the vulnerable scenarios that could jeopardise project completion. The developed approach is an applicable uncertainty analysis approach to support decision-making of construction project under deep uncertainty.

  • 281.
    Fjellström, Caroline
    et al.
    Vägverket Region Norr.
    Lundborg, Glenn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Lundberg, Stellan
    ÅF Infraplan AB.
    Kommunal utvecklingsplan för lokal kollektivtrafik och bebyggelse1990Report (Other academic)
  • 282.
    Flanagan, Kelsey
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Heléne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Contamination of Urban Stormwater Pond Sediments: A Study of 259 Legacy and Contemporary Organic Substances2021In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 55, no 5, p. 3009-3020Article in journal (Refereed)
    Abstract [en]

    Stormwater ponds improve water quality by facilitating the sedimentation of particles and particulate contaminants from urban runoff. Over time, this function entails the accumulation of contaminated sediments, which must be removed periodically to maintain a pond’s hydraulic and treatment capacity. In this study, sediments from 17 stormwater sedimentation facilities from four Swedish municipalities were analyzed for 259 organic substances likely to be found in the urban environment. A total of 92 substances were detected in at least one sample, while as many as 52 substances were detected in a single sample. A typical profile of urban contamination was identified, including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organotins, aliphatic hydrocarbons, phthalates, aldehydes, polybrominated diphenyl ethers, perfluorinated substances, and alkylphenols. However, levels of contamination varied greatly between ponds, influenced heavily by the dilution of urban pollutants and wear particles from other sources of particles such as eroded soil, sand, or natural organic matter. For 22 of 32 samples, the observed concentrations of at least one organic substance exceeded the regulatory threshold values derived from toxicity data for both sediment and soil.

  • 283.
    Flanagan, Kelsey
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. Université Paris Est, LEESU (MA102), École des Ponts ParisTech , UPEC, AgroParisTech, 6-8 avenue Blaise Pascal, F 77455 Marne la Vallée cedex 2.
    Cartwright, Mathilde
    Université Paris Est, LEESU (MA102), École des Ponts ParisTech , UPEC, AgroParisTech, 6-8 avenue Blaise Pascal, F 77455 Marne la Vallée cedex 2.
    Shen, Pengfei
    Department of Civil Engineering, Monash University, Wellington Rd, Clayton, Victoria, 3810, Australia.
    McCarthy, David
    Department of Civil Engineering, Monash University, Wellington Rd, Clayton, Victoria, 3810, Australia.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Gromaire, Marie-Christine
    Université Paris Est, LEESU (MA102), École des Ponts ParisTech , UPEC, AgroParisTech, 6-8 avenue Blaise Pascal, F 77455 Marne la Vallée cedex 2.
    Treatment of micropollutants in stormwater biofilters: comparing model results with field and lab data: [Traitement de micropolluants par une noue filtrante : confrontation d’un modèle aux données expérimentales]2023Conference paper (Refereed)
  • 284.
    Flaquer, Berta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Urbanization as Socionatures' Reproduction: from Territories of Extraction2023Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Through an engagement with the strand of critical urban theory, this dissertation brings the reworkings of Henri Lefebvre’s notion of ‘planetary urbanisation’ into a new synthesis with further inputs from urban political ecology and feminism—towards developing an ecofeminist lens to urbanization. Guided by the hypothesis “urbanization has been historically sustained through the patriarchal domination of women and nature’s reproduction,” the thesis seeks to critically explore how urbanization processes have historically and multiscalarly recurrently transformed the spatial configurations of reproduction from territories of extraction. It does so by engaging with the long durée historical problematique of the malm territory of extraction, as situated from Swedish Sápmi and through an intersectional ecofeminist approach. From the mid-1500s—Indigenous Sámi, Natures, and the bodies of especially women—have been violently subordinated through patriarchal-colonial-capitalist urbanization processes. Across scales and time, the so-called production has been designed by and for the BWMAh* as extraction. Through the malm territory—within and beyond Sweden—this has taken the form of iron ore mining, but also historically in linkage with other forms (i.e. fur and leather, large-scale reindeer, fishing, agriculture, forestry, coal, hydropower, research and development, tourism, data centres, fertilizers, space industry, dredging, fossil-free steel, or fossil- free hydrogen). Backgrounded and at the basis, however, extraction has been sustained through the violent domination of nature and women’s reproduction, as through the witch-hunts in different forms historically and still ongoing, femicides, the creation of the ideals of ‘the good woman,’ the myth of ‘the strong Sámi women,’ successive scientific revolutions, race biology, genetics, industrial colonialism, or the new green colonialism. Under the current ‘green everything’ transition where once again capital’s project is rearticulating and preparing for the next wave of accumulation underway—through an ever-backgrounded and deeper preceding crisis of reproduction—, it is ever more relevant to question the spatiality of the reproduction processes and the ways in which earlier rearticulations have dominated the reproduction of life in new forms.

    The malm territory is then synchronically and diachronically mapped yet foregrounding the processes of subordination of nature and women—across scales and time—building up the ‘palimpsests of extraction.’ It uses Corboz’s metaphor of ‘the territory as palimpsest’ and expands its conception as a mapping method beyond cartography, to explore in which ways reproduction relations have been masked and not represented historically. The dissertation then goes on to argue that the existing literature on planetary urbanisation has been giving ontological priority to production, and this has precluded an analysis of the actual reproduction relations that have been at the root sustaining life however subordinated in the complete urbanization of society. By advancing an ecofeminist materialist lens to urbanization that reads—representationally and spatially—grasping the complex specificities through the key moments of rearticulation of patriarchal-colonial-capitalist urbanization—temporally and multiscalarly—in the long durée history of the malm territory yet foregrounding the forms of subordination of nature and women, I focus on the linkages that can be drawn between the relations of domination and alternatively collectively transformed.

    * BWMAh: Bourgeois White Male Adult heterosexual

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  • 285.
    Fletcher, Tim D.
    et al.
    Waterway Ecosystem Research Group, Dept. of Resource Mgt. and Geography, The University of Melbourne.
    Shuster, William D.
    United States Environmental Protection Agency, Office of Research and Development, Cincinnati.
    Hunt, William F.
    Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh.
    Ashley, Richard M.
    Pennine Water Group and Department of Civil and Structural Engineering, University of Sheffield.
    Butler, David
    Centre for Water Systems, College of Engineering, Mathematics and Physical Sciences, University of Exeter.
    Arthur, Scott
    Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh.
    Trowsdale, Sam A.
    School of Environment, The University of Auckland.
    Barraud, S.
    University of Lyon, INSA Lyon.
    Sémadeni-Davies, Annette F.
    NIWA, National Institute of Water and Atmospheric Research, Private Bag 99940, Auckland.
    Bertrand-Krajewski, Jean Luc
    University of Lyon, INSA Lyon.
    Mikkelsen, Peter Steen
    Department of Environmental Engineering (DTU Environment), Technical University of Denmark.
    Rivard, Gilles
    Genivar Inc.
    Uhl, M.
    Muenster University of Applied Sciences, Faculty of Civil Engineering, Institute for WaterResourcesEnvironment (IWARU).
    Dagenais, Danielle
    School of Landscape Architecture, Faculty of Environmental Design, University of Montreal.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    SUDS, LID, BMPs, WSUD and more: The evolution and application of terminology surrounding urban drainage2015In: Urban Water Journal, ISSN 1573-062X, Vol. 12, no 7, p. 525-542Article in journal (Refereed)
    Abstract [en]

    The management of urban stormwater has become increasingly complex over recent decades. Consequently, terminology describing the principles and practices of urban drainage has become increasingly diverse, increasing the potential for confusion and miscommunication. This paper documents the history, scope, application and underlying principles of terms used in urban drainage and provides recommendations for clear communication of these principles. Terminology evolves locally and thus has an important role in establishing awareness and credibility of new approaches and contains nuanced understandings of the principles that are applied locally to address specific problems. Despite the understandable desire to have a 'uniform set of terminology', such a concept is flawed, ignoring the fact that terms reflect locally shared understanding. The local development of terminology thus has an important role in advancing the profession, but authors should facilitate communication between disciplines and between regions of the world, by being explicit and accurate in their application. © 2014 © The work of Tim D. Fletcher is Crown copyright in the Commonwealth of Australia 2014, University of Melbourne. The work of Danielle Dagenais is Copyright of the Crown in Canada 2014, University of Montreal. The work of William Shuster was authored as part of his official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 USC. 105, no copyright protection is available for such works under US Law. William F. Hunt, Richard Ashley, David Butler, Scott Arthur, Sam Trowsdale, Sylvie Barraud, Annette Semadeni-Davies, Jean-Luc Bertrand-Krajewski, Peter Steen Mikkelsen, Gilles Rivard, Mathias Uhl and Maria Viklander hereby waive their right to assert copyright, but not their right to be named as co-authors in the article.

  • 286.
    Florén, Tina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Integrerad arkitektur: en metodutveckling2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
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  • 287.
    Fong, K. F.
    et al.
    Division of Building Science and Technology, College of Engineering, City University of Hong Kong, Hong Kong, China.
    Lee, C. K.
    Division of Building Science and Technology, College of Engineering, City University of Hong Kong, Hong Kong, China.
    Lau, Kevin Ka-Lun
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ng, Edward Yan Yung
    School of Architecture, The Chinese University of Hong Kong, Hong Kong, China.
    Residential building performance analysis at near extreme weather conditions in Hong Kong through a thermal-comfort-based strategy2023In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 16, p. 13-25Article in journal (Refereed)
    Abstract [en]

    The precise building performance assessment of residential housings in subtropical regions is usually more difficult than that for the commercial premises due to the much more complicated behavior of the occupants with regard to the change in indoor temperature. The conventional use of a fixed schedule for window opening, clothing insulation and cooling equipment operation cannot reflect the real situation when the occupants respond to the change in thermal comfort, thus affecting the appropriateness of the assessment results. To rectify the situation, a new modeling strategy in which the modification of the various operation schedules was based on the calculated thermal comfort (TC), was developed in this study. With this new TC-based strategy, the realistic building performances under different cooling provision scenarios applied to a high-rise residential building under the near extreme weather conditions were investigated and compared. It was found that sole provision of ventilation fans could not meet the zone thermal comfort by over 68% of the time, and air-conditioning was essential. The optimal use of ventilation fans for cooling could only help reduce the total cooling energy demand by less than 12% at best which could only be realistically evaluated by adopting the present strategy. Parametric studies were conducted which revealed that some design factors could offer opportunities for reducing the total cooling energy under the near extreme weather conditions.

  • 288.
    Fornander, Alexandra
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Investigating the Potential of Bridging as a Strategy for Handling Barriers: Project site: Bodenvägen, Luleå2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is to clarify which potential a bridging structure has for handling the consequences created by a physical barrier.

    The following questions are posed:

    -Is bridging a suitable strategy for handling a physical barrier?

    -In what aspects do barriers counteract the development of a qualitative urban environment?

    -What potential does bridging have as a strategy for addressing these aspects?

    By studying literature, reference projects and the project site, a framework is set up for handling barriers in general and for the requirements of the specific project site.

    A design suggestion is made with the objective to address these needs. It uses a combination of the strategies presented in order to adress the consequences of the barrier: decreased intensity, connectivity and lack of pedestrian invitation.

    The thesis does not recommend bridging as a general solution, as it is complex and requires thorough analyses. However, the thesis argues that the strategy of bridging should not be rejected immidiately, since it has a potential of place-making. The strategy can provide for qualitative public space while offering a direct passage across a barrier.

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  • 289.
    Francki, Kristina Björling
    Luleå kommun.
    Gilla snölegan2014Report (Other academic)
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  • 290.
    Fredriksson, Maja
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Axelsson, Linnea
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Analys och gestaltning av återbrukade restmaterial: Inventering av materialflöden som kan bidra till ett cirkulärt byggande i region Norrbotten2024Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In order for the world to become more socially, economically and environmentally sustainable by the year 2030, the UN created the global goals. A transition to a circular economy is necessary to reach the global goals. Circular economy means that resources are used in efficient circular flows and replace virgin material. Circular flows can reduce the large material consumption and emissions of greenhouse gases that the construction and industrial sectors are responsible for. Sweden's economy is currently linear. Only 3% of all the material that the nation consumes is reintroduced into the economy. There is a large supply of material from industrial waste in urban areas that is currently discarded but still has potential value to be reused.

    The purpose of the study is to inventory material flows in the Norrbotten region that are classified as condemned by companies and industries outside the construction sector. The study focuses in particular on inventorying residual materials in the cities of Luleå, Boden and Piteå and analyzing whether the materials can be reused as surface layer material for facade and roof of an environmental house. The analysis should result in use case scenarios for the residual materials with the greatest reuse potential to inspire for reuse. The study also examines the most common barriers for reuse in the construction sector.

    According to Ashby's material selection method, twelve criteria were defined. Of seven companies that were inventoried, twenty-six out of thirty-seven residual materials were excluded from the study. Eleven residual materials fulfilled the criteria necessary for reuse as surface layer material and were ranked according to a multi-criteria decision analysis. The three materials with the highest rank were stainless steel plate from heat exchangers, plate from sandwich elements and gabion wall of blast furnace slag. Use case scenarios for facade and roof surface layers were designed for these three materials. This showed good opportunities for the inventoried residual materials to be reused as surface layer material.

    The inventory of the few companies that was made showed that there is a large availability of material in the Norrbotten region that has the potential to be reused. The analysis showed that there are interesting material flows in industries that the construction sector can benefit from. Reuse of materials requires cooperation between the parties involved. The collaboration involves, among other things, sharing information on available resources in material flows, the properties and origin of the materials. This is necessary to facilitate the inventory of potential material to reuse. Integrity and competitiveness of companies and industries can affect the cooperation. A conceivable aspect that was discovered during the study was to allow the residual materials to be reused for other functions on the building. This, in combination with carrying out a large-scale material inventory, would be interesting for further studies.

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  • 291.
    Furlan, John M.
    et al.
    GIW Industries Inc..
    Visintainer, Robert J.
    GIW Industries Inc..
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Centrifugal pump performance when handling highly non-Newtonian clays and tailings slurries2014In: 19th International Conference on Hydrotransport 2014: Golden, 24 - 26 September 2014, Curran Associates, Inc., 2014, p. 117-130Conference paper (Refereed)
    Abstract [en]

    Recent loop testing performed at the GIW Hydraulic Lab (Furlan et al. 2013, 2014) has provided pump performance data for two highly non-Newtonian slurries of significantly different character: a high clay content slurry with minimal coarse solids; and a typical, low clay content, two component tailings slurry. The importance of air removal in the sump and pipe loop was demonstrated using a simple, yet novel de-aeration system. In addition to the measurement of performance losses, determination of the upper limit of "pumpability" for these slurries relative to their concentration and associated yield stress was investigated. However, once the slurry was de-aerated, no limits could be found, other than those dictated by suction side losses (NPSHA) or excessive pipeline friction gradients, indicating that the only true limit in practice is one of system economics, i.e. pump operating and capital cost. Experimentally measured pump head and efficiency were compared against corresponding predictions from two different models: the Walker and Goulas technique (Walker and Goulas, 1983), and the Graham et al. technique (Graham et al., 2009), with special focus given to the dependence of the losses on pump rotary speed.

  • 292.
    Furlan, John M.
    et al.
    GIW Industries Inc., Department of Engineering and R&D.
    Visintainer, Robert J.
    GIW Industries, Department of Engineering and R&D.
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Centrifugal pump performance when handling highly non-Newtonian clays and tailings slurries2016In: Canadian Journal of Chemical Engineering, ISSN 0008-4034, E-ISSN 1939-019X, Vol. 94, no 6, p. 1108-1115Article in journal (Refereed)
    Abstract [en]

    Recent loop testing performed at the GIW Hydraulic Lab (Furlan et al. 2013, 2014) has provided pump performance data for two highly non-Newtonian slurries of significantly different character: a high clay content slurry with minimal coarse solids; and a typical, low clay content, two component tailings slurry. The importance of air removal in the sump and pipe loop was demonstrated using a simple, yet novel de-aeration system. In addition to the measurement of performance losses, determination of the upper limit of "pumpability" for these slurries relative to their concentration and associated yield stress was investigated. However, once the slurry was de-aerated, no limits could be found, other than those dictated by suction side losses (NPSHA) or excessive pipeline friction gradients, indicating that the only true limit in practice is one of system economics, i.e. pump operating and capital cost. Experimentally measured pump head and efficiency were compared against corresponding predictions from two different models: the Walker and Goulas technique (Walker and Goulas, 1983), and the Graham et al. technique (Graham et al., 2009), with special focus given to the dependence of the losses on pump rotary speed.

  • 293.
    Furén, Robert
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Stormwater bioretention: Pollutant occurrence and accumulation in filter materials and forebays2022Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Urban areas are affected by anthropogenic activities and produce pollutants that are transported to recipients and receiving waters during precipitation. Untreated stormwater runoff is a main driver of environmental degradation, and the interest in stormwater quality treatment has increased with the awareness of stormwater pollution. Several pollutants, including metals PAHs, PCBs, phthalates, and phenols, pose a hazard to aquatic life and are listed among the 45 priority substances in The European Water Framework Directive list (Directive 2013/39/EU).

    Stormwater bioretention technology is employed to efficiently remove pollutants during stormwater treatment in urban areas. However, the resulting accumulation of pollutants in bioretention facilities could ultimately create a pollutant depot. Hence, it is important to understand the occurrence, availability, and mobility of pollutants in bioretention facilities, as well as the processes that control their accumulation and mobility over time. The aim of the work in this licentiate thesis was to investigate the occurrence, accumulation, distribution, and concentration of organic micropollutants and metals inbioretention facilities after long-term stormwater treatment in urban areas of Ohio, Michigan, and Kentucky in November 2019.

    Samples were collected from 29 bioretention facilities, 20 of which were equipped with forebays. A total of 269 samples were analysed for metals commonly found in stormwater (Cr, Cu, Ni, Pb, and Zn), and a five-step sequential extraction method was used to assess the metal mobility in the filter material. Additionally, 116 samples from 12 sites were analysed for 38 organic micropollutants (OMPs), including 16 PAHs, 7 PCBs, 13 phthalates, and 2 alkylphenols.

    All studied metals were found in all samples, except for Cd, which was detected in 245 samples (91%). For the OMPs, 32 of 38 analytes were detected in at least one sample. PAHs and PCBs were the most frequently detected pollutants, and were found in 12 and 10 sites, respectively. The bioretention sites showed large variations in the concentrations of pollutants. The concentration of OMPs was highest in the upper 10 cm of the filter material and decreased with increasing depth, while a similar, but less obvious trend was observed for Cr, Cu, Pb, and Zn. A trend of decreasing concentration with increasing distance from the inlet was observed for OMPs but was less clear for the metals. Thefore bays, which contain sediment but no filter material, had the highest concentrations of OMPs. A strong correlation was observed between the pollutant concentrations and the ratio between the filter area and catchment area in a Principle Component Analysis. The accumulation and pathways of particle-bound OMPs and particle-bound metals showed similarities.

    These results will assist with improving the methods used for stormwater management. Importantly, regular replacement of the top filter layer and regular forebay maintenance may prevent pollutant accumulation and clogging, thereby extending the filters’ treatment function.

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  • 294.
    Furén, Robert
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. NCC Sverige AB, Department of Research and Innovation.
    Flanagan, Kelsey
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Winston, Ryan
    Department of Food, Agriculture, and Biological Engineering, Deprtment of Civil, Environmental, and Geodetic Engineering, Core Faculty, Sustainability Institute, Ohio State University.
    Dorsey, Jay
    Department of Food, Agriculture, and Biological Engineering, Deprtment of Civil, Environmental, and Geodetic Engineering, Core Faculty, Sustainability Institute, Ohio State University.
    Tirpak, Andrew
    Department of Food, Agriculture, and Biological Engineering, Deprtment of Civil, Environmental, and Geodetic Engineering, Core Faculty, Sustainability Institute, Ohio State University.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Occurrence and concentrations of organic micropollutants in bioretention filter media2021Conference paper (Refereed)
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  • 295.
    Furén, Robert
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. NCC Sverige AB, Department of Research & Innovation, 170 80 Solna, Sweden.
    Flanagan, Kelsey
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Winston, Ryan J.
    Department of Food, Agricultural, and Biological Engineering, The Ohio State University, Columbus, OH, United States; Department of Civil, Environmental, and Geodetic Engineering, The Ohio State University, Columbus, OH, United States.
    Tirpak, R. Andrew
    Department of Food, Agricultural, and Biological Engineering, The Ohio State University, Columbus, OH, United States.
    Dorsey, Jay D.
    Department of Food, Agricultural, and Biological Engineering, The Ohio State University, Columbus, OH, United States.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Occurrence, concentration, and distribution of 38 organic micropollutants in the filter material of 12 stormwater bioretention facilities2022In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 846, article id 157372Article in journal (Refereed)
    Abstract [en]

    The increased use of bioretention facilities as a low impact development measure for treating stormwater runoff underscores the need to further understand their long-term function. Eventually, bioretention filter media must be (partly) replaced and disposed of at the end of its functional lifespan. While there are several studies of metal accumulation and distributions in bioretention media, less is known about organic pollutant pathways and accumulation in these filters. The present study considers the occurrence and accumulation of 16 polycyclic aromatic hydrocarbons, 7 polychlorinated biphenyls, 13 phthalates, and two alkylphenols throughout 12 older bioretention facilities (7–13 years old) used for stormwater treatment in Michigan and Ohio, USA. These pollutant groups appear to behave similarly, with greater instances of detection and higher concentrations in the upper media layers which decrease with increased depth from the surface. The patterns of detection and concentration in the filter material may be explained by characteristics of the pollutants, such as molecular structures and solubility that affect the removal of the organic pollutants by the filter material. There is also a large variation in concentration magnitudes between the bioretention sites, most likely due to differences in pollutant sources, contributing catchment size and/or land uses.

  • 296.
    Furén, Robert
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. NCC Sverige AB, Department of Research and Innovation, Herrjärva Torg 4, 17080 Solna, Sweden.
    Österlund, Heléne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Winston, Ryan J.
    Department of Food, Agricultural, and Biological Engineering, Ohio State University, Agricultural Engineering Building AE, Building 298, 590 Woody Hayes Dr, Columbus, OH, USA; Department of Civil, Environmental, and Geodetic Engineering, Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH, USA.
    Tirpak, R. Andrew
    Department of Food, Agricultural, and Biological Engineering, Ohio State University, Agricultural Engineering Building AE, Building 298, 590 Woody Hayes Dr, Columbus, OH, USA.
    Dorsey, Jay D.
    Department of Food, Agricultural, and Biological Engineering, Ohio State University, Agricultural Engineering Building AE, Building 298, 590 Woody Hayes Dr, Columbus, OH, USA.
    Smith, Joseph
    Department of Food, Agricultural, and Biological Engineering, Ohio State University, Agricultural Engineering Building AE, Building 298, 590 Woody Hayes Dr, Columbus, OH, USA.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Concentration, distribution, and fractionation of metals in the filter material of 29 bioretention facilities: a field study2023In: Environmental Science: Water Research & Technology, ISSN 2053-1400, E-ISSN 2053-1419, Vol. 9, no 12, p. 3158-3173Article in journal (Refereed)
    Abstract [en]

    Pollutant loads stemming from anthropogenic activities conveyed in urban stormwater runoff contribute to the impairment of downstream water bodies. Cities and municipalities are increasingly turning toward green infrastructure stormwater control measures to treat pollutants at the source of runoff. One example of these technologies is bioretention, which is commonly applied for stormwater treatment in urban areas due to its demonstrated effectiveness in removing various pollutants from water, including sediment, nutrients (e.g., N and P), and metals. As metals are mainly removed by filtration or adsorption to soil particles, the filter media is important for metal removal in bioretention. However, the capacity to remove metals through adsorption by bioretention media is finite; thus, the media may need to be replaced and disposed of after maintenance or at the end of its operational lifespan. Pollutant accumulation in bioretention media has the potential to approach toxicity thresholds, which may introduce complexities for safe handling and disposal. To fully capture the potential challenges associated with metals accumulation in media over time, it is important to understand the accumulation processes and mobility of metals in bioretention facilities as they age. Although several studies have investigated metal accumulation and distribution in bioretention media, few have assessed metal mobility by fractionation using sequential extraction methods in older (i.e., >7 years) facilities. In November 2019, we conducted a comprehensive field study of older facilities in Ohio, Michigan, and Kentucky (USA) to improve the understanding of the accumulation processes and metal mobility in bioretention. In this study, concentrations of several metals (i.e., Cr, Cu, Ni, Pb, and Zn) were analyzed in samples of filter material from 29 bioretention sites in operation for 7–16 years. Except for Cd, all metals were found in all samples. Metals accumulation was clear with highest concentrations found in the top (0–5 cm) layer of the filter material, attributable to the filtration of particles percolating through the media profile. Lower concentrations were observed in deeper (i.e., >10 cm) layers of the bioretention media. The fractionation showed that the metals of interest were present at high levels with a risk of leaching over time, among which Cd, Zn, and Pb were suggested to be mobile from the filter material during precipitation. Thus, there is a potential risk of leakage from filter material or sediment removed from biofilters, e.g., during maintenance and disposal. The results of principal component analysis indicated specifically correlations between metal concentrations and the filter material soil texture including the organic matter content. These results contribute to improved design and operation and suggest regular maintenance to reduce long-term risks associated with the accumulation of metals in bioretention and similar urban stormwater treatment facilities. Since most metals are trapped in the top layer of the filter it may be enough to remove only the top layer. However, metal fractionation should be considered when handling the material.

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  • 297.
    Füssl, Elisabeth
    et al.
    Factum Chaloupka and Risser OG, Danhausergasse 6/4, 1040 Wien.
    Oberlader, Manuel
    Factum Chaloupka and Risser OG, Danhausergasse 6/4, 1040 Wien.
    Beanland, Vanessa
    Research School of Psychology, Australian National University.
    Spyropoulou, Ioanna
    National Technical University of Athens.
    Lenné, Michael G.
    Accident Research Centre, Monash University.
    Joshi, Somya
    Department of Computer and Systems Sciences (DSV), Stockholm University.
    Rößger, Lars
    Technical University Dresden.
    Leden, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. VTT.
    Underwood, Geoff
    University of Notttingham.
    Carvalhais, Jose
    Faculty of Human Kinetics, Universidade de Lisboa.
    Methodological development of a specific tool for assessing acceptability of assistive systems of powered two-wheeler-riders2015In: IET Intelligent Transport Systems, ISSN 1751-956X, E-ISSN 1751-9578, Vol. 9, no 1, p. 12-21Article in journal (Refereed)
    Abstract [en]

    Research on the acceptability of assistive systems for improving the safety of powered two-wheelers (PTWs) is a pressing issue. The use of safety-enhancing assistive systems for motorised vehicles, including advanced driver assistance systems and in-vehicle information systems is widespread in many countries. Yet, there is only a limited number of equivalent intelligent transport systems (ITS) for PTWs, namely advanced rider assistance systems and on-bike information systems. This study describes the methodological development of a specific tool for assessing motorcyclists' acceptability of ITS, as part of the motorcyclists' profiling questionnaire (MOPROQ). There were three stages of development. First, a literature review was undertaken to assess the current state of the art regarding ITS for PTWs and to determine the most relevant facets of acceptability that should be measured. Second, a series of focus group interviews were conducted to explore riders' attitudes towards ITS. Finally, the focus group results were used to develop a large-scale survey (MOPROQ), which was administered to an initial sample of over 6000 riders internationally. The designed tool can be used as a basis for the determination of rider acceptability of ITS systems in the future.

  • 298.
    Füssl, Elisabeth
    et al.
    Factum Chaloupka and Risser OG, Danhausergasse 6/4, 1040 Wien.
    Oberlader, Manuel
    Factum Chaloupka and Risser OG, Danhausergasse 6/4, 1040 Wien.
    Lenné, Michael G.
    Monash University, Melbourne, VIC.
    Beanland, Vanessa
    Monash University, Melbourne, VIC.
    Pereira, Marta
    Chemnitz University of Technology.
    Simões, Ana V.C.
    Humanist Network.
    Turetschek, Ch.
    Factum Chaloupka and Risser OG, Danhausergasse 6/4, 1040 Wien.
    Kaufmann, C.
    Factum Chaloupka and Risser OG, Danhausergasse 6/4, 1040 Wien.
    Joshi, Somya
    Institute of Communication and Computer Systems, Athens.
    Rößger, Lars
    Technische Universität Dresden.
    Leden, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Spyropoulou, Ioanna
    Ethniko Metsovio Polytechnico, School of Rural and Surveying Engineering, Athens.
    Roebroeck, Hugo
    Federation of European Motorcyclists' Associations (FEMA), Brussels.
    Carvalhais, José
    University of Tecnology Lisboa, Faculdade de Motricidade Humana.
    Underwood, J.
    Nottingham Trent University.
    Riders acceptance of advanced rider assistance systems2012Conference paper (Refereed)
    Abstract [en]

    The development of assistive systems and intelligent transport systems (ITS) plays an important role for improving the safety of powered two-wheelers (PTWs). Assistive systems for cars are well known and increasingly popular but for PTW riders the development of Advanced Rider Assistance Systems (ARAS) and On-Bike Information Systems (OBIS) has not progressed far enough yet. Estimates suggest that population-wide deployment of ARAS could reduce crashes by up to 40% (Lenné et al., 2011). Within the 2BESAFE project the factors that affect the acceptance of ARAS and OBIS of PTW riders and the obstacles that may hold PTW riders off from the use of assistive systems have been identified. A literature review, focus group interviews and an online survey have been conducted. The results show that the acceptability of systems depends on their function. The acceptability is higher for systems that were perceived to be more useful in emergencies. Survey respondents raised several concerns regarding the acceptance of assistive systems for PTWs. Respondents of the on-line survey felt that there was too much focus on assistive systems as a means of improving PTW rider safety, and less on the dangers that motorcyclists face actually from the actions of other road users.

  • 299.
    Galfi, Helen
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Assessment of stormwater and snowmelt quality based on water management priorities and the consequent water quality parameters2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stormwater and snowmelt pollution contributes to degradation of quality of the receiving waters. For assessing such impacts, it is effective to focus on specific causes of degradation, as done in this study of the quality of stormwater and snowmelt discharges into the receiving waters serving for supply of raw drinking water and water-based recreation. While the main priority were faecal indicator bacteria (FIBs), the understanding of their occurrence, and of other potential effects on the receiving waters, required addressing additional water quality parameters as well.     

    Exports of FIBs in stormwater and snowmelt discharged from four urban catchments yielded the following findings: (a) E.coli, with mean concentration of all stormwater data Cmean = 430 cfu (colony forming units)/100 mL, and enterococci (Cmean=1380 cfu/100 mL) were the best indicators of faecal pollution of stormwater, but total coliform (Cmean=3130 cfu/100 mL) and C. perfringens (Cmean=150 cfu/100 mL) were much less effective: the former indicator includes non-faecal bacteria and the latter one barely varied; (b) Among the different catchments, the central catchment with mixed land use produced the highest concentrations of FIBs; (c) FIB concentrations in snowmelt were significant only in the case of enterococci (400 cfu/100 mL); and, (d) Baseflows in two catchments were practically devoid of FIBs, with Cmean=10 cfu/100 mL for both E.coli and enterococci. Hence, there were no contributions of sanitary sewage to the storm sewer baseflows.

    FIB concentrations varied with stormwater or snowmelt quality, described by associated parameters, which were identified by cluster analysis as: temperature, conductivity, TSS, flow rate, and TP. Such findings were used in statistical regressions indicating that E. coli and enterococci could be statistically modelled in three of the four catchments, with determination coefficients R2 ranging from 38-66%. In spite of uncertainties, such modelling would be useful for future FIB monitoring, or for comparing remediation alternatives. Estimation of FIBs by microbial partitioning to settleable solids (represented by gully pot sediments) was infeasible, because these highly mineral sediments contained little FIBs.

    Storm sewer outfall effluents were also analyzed for mineral (Al, Ca, Fe, K, Mg, Na) and anthropogenic indicator trace metal (TM) inorganics (Cd, Cr, Cu, Ni, Pb, Zn). The total mass of inorganics exported from the catchments by runoff or snowmelt was dominated by mineral inorganics, which were particularly high in baseflows. TM concentrations were compared to the tentative guidance limits suggested in Sweden as annual mean, or maximum event mean, total TM concentrations. Effluents from the catchments studied clearly exceeded the recommended values 5 times in the case of Zn.

    Field studies drew attention to uncertainties in measured FIBs and solids. Automated sampling of greatly varying FIB concentrations was affected by sampling line water residuals, which can be minimized by short sampling lines and avoidance of sags in the sampling line. Stormwater and snowmelt solids were underestimated by the conventional TSS method requiring withdrawal of aliquots from total samples. This bias can be eliminated by using whole-sample methods; either the existing SSC (suspended sediment concentration) method, or the newly proposed (and easier to use) multiple filter procedure (MFP), filtering whole samples through progressively finer filters (pore sizes 25, 1.6 and 0.45 µm). The MFP produced data equivalent to those obtained with SSC, as confirmed by the Limits of Agreement (LoA) statistical procedure.

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  • 300.
    Galfi, Helen
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Suspended solids and indicator bacteria in stormwater runoff: Sources of bias in field measurements2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stormwater quality monitoring and control is a prerequisite for sustainable water resources management in urban areas. Stormwater monitoring programs are based on general water sampling guidance and, in the absence of standard procedures, employ various sampling and analytical methods. The aim of this thesis is to assess stormwater sampling methods and sample analyses with respect to the bias which may be introduced at different stages of the process of monitoring suspended solids and indicator bacteria.The focus was on the bias introduced by automated sampling methods and by analyses of suspended solids. Towards this end, suspended solids and four indicator bacteria (total coliforms, E. coli, int. enterococci and C. perfringens) concentrations were compared in stormwater samples in two urban catchments, which were collected manually or by automatic samplers. The impact of automatic samplers on E. coli concentrations in stormwater samples was further investigated by conducting a study of sampling line cross-contamination. The representativeness of suspended solids results obtained by the standard Total Suspended Solids (TSS) method was studied in urban bulk snow by assessing the ratio of suspended and settleable solids. TSS concentrations were compared to those obtained by other analytical procedures, including the Suspended Sediment Concentration (SSC) method and a newly introduced Multiple Filter Procedure (MFP). The MFP builds on the existing standard methods involving the filtration of whole water samples, but uses three filters with decreasing pore sizes to reduce filter clogging, and is designed to retain a broad range of solids, which is typical for stormwater. Finally, recognizing the affinity of indicator bacteria to suspended solids, both constituents were manually sampled in stormwater in four urban catchments during fall to assess their natural variation and correlation patterns between these contaminants.The comparison of samples collected manually and by automatic samplers yielded large differences in suspended solids concentrations, especially in the lower concentration range (0-100 mg/L), whereas the agreement between the two types of samples was within the analytical uncertainty (±30%) for all the four indicator bacteria. During the laboratory study, E. coli concentration in the first sample (following sudden bacteria concentration changes) were positively biased in automated samples due to the stormwater residue in the sampling line. When high E. coli concentrations were followed by low concentrations, the low concentrations were overestimated 10-20 times depending on the sampling line length (tested up to 5 m). The study findings should be helpful for improving field protocols for suspended solids and indicator bacteria sampling.The standard TSS analytical method underestimated solids in urban snow packs, because of high amounts of settleable particles remaining in situ, rather than leaving with snowmelt. The comparison between analytical procedures, including TSS, SSC and MFP yielded highly varying results for stormwater samples. The methods using whole water-samples, rather than aliquots withdrawn from such samples, as done in the case of TSS, produced more accurate estimates of solids concentrations, with a fairly good precision. The precision of the newly proposed MFP was generally better than ±10% and its results were comparable to those of standard methods using whole water samples, but the new procedure was less labourious. Consequently, the MFP was recommended for use when the total mass of solids in stormwater runoff is needed.The suspended solids and indicator bacteria concentrations in stormwater runoff varied from catchment to catchment and weak correlations were found between solids and bacteria, partly due to low concentrations of bacteria during the fall period. However, it was shown that the natural variation of the studied concentrations was affected by the sampling and the analytical method. Thus, the bias introduced during the stormwater quality monitoring process is relevant when assessing pollutant concentrations and the compliance of stormwater discharges with prescribed threshold values in the receiving waters.

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