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  • 1.
    Müller, Alexandra
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    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.
    Marsalek, Jiri
    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.
    Building surface materials as sources of micropollutants in building runoff: A pilot study2019In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 680, p. 190-197Article in journal (Refereed)
    Abstract [en]

    Control of diffuse pollution is critical for achieving good surface water quality status. In this context, pollutant contributions from building materials have received increased attention in recent decades. This study examined the releases of metals, nonylphenols and phthalates from ten common building surface materials (installed in triplicates) into rainwater runoff from six rain events. The highest releases of metals were from copper and zinc sheets (average concentrations of 3090 μg/L Cu and 7770 μg/L Zn respectively), while other metal materials, e.g., Corten weathering steel, exhibited lower releases. PVC roofing released high concentrations of nonylphenols and phthalates (average concentrations of up to 26 μg/L nonylphenols and 455 μg/L Diisononyl phthalate, DINP) which have not been investigated in the earlier studies. Pollutant releases varied between events, likely because of weather conditions and rainfall characteristics. Study findings should be valuable for environmentally responsible applications of the existing building materials and the development of new ones, as well as the investigations and risk assessment of specific pollutants in stormwater.

  • 2.
    Broekhuizen, Ico
    et al.
    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.
    Marsalek, Jiri
    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.
    Calibration event selection for green urban drainage modelling2019In: Hydrology and Earth System Sciences Discussions, ISSN 1812-2108, E-ISSN 1812-2116Article in journal (Refereed)
    Abstract [en]

    Calibration of urban drainage models is typically performed based on a limited number of observed rainfall-runoff events, which may be selected from a longer time-series of measurements in different ways. In this study, 14 single- and two-stage strategies for selecting these events were tested for calibration of a SWMM model of a predominantly green urban area. The event selection was considered in relation to other sources of uncertainty such as measurement uncertainties, objective functions, and catchment discretization. Even though all 14 strategies resulted in successful model calibration, the difference between the best and worst strategies reached 0.2 in Nash–Sutcliffe Efficiency (NSE) and the calibrated parameter values notably varied. Most, but not all, calibration strategies were robust to changes in objective function, perturbations in calibration data and the use of a low spatial resolution model in the calibration phase. The various calibration strategies satisfactorily predicted 7 to 13 out of 19 validation events. The two-stage strategies performed better than the single-stage strategies when measuring performance using the Root Mean Square Error, flow volume error or peak flow error (but not using NSE); when flow data in the calibration period had been perturbed by ±40 %; and when using a lower model resolution. The two calibration strategies that performed best in the validation period were two-stage strategies. The findings in this paper show that different strategies for selecting calibration events may lead in some cases to different results for the validation period, and that calibrating impermeable and green area parameters in two separate steps may improve model performance in the validation period, while also reducing the computational demand in the calibration phase.

  • 3.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Bruaset, Stian
    Norwegian University of Science and Technology.
    Ugarelli, Rita
    Norwegian University of Science and Technology.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Correcting for the impact of past coordination on the estimation of pipe cohorts survival functions2019Conference paper (Other academic)
  • 4.
    Søberg, Laila
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Winston, Ryan
    Departments of Food, Agricultural, and Biological Engineering and Civil, Environmental, and Geodetic Engineering, Ohio State University, 590 Woody Hayes Drive, Columbus, OH, United States of America.
    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.
    Dissolved metal adsorption capacities and fractionation in filter materials for use in stormwater bioretention facilities2019In: Water Research X, ISSN 2589-9147, Vol. 4, article id 100032Article in journal (Refereed)
    Abstract [en]

    The dissolved metal adsorption and association was determined for ten different filter materials recommended and/or implemented in bioretention facilities. Batch adsorption and batch kinetic experiments were performed at lab-scale using both single and multi-metal solutions. Metal strengths and association were determined by sequential extraction analysis. All materials adsorbed metals and 90% of adsorption occurred within 1 h. However, as metal solutions became more complex, adsorption behavior changed. Generally, filter materials classified as sand with a naturally high pH, relatively low organic matter (OM) content and large specific surface area seem to be good choices for removing dissolved metals. Additionally, a chalk additive might improve metal adsorption whereas biochar did not significantly improve metal retention and may be an unwanted (due to degradation over time) extra source of OM. Regardless of filter material, metals primarily adsorbed to the exchangeable form which indicates that metal adsorption might not be permanent, but rather substantially reversible in some cases. More research is needed to assess whether dissolved metals adsorbed in filter materials of bioretention systems pose a delayed threat instead of an immediate threat. Finally, the authors strongly recommend filter materials intended for stormwater bioretention facilities to be tested prior to implementation.

  • 5.
    Viklander, Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Müller, Alexandra
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Borris, Matthias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kunskapssammanställning: Dagvattenkvalitet2019Report (Other (popular science, discussion, etc.))
    Abstract [en]

    This report summarizes stormwater pollutants, their sources, concentrations, and variations in concentrations. Practical guidance for field data collection, adoption of standard data from the literature and computer modelling are given. Furthermore, the effects on health, the environment and society, and associated regulations are discussed.

  • 6.
    Vijayan, Arya
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    Laboratory Melting of Late-Winter Urban Snow Samples: The Magnitude and Dynamics of Releases of Heavy Metals and PAHs2019In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 230, no 8, article id 182Article in journal (Refereed)
    Abstract [en]

    Laboratory snow melting experiments were conducted with actual late-winter snow samples, collected just before the final snowmelt, in two similar northern Swedish cities, Luleå and Umeå, to investigate releases of the selected heavy metals (HM) (Cu, Pb, Zn, and Cd) and 16 USEPA PAHs from melting snow. Metal concentrations were determined in three fractions: total, dissolved, and truly dissolved (defined as the fraction passing through a 3-kMWCO ultrafilter). Total HM concentrations in snowmelt were rather high at both sites and reflected the accumulation of pollutants in the roadside snowbanks over a period of about 5 months: Cd = 0.43, Cu = 303, Pb = 41.9, Zn = 817 (μg/l), and TSS = 2000 (mg/l) in Luleå samples and Cd = 1.87, Cu = 905, Pb = 165, Zn = 3150 (μg/l), and TSS = 4800 (mg/l) in Umeå samples. The difference between metal and TSS concentrations at the two sites of similar characteristics was attributed to a smaller volume snowbank in Umeå. The dissolved HM concentrations represented relatively small fractions of the total concentrations (0.3–6.9% in Luleå and 0.01–3.1% in Umeå). The truly dissolved fraction represented 71–90% of the dissolved fraction in Luleå and 74–98% in Umeå. At both sites, the dissolved fractions exhibited preferential elution from the laboratory snow piles. The PAHs studied (16 US EPA PAHs) were mostly particulate bound, with only 5–12% of the total burden contributed by the meltwater, and most dissolved concentrations below the reporting limits. PAH concentrations in the Luleå samples were about one-third to one-fourth of those in Umeå. In general, the releases of PAHs from the snowbank were delayed, compared with releases of meltwater, and showed similar release patterns as TSS.

  • 7.
    Gavric, Snezana
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Larm, Thomas
    StormTac corporation, Stockholm, Sweden.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Wahlsten, Anna
    StormTac corporation, Stockholm, Sweden.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Measurement and conceptual modelling of retention of metals (Cu, Pb, Zn) in soils of three grass swales2019In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 574, p. 1053-1061Article in journal (Refereed)
    Abstract [en]

    Grass swales are important elements of the urban green infrastructure that convey and attenuate urban runoff and improve its quality mostly through stormwater infiltration into, and retention of conveyed pollutants by, swale soils. The retention of metals by grass swales was addressed in this study investigating the enrichment of swale soils by three common traffic-related metals: Cu, Pb and Zn. Three swales of various characteristics (L1, L2, L3) were selected for study and their soils were sampled by coring the top 30 cm and dividing the cores into 5 cm thick layers. Cumulative metal burdens were compared to those modelled by the proprietary StormTac Web model, which estimates annual loads of specific constituents for the given land uses and stormwater treatment. The comparisons of measured (MBm) and simulated (MBs) metal burdens retained by swales showed that the measured values exceed the simulated ones, as described by average ratios MBs/MBm = 0.64, 0.50 and 0.59, for swales L1, L2 and L3, respectively. The measured burdens were calculated after subtracting the native soil metal concentrations, assumed equal to those found in the deepest sampled layer, 25–30 cm below the surface. The results suggest the feasibility of assessing performance of grass swales by modelling metal (Cu, Pb, Zn) retention by swales, however for older facilities considered for rehabilitation, the simulated results should be supplemented by soil chemistry sampling.

  • 8.
    Gavric, Snezana
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Larm, Thomas
    StormTac AB, Stockholm.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Wahlsten, Anna
    StormTac AB, Stockholm.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Measurement and Planning–Level Modelling of Retention of Trace Metals (Cu, Pb, Zn) in Soils of Three Urban Drainage Grass Swales2019In: New Trends in Urban Drainage Modelling: UDM 2018 / [ed] Giorgio Mannina, Cham: Springer, 2019, p. 85-90Conference paper (Refereed)
    Abstract [en]

    Grass swales are important elements of urban green infrastructure that convey, attenuate and improve the quality of urban runoff mostly through stormwater infiltration into and retention of conveyed pollutants by swale soils. Such processes were addressed in this study, investigating the enrichment of swale soils by ubiquitous urban trace metals, Cu, Pb and Zn. Three swales were selected for study in the City of Lulea (Northern Sweden) and their soils were sampled by coring. Sample cores covered soil depths up to 30 cm, but only the results from the top 5 cm layer characterized by 9–15 samples in each swale are discussed here. After estimating metal mass in this layer in individual swales, such burdens were compared to those modelled by the proprietary StormTac Web model, which estimates annual loads of specific constituents for given land uses and is supported by an extensive database referenced to Swedish environmental conditions. The annual loads modelled for individual swales were multiplied by the swale age to obtain long–term inputs of the trace metals. A good agreement between the measured and modelled loads in soils was obtained and characterized by the ratio Lmod/Lmeas, with an average value of 0.96 and standard deviation of 0.55. Such results suggest the feasibility of assessing the long–term performance of grass swales by modelling trace metal (Cu, Pb, Zn) inputs into swales, estimating the metal loads retained in soils by sampling and analyses, and taking the difference (Lin − Lret) as the exported load.

  • 9.
    Gavric, Snezana
    et al.
    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.
    Marsalek, Jiri
    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.
    Processes improving urban stormwater quality in grass swales and filter strips: A review of research findings2019In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 669, p. 431-447Article in journal (Refereed)
    Abstract [en]

    Increasing interest in urban drainage green infrastructure brings attention to grass swales and filter strips (GS&GFS) and their role in stormwater management. While the understanding of the hydrology and hydraulics of these stormwater control measures is adequate for current needs, there are knowledge gaps in understanding the water quality processes in GS&GFS and such a finding motivated preparation of the review paper that follows. The review revealed that most of the empirical studies of GS&GFS flow quality focused on the removal of pollutants associated with road runoff, and particularly solids, with relatively few studies addressing nutrients, traffic associated hydrocarbons, oxygen demanding substances, chloride, and faecal indicator bacteria. The reported results suffer from limitations caused by experimental conditions often representing a steady flow used to irrigate GS&GFS and generate runoff, non-submerged flows, no lateral inflows along swale side slopes, constant dosing of solids, emphasis on larger-than-typical solids, incomplete descriptions of experimental conditions, and limited attention to experimental uncertainties. Besides settling, other treatment processes, like adsorption/desorption, plant uptake, chemical precipitation and microbial degradation are often acknowledged, but without attempting to quantify their effects on flow quality. The modelling of GS&GFS flow quality would be beneficial for an improved understanding of green urban drainage infrastructure, but currently it is infeasible without a better knowledge of stormwater quality processes in GS&GFS facilities.

  • 10.
    Søberg, Laila
    et al.
    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.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Reduction of Escherichia coliEnterococcus faecalisand Pseudomonas aeruginosa in stormwater bioretention: Effect of drying, temperature and submerged zone2019In: Journal of Hydrology X, ISSN 2589-9155, Vol. 3, article id 100025Article in journal (Refereed)
    Abstract [en]

    The impact of drying and temperature on the reduction of Escherichia coliEnterococcus faecalis and Pseudomonas aeruginosa in stormwater bioretention systems with and without a submerged zone was assessed using 16 pilot-scale bioretention columns under controlled laboratory conditions. The experimental design enabled analysis of possible interactions between the factors. First outflow and event-based samples were collected. Outflow concentrations were independent of inflow concentrations and hence controlled by internal processes. Overall TSS removal was high but sensitive to bacterial synthesis. Event-based samples had significantly higher bacteria concentrations than first outflow samples, suggesting that remaining/surviving bacteria in the bioretention cells have little effect on initial peak outflow concentrations. The effect of temperature varied between bacterial species and sample types. Long dry periods seemed beneficial for bacteria reduction, but outflow bacteria concentrations peaked during the second watering after long dry periods. Submerged zones significantly reduced bacteria outflow concentrations. However, sudden temperature increases caused bioretention cells with a submerged zone to produce significantly higher bacteria outflow concentrations than before the temperature increase, which was not the case for standard cells. Bioretention cells with submerged zones may thus be poor choices for reducing bacterial concentrations in stormwater runoff in areas experiencing winter conditions. Finally, our results suggest that adsorption (e.g. further enhanced by biofilm formation) is the major mechanism governing bacteria reduction in bioretention systems.

  • 11.
    Broekhuizen, Ico
    et al.
    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.
    Marsalek, Jiri
    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.
    Selection of Calibration Events for Modelling Green Urban Drainage2019In: New Trends in Urban Drainage Modelling: UDM 2018 / [ed] Giorgio Mannina, Cham: Springer, 2019, p. 608-613Conference paper (Refereed)
    Abstract [en]

    Urban drainage models are often calibrated using a limited number of rainfall-runoff events, which may be selected in different ways from a longer observation series. This paper compares 13 different single- and two-stage strategies for selecting events used to calibrate a SWMM model of a predominantly green urban area. Most led to successful calibration, but performance varied for various validation events. Most selection strategies were insensitive to the choice of Nash-Sutcliffe Model Efficiency or Root Mean Squared Error as the objective function. Calibrating impervious and green area parameters separately in two-stage strategies can help improve prediction of low-flow events in validation.

  • 12.
    Panasiuk, Oleksandr
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ashley, Richard
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    The feasibility of using flap gates as constriction flow meters for estimating sanitary sewer overflows (SSO)2019In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 155, p. 113-119Article in journal (Refereed)
    Abstract [en]

    Increased awareness of the negative effects of sanitary sewer overflow (SSO) events on human health and aquatic life led to the development of various control measures, of which implementation is impeded by the lack of information on SSO occurrences, flows and volumes. The collection of such information requires data acquisition systems, which can be costly and are fully utilized just during limited time periods of the year. In search for inexpensive approaches to SSO monitoring, the feasibility of using existing flap gate installations, serving for prevention of back-up flows into sewers, as constriction flow meters was investigated, with promising results. An experimental pilotscale setup was designed to allow steady water flow through a flap gate built into a partition wall between two chambers. The stabilized water heads in the chambers and the flow rate through the flap gate were measured, for both dry and submerged flap gate conditions, and five flap gate sizes (200, 300, 400, 500 and 600 mm), with relatively heavy covers (6–102 kg). The measured data were used to develop flow rating curves, by non-linear regression, in the form Q = f (ΔH), where Q is the discharge through the flap gate and ΔH is the pressure differential upstream and downstream of the gate. The regression curves fitted the experimental data with high precision (R2 >0.99). The use of flow rating curves for estimation of the SSO volume was discussed. This study demonstrated that the water head measurements upstream and downstream of the flap gate can provide a reliable, accurate and inexpensive method for quantification of the SSO discharges and volumes.

  • 13.
    Broekhuizen, Ico
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Rujner, Hendrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Roldin, Maria
    DHI Sweden.
    Leonhardt, Günther
    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.
    Towards using soil water content observations for calibration of distributed urban drainage models2019Conference paper (Refereed)
    Abstract [en]

    Fully distributed urban drainage models can be used to analyse and predict the behaviour of green urban drainage infrastructure such as swales, but they need to be calibrated for specific study sites. Using only drainage outflow measurements may not provide enough information to do this in an optimal way, so additional types of measurements have to be considered. This study identifies different approaches to including soil water content (SWC) observations in the calibration process and investigates how they affect parameter identifiability and the predictive uncertainty of the calibrated model. This is done using the Generalized Likelihood Uncertainty Estimation methodology applied to a model of a large urban swale. It was found that setting initial conditions based on the SWC measurements improved the fit between observed and simulated SWC, but also reduced the accuracy of the simulated amount of infiltration. Including SWC observations allowed to identify one parameter (saturated moisture content of the swale bottom) that was not identifiable from outflow measurements alone. Including SWC observations in the derivation of predictive uncertainty bounds made those bounds narrower (more precise), but where SWC had been used to set initial conditions the uncertainty bound failed to capture the observations. It is concluded that SWC observations can provide useful information for the calibration of distributed urban drainage models.

  • 14.
    Nyström, Fredrik
    et al.
    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.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    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.
    Treatment of road runoff by coagulation/flocculation and sedimentation2019In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 79, no 3, p. 518-525Article in journal (Refereed)
    Abstract [en]

    A laboratory investigation of the treatment potential of a coagulation process in the context of stormwater treatment was undertaken. The initial 25 L road runoff generated from four rain events was collected and subjected to a jar-testing regime with two commercial coagulants. The treatment effect was assessed by analysing the runoff before and after treatment for turbidity, suspended solids and metal content. The coagulation process resulted in particle and total metal reduction of more than 90% compared to 40% for only sedimentation. Up to 40% reduction of dissolved Cr, Cu and Pb was also observed compared to 0% for sedimentation. This study shows that coagulation may be a useful process for stormwater treatment systems when the treatment requirements are high.

  • 15.
    Panasiuk, Oleksandr
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Langeveld, Jeroen
    Department of Water Management, TU Delft. Partners4UrbanWater, The Netherlands.
    de Haan, Cornelis
    Partners4UrbanWater, The Netherlands.
    Liefting, Erik
    Partners4UrbanWater, The Netherlands.
    Schilperoort, Remy
    Partners4UrbanWater, The Netherlands.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Using Distributed Temperature Sensing (DTS) for Locating and Characterising Infiltration and Inflow into Foul Sewers before, during and after Snowmelt Period2019In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, no 8, article id 1529Article in journal (Refereed)
    Abstract [en]

    Infiltration and inflow (I/I) into sewers cause negative effects on the sewer system,wastewater treatment plant and environment. Identifying the causes and locating the inflows isnecessary in order to address the I/I problem. This paper focuses on using distributed temperaturesensing (DTS) for identifying, locating and characterising I/I into a sewer system during the endof winter–beginning of summer transition period under dry and wet weather conditions. Duringsnowmelt, several locations with I/I were identified, while these locations did not show I/I duringstorm events after the snowmelt. In addition, during a very heavy storm after the snowmelt period,I/I was found at other locations. Therefore, DTS was demonstrated to be effective in identifying thetype of I/I and in locating I/I. Finally, I/I monitoring campaigns in cold climates should take intoaccount the variety of pathways of I/I during snowmelt and during rainfall.

  • 16.
    McCarthy, David T.
    et al.
    Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash University.
    Zhang, Kefeng
    Monash Infrastructure Research Institute, Department of Civil Engineering, Monash University.
    Westerlund, Camilla
    Water Coordinator, Water Authority-bottenvikens Water District Lulea.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Bertrand-Krajewski, Jean-Luc
    Univ Lyon, INSA Lyon.
    Fletcher, Tim D.
    School of Ecosystem and Forest Sciences, Faculty of Science, The University of Melbourne.
    Deletic, Ana
    Monash Infrastructure Research Institute, Department of Civil Engineering, Monash University.
    Assessment of sampling strategies for estimation of site mean concentrations of stormwater pollutants2018In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 129, p. 297-304Article in journal (Refereed)
    Abstract [en]

    The estimation of stormwater pollutant concentrations is a primary requirement of integrated urban water management. In order to determine effective sampling strategies for estimating pollutant concentrations, data from extensive field measurements at seven different catchments was used. At all sites, 1-min resolution continuous flow measurements, as well as flow-weighted samples, were taken and analysed for total suspend solids (TSS), total nitrogen (TN) and Escherichia coli (E. coli). For each of these parameters, the data was used to calculate the Event Mean Concentrations (EMCs) for each event. The measured Site Mean Concentrations (SMCs) were taken as the volume-weighted average of these EMCs for each parameter, at each site. 17 different sampling strategies, including random and fixed strategies were tested to estimate SMCs, which were compared with the measured SMCs. The ratios of estimated/measured SMCs were further analysed to determine the most effective sampling strategies. Results indicate that the random sampling strategies were the most promising method in reproducing SMCs for TSS and TN, while some fixed sampling strategies were better for estimating the SMC of E. coli. The differences in taking one, two or three random samples were small (up to 20% for TSS, and 10% for TN and E. coli), indicating that there is little benefit in investing in collection of more than one sample per event if attempting to estimate the SMC through monitoring of multiple events. It was estimated that an average of 27 events across the studied catchments are needed for characterising SMCs of TSS with a 90% confidence interval (CI) width of 1.0, followed by E.coli (average 12 events) and TN (average 11 events). The coefficient of variation of pollutant concentrations was linearly and significantly correlated to the 90% confidence interval ratio of the estimated/measured SMCs (R2 = 0.49; P < 0.01) as well as the number of events required to achieve certain accuracy, and hence could be a promising surrogate for determining the sampling frequency needed to accurately estimate SMCs of pollutants

  • 17.
    Blecken, Godecke-Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Karlsson, Kristin
    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.
    Closure to “Environmental Risk Assessment of Sediments Deposited in Stormwater Treatment Facilities: Trace Metal Fractionation and Its Implication for Sediment Management”2018In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 144, no 4Article in journal (Refereed)
  • 18.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kärrman, Erik
    RISE Research Institutes of Sweden, 11894 Stockholm, Sweden.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Data supporting the life cycle impact assessment and cost evaluation of technical alternatives for providing water and heating services to a suburban development in Gällivare Sweden2018In: Data in Brief, E-ISSN 2352-3409, Vol. 21, p. 1204-1208Article in journal (Refereed)
    Abstract [en]

    The article presents input data that were used in Pericault et al. (2018) for life cycle impact assessment and total cost assessment of five technical alternatives for heat and water services provision in a suburban development in Sweden. The data consists of a list of environmental impacts (cumulative exergy demand of energy carriers – CExDe, global warming potential – GWP, abiotic depletion potential of elements – ADPE), costs, amortisation periods, lifetimes and output flows of the system processes composing the alternatives. The data was derived from values collected in lifecycle databases, environmental product declarations, scientific publications and personal communications with companies.

  • 19.
    Tondera, Katharina
    et al.
    Institute of Environmental Engineering, RWTH Aachen University, Aachen.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Tournebize, Julien
    Hydrosystems and Bioprocessus Research Unit, Irstea—National Research Institute of Science and Technology for Environment and Agriculture, Antony.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Andersson-Wikström, Alexandra
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Tanner, Chris C.
    National Institute of Water and Atmospheric Research, Hamilton.
    Emerging Contaminants: Occurrence, Treatment Efficiency and Accumulation Under Varying Flows2018In: Ecotechnologies for the Treatment of Variable Stormwater and Wastewater Flows / [ed] Katharina Tondera, Godecke-Tobias Blecken, Florent Chazarenc, Chris C. Tanner, Cham: Springer, 2018, p. 93-109Chapter in book (Refereed)
    Abstract [en]

    Emerging contaminants became a major topic in water treatment when laboratory detection methods for concentrations at a nanogram-scale improved approximately two decades ago. Research on using ecotechnologies to remove emerging contaminants in variable stormwater and wastewater flows has been conducted for more than a decade, but so far, not all removal mechanisms are well understood and only few setups have been investigated. This chapter summarises the current knowledge, focussing on pesticides and emerging contaminants listed on the watch list of the European Union. However, large-scale investigations are still rare and further research will have to be conducted in this field to enable practitioners to provide recommendations for design and maintenance of treatment facilities in the field of ecotechnologies.

  • 20.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kärrman, Erik
    RISE Built Environment, Research Institutes of Sweden, Stockholm.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Expansion of Sewer, Water and District Heating Networks in Cold Climate Regions: an Integrated Sustainability Assessment2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 10, article id 3743Article in journal (Refereed)
    Abstract [en]

    This study presents an integrated sustainability assessment of technical alternatives for water and heating services provision in suburban areas affected by a cold climate. Each alternative combines a drinking water supply, sewerage (gravity or low-pressure), pipe freeze protection (deep burial or shallow burial with heat tracing) and heating solution (district heating or geothermal heat pumps). An innovative freeze protection option was considered, in which low-temperature district heating (LTDH) is used to heat trace shallow sewer and water pipes. First, the performance of each alternative regarding seven sustainability criteria was evaluated on a projected residential area in Sweden using a systems analysis approach. A multi-criteria method was then applied to propose a sustainability ranking of the alternatives based on a set of weights obtained from local stakeholders. The alternative with a deep buried gravity sewer and geothermal heat pumps was found to have the highest sustainability score in the case study. In the sensitivity analysis, the integrated trench solution with a gravity sewer, innovative heat tracing and LTDH was found to potentially top the sustainability ranking if geothermal energy was used as the district heating source, or if the weight of the cost criterion increased from 24% to 64%. The study highlights the need for integrated decision-making between different utility providers as an integrated solution can represent sustainability gains.

  • 21.
    Rujner, Hendrik
    et al.
    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.
    Marsalek, Jiri
    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.
    High-resolution modelling of the grass swale response to runoff inflows with Mike SHE2018In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 562, p. 411-422Article in journal (Refereed)
    Abstract [en]

    The feasibility of simulating the hydrological response of a grass swale to runoff inflows was examined using the hydrological model Mike SHE and the available input data from 12 irrigation events mimicking runoff from block rainfalls. The test swale channel had a trapezoidal cross-section, bottom slope of 1.5%, length of 30 m, and was built in loamy fine sand. The irrigation events consisted in releasing two equal constant inflows to the swale: a concentrated longitudinal flow at the upstream end and a distributed lateral inflow along the swale side slope adjacent to the contributing drainage area. The total inflows approximated runoff from two events with return periods of 2 months and 3 years, respectively, for durations of 30 min. Irrigation experiments were done for two states of the initial soil moisture, dry or wet antecedent moisture conditions (AMC). Mike SHE has been extensively used on catchments of various sizes, but rarely for small stormwater management facilities and their detailed topography investigated in this study. The latter application required high spatial and temporal resolutions, with computational cells of 0.2 × 0.2 m and time steps as short as 0.6 s to avoid computational instabilities. For dominant hydrological processes, the following computational options in Mike SHE were chosen: Soil infiltration – the van Genuchten equation, unsaturated zone flow – the one-dimensional Richards equation, and overland flow – the diffusive wave approximation of the St. Venant equations. For study purposes, the model was calibrated for single events representing one of four combinations of low and high inflows, and dry and wet AMC, and then applied to the remaining 11 events. This was complemented by calibration for two events, representing high inflow on wet AMC and low inflow in dry AMC. The goodness of fit was statistically assessed for observed and simulated peak flows, hydrograph volumes, Nash-Sutcliffe model efficiencies (NSE), and soil water content (SWC) in swale soil layers. The best fit (NSE > 0.8) was obtained for high inflows and wet AMC (i.e., when the primary swale function is flow conveyance); the least fit was noted for low inflows and dry AMC, when the primary swale function is flow attenuation. Furthermore, this observation indicates the overall importance of correct modelling of the soil infiltration. The effects of spatial variation of SWC on the swale discharge hydrograph could not be confirmed from simulation results, but high topographical accuracy was beneficial for reproducing well the locations of the observed water ponding. No significant increases in simulated SWC at 0.3 m or greater depths were noted, which agreed with field observations. Overall, the results indicated that Mike SHE was effective in process-oriented small-scale modelling of grass swale flow hydrographs.

  • 22.
    Mattsson, Jonathan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. S-Group Solutions, Malmö.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Westerlund, Lars
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ashley, Richard
    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.
    Impacts on rural wastewater systems in subarctic regions due to changes in inputs from households2018In: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 32, no 1, article id 04017019Article in journal (Refereed)
    Abstract [en]

    The use of water-saving appliances and heat exchangers is becoming increasingly popular to decrease water consumption and recover energy from preheated water. However, such in-household changes can bring particular implications for subarctic rural areas, in terms of solids deposition in sewers and drops in performance of wastewater treatment plants (WWTPs), because these are already experiencing diminishing wastewater flows due to depopulation and seasonal dips in wastewater temperature resulting from infiltration into sewers. Hence, this study has considered two communities in Sweden, postulating three different cases with various scales of retrofitting and usage. The results indicate that the decrease in in-pipe velocities when all households are retrofitted with water-saving appliances could be counteracted by sewer relining, but not by the inclusion of a conventional estimate of infiltration. However, for the case in which retrofitting was combined with decreased usage of the appliances, the decrease in self-cleansing capacity could not be counteracted. The retrofitting of heat exchangers under shower trays in all households did not have a significant effect on treatment processes at the WWTP.

  • 23.
    Blecken, Godecke-Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Tondera, Katharina
    Stormwater Research Group, University of the Sunshine Coast, Maroochydore.
    Österlund, Helene
    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.
    Metals: Occurrence, Treatment Efficiency and Accumulation Under Varying Flows2018In: Ecotechnologies for the Treatment of Variable Stormwater and Wastewater Flows / [ed] Katharina Tondera, Godecke-Tobias Blecken, Florent Chazarenc, Chris C. Tanner, Cham: Springer, 2018, p. 75-91Chapter in book (Refereed)
    Abstract [en]

    Metals were the first priority pollutants to be widely investigated in stormwater. In solid phase, they are often attached to very fine particles. The dissolved fraction creates considerable environmental problems as it is the most bioavailable fraction. Hence, removal of both fine and dissolved particles plays a major role in the treatment of polluted runoff. Ecotechnologies specifically designed to remove metals should be able to address different treatment mechanisms. However, the exhaustion of sorption capacity reduces the lifespan of treatment facilities. Additionally, metal concentrations fluctuate extremely—spatially, seasonally and over time—which poses another challenge for further increasing removal efficiencies. While soil- or sand-based systems should be designed in a way that the filter material can be exchanged, newer developments such as Floating Treatment Wetlands show promising removal capacities as the installations bind metals in sludge sediments, which can be removed from time to time. The different treatment mechanisms, aforementioned developments and techniques as well as their removal capacities will be discussed in this chapter

  • 24.
    Moghadas, Shahab
    et al.
    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.
    Marsalek, Jiri
    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.
    Modeling Urban Runoff from Rain-on-Snow Events with the U.S. EPA SWMM Model for Current and Future Climate Scenarios2018In: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 32, no 1, article id 04017021Article in journal (Refereed)
    Abstract [en]

    A methodological study of modeling runoff from rain-on-snow events was conducted using the northern Swedish city of Kiruna as a test case, with respect to physiographic, drainage system, and the current and projected future climate data. Runoff simulations were carried out with the PCSWMM, which is a geographic information system (GIS) supported version of the U.S. EPA Storm Water Management Model (U.S. EPA SWMM5) developed by Computational Hydraulics International (CHI). In total, 177 simulations were run covering four scenario categories: eight rain events, three climates (the current and two projected), three soil infiltration rates, and five snow water equivalent (SWE) values. Simulation results were analyzed with respect to influential rainfall/snowmelt/runoff factors and the noted differences were statistically tested for significance. Result analysis revealed new findings concerning the differences between runoff generated by rain-on-snow and summer thunderstorm events. In particular, it was noted that a relatively frequent rain-on-snow event, with a return period of 1.4 year, caused fewer flooded nodes and surcharged pipes in the catchment sewer system, but almost five times greater runoff volume, when compared to the same drainage system performance indicators corresponding to a 10-year event occurring in the summer. Depending on the physical characteristics of the snow cover, among which the depth appears the most important, rainwater and snowmelt may be retained in, or released from, the snowpack, which acts as a dynamic reservoir controlling the generation and release of runoff. Smaller snow depths produce smaller volumes of melt, smaller storage capacity and less effective insulation of soils, which may freeze to greater depths and become practically impervious, until the process of soil thawing has been completed. The impacts of climate change in the study area, described by increases in precipitation and air temperatures, are likely to cause more frequent runoff problems attributed to the future rain-on-snow events. Even though the runoff tendencies reported here reflect the characteristics of the study area and climate, they suggest the need to consider rain-on-snow events in sewer design and storm water management in regions with seasonal snow covers, certainly with respect to runoff volumes.

  • 25.
    Rujner, Hendrik
    et al.
    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.
    Marsalek, Jiri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Perttu, Anna-Maria
    SENS Sustainable Energy Solutions, 12154 Nacka, Sweden.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    The effects of initial soil moisture conditions on swale flow hydrographs2018In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 32, no 5, p. 644-654Article in journal (Refereed)
    Abstract [en]

    The effects of soil water content (SWC) on the formation of run‐off in grass swales draining into astorm sewer system were studied in two 30‐m test swales with trapezoidal cross sections. Swale1 was built in a loamy fine‐sand soil, on a slope of 1.5%, and Swale 2 was built in a sandy loam soil,on a slope of 0.7%. In experimental runs, the swales were irrigated with 2 flow rates reproducing run‐off from block rainfalls with intensities approximately corresponding to 2‐month and 3‐year events. Run‐off experiments were conducted for initial SWC (SWCini) ranging from 0.18 to 0.43 m3/m3. For low SWCini, the run‐off volume was greatly reduced by up to 82%, but at highSWCini, the volume reduction was as low as 15%. The relative swale flow volume reductions decreased with increasing SWCini and, for the conditions studied, indicated a transition of the dominating swale functions from run‐off dissipation to conveyance. Run‐off flow peaks were reduced proportionally to the flow volume reductions, in the range from 4% to 55%. The swale outflow hydrograph lag times varied from 5 to 15 min, with the high values corresponding tolow SWCini. Analysis of swale inflow/outflow hydrographs for high SWCini allowed estimations of the saturated hydraulic conductivities as 3.27 and 4.84 cm/hr in Swales 1 and 2, respectively. Such estimates differed from averages (N = 9) of double‐ring infiltrometer measurements (9.41 and 1.78 cm/hr). Irregularities in swale bottom slopes created bottom surface depression storage of 0.35 and 0.61 m3 for Swales 1 and 2, respectively, and functioned similarly as check bermscontributing to run‐off attenuation. The experimental findings offer implications for drainage swale planning and design: (a) SWCini strongly affect swale functioning in run‐off dissipation and conveyance during the early phase of run‐off, which is particularly important for design storms and their antecedent moisture conditions, and (b) concerning the longevity of swale operation, Swale 1 remains fully functional even after almost 60 years of operation, as judged from its attractive appearance, good infiltration rates (3.27 cm/hr), and high flow capacity.

  • 26.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Risberg, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    A novel freeze protection strategy for shallow buried sewer pipes: temperature modelling and field investigation2017In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 76, no 2, p. 294-301Article in journal (Refereed)
    Abstract [en]

    The burial of sewer and water pipes below the maximum ground frost depth can be very costly and laborious in regions with cold winters. If a freeze protection measure is applied, the utility lines can be installed in a shallower trench to reduce the excavation needs. One freeze protection measure, so called heat tracing, consists in supplying heat along the pipes. In this work, the use of 4th generation district heating as a heat tracing solution was investigated at a pilot site in Kiruna, Sweden. The influence of the system on sewer and water pipe temperatures was studied at a snow-free and snow-covered cross section. To this end, five heat tracing temperatures were tested and the corresponding sewer and water pipe temperatures were measured. The field experiment was also simulated with a two dimensional finite volume model. The study showed that, under the climatic conditions of the experiment, a heat tracing temperature of 25 °C allowed to prevent freezing of the pipes while keeping drinking water pipes in a safe temperature range at both cross sections. The other main result was that the developed finite volume model of the sections showed a good fitting to the experimental data

  • 27.
    Leonhardt, Günther
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Moghadas, Shahab
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    An exploratory study of snowmelt runoff modelling in an urban catchment using the US EPASWMM model2017In: 14th IWA/IAHR International Conference On Urban Drainage, 2017, p. 78-81Conference paper (Refereed)
  • 28.
    Borris, Matthias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    An exploratory study of the effects of stormwater pipeline materials on transported stormwater quality2017In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 76, no 2, p. 247-255Article in journal (Refereed)
    Abstract [en]

    Implications of three sewer pipe materials (concrete, galvanized corrugated steel, and polyvinyl chloride (PVC)) for stormwater quality were explored in laboratory experiments, in which three types of stormwater, SW1-SW3, were circulated in 0.5 m long sewer pipe sections. SW1 and SW2 represented synthetic rainwater, without and with fine street sediment added (CTSS = 150 mg/L), respectively, and SW3 was actual stormwater with the same sediment addition as SW2. Following 20-min runs, with an equivalent distance of 500 m travelled by water particles, a number of statistically significant changes in the stormwater chemistry were observed: (i) pH of all the simulated stormwaters increased in the concrete pipe (from 7.0-7.3 to 8.1-9.3), (ii) turbidity decreased in two stormwaters with sediments (SW2 and SW3) in concrete and galvanized corrugated steel pipes (by 50 and 85%, respectively), (iii) the type of stormwater affected the observed copper (Cu) concentrations, with Cudiss concentrations as high as 25.3 μg/L noted in SW3 passing through the PVC pipe, and (iv) zinc (Zn) concentrations sharply increased (Zntot = 759-1,406 μg/L, Zndiss = 670-1,400 μg/L) due to Zn elution from the galvanized steel pipe by all three stormwaters. Such levels exceeded the applicable environmental guidelines.

  • 29.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Bruaset, Stian
    Institutt for bygg- og miljøteknikk , NTNU.
    Ugarelli, Rita
    Department of Civil and Environmental Engineering, NTNU.
    Saegrov, Sveinung
    Department of Civil and Environmental Engineering, NTNU.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Coordinated long term planning of sewer and water mains rehabilitation2017Conference paper (Other academic)
    Abstract [en]

    Long term planning methodologies for sewer and water mains rehabilitation play a key role in water infrastructure asset management by enabling modelling the influence of renewal strategies on various sustainability indicators. Long term rehabilitation scenarios defining annual replacement rates are typically compared in order to choose the best strategy for the sewer and drinking water network, separately. Another important factor for long term rehabilitation planning is the share of replacement work that will be coordinated with other infrastructures (e.g. water network for the sewer network and vice versa, roads, etc.). This reduces linear replacement costs but also shortens the service life of pipes replaced for coordination reason. The paper proposes an integrated methodology to evaluate the impact of different coordination strategies on future replacement costs for water and sewer networks renewal. The method is applied on a newly built residential area in the town of Gällivare in Sweden.

  • 30.
    Søberg, Laila
    et al.
    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.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Do salt and low temperature impair metal treatment in stormwater bioretention cells with or without a submerged zone?2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 579, p. 1588-1599Article in journal (Refereed)
    Abstract [en]

    Although seasonal temperature changes and (road) salt in winter and/or coastal stormwater runoff might interfere with the metal treatment performance of stormwater bioretention cells, no previous study has evaluated the effect of these factors and their interactions under controlled conditions. In this 18 week long study 24 well established pilot-scale bioretention columns were employed to evaluate the individual and combined effect(s) of low/high temperature, salt and presence of a submerged zone with an embedded carbon source on metal removal using a three factor, two-level full factorial experimental design. In most instances, the three factors significantly influenced the metal outflow concentrations and thus the treatment performance; the effect of temperature depended on the metal in question, salt had an overall negative effect and the submerged zone with carbon source had an overall positive effect. Despite these statistically significant effects, the discharge water quality was generally markedly improved. However, leaching of dissolved Cu and Pb did occur, mainly from bioretention cells dosed with salt-containing stormwater. The highest concentrations of metals were captured in the top layer of the filter material and were not significantly affected by the three factors studied. Overall, the results confirmed that bioretention provides a functioning stormwater treatment option in areas experiencing winter conditions (road salt, low temperatures) or coastal regions (salt-laden stormwater). However, validation of these results in the field is recommended, especially focusing on dissolved metal removal, which may be critically affected under certain conditions.

  • 31.
    Al-Rubaei, Ahmed Mohammed
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Engström, Malin
    Växjö Municipality.
    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.
    Effectiveness of a 19-Year Old Combined Pond-Wetland System in Removing Particulate and Dissolved Pollutants2017In: Wetlands (Wilmington, N.C.), ISSN 0277-5212, E-ISSN 1943-6246, Vol. 37, no 3, p. 485-496Article in journal (Refereed)
    Abstract [en]

    This study monitored the stormwater runoff quantity and quality treatment performance of a 6.8 ha 19-year old combined pond-wetland system, located in south Sweden, over one year. The mean volume reductions for 53 storm events for the pond and wetland were 40% and 28%, respectively, while the mean flow reductions were 60% and 76%, respectively. Pollutant concentrations in the influent to the wetland were highly variable. The pond-wetland system could efficiently remove an average of 91%, 80%, 94%, 91%, 83% and 92% of TSS, TP, particulate Cd, Cu, Pb, and Zn, respectively, whereas the removal of particulate and dissolved Ni was highly variable with an average of 67% ± 62% and −5% ± 41%, respectively. The removal of TN, NH4-N and NO3 + NO2-N was highly variable with an average of 45% ± 27%, 12% ± 96% and 45% ± 43%, respectively. These removal percentages are high in comparison to other studies and underline that relatively old systems can also provide efficient treatment. Although the pond accounted for a substantial reduction of pollutant concentration, the wetland significantly enhanced both the treatment performance and the peak flow reduction. This underlines that a combined pond/wetland system is a more beneficial solution than a pond only. The pollutant removal efficiency was significantly influenced by some factors including Antecedent Dry Days, seasonal variations, air temperature, retention times, rainfall depth and duration, and peak rainfall intensity.

  • 32.
    Lönnqvist, Joel
    et al.
    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.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Evaluating the plant cover of northern Sweden's green roofs2017In: Proceedings of EtW2017, 2017Conference paper (Other academic)
  • 33.
    Merriman, Laura S.
    et al.
    Biological & Agricultural Engineering, North Carolina State University.
    Moore, T.L.C.
    Biological & Agricultural Engineering, Kansas State University.
    Wang, J.W.
    Centre for Urban Greenery and Ecology, National Parks Board, 1E Cluny Road, 259569, Singapore.
    Osmond, D.L.
    Soil Science, North Carolina State University.
    Al-Rubaei, Ahmed
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Smolek, A.P.
    Biological & Agricultural Engineering, North Carolina State University.
    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.
    Biological & Agricultural Engineering, North Carolina State University.
    Evaluation of factors affecting soil carbon sequestration services of stormwater wet retention ponds in varying climate zones.2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 583, p. 133-141Article in journal (Refereed)
    Abstract [en]

    The carbon sequestration services of stormwater wet retention ponds were investigated in four different climates: U.S., Northern Sweden, Southern Sweden, and Singapore, representing a range of annual mean temperatures, growing season lengths and rainfall depths: geographic factors that were not statistically compared, but have great effect on carbon (C) accumulation. A chronosequence was used to estimate C accumulations rates; C accumulation and decomposition rates were not directly measured. C accumulated significantly over time in vegetated shallow water areas (0–30 cm) in the USA (78.4 g C m− 2 yr− 1), in vegetated temporary inundation zones in Sweden (75.8 g C m− 2 yr− 1), and in all ponds in Singapore (135 g C m− 2 yr− 1). Vegetative production appeared to exert a stronger influence on relative C accumulation rates than decomposition. Comparing among the four climatic zones, the effects of increasing rainfall and growing season lengths (vegetative production) outweighed the effects of higher temperature on decomposition rates. Littoral vegetation was a significant source to the soil C pool relative to C sources draining from watersheds. Establishment of vegetation in the shallow water zones of retention ponds is vital to providing a C source to the soil. Thus, the width of littoral shelves containing this vegetation along the perimeter may be increased if C sequestration is a design goal. This assessment establishes that stormwater wet retention ponds can sequester C across different climate zones with generally annual rainfall and lengths of growing season being important general factors for C accumulation.

  • 34.
    Goldkuhl, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ljung, Stina
    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.
    How to achieve cross-functional, collaborative stormwater planning?: A multiple-case study of Swedish municipalities2017In: Proceedings of EtW2017, 2017Conference paper (Refereed)
  • 35.
    Zischg, Jonatan
    et al.
    Unit of Environmental Engineering, University of Innsbruck, Austria.
    Goncalves, Mariana L. R.
    Unit of Environmental Engineering, University of Innsbruck, Austria.
    Bacchin, Taneha K.
    Environmental Technology & Design, Department of Urbanism, Faculty of Architecture and the Built Environment, Delft University of Technology, The Netherlands.
    Leonhardt, Günther
    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.
    van Timmeren, Arjan
    Environmental Technology & Design, Department of Urbanism, Faculty of Architecture and the Built Environment, Delft University of Technology, The Netherlands.
    Rauch, Wolfgang
    Unit of Environmental Engineering, University of Innsbruck, Austria.
    Sitzenfrei, Robert
    Unit of Environmental Engineering, University of Innsbruck, Austria.
    Info-Gap robustness pathway method for transitioning of urban drainage systems under deep uncertainties2017In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 76, no 5, p. 1272-1281Article in journal (Refereed)
    Abstract [en]

    In the urban water cycle, there are different ways of handling stormwater runoff. Traditional systems mainly rely on underground piped, sometimes named ‘gray’ infrastructure. New and so-called ‘green/blue’ ambitions aim for treating and conveying the runoff at the surface. Such concepts are mainly based on ground infiltration and temporal storage. In this work a methodology to create and compare different planning alternatives for stormwater handling on their pathways to a desired system state is presented. Investigations are made to assess the system performance and robustness when facing the deeply uncertain spatial and temporal developments in the future urban fabric, including impacts caused by climate change, urbanization and other disruptive events, like shifts in the network layout and interactions of ‘gray’ and ‘green/blue’ structures. With the Info-Gap robustness pathway method, three planning alternatives are evaluated to identify critical performance levels at different stages over time. This novel methodology is applied to a real case study problem where a city relocation process takes place during the upcoming decades. In this case study it is shown that hybrid systems including green infrastructures are more robust with respect to future uncertainties, compared to traditional network design.

  • 36.
    Panasiuk, Oleksandr
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Langeveld, Jeroen
    Department of Water Management, TU Delft.
    Liefting, Erik
    Partners4UrbanWater.
    Schilperoort, Remy
    Partners4UrbanWater.
    de Haan, Cornelis
    Partners4UrbanWater.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Methods for localization and volume estimation of the infiltration and inflow: Comparative study2017In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings / [ed] Jiri Marsalek, 2017Conference paper (Refereed)
    Abstract [en]

    Infiltration and inflow (I/I) into wastewater sewers have numerous negative effects on the whole wastewater system. A number of methods have been developed to estimate performance of sewer system with regards to I/I. This abstract presents and compares selected results of Distributed Temperature Sensing (DTS), Closed-circuit television (CCTV) and ammonium sampling for identifying I/I in wastewater sewers during the snowmelt period, under dry and wet weather conditions. The results showed that different methods produce results that vary in precision, accuracy, time and spatial resolution.

  • 37.
    Galfi, Helen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    Mineral and Anthropogenic Indicator Inorganics in Urban Stormwater and Snowmelt Runoff: Sources and Mobility Patterns2017In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 228, no 7, article id 263Article in journal (Refereed)
    Abstract [en]

    Inorganic chemicals in urban stormwater and snowmelt runoff originate from catchment geology and anthropogenic activities. The occurrence, partitioning and mobility of six minerals and six trace metal (TM) indicators of anthropogenic activities were studied in stormwater, snowmelt and baseflow in four urban catchments, and the sampling of inorganics was supplemented by measurements of electrical conductivity (EC), pH and total suspended solids (TSSs). Minerals occurred at concentrations several orders of magnitude higher (1–102 mg/L) than those of TMs (10−2–102 μg/L) and reflected the composition of local groundwater seeping into sewers. Concentrations of Ca, K, Mg and Na were enhanced by baseflow contributions and followed closely the electrical conductivity. Al and Fe minerals occurred in insoluble forms, and their pollutographs were similar to those of TMs, whose concentrations mimicked, to some extent, the flux of TSS. The TMs with the highest and lowest particulate fractions were Cr&Pb and Cu&Zn, respectively. The concentrations of total TMs in snowmelt were two to four times higher than those in stormwater, and both sources likely exceeded some of the stormwater effluent limits (for Cd, Cu and Zn) proposed in Sweden. Where such concentrations depended on water hardness, the risk of toxicity might be reduced by elevated hardness of the monitored snowmelt and stormwater. Recognizing the good ecological status of the study area receiving water, Lake Storsjön, some protection against polluted runoff and snowmelt may be needed and could be achieved by implementing stormwater management measures controlling TSS and TMs.

  • 38.
    Broekhuizen, Ico
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Muthanna, Tone Murete
    Norwegian University of Science and Technology.
    Leonhardt, Günther
    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.
    Model structure uncertainty in urban drainage models for green areas2017In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017, Prague, 2017, p. 1490-1494Conference paper (Refereed)
    Abstract [en]

    Two urban drainage models (SWMM and MOUSE) were used to study the impact of model structureuncertainty on long-term simulation of green areas. Depending on the soil profile being consideredsignificant differences were observed between the models, both on an annual and event basedscale. In general MOUSE generates more runoff and is more sensitive to changing soil depth. Thedifferences can be explained by the conceptual approaches used to model infiltration, which alsoaffects how much water is apportioned to evapotranspiration, surface runoff, and baseflow.

  • 39.
    Lönnqvist, Joel
    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.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Plant cover and species compositions on subarctic green roofs2017In: 14th IWA/IAHR International Conference on Urban Drainage in Prague, Czech Republic 10-15 September 2017, 2017Conference paper (Other academic)
    Abstract [en]

    Thisstudy looked at the plant cover and species composition of green roofs in a subarctic climate. The study’s aim was to evaluate the cover of plants and moss on green roofs in northern Sweden. Data was gathered from a field survey in summer 2016 andevaluatedroof sections located on buildings in three different towns located on a latitudinal gradient.Apart from plant cover substrate depth, slope andexposure was recorded. The results showed that the average vascular plant cover was low in the two northern locations (32% and 27%) while in the southernmost location it was high (>85%).

  • 40.
    Nyström, Fredrik
    et al.
    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.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    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.
    Removal of small particles from urban snow melt mixture by coagulation/flocculation and sedimentation2017In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017, 2017Conference paper (Other academic)
    Abstract [en]

    This abstract presents a laboratory study of a coagulation/flocculation process on an urban snow melt mixture. Coagulation/flocculation is ubiquitous in water treatment, but has seen little use in the stormwater context. Using a jar-test procedure five different chemicals are evaluated as primary coagulants and their treatment performance on urban snow melt with respect to solids removal and metal content. Particle-size distribution measurements will indicate the process effect on different size fractions in the urban snow melt. Analysis for metal content will show the extent of metal reduction that occurs, either by separating out the particulate fraction or due to precipitation reactions.

  • 41.
    Blecken, Godecke-Tobias
    et al.
    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, Raleigh.
    Al-Rubaei, Ahmed
    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.
    Lord, William G.
    North Carolina Cooperative Extension, North Carolina State University, Raleigh.
    Stormwater control measure (SCM) maintenance considerations to ensure designed functionality2017In: Urban Water Journal, ISSN 1573-062X, Vol. 14, no 3, p. 278-290Article in journal (Refereed)
    Abstract [en]

    Great investment is made in the design and installation of stormwater control measures (SCMs). Substantial research investment, too, is made to optimise the performance of SCMs. However, once installed, SCMs often suffer from lack of maintenance or even outright neglect. Key maintenance needs for wet ponds, constructed stormwater wetlands, bioretention, infiltration practices, permeable pavement, swales, and rainwater harvesting systems are reviewed with many tasks, such as the cleaning of pre-treatment areas and the preservation of infiltration surfaces, being common maintenance themes among SCMs. Consequences of lacking maintenance are illustrated (mainly insufficient function or failure). Probable reasons for neglect include insufficient communication, unclear responsibilities, lack of knowledge, financial barriers, and decentralised measures. In future designs and research, maintenance (and lack thereof) should be considered. Assessing the performance of SCMs conservatively and including safety factors may prevent consequences of under-maintenance; and requiring regular inspection may help to enforce sufficient maintenance.

  • 42.
    Al-Rubaei, Ahmed
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Merriman, Laura S.
    Biological & Agricultural Engineering, North Carolina State University.
    Hunt, William F.
    Biological & Agricultural Engineering, North Carolina State University.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    Survey of the operational status of 25 Swedish municipal stormwater management ponds2017In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 143, no 6, article id 05017001Article in journal (Refereed)
    Abstract [en]

    During the past 50 years, wet stormwater ponds have been constructed to reduce negative environmental impacts of urban stormwater discharges on receiving aquatic environments. However, in many jurisdictions there is little information on the current operational status of such ponds and their functioning. This paucity of information prompted a field survey of 25 Swedish municipal stormwater ponds, aged between 3 and 26 years. The pond survey focused on estimating the pond hydraulic loading and efficiency, the state of littoral vegetation, characteristics of bottom sediment in the inlet and outlet zones (sizes and the chemistry), and the overall operational pond status, including the access for maintenance. The hydraulic efficiencies of ponds were estimated for pond footprint shapes and relative locations of the inlets and outlets using literature data. The estimated hydraulic efficiencies correlated well with the pond length-to-width ratios and the ratio of the pond surface area to the impervious area of the runoff contributing catchment (i.e., the hydraulic loading). Littoral vegetation was inspected visually and found to be overgrown at some facilities, which impeded the maintenance access. Benthic sediments in ponds contained silt and clay (&lt;63&#x2009;&#x2009;&#x3BC;m" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;"><63  μm<63  μm), sand and gravel fractions, and when compared with the literature data, such sediments appeared relatively coarse. Chemical characteristics of sediments reflected anthropogenic (traffic) activities, but without excessive contamination warranting special disposal requirements. Of the 25 ponds surveyed, four were fenced off and inaccessible to machinery. In fact, the design of these four ponds was such that it made inspection and maintenance very difficult, which may pose potential risks to ponds operation. Fifty-four percent of the investigated ponds were in need of minor maintenance, primarily because of sediment and litter accumulation in their inflow and outflow sections. The fact that the inspection survey revealed relatively few minor issues that could be corrected easily demonstrates the importance of relatively simple regular inspections serving to detect minor problems at an early stage before they would seriously impact pond functioning. The above survey methodology should be helpful for developing similar low-cost surveys in other jurisdictions.

  • 43.
    Lindfors, Sarah
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    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.
    Truly dissolved and labile Cu and Zn in urban runoff from a parking lot, an industrial area and copper and zinc roofs2017In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017, Prague, 2017,, 2017Conference paper (Refereed)
    Abstract [en]

    In this work two approaches were used in order to characterise the chemical speciation of Cu and Zn in urban runoff: ultrafiltration and passive sampling using diffusive gradients in thin films (DGT). Grab samples were taken from two catchments during snowmelt and from copper and zinc roofs during a snow-mixed-with-rain event. The results indicated that the catchment runoff composed of high amountsof particulate Cu and Zn, and that the dissolved Cu and Zn comprised of a variety of mobile and labile species. Whereas, the total Cu and Zn concentrations in roof runoff, to a great extent, composed of free ions

  • 44.
    Goldkuhl, Lena
    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.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Urban water research in an urban living lab setting: How does it work?2017In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017Conference paper (Refereed)
  • 45.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Risberg, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedström, Annelie
    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.
    A novel freeze protection strategy for shallow buried sewer pipes: temperature modelling and field investigation2016In: Proceedings of the 8th International Conference on Sewer Processes & Networks, 2016Conference paper (Other academic)
    Abstract [en]

    The burial of sewer and water pipes below the maximum ground frost depth can be very costly and laborious in regions with cold winters. If a freeze protection measure is applied, the utility lines can be installed in a shallower trench to reduce the excavation needs during construction and maintenance works. One freeze protection measure, so called heat tracing, consist in supplying heat along the pipes. In this work, the use of 4th generation district heating as a heat tracing solution was investigated at a pilot site in Kiruna, Sweden. The influence of the system on sewer and water pipes temperatures was studied experimentally and numerically at a snow-free and snow-covered cross section. The study showed that, under the climatic conditions of the experiment, a heat tracing temperature of 25 ˚C allowed to prevent freezing of the pipes while keeping drinking water pipes in safe temperature range at both cross sections. The other main result was that a finite volume model of the sections was developed and showed a good fitting to the experimental data.

  • 46.
    Rujner, Hendrik
    et al.
    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. Unit of Environmental Engineering, University of Innsbruck.
    Perttu, Anna-Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    Advancing green infrastructure design: Field evaluation of grassed urban drainage swales2016In: Novatech proceedings 2016, 2016Conference paper (Refereed)
    Abstract [en]

    Grassed drainage swales, which represent common elements of urban green infrastructures, are designed for different soils, flow capacities, dimensions, slopes and vegetation. Their design is often based on local experience rather than technical guidelines, and consequently, the design and performance of grassed swales, with respect to flow capacity and stormwater management objectives may significantly vary from one jurisdiction to another. To improve this situation and reduce design uncertainties, a field study of grassed swales was conducted by assessing their hydrologic performance. A 30-m section of an urban grassed swale in sandy soils, located in the City of Luleå (Northern Sweden), was equipped with a mobile water supply system and instrumented for measuring swale flow characteristics. The water supply system comprised five containers (~ 1 m3 each) providing controlled longitudinal and lateral inflows into the tested swale section. These inflows were selected to mimic stormwater runoff from a typical drainage area. At the first test site, 14 rainfall events of 30- minute duration were simulated and the resulting swale flows and soil moisture conditions were measured. The experimental variables addressed included wet and dry antecedent conditions, and three inflow rates. The preliminary results indicate that the degree of swale inflow attenuation depended on the magnitude of runoff inflow, on the initial soil moisture conditions and that significant volumes of water can be stored and transmitted during the stormwater drainage process.

  • 47.
    Søberg, Laila
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Vollertsen, Jes
    Department of Civil Engineering, Aalborg University.
    Blecken, Godecke-Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nielsen, Asbjørn Haaning
    Department of Civil Engineering, Aalborg University.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Bioaccumulation of heavy metals in two wet retention ponds2016In: Urban Water Journal, ISSN 1573-062X, Vol. 13, no 7, p. 697-709Article in journal (Refereed)
    Abstract [en]

    Metal accumulation in stormwater ponds may contaminate the inhabiting fauna, thus jeopardizing their ecosystem services function. We evaluated bioaccumulation of metals in natural fauna and caged mussel indicator organisms in two wet retention ponds. Mussel cages were distributed throughout the ponds to detect bioaccumulation gradients and obtain a time-integrated measure of metal bioavailability. We further investigated if sediment metal concentrations correlate with those in the fauna and mussels. Metal concentrations in the fauna tended to be higher in the ponds than in a reference lake, but statistical significance was only shown for Cu. Positive correlations were found for some metals in fauna and sediment. Sediment metal concentrations in one pond decreased from inlet to outlet while no gradients were observed in the mussels in either pond. These findings indicate that metal accumulation in the examined ponds currently does not pose a threat to their habitat function.

  • 48.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Svensson, Gilbert
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. SP Urban Water Management.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Challenges in water and wastewater transport systems in cold regions2016In: Water and wastewater management – challenges in cold climate / [ed] Harsha Ratnaweera, 2016Conference paper (Refereed)
    Abstract [en]

    The water and wastewater transport systems faces severe challenges due to climate change, resource constrain and an aging infrastructure. In cold regions the challenges are also related to general conditions societies have in common, e.g. sparsely populated, depopulation, long distances between populated areas and difficulties with recruiting right competence, beside the influence of the harsh climate on the technical system. In Sweden, municipal water services are financed by fees paid by the water utility users in a specific municipality. This means that water utilities in sparsely populated cold regions with on-going depopulation have limited economical resources to operate and maintain the transport and treatment systems for water and wastewater. The objectives of this paper are to illustrate the challenges for managing the transport system by comparing benchmark values for municipalities in cold regions with the Swedish averages, suggest possible measures to meet the challenges and give examples of on-going research in Stormwater&Sewers related to these questions.

  • 49.
    Borris, Matthias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    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.
    Contribution of coarse particles from road surfaces to dissolved and particle-bound heavy metal loads in runoff: A laboratory leaching study with synthetic stormwater2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 573, p. 212-221Article in journal (Refereed)
    Abstract [en]

    Laboratory leaching experiments were performed to study the potential of coarse street sediments (i.e. > 250 μm) to release dissolved and particulate-bound heavy metals (i.e. Cd, Cr, Cu, Ni, Pb and Zn) during rainfall/runoff. Towards this end, street sediments were sampled by vacuuming at seven sites in five Swedish cities and the collected sediments were characterized with respect to their physical and chemical properties. In the laboratory, the sediments were combined with synthetic rainwater and subject to agitation by a shaker mimicking particle motion during transport by runoff from street surfaces. As a result of such action, coarse street sediments were found to release significant amounts of heavy metals, which were predominantly (up to 99%) in the particulate bound phase. Thus, in dry weather, coarse street sediments functioned as collectors of fine particles with attached heavy metals, but in wet weather, metal burdens were released by rainfall/runoff processes. The magnitude of such releases depended on the site characteristics (i.e. street cleaning and traffic intensity), particle properties (i.e. organic matter content), and runoff characteristics (pH, and the duration of, and energy input into, sediment/water agitation). The study findings suggest that street cleaning, which preferentially removes coarser sediments, may produce additional environmental benefits by also removing fine contaminated particles attached to coarser materials

  • 50.
    Panasiuk, Oleksandr
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ashley, Richard
    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.
    Detection of Wastewater Discharges into Stormwater Sewers: Effects of Travel Distance on Parameters2016In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 142, no 5, article id 4016016Article in journal (Refereed)
    Abstract [en]

    In separate sewer systems, there is a risk that wastewater from illicit connections may enter a stormwater sewer and ultimately outfall into receiving waters, adversely affecting receiving water quality and increasing risks to public health. A common approach in using methods for the detection of wastewater pollution in stormwater systems for some municipalities is to take grab samples at the outlet of a stormwater sewer, some distance away from the point(s) of ingress of the pollution. However, once pollution enters a stormwater network, the concentration or detectability of indicator parameters may change. The aim of this study was to evaluate the variation in detectability of various wastewater quality parameters depending upon the distance from the point of ingress of the wastewater into a stormwater sewer. This includes E. coli, total coliform, Enterococci, conductivity, turbidity, total suspended solids, and ammonium. This study introduces a maximum detection distance—the maximum distance at which the detection of individual quality parameters would no longer be reliable. Recommendations on planning a wastewater detection program and selecting appropriate indicator parameters are given.

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