Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 82) Show all publications
Milovanovic, I., Vojtěch, B., Hedström, A., Herrmann, I., Picek, T., Marsalek, J. & Viklander, M. (2020). Enhancing stormwater sediment settling at detention pond inlets by a bottom grid structure (BGS). Water Science and Technology, 81(2), 274-282
Open this publication in new window or tab >>Enhancing stormwater sediment settling at detention pond inlets by a bottom grid structure (BGS)
Show others...
2020 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 81, no 2, p. 274-282Article in journal (Refereed) Published
Abstract [en]

Stormwater sediments of various sizes and densities are recognised as one of the most important stormwater quality parameters that can be conventionally controlled by settling in detention ponds. The bottom grid structure (BGS) is an innovative concept proposed in this study to enhance removal of stormwater sediments entering ponds and reduce sediment resuspension. This concept was studied in a hydraulic scale model with the objective of elucidating the effects of the BGS geometry on stormwater sediment trapping. Towards this end, the BGS cell size and depth, and the cell cross-wall angle were varied for a range of flow rates, and the sediment trapping efficiency was measured in the model. The main value of the observed sediment trapping efficiencies, in the range from 13 to 55%, was a comparative assessment of various BGS designs. In general, larger cells (footprint 10 × 10 cm) were more effective than the smaller cells (5 × 5 cm), the cell depth exerted small influence on sediment trapping, and the cells with inclined cross-walls proved more effective in sediment trapping than the vertical cross-walls. However, the BGS with inclined cross-walls would be harder to maintain. Future studies should address an optimal cell design and testing in an actual stormwater pond.

Place, publisher, year, edition, pages
London, UK: IWA Publishing, 2020
Keywords
hydraulic scale modelling, sediment settling, sediment trapping efficiency, stormwater ponds
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-78470 (URN)10.2166/wst.2020.101 (DOI)000529870200008 ()32333660 (PubMedID)2-s2.0-85084030768 (Scopus ID)
Funder
Swedish Research Council Formas, 2016-20075Swedish Research Council Formas, 2016-01447Vinnova, 2017-04390
Note

Validerad;2020;Nivå 2;2020-05-05 (alebob)

Available from: 2020-04-14 Created: 2020-04-14 Last updated: 2020-05-28Bibliographically approved
Nyström, F., Nordqvist, K., Herrmann, I., Hedström, A. & Viklander, M. (2020). Laboratory scale evaluation of coagulants for treatment of stormwater. Journal of Water Process Engineering, 36, Article ID 101271.
Open this publication in new window or tab >>Laboratory scale evaluation of coagulants for treatment of stormwater
Show others...
2020 (English)In: Journal of Water Process Engineering, ISSN 2214-7144, Vol. 36, article id 101271Article in journal (Refereed) Published
Abstract [en]

The treatment effect and process characteristics of coagulation were investigated in semi-synthetic stormwater in laboratory-scale using jar tests. An initial screening of twelve coagulants and flocculant aids was carried out to find a selection of chemicals that efficiently reduced turbidity and suspended solids. Five coagulants were then further investigated with additional parameters measured (conductivity, alkalinity, and ζ-potential). The semi-synthetic stormwater was characterized by a high but variable, particle content, and low alkalinity. In the jar tests, a high treatment efficiency (>90 % reduction of both turbidity and suspended solids) was achieved for all coagulants. For very low alkalinity waters, the use of a biopolymer such as chitosan may be advantageous due to minimal alkalinity consumption. Based on the occurrence of charge reversal for all chemicals investigated, the mechanism for coagulation was likely charge neutralization. Treatment effect occurred in the ζ-potential span of -14 to +1 mV depending on the coagulant used. Initial turbidity and the ζ-potential are interesting parameter candidates for dosing control in stormwater treatment applications.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Stormwater, treatment, coagulation mechanism, sweep floc, charge neutralization, zeta potential
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-73088 (URN)10.1016/j.jwpe.2020.101271 (DOI)2-s2.0-85083768623 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-04-29 (alebob)

Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2020-05-05Bibliographically approved
Okwori, E., Viklander, M. & Hedström, A. (2020). Performance assessment of Swedish sewer pipe networks using pipe blockage and other associated performance indicators. H2Open Journal, 3(1), 46-57
Open this publication in new window or tab >>Performance assessment of Swedish sewer pipe networks using pipe blockage and other associated performance indicators
2020 (English)In: H2Open Journal, E-ISSN 2616-6518, Vol. 3, no 1, p. 46-57Article in journal (Refereed) Published
Abstract [en]

Sewer pipe networks are expected to operate with minimal or no interruptions. The complex nature of randomlyoccurring failures in sewer networks arising from blockages significantly adds to the cost of operation and maintenance.Blockages are significant due to sewage backup or basements flooding, resulting from theiroccurrence. Therefore, continuous performance assessment of sewer pipe networks is necessary to ensurerequired levels of service at an acceptable cost. This study provides insight into the performance of the sewerpipe networks by assessing the proneness of the network to blockages. Furthermore it draws inferences at a holisticstrategic level of influential explanatory factors of blockage proneness, using data available in the SwedishWater and Wastewater Association’s benchmarking system. Results indicate that medium sized municipalitiesare prone to at least 30% more blockages per km per year compared to other municipalities. A hypothesis ofexplanatory factors includes reduced flow volumes and flow depth. Flow velocities below self-cleaning velocityin sewer pipe networks, encouraged by sluggishness of flow are responsible for increased possibility for sedimentdeposition and accumulation in sewers leading to blockages. This is also exacerbated by the deposition of nondisposables(wet wipes, baby diapers, hard paper, etc.), accumulation of fats, oils and grease in sewers andincreased water conservation measures.

Place, publisher, year, edition, pages
London: IWA Publishing, 2020
Keywords
benchmarking, wastewater
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-79003 (URN)10.2166/h2oj.2020.027 (DOI)
Projects
Resource efficient and coordinated maintenance and renewal of horizontal water and road assets
Funder
Swedish Research Council Formas, 2018-01178
Note

Godkänd;2020;Nivå 0;2020-05-27 (alebob)

Available from: 2020-05-26 Created: 2020-05-26 Last updated: 2020-05-27Bibliographically approved
Nyström, F., Nordqvist, K., Herrmann, I., Hedström, A. & Viklander, M. (2020). Removal of metals and hydrocarbons from stormwater using coagulation and flocculation. Water Research
Open this publication in new window or tab >>Removal of metals and hydrocarbons from stormwater using coagulation and flocculation
Show others...
2020 (English)In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448Article in journal (Refereed) Epub ahead of print
Abstract [en]

As the understanding of how stormwater pollutants are fractioned and need for mitigation has increased, so has the investigation into more advanced treatment techniques. The present study investigated the treatment efficiency of coagulation/flocculation and sedimentation in semi-synthetic stormwater. Five coagulants were evaluated in terms of reducing particle content, organic carbon, total and dissolved metals, hydrocarbon oil index, and polycyclic aromatic hydrocarbons (PAHs). Changes in the resulting particle size distribution as a consequence of the coagulation treatment were also investigated. The pollutants in the semi-synthetic stormwater were predominantly in the particulate phase. The medium and longer chained hydrocarbons dominated the hydrocarbon oil index, while medium to high molecular weight PAHs were most abundant. Iron chloride was the only coagulant that affected particle size distribution post-treatment, shifting the distribution toward larger particles. In terms of total metal removal, the performance of the coagulants was similar, with over 90% removal on average. Concentration of zdissolved copper, one of the metals found in the dissolved phase, was reduced by 40% via coagulation treatment. The iron chloride coagulant increased dissolved Zn, a change attributed to a considerable drop in pH resulting in higher ion mobility. Similarly, the reduction in organic content (total organic carbon, oil, and PAHs) was over 90% for most coagulants.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Stormwater treatment, Coagulation/flocculation, Pollutant removal, Metals, Hydrocarbons, Treatment efficiency
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-78988 (URN)10.1016/j.watres.2020.115919 (DOI)
Available from: 2020-05-26 Created: 2020-05-26 Last updated: 2020-05-26
Pericault, Y., Risberg, M., Viklander, M. & Hedström, A. (2020). Temperature performance of a heat-traced utilidor for sewer and water pipes in seasonally frozen ground. Tunnelling and Underground Space Technology, 97, Article ID 103261.
Open this publication in new window or tab >>Temperature performance of a heat-traced utilidor for sewer and water pipes in seasonally frozen ground
2020 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 97, article id 103261Article in journal (Refereed) Published
Abstract [en]

Heat-traced utility corridors (utilidors) can be used in cold regions to install the drinking water and sewer pipes in a shallow trench above the frost depth, thereby limiting excavation needs and the associated economic, social, and environmental costs. Several of these infrastructures were built in the 60s and 70s in Canada, Alaska, Russia, and Norway. More recently, a new type of heat-traced utilidor was built as a pilot project in Kiruna, Sweden to increase the viability of district heating in the area by allowing co-location of all the utility pipes in a shallow trench. Despite several reported cases of undesirably warm drinking water from full-scale projects, previous research efforts on heat-traced utilidors have mainly focused on pipe freeze protection, not on the prevention of excessive temperatures of the drinking water. To ensure comfortable drinking water in terms of taste and smell, an upper temperature limit of 15 °C is usually recommended. The objective of this study was to evaluate the long-term ability of a heat-traced utilidor to maintain sewer temperatures above 0 °C and drinking water temperatures between 0 and 15 °C. Pipe temperatures were measured continuously at two cross sections of a heat-traced utilidor located in Northern Sweden over a period of 22 months. A thermal model, set up and calibrated on the measurements, was used to simulate the impact of extraordinary cold weather conditions on the pipes’ temperatures. The results showed that the utilidor could keep the pipe temperatures within the desired ranges in most cases but that special care should be taken during design to limit drinking water temperatures during the summer.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Drinking water distribution, Drinking water temperature, Sewage collection, Low temperature district heating, Pipe insulation, Freeze protection
National Category
Water Engineering Infrastructure Engineering Energy Engineering
Research subject
Urban Water Engineering; Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-73076 (URN)10.1016/j.tust.2019.103261 (DOI)000514214800034 ()2-s2.0-85077514338 (Scopus ID)
Funder
Vinnova, 2014-04287Swedish Research Council Formas, 2011-1710
Note

Validerad;2020;Nivå 2;2020-01-29 (johcin)

Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2020-04-16Bibliographically approved
Garmabaki, A. S., Marklund, S., Thaduri, A., Hedström, A. & Kumar, U. (2020). Underground pipelines and railway infrastructure: failure consequences and restrictions. Structure and Infrastructure Engineering, 16(3), 412-430
Open this publication in new window or tab >>Underground pipelines and railway infrastructure: failure consequences and restrictions
Show others...
2020 (English)In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 16, no 3, p. 412-430Article in journal (Refereed) Published
Abstract [en]

Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.

Authors gratefully acknowledge the funding provided by Sweden’sinnovation agency, Vinnova, through the strategic innovation programmeInfraSweden2030. The funding was granted in a competitiveapplication process that assessed replies to an open call for proposalsconcerning “Condition Assessment and Maintenance of TransportInfrastructure (Grant No. 2016-033113)”.

Authors gratefully acknowledge the technical support and collaboration(In-kind support) of Arrsleff R€orteknik at Sweden, Luleå RailwayResearch Center (JVTC), Stormwater&Sewers and the SwedishTransport Administration (Trafikverket). In addition, the authors arethankful to the anonymous referees for their constructive commentsand Dr Matthias Asplund and Dr Masoud Naseri for their support andsuggestions.

Place, publisher, year, edition, pages
Taylor & Francis, 2020
Keywords
Pipes, pipelines, renovation, maintenance, inspection, maintenance debt, life cycle costs, failure modes, axial loads, pipeline-railway crossings
National Category
Reliability and Maintenance Water Engineering Other Civil Engineering
Research subject
Operation and Maintenance; Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-76470 (URN)10.1080/15732479.2019.1666885 (DOI)000487636800001 ()2-s2.0-85073959583 (Scopus ID)
Projects
PipeXrail
Funder
Vinnova, 2016-033113
Note

Validerad;2020;Nivå 2;2020-01-28 (johcin)

Available from: 2019-10-22 Created: 2019-10-22 Last updated: 2020-01-28Bibliographically approved
Garmabaki, A. S., Thaduri, A., Hedström, A., Kumar, U., Laue, J., Marklund, S., . . . Indahl, S. (2019). A Survey on Underground Pipelines and Railway Infrastructure at Cross-Sections. In: Michael beer, Enrico Zio (Ed.), ESREL-2019: . Paper presented at ESREL 2019 | European Safety and Reliability Conference.
Open this publication in new window or tab >>A Survey on Underground Pipelines and Railway Infrastructure at Cross-Sections
Show others...
2019 (English)In: ESREL-2019 / [ed] Michael beer, Enrico Zio, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures are critical for society and industry resulting in direct and indirect costs for all the related stakeholders. Pipeline failures are complex processes, which are affected by many factors, both static (e.g., pipe material, size, age, and soil type) and dynamic (e.g., traffic load, pressure zone changes, and environmental impacts). These failures have serious impacts on public due to safety, disruption of traffic, inconvenience to society, environmental impacts and shortage of resources. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within transportation infrastructure. The aim of this study is to identify failure modes and consequences related to the crossing of pipelines in railway corridors. Expert opinion have been collected through two set of questionnaires which have been distributed to the 291 municipalities in the whole Sweden. The failure analysis revealed that pipe deformation has higher impact followed by pipe rupture at cross-section with railway infrastructure. For underground pipeline under railway infrastructure, aging and external load gets higher ranks among different potential failure causes to the pipeline.

Keywords
Underground Pipelines, Transportation Infrastructure, Railway, Maintenance, FMEA
National Category
Reliability and Maintenance Water Engineering Geotechnical Engineering
Research subject
Structural Engineering; Traffic Engineering
Identifiers
urn:nbn:se:ltu:diva-76471 (URN)10.3850/978-981-11-2724-3_0037-cd (DOI)978-981-11-2724-3 (ISBN)
Conference
ESREL 2019 | European Safety and Reliability Conference
Projects
PipeXrail
Funder
Vinnova, 2016-033113
Note

We gratefully acknowledge the funding provided by Sweden’s Innovation Agency, Vinnova, through the Strategic Innovation Programme InfraSweden2030. The funding was granted in competition within the Open Call “Condition assessment and maintenance of transport infrastructure – Grant No. 2016-033113”. In addition, the technical support and collaboration of, Arrsleff Rörteknik, Luleå Railway Research Center (JVTC) and the Swedish Transport Administration (Trafikverket) are greatly appreciated

Available from: 2019-10-22 Created: 2019-10-22 Last updated: 2019-11-22
Vidal, B., Hedström, A., Barraud, S., Kärrman, E. & Herrmann, I. (2019). Assessing the sustainability of on-site sanitation systems using multi-criteria analysis. Environmental Science: Water Research & Technology, 5, 1599-1615
Open this publication in new window or tab >>Assessing the sustainability of on-site sanitation systems using multi-criteria analysis
Show others...
2019 (English)In: Environmental Science: Water Research & Technology, ISSN 2053-1400, Vol. 5, p. 1599-1615Article in journal (Refereed) Published
Abstract [en]

Small on-site sanitation systems are widely present in suburban and rural areas in many countries. As these systems often underperform and have an impact on receiving waters, understanding their overall sustainability is of interest for policy and decision-makers. However, the definition and estimation of indicators defining sustainability are challenging, as it is finding the methodological approach to combine qualitative and quantitative indicators into one comprehensive assessment. In this study, twelve indicators defined by environmental, economic, social, technical and health-related criteria were used to compare nine alternatives of on-site sanitation for single households. A non-compensatory method for multi-criteria decision analysis, ELECTRE III, was used for the assessment together with weights assigned to each indicator by a reference group. Several scenarios were developed to reflect different goals and a sensitivity analysis was conducted. Overall, the graywater–blackwater separation system resulted as the most sustainable option and, in terms of polishing steps for phosphorus removal, chemical treatment was preferred over the phosphorus filter, both options being implemented together with sand filters. Assessing the robustness of the systems was a crucial step in the analysis given the high importance assigned to the aforementioned indicator by the stakeholders, thus the assessment method must be justified. The proposed multi-criteria approach contributes to aid the assessment of complex information needed in the selection of sustainable sanitation systems and in the provision of informed preferences.

Place, publisher, year, edition, pages
Cambridge: Royal Society of Chemistry, 2019
Keywords
ELECTRE III, package plant, phosphorus removal, sand filter, small-scale, source separation
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-75465 (URN)10.1039/c9ew00425d (DOI)000482436200009 ()
Funder
Swedish Research Council Formas, 942-2015-758
Note

Validerad;2019;Nivå 2;2019-09-13 (johcin)

Available from: 2019-08-09 Created: 2019-08-09 Last updated: 2019-09-13Bibliographically approved
Pericault, Y., Bruaset, S., Ugarelli, R., Viklander, M. & Hedström, A. (2019). Correcting for the impact of past coordination on the estimation of pipe cohorts survival functions. In: : . Paper presented at 9th International Conference on Sewer Processes & Networks, Aalborg Denmark, August 27-30 2019.
Open this publication in new window or tab >>Correcting for the impact of past coordination on the estimation of pipe cohorts survival functions
Show others...
2019 (English)Conference paper, Oral presentation with published abstract (Other academic)
Keywords
Asset management, coordinated replacement, cohort survival functions
National Category
Water Engineering Infrastructure Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-75082 (URN)
Conference
9th International Conference on Sewer Processes & Networks, Aalborg Denmark, August 27-30 2019
Funder
Swedish Research Council Formas
Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-09-20
Søberg, L., Viklander, M., Blecken, G.-T. & Hedström, A. (2019). Reduction of Escherichia coli, Enterococcus faecalisand Pseudomonas aeruginosa in stormwater bioretention: Effect of drying, temperature and submerged zone. Journal of Hydrology X, 3, Article ID 100025.
Open this publication in new window or tab >>Reduction of Escherichia coliEnterococcus faecalisand Pseudomonas aeruginosa in stormwater bioretention: Effect of drying, temperature and submerged zone
2019 (English)In: Journal of Hydrology X, ISSN 2589-9155, Vol. 3, article id 100025Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Bacteria, Submerged zone, Stormwater, Bioretention, Winter performance, Wet and dry periods
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-73082 (URN)10.1016/j.hydroa.2019.100025 (DOI)
Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2019-04-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9541-3542

Search in DiVA

Show all publications