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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)
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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
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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
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
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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
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
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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
Herrmann, I., Larsson, C. & Wilen, B. (2019). Slambildning och mikrobiell sammansättning av biofilm i infiltrationsanläggningar.
Open this publication in new window or tab >>Slambildning och mikrobiell sammansättning av biofilm i infiltrationsanläggningar
2019 (Swedish)Report (Other academic)
Publisher
p. 31
Series
Technical report / Luleå University of Technology, ISSN 1402-1536
Keywords
bakterier, markbaserad rening, slamavskiljare, ventilation, fett, små avlopp, mikroflora, igensättning
National Category
Other Environmental Engineering Infrastructure Engineering Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-76309 (URN)978-91-7790-464-9 (ISBN)
Funder
Swedish Agency for Marine and Water Management, 1:11
Available from: 2019-10-09 Created: 2019-10-09 Last updated: 2019-11-22Bibliographically approved
Vidal, B., Herrmann, I. & Hedström, A. (2019). Små avloppssystem: hur hållbara är de?. Luleå tekniska universitet
Open this publication in new window or tab >>Små avloppssystem: hur hållbara är de?
2019 (Swedish)Other (Other (popular science, discussion, etc.))
Abstract [sv]

Små avloppssystem släpper ut avloppsvattnet lokalt, och därför är det viktigt att systemen uppfyller de krav som finns för utsläpp av organiskt material och näringsämnen och även klarar krav på smittskydd. Ofta fungerar, tyvärr, de små systemen inte som de borde, och när anläggningar ska uppgraderas eller när det ska byggas nya system bör det ske med tanke på hållbarheten. I ett nyligen avslutat projekt har vi arbetat med små avloppssystem i relation till hållbarhetskriterier och olika scenarier. Studien visar att det är viktigt att sätta upp mål och prioriteringar när man ska välja avloppslösning. Vilket som är det mest hållbara alternativet beror på vilka aspekter som prioriteras.

Place, publisher, year, pages
Luleå tekniska universitet, 2019. p. 8
Series
Artikelserie Ny forskning och teknik ; 8
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-77182 (URN)
Available from: 2019-12-16 Created: 2019-12-16 Last updated: 2020-02-18Bibliographically approved
Nyström, F., Nordqvist, K., Herrmann, I., Hedström, A. & Viklander, M. (2019). Treatment of road runoff by coagulation/flocculation and sedimentation. Water Science and Technology, 79(3), 518-525
Open this publication in new window or tab >>Treatment of road runoff by coagulation/flocculation and sedimentation
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2019 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 79, no 3, p. 518-525Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
IWA Publishing, 2019
Keywords
advanced stormwater treatment, coagulation, metals, particles, road runoff, suspended solids
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-73090 (URN)10.2166/wst.2019.079 (DOI)30924806 (PubMedID)2-s2.0-85063686388 (Scopus ID)
Funder
Swedish Research Council Formas, 2016-20075Swedish Research Council Formas, 2016-01447
Note

Validerad;2019;Nivå 2;2019-04-08 (oliekm)

Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2019-08-16Bibliographically approved
Herrmann, I., Wilen, B.-M., Larsson, C., Forsberg, B., Hedström, A. & Viklander, M. (2018). Microorganisms in sand filters for on-site wastewater treatment. In: : . Paper presented at 15th International Specialised Conferences on Small Water and Wastewater Systems (SWWS), 14-18 Oct 2018, Haifa, Israel.
Open this publication in new window or tab >>Microorganisms in sand filters for on-site wastewater treatment
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2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Engineering and Technology
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-72028 (URN)
Conference
15th International Specialised Conferences on Small Water and Wastewater Systems (SWWS), 14-18 Oct 2018, Haifa, Israel
Available from: 2018-12-13 Created: 2018-12-13 Last updated: 2019-09-26
Vidal, B., Herrmann, I., Sharp, L. & Hedström, A. (2018). What are the drivers to decentralize wastewater treatment systems?: A Swedish perspective. In: : . Paper presented at IWA 15th International Specialised Conferences on Small Water and Wastewater Systems, 14-18 October 2018, Haifa, Israel.
Open this publication in new window or tab >>What are the drivers to decentralize wastewater treatment systems?: A Swedish perspective
2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
Keywords
case study, decentralized sanitation, on-site treatment, small-scale, questionnaire
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-71322 (URN)
Conference
IWA 15th International Specialised Conferences on Small Water and Wastewater Systems, 14-18 October 2018, Haifa, Israel
Available from: 2018-10-24 Created: 2018-10-24 Last updated: 2018-12-13Bibliographically approved
Nyström, F., Nordqvist, K., Herrmann, I., Hedström, A. & Viklander, M. (2017). Removal of small particles from urban snow melt mixture by coagulation/flocculation and sedimentation. In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017. Paper presented at 14th IWA/IAHR International Conference on Urban Drainage, ICUD 2017, Prague, September 10-15 2017.
Open this publication in new window or tab >>Removal of small particles from urban snow melt mixture by coagulation/flocculation and sedimentation
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2017 (English)In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017, 2017Conference paper, Oral presentation with published abstract (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.

National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-66522 (URN)
Conference
14th IWA/IAHR International Conference on Urban Drainage, ICUD 2017, Prague, September 10-15 2017
Available from: 2017-11-09 Created: 2017-11-09 Last updated: 2017-11-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0520-796x

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