Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Enhancing stormwater sediment settling at detention pond inlets by a Bottom Grid Structure
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. (Urban Water Engineering)ORCID iD: 0000-0003-2186-453X
Czech Technical University in Prague.
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. (Urban Water Engineering)
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. (Urban Water Engineering)
Show others and affiliations
2019 (English)Conference paper, Poster (with or without abstract) (Refereed)
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 (non-proprietary) 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 10x10 cm, in the model) were more effective than the smaller cells (5x5 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
2019.
Keywords [en]
Stormwater ponds, sediment settling, hydraulic scale modelling, sediment trapping efficiency
National Category
Water Engineering
Research subject
Urban Water Engineering; Centre - Centre for Stormwater Management (DRIZZLE)
Identifiers
URN: urn:nbn:se:ltu:diva-76465OAI: oai:DiVA.org:ltu-76465DiVA, id: diva2:1362878
Conference
Sewer Processes and Networks - SPN9
Funder
Swedish Research Council Formas, 2016-20075Available from: 2019-10-21 Created: 2019-10-21 Last updated: 2021-06-14
In thesis
1. Components for area-efficient stormwater treatment systems
Open this publication in new window or tab >>Components for area-efficient stormwater treatment systems
2021 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

With progressing urbanisation, treatment of urban stormwater is a vital issue that should be addressed to ensure good water quality in receiving water bodies. Treatment may be performed near the source, with different filter systems using various filter materials, or by using an end-of-pipe method, e.g. a stormwater pond. One constraint in the urban environment is the lack of available space in developed areas, where stormwater treatment facilities are needed the most. Methods developed to treat the stormwater runoff have been the focus of previous studies but the increasing standards of water quality and increasing land constraint pressures demand the further development of stormwater treatment systems. Both laboratory and field experiments are necessary to understand and improve the treatment processes as well as to evaluate how the implemented methods perform under field conditions. The aim of the thesis was to increase the knowledge about the components in stormwater treatment systems that can be used in area-efficient treatment facilities. In order to compare four potential stormwater filter materials (peat, bark, air-blown polypropylene and milkweed), column experiments were carried out using synthetic stormwater that simulated road runoff. Experiments were carried out to evaluate the impacts of the ageing of synthetic stormwater quality during laboratory testing, including dissolved metal concentrations and their impact on the estimation of filter efficiency. In a field study, a full-scale application of a zeolite filter installation was investigated, with a focus on service life and the efficiency of treating copper roof runoff. In order to further investigate a novel sedimentation device, a bottom grid structure (BGS), promoting sediment settling in a smaller area of a stormwater pond, a hydraulic modelling study was conducted to investigate the impact of the cell geometry of the structure on sediment settling and the impact of the structure on pond maintenance and sediment resuspension.  The column tests of four different filter materials showed that bark and peat had higher treatment efficiency for dissolved metals than milkweed and polypropylene, with the order of efficiency being peat>bark>milkweed>polypropylene. All four of the filter materials showed a total metal reduction of over 70%, which could be due to the separation of particle-bound metals in the columns. The ageing of the synthetic stormwater showed that dissolved metals, particularly copper, decreased in concentration, quite rapidly. During one experiment run, the dissolved copper concentration was reduced to 15% of its initial value. In order to account for the concentration changes an equation was proposed that normalised the concentration of dissolved metal over the duration of the experiment. During the observation period of 16 months, the zeolite installation removed 52% to 82% and 48% to 94% of total and dissolved copper, respectively. However, the effluent concentrations were still high (360-600 μg/l). There was also an indication of the decreasing filter performance over time with a prediction that the treatment level of total copper would drop to approximately 25% by the end of the service life of three years. The hydraulic experiments on a scaled model of a BGS showed that wider cells were on average 13% more efficient in trapping the particles than the narrower variant. The cell wall angle also had an impact (tilted walls added to the sedimentation efficiency), although the applicability of such cell structures can be questioned, as this cell shape may hinder maintenance efforts. It was also hypothesised that the inclusion of the BGS in the pond reduces the area needed for sediment settling, thus making the pond more area-efficient and easier to include in an urbanised setting. 

Place, publisher, year, edition, pages
Luleå University of Technology, 2021
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
Stormwater
National Category
Water Engineering
Research subject
Urban Water Engineering; Centre - Centre for Stormwater Management (DRIZZLE)
Identifiers
urn:nbn:se:ltu:diva-83877 (URN)978-91-7790-828-9 (ISBN)978-91-7790-829-6 (ISBN)
Presentation
2021-06-17, E632, LTU, Luleå, 14:00 (English)
Opponent
Supervisors
Available from: 2021-04-22 Created: 2021-04-21 Last updated: 2024-03-22Bibliographically approved

Open Access in DiVA

No full text in DiVA

Search in DiVA

By author/editor
Milovanovic, Ivan
By organisation
Architecture and Water
Water Engineering

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 329 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf