| 1. |
- Björklund, Karin, 1979, et al.
(författare)
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Hydrodynamic modelling of the influence of stormwater and combined sewer overflows on receiving water quality: Benzo(a)pyrene and copper risks to recreational water
- 2018
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 207, s. 32-42
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Tidskriftsartikel (refereegranskat)abstract
- The risk from chemical substances in surface waters is often increased during wet weather, due to surface runoff, combined sewer overflows (CSOs) and erosion of contaminated land. There are strong incentives to improve the quality of surface waters affected by human activities, not only from ecotoxicity and ecosystem health perspectives, but also for drinking water and recreational purposes. The aim of this study is to investigate the influence of urban stormwater discharges and CSOs on receiving water in the context of chemical health risks and recreational water quality. Transport of copper (Cu) and benzo[a]pyrene (BaP) in the Göta River (Sweden) was simulated using a hydrodynamic model. Within the 16 km modelled section, 35 CSO and 16 urban stormwater point discharges, as well as the effluent from a major wastewater treatment plant, were included. Pollutant concentrations in the river were simulated for two rain events and investigated at 13 suggested bathing sites. The simulations indicate that water quality guideline values for Cu are exceeded at several sites, and that stormwater discharges generally give rise to higher Cu and BaP concentrations than CSOs. Due to the location of point discharges and the river current inhibiting lateral mixing, the north shore of the river is better suited for bathing. Peak concentrations have a short duration; increased concentrations of the pollutants may however be present for several days after a rain event. Monitoring of river water quality indicates that simulated Cu and BaP concentrations are in the same order of magnitude as measured concentrations. It is concluded that hydrodynamic modelling is a useful tool for identifying suitable bathing sites in urban surface waters and areas of concern where mitigation measures should be implemented to improve water quality.
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| 2. |
- Björklund, Karin, 1979
(författare)
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Adsorbents for the removal of contaminants from stormwater
- 2015
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Ingår i: BC Water & Waste Association Annual Conference & Trade Show, Book of Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Contaminated urban runoff is a major cause of concern for water quality and aquatic ecosystems worldwide. Recent research shows that stormwater often contains metals and emerging organic contaminants at levels exceeding environmental quality standards. To comply with quality guidelines for receiving waters, stormwater treatment is considered to be critical. Filtration of stormwater through an adsorptive material is one of the most promising techniques for removal of particulate, colloidal and dissolved pollutants. The aim of this research was to use laboratory-based experiments to determine the removal capacity of selected sorbents for organic pollutants and metals found in stormwater. The ideal sorbent should be efficient in removing pollutants, inexpensive, abundant and easily accessible. A variety of materials, including minerals, wood- and bark-based media, were subjected to batch tests. By comparing the capacity of a range of sorbents under identical laboratory conditions, the most promising sorbent can be identified.The study revealed that cellulose and minerals adsorbed organic pollutants to a negligible degree. However, these materials may serve as efficient adsorbents of metals because of their potential to attract cations. Sawdust and bark efficiently and promptly sorbed organic compounds, whereas their capacity for metals was found to be low. Activated carbon produced from sewage sludge exhibited substantially higher adsorption capacity for organic pollutants than the wood- and bark-based media tested.
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| 3. |
- Björklund, Karin, 1979, et al.
(författare)
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Adsorption of Organic Pollutants in Stormwater: Evaluation of Four Potential Sorbents
- 2014
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Ingår i: Proceedings of the 13th International Conference on Urban Drainage.
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Konferensbidrag (refereegranskat)abstract
- Adsorption filters is one of the most promising techniques for removal of dissolved, colloidal and particulate pollutants from stormwater. The aim of this study was to compare the capacity of four filter materials – zeolite, cellulose, polypropylene/polyethylene (PP/PE) fibres and pine bark – to adsorb organic pollutants frequently detected in stormwater. In batch tests, synthetic stormwater spiked with polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates was contacted with media for up to 24 h. The compounds were then liquid-liquid extracted and analyzed using GC-MS. Zeolite and cellulose showed very low sorption capacity for the organic contaminants, whereas >70% of the initial concentration of all tested compounds was removed using PP/PE fibres, and >80% with pine bark. The highest adsorption capacity was found for PAHs (up to 44 µg/g) using PP/PE fibres and bark. For all tested compounds, maximum adsorption was approached within 30 min using these materials. Future research using natural stormwater should investigate the effect of colloidal transport of pollutants through PP/PE fibres and pine bark and the materials’ capacities to adsorb other pollutants, including metals.
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| 4. |
- Björklund, Karin, 1979, et al.
(författare)
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Adsorption of Organic Stormwater Pollutants onto Activated Carbon from Sewage Sludge
- 2017
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 197, s. 490-497
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption filters have the potential to retain suspended pollutants physically, as well as attracting andchemically attaching dissolved compounds onto the adsorbent. This study investigated the adsorption ofeight hydrophobic organic compounds (HOCs) frequently detected in stormwater e including fourpolycyclic aromatic hydrocarbons (PAHs), two phthalates and two alkylphenols e onto activated carbonproduced from domestic sewage sludge. Adsorption was studied using batch tests. Kinetic studiesindicated that bulk adsorption of HOCs occurred within 10 min. Sludge-based activated carbon (SBAC)was as efficient as tested commercial carbons for adsorbing HOCs; adsorption capacities ranged from 70to 2800 mg/g (Cinitial ¼ 10e300 mg/L; 15 mg SBAC in 150 mL solution; 24 h contact time) for each HOC. Inthe batch tests, the adsorption capacity was generally negatively correlated to the compounds' hydrophobicity(log Kow) and positively associated with decreasing molecule size, suggesting that molecularsieving limited adsorption. However, in repeated adsorption tests, where competition between HOCs wasmore likely to occur, adsorbed pollutant loads exhibited strong positive correlation with log Kow. Sewagesludge as a carbon source for activated carbon has great potential as a sustainable alternative for sludgewaste management practices and production of a high-capacity adsorption material.
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| 5. |
- Björklund, Karin, 1979, et al.
(författare)
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Best Management Practices to Reduce Phthalate and Nonylphenol Loads in Urban Runoff
- 2008
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Ingår i: Proceedings of the International Conference on Urban Drainage, 1-5 September, Edinburgh, UK.
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Konferensbidrag (refereegranskat)abstract
- Phthalates and nonylphenols, organic substances of widespread use, are believed to be ubiquitous in Swedish stormwater and urban sediments. Due to their reported hazardous properties, it is of great interest to identify effective best management practices (BMPs) to reduce the release of these substances to recipient waters. The stormwater-quality model SEWSYS was used to identify sources and quantify loads of phthalates and nonylphenols in two urban catchment areas. Based on the modelling results, BMPs were proposed, and their efficiencies evaluated. The SEWSYS simulations showed that discharges of phthalates and nonylphenols depend on catchment area characteristics: pollutants in a residential area originate mainly from building materials, whereas vehicles are the dominant source in a high-density traffic area. By replacing traditional building materials by phthalate and nonylphenol-free alternatives and by implementing congestion taxes to reduce traffic, the simulated pollutant loads could be reduced by more than 20% in the high-density traffic area. However, discharges from many diffuse sources cannot entirely be stopped, and a structural BMP, e.g. a sedimentation pond, is essential to further decrease pollutant loads in urban runoff. This study shows that SEWSYS can be a useful tool for selecting and evaluating adequate BMPs to reduce stormwater contamination.
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| 6. |
- Björklund, Karin, 1979, et al.
(författare)
-
Evaluation of low-cost materials for sorption of hydrophobic organic pollutants in stormwater
- 2015
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 159, s. 106-114
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Tidskriftsartikel (refereegranskat)abstract
- Conventional stormwater treatment techniques such as sedimentation and filtration are inefficient for removing the dissolved and colloidal phases of hydrophobic organic compounds (HOCs) present in stormwater. Adsorption could be a promising technique for removing colloidal and dissolved pollutants. Five low-cost sorbent materials were investigated in this project, including two minerals - vermiculite and perlite - and three waste products - two pine barks and a sawdust - as potential adsorbents for removal of polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates; HOCs commonly found in stormwater. Adsorption capacity and kinetics were studied through batch adsorption tests using synthetic stormwater spiked with a mixture of HOCs. Vermiculite and perlite exhibited insignificant removal of the organic contaminants. The three wood-based materials retained >80% of the initial HOC concentration (10-300μg/L). The two barks exhibited slightly higher adsorption capacities of HOCs than the sawdust. For all compounds tested, maximum adsorption onto the wood-based media was reached in
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| 7. |
- Björklund, Karin, 1979, et al.
(författare)
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Evaluation of low-cost media for sorption of organic pollutants in stormwater
- 2014
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Ingår i: World Environmental & Water Resources Congress 2014, Portland OR, USA, June 1-5, 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Recent studies have shown that many organic compounds, including polycyclic aromatic hydrocarbons (PAHs) emitted through combustion and via petroleum sources, phthalate plasticizers and plastic additives such as alkylphenols, are found in stormwater at levels that exceed national and international water quality standards. This calls for efficient mitigation practices to reduce and eventually terminate the emission of these pollutants into stormwater and aquatic environments. Filtration of stormwater is one of the most promising technologies to remove particulate, colloidal and dissolved contaminants, provided that effective filtration and sorption materials are used. The aim of this research was to use laboratory-based experiments to determine the removal capacity of some selected sorbents for organic pollutants. A variety of materials previously used for metal and oil sorption, including minerals, wood- and bark-based media, were examined in 24 h batch tests using synthetic stormwater, spiked with humic acids (representing dissolved organic matter) and seven different organic pollutants. The samples were then centrifuged and filtered, liquid-liquid extracted, and analyzed using gas chromatography-mass spectrometry. As expected, the sorption tests showed that the minerals were ineffective for removing organic pollutants from stormwater. Despite its high water absorption capacity, cellulose sorbed organic contaminants only to a moderate degree. The bark-based media, however, were efficient sorbents. In general, the PAHs (90-95% of initial concentration removed) were more efficiently sorbed than alkylphenols (85-90%) and phthalates (75-85%) by bark. The results can be used as a guide in the selection of effective sorbents for the treatment of polluted stormwater in, for example, manhole filters, swales and rain gardens.
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| 8. |
- Björklund, Karin, 1979, et al.
(författare)
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Källor till och flöden av ftalater och nonylfenoler i Stockholms dagvatten
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SEWSYS is a computer model designed for simulating fluxes of pollutants from its’ sources to the urban stormwater system. The model is able to simulate concentrations of substances in stormwater – thereby reducing the need for sampling and analyses of stormwater – as well as establishing the major sources of the pollutants in the urban environment. The aim of this work has been to identify the sources of some selected organic pollutants, adjusting SEWSYS to these new substances and simulating their fluxes in urban stormwater. The simulation results have then been used to investigate proper barriers to prevent these substances to reach the environment.The prioritised pollutants chosen to be studied were four phthalates – DBP, DEHP, DINP and DIDP – nonylphenols (NP) and their ethoxylates (NPE). Phthalates are plasticisers used in PVC (often as coil coating), paint and sealants. NP/E:s are surfactants used in a range of materials, such as concrete, paint and plastics. In order to add these pollutants into the SEWSYS model, the emission of each substance from each of the identified sources was scrutinised. Depending on the overall lack of data, assumptions and estimations were necessary to be made for the emission calculations.Two housing areas and one area dominated by traffic were selected for the modelling. Information on the prevalence of the different sources together with rainfall data were used for the simulation of stormwater runoff and pollution load. The model was calibrated with measured stormwater flows and volumes, as well as analysed concentrations of the pollutants in stormwater from the chosen housing and traffic areas. The traffic area showed high concentrations of phthalates in the stormwater samples. DIDP, and particularly DINP, showed the highest concentrations in most samples, both from the traffic area and the housing areas. The NP and NPE concentrations in most samples were close to or under the detection limits for the analytical methods used.The calibration of the model showed that the runoff module in SEWSYS is able to predict the runoff volume well. After recalculating and adjusting some of the emission factors, the concentrations of the pollutants were in the same magnitude as the measured values. The simulations showed that vehicles are the dominating source of the phthalates in the traffic area. Parking spaces and concrete are indicated to emit significant amounts of NP/E:s. In the housing areas the construction materials – such as plastic coated steel for roofing and cladding – were the most important sources of phthalates. Parking spaces tend to cause high pollution loads of NP/E:s.To reduce the load of organic pollutants in the environment a combination of barriers can be used – these barriers may include legislative measures to prohibit the use of a substance, recommendations to the consumers (not) to use specific construction materials or installing technical measures such as sedimentation facilities. A preliminary simulation show that by using construction materials free from phthalates or NP/E:s or reducing the traffic load, combined with a technical barrier such as a sedimentation pond, the pollution load from housing or traffic area is considerably decreased.
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| 9. |
- Björklund, Karin, 1979, et al.
(författare)
-
Metals and polycyclic aromatic hydrocarbons (PAHs) in stormwater sediments: particle distribution and catchment area emission factors (CAEFs)
- 2010
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Ingår i: Book of abstracts - 10th Urban Environment Symposium, 9-11 June 2010, Gothenburg, Sweden. ; , s. 19-
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Konferensbidrag (refereegranskat)abstract
- Emissions from traffic and construction materials contaminate stormwater with both metals and organicpollutants, and techniques for efficient removal of contaminants are reguested. The purpose of this studywas to determine the particle distribution of some selected metals and polycyclic aromatic hydrocarbons(PAHs) in a stormwater sedimentation facility, and to caiculate the emitted amounts of these contaminantsin the studied catchment area. Chemical analysis and determination of physical parameters wereperformed on sediments sampled at a stormwater treatment facility consisting of seven sedimentationchambers connected in series. The facility is located in central Gothenburg, Sweden, and receives runofffrom the E6 and E20 motorway, with a daily traffic bad of approximately 86 000 vehicies. Theconcentrations of the PAHs and metals showed a trend with sediment concentrations increasing from thefirst to the last chamber. The pollutant concentrations were weil correlated with the particle sizedistribution, dry densities, water and organic content of the sediments. in two or more of the chambers, theconcentrations of Cd, Pb, Cu, Zn, Ni, Cr and carcinogenic PAHs were higher than the given guideline vaiuesfor contaminated soil. The relative composition of the PAHs in sediment, with a dominance of pyrene,phenanthrene, fluoranthene and chrysene, indicates that rubber tyres, diesel exhaust and road asphaltcould be important sources of PAH pollution. The calculated catchment area emission factors (CAEFs)showed, in Wyear ha, the following order: petroleum hydrocarbons Cio - C4o (15 000) > Zn (3200) > Ni(~3000) > Cu (1500) > Sb (930) > Cr (820) > V (640)> Pb (260) > Co (120) > As (87) > Sn (25)> Mo (43)> ~16-EPA PAH (13) > Cresols (3.4) > Cd (1.3)> Hg (0.43). The results show that large parts of the finestsediment particle fractions, with high concentrations of the contaminants, are released with outiet waterfrom the sedimentation facility. The treatment facility could be more efficient if a filter was installed afterthe sedimentation steps, before discharge of water to the nearby stream.
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| 10. |
- Björklund, Karin, 1979, et al.
(författare)
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Mineral Adsorbents for Removal of Metals in Urban Runoff
- 2014
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Ingår i: European Geosciences Union General Assembly 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this research was to determine the capacity of four different soil minerals to adsorb metals frequently detected in urban runoff. These are low-cost, natural and commercially available soil minerals. Contaminated surface runoff from urban areas is a major cause of concern for water quality and aquatic ecosystems worldwide. Pollution in urban areas is generated by a wide array of non-point sources, including vehicular transportation and building materials. Some of the most frequently detected pollutants in urban runoff are metals. Exhaust gases, tire wear and brake linings are major sources of such metals as Pb, Zn and Cu, while impregnated wood, plastics and galvanized surfaces may release As, Cd, Cr and Zn. Many metals have toxic effects on aquatic plants and animals, depending on metal speciation and bioavailability. The removal efficiency of pollutants in stormwater depends on treatment practices and on the properties the pollutant. The distribution of metals in urban runoff has shown, for example, that Pb is predominantly particle-associated, whereas Zn and Cd are present mainly in dissolved form. Many metals are also attached to colloids, which may act as carriers for contaminants, thereby facilitating their transport through conventional water treatment processes. Filtration of stormwater is one of the most promising techniques for removal of particulates, colloidal and truly dissolved pollutants, provided that effective filtration and adsorption media are used. Filtration and infiltration are used in a wide array of stormwater treatment methods e.g. porous paving, infiltration drains and rain gardens. Several soil minerals were investigated for their potential as stormwater filter materials. Laboratory batch tests were conducted to determine the adsorption capacity of these minerals. A synthetic stormwater was tested, with spiked concentrations corresponding to levels reported in urban runoff, ranging from 50–1,500 µg/L for Zn; 5–250 µg/L for Cu, 2–20 µg/L for Cd and 10–150 µg/L for Ni and Pb. Humic acids were used to imitate natural stormwater contaminated with natural organic matter (NOM). The adsorption kinetics was also investigated through a sequence (10–120 min) of batch tests. By studying the capacity of a range of sorbents in batch tests under identical conditions, the most promising sorbent can be identified. The research is ongoing. Preliminary results will be presented.
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