| 1. |
- Eriksson, Eva, 1973-, et al.
(författare)
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Biocides in urban wastewater treatment plant influent at dry and wet weather : concentrations, mass flows and possible sources
- 2014
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 60, s. 64-74
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, exterior thermal insulation systems became more and more important leading to an increasing amount of houses equipped with biocide-containing organic façade coatings or fungicide treated wood. It is known that these biocides, e.g. terbutryn, carbendazim, and diuron, as well as wood preservatives as propiconazole, leach out of the material through contact with wind driven rain. Hence, they are present in combined sewage during rain events in concentrations up to several hundred ng L(-1). The present study focused on the occurrence of these biocides in five wastewater treatment plants in Denmark and Sweden during dry and wet weather. It was discovered, that biocides are detectable not only during wet weather but also during dry weather when leaching from façade coatings can be excluded as source. In most cases, the concentrations during dry weather were in the same range as during wet weather (up to 100 ng L(-1)); however, for propiconazole noteworthy high concentrations were detected in one catchment (4.5 μg L(-1)). Time resolved sampling (12 × 2 h) enabled assessments about possible sources. The highest mass loads during wet weather were detected when the rain was heaviest (e.g. up to 116 mg h(-1) carbendazim or 73 mg h(-1) mecoprop) supporting the hypothesis that the biocides were washed off by wind driven rain. Contrary, the biocide emissions during dry weather were rather related to household activities than with emissions from buildings, i.e., emissions were highest during morning and evening hours (up to 50 mg h(-1)). Emissions during night were significantly lower than during daytime. Only for propiconazole a different emission behaviour during dry weather was observed: the mass load peaked in the late afternoon (3 g h(-1)) and declined slowly afterwards. Most likely this emission was caused by a point source, possibly from inappropriate cleaning of spray equipment for agriculture or gardening.
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| 2. |
- Furén, Robert, Industridoktorand
(författare)
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Stormwater bioretention: Pollutant occurrence and accumulation in filter materials and forebays
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Urban areas are affected by anthropogenic activities and produce pollutants that are transported to recipients and receiving waters during precipitation. Untreated stormwater runoff is a main driver of environmental degradation, and the interest in stormwater quality treatment has increased with the awareness of stormwater pollution. Several pollutants, including metals PAHs, PCBs, phthalates, and phenols, pose a hazard to aquatic life and are listed among the 45 priority substances in The European Water Framework Directive list (Directive 2013/39/EU).Stormwater bioretention technology is employed to efficiently remove pollutants during stormwater treatment in urban areas. However, the resulting accumulation of pollutants in bioretention facilities could ultimately create a pollutant depot. Hence, it is important to understand the occurrence, availability, and mobility of pollutants in bioretention facilities, as well as the processes that control their accumulation and mobility over time. The aim of the work in this licentiate thesis was to investigate the occurrence, accumulation, distribution, and concentration of organic micropollutants and metals inbioretention facilities after long-term stormwater treatment in urban areas of Ohio, Michigan, and Kentucky in November 2019.Samples were collected from 29 bioretention facilities, 20 of which were equipped with forebays. A total of 269 samples were analysed for metals commonly found in stormwater (Cr, Cu, Ni, Pb, and Zn), and a five-step sequential extraction method was used to assess the metal mobility in the filter material. Additionally, 116 samples from 12 sites were analysed for 38 organic micropollutants (OMPs), including 16 PAHs, 7 PCBs, 13 phthalates, and 2 alkylphenols.All studied metals were found in all samples, except for Cd, which was detected in 245 samples (91%). For the OMPs, 32 of 38 analytes were detected in at least one sample. PAHs and PCBs were the most frequently detected pollutants, and were found in 12 and 10 sites, respectively. The bioretention sites showed large variations in the concentrations of pollutants. The concentration of OMPs was highest in the upper 10 cm of the filter material and decreased with increasing depth, while a similar, but less obvious trend was observed for Cr, Cu, Pb, and Zn. A trend of decreasing concentration with increasing distance from the inlet was observed for OMPs but was less clear for the metals. Thefore bays, which contain sediment but no filter material, had the highest concentrations of OMPs. A strong correlation was observed between the pollutant concentrations and the ratio between the filter area and catchment area in a Principle Component Analysis. The accumulation and pathways of particle-bound OMPs and particle-bound metals showed similarities.These results will assist with improving the methods used for stormwater management. Importantly, regular replacement of the top filter layer and regular forebay maintenance may prevent pollutant accumulation and clogging, thereby extending the filters’ treatment function.
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| 6. |
- Rullander, Gabriella, et al.
(författare)
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Bark and biochar in horizontal flow filters effectively remove microplastics from stormwater
- 2024
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 356
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Tidskriftsartikel (refereegranskat)abstract
- Organic materials such as bark and biochar can be effective filter materials to treat stormwater. However, the efficiency of such filters in retaining microplastics (MPs) – an emerging stormwater pollutant – has not been sufficiently studied. This study investigated the removal and transport of a mixture of MPs commonly associated with stormwater. Different MP types (polyamide, polyethylene, polypropylene, and polystyrene) were mixed into the initial 2 cm material of horizontal bark and biochar filters of 25, 50, and 100 cm lengths. The MP types consisted of spherical and fragmented shapes in size ranges of 25–900 μm. The filters were subjected to a water flow of 5 mL/min for one week, and the total effluents were analyzed for MPs by μFTIR imaging. To gain a deeper insight, one 100 cm bark filter replica was split into 10 cm segments, and MPs in each segment were extracted and counted. The results showed that MPs were retained effectively, >97%, in all biochar and bark filters. However, MPs were detected in all effluents regardless of filter length. Effluent concentrations of 5–750 MP/L and 35–355 MP/L were measured in bark and biochar effluents, respectively, with >91% of the MP counts consisting of small-sized (25 μm) polyamide spherical particles. Combining all data, a decrease in average MP concentration was noticed with longer filters, likely attributed to channeling in a 25 and 50-cm filter. The analyses of MPs in the bark media revealed that most MPs were retained in the 0–10 cm segment but that some MPs were transported further, with 19% of polyamide retained in the 80–90 cm segment. Overall, this study shows promising results for bark and biochar filters to retain MPs, while highlighting the importance of systematic packing of filters to reduce MP emissions to the environment from polluted stormwater.
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| 7. |
- Rullander, Gabriella, et al.
(författare)
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How effective is the retention of microplastics in horizontal flow sand filters treating stormwater?
- 2023
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Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 344
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics accumulate in stormwater and can ultimately enter freshwater recipients, and pose a serious risk to aquatic life. This study investigated the effectiveness of lab-scale horizontal flow sand filters of differing lengths (25, 50 and 100 cm) in retaining four types of thermoplastic microplastics commonly occurring in stormwater runoff (polyamide, polyethylene, polypropylene, and polyethylene terephthalate). Despite the differences in particle shape, size and density, the study revealed that more than 98% of the spiked microplastics were retained in all filters, with a slightly increased removal with increased filter length. At a flow rate of 1 mL/min and after one week of operation, 62–84% of the added microplastics agglomerated in the first 2 cm of the filters. The agglomerated microplastics included 96% of high-density fibers. Larger-sized particles were retained in the sand media, while microplastics smaller than 50 μm were more often detected in the effluent. Microplastics were quantified and identified using imaging based micro Fourier Transform Infrared Spectroscopy. The efficient retention of microplastics in low-flow horizontal sand filters, demonstrated by the results, highlights their potential importance for stormwater management. This retention is facilitated by various factors, including microplastic agglomeration, particle sedimentation of heavy fibers and favorable particle-to-media size ratios.
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| 8. |
- Rullander, Gabriella, 1992-
(författare)
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Microplastic Mitigation in Urban Stormwater : Assessing Horizontal-Flow Filters of Bark, Biochar and Sand as Remediation Strategies
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Urban stormwater has been suggested as a significant vector through which microplastics (MPs) reach aquatic environments. Currently, only a small fraction of stormwater in Sweden undergoes any form of treatment. Therefore, a considerable portion of the runoff reaches and pollutes recipients with microplastics, which have demonstrated adverse effects on aquatic life. In recent years, there has been a growing interest in the decentralized treatment of stormwater, shifting the treatment of stormwater upstream and close to the runoff source through filtration-based techniques. Filtration-units can be incorporated into urban environments prone to high runoff coefficients– such as roads, parking lots, and other paved surfaces. At present, there is an opportunity to also shape decentralized treatments towards sustainable and environmentally positive approaches, by utilizing forestry by-products as filter media. Due to the promising characteristics of large specific surface areas and high porosity, the carbon-rich bark and biochar materials have been suggested as potential filter media. This thesis aims to evaluate MP pollution in urban environments, with the city of Uppsala as a case study and parking lots as sampling sites. Then, the thesis assesses the current capabilities of removing MPs in traditional sand media, followed by an evaluation of the potential of bark and biochar, as filter media for removing MPs in stormwater.Road dust and spiderwebs were sampled from parking lots in Uppsala City, to assess the ground-based and airborne MP pollution. A wide range of MP types were identified, such as polyurethane (PU), polypropylene (PP), polyester (PET), Acrylic (PMMA), polyethylene (PE), polystyrene (PS), polyamide (PA), and cellulose acetate. The PU was especially dominant in the indoor parking and PET fibers were commonly found to be airborne. Overall, the road dust and spiderwebs contained 5.78–4951 and 2500–505000 MPs/g, respectively. Horizontal-flow filters of 25, 50, and 100 cm were established to evaluate the removal efficacy of MPs using sand, bark and biochar as filtration media. The filters were introduced to a heterogeneous mix of MPs, including PET and PP fibers, spherical PA, PE and PS, and fragmented PP, representative of the polymer types identified in Uppsala city. The analysis revealed a substantial removal, >97%, of individual MPs for all filter media, achieving an overall MP retention exceeding 99%. The high removal was achieved even with filter lengths of 25 cm, with a slight increased removal with increased filter length. This thesis has proved that MPs are present in a multitude of surfaces in the urban environment, including air, and showed that sand, bark, and biochar should be considered as potential media for filtration-based remedies to improve MP mitigation in urban stormwater.
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| 9. |
- Søberg, Laila, et al.
(författare)
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A comparison of freshwater mussels and passive samplers as indicators of heavy metal pollution in aquatic systems
- 2013
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Konferensbidrag (refereegranskat)abstract
- The utility of passive sampling as a tool for determining the ecological state of wet retention ponds was investigated as an alternative to the analysis of living organisms. The accumulation of heavy metals over time in mussels and passive samplers exposed to artificial stormwater was examined under controlled conditions in order to determine whether either system was capable of functioning as a reliable source of data on aquatic pollution. The laboratory results indicated that mussels are useful in this context. However, passive samplers will require further development to be useful since there was no strong correlation between the heavy metal concentrations observed in the mussels and those in the passive samplers.
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| 10. |
- Søberg, Laila, et al.
(författare)
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Bioaccumulation of heavy metals in two wet retention ponds
- 2016
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Ingår i: Urban Water Journal. - 1573-062X. ; 13:7, s. 697-709
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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