| 1. |
- Hedström, Annelie, 1972-, et al.
(författare)
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Erfarenheter av LTA-system
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Hur ser va-branschens erfarenheter av lättryckavloppsystemut? I rapporten presenteras utmaningar och framgångsfaktorerkopplade till dessa LTA-system. Om systemen anläggsoch används på rätt sätt kan de vara ett bra alternativ tillkonventionella självfallssystem, men frågor kring svavelväteoch livscykelkostnader behöver redas ut för att säkerställasystemens långsiktiga hållbarhet.Lättryckavloppssystem (LTA-system) används ofta som alternativ till självfallssystemi omvandlingsområden och där va-huvudmännens verksamhetsområden utvidgas.Under de senaste 20 åren har användningen av LTA-system ökat kraftigt, och i dag ärutbyggnadstakten mycket stor i vissa delar av landet. LTA-system är enklare att anläggai områden med utmanande topografi och markförhållanden, och ledningsgravarnakan göras relativt grunda så att schaktningsbehovet blir mindre än för konventionellasjälvfallsledningar.Genom bättre förståelse för LTA-system finns det stora möjligheter för det svenskava-kollektivet att minska sina investerings- och driftkostnader vid utvidgning av verksamhetsområden, sannolikt med hundratals miljoner kronor de närmaste 20 åren dåbranschen står inför stora investeringar. För att möjliggöra besparingarna behövs deten tydlig helhetsbild av LTA-system och av alla de erfarenheter och den kunskap somfinns. Vilka är framgångsfaktorerna för att lyckas med LTA-system och vad bör mansom va-huvudman akta sig för?Många va-huvudmän har lång erfarenhet av att förvalta LTA-system, medan andraupplever att de behöver mer och bättre underlag innan de kan känna sig trygga attanlägga och förvalta en ny typ av system. Projektet har sammanställt de erfarenhetersom va-huvudmän har av LTA-system. Man har gått igenom litteratur och juridisk praxiskring LTA-system i Sverige, samt genomfört en workshop, en enkät och intervjuer föratt inhämta branschens erfarenheter av LTA i planerings-, bygg- och driftskedena. Vilkautmaningar ser branschen med systemen och var finns det kunskapsluckor? Underprojektets genomförande visade det sig att va-huvudmännen har mycket att lära avvarandra och att erfarenhetsutbyte är viktigt.Resultaten visar att det är viktigt med god planering och anpassning till lokala förhållanden för att lyckas med LTA. Svavelvätebildning är en stor och svårhanterlig fråga.Problemen uppkommer delvis på grund av att det är svårt att planera och dimensionerakorrekt. Ansvarsfrågorna regleras visserligen i lagstiftning men upplevs ändå som svårnavigerade. Det beror på att vissa delar av LTA-systemet är brukarens ansvar och andradelar är va-huvudmannens. Goda relationer mellan fastighetsägare och va-huvudmänär en framgångsfaktor för att säkerställa god funktion hos systemen över tid eftersomLTA ställer högre krav på brukaren än självfallssystemen gör.Frågor som behöver hanteras i fortsättningen är bland annat svavelvätebildning ochsystemens långsiktiga kostnader. Svavelväte är ett stort problem, och samma lösningför att minska svavelväte ger olika resultat på olika platser. Branschen behöver merkunskap och riktlinjer för hur man bäst undviker och avhjälper problemen. De långsiktiga kostnaderna för LTA är oklara och svåra att uppskatta korrekt och planera för. Desamlade livscykelkostnaderna för anläggning, drift och underhåll saknas, och underlagbehöver sammanställas för att man ska kunna ta bättre beslut och skapa mer effektivadriftorganisationer.
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| 2. |
- Isaksson, Frida, et al.
(författare)
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Evaluating the Use of Alternative Normalization Approaches on SARS-CoV-2 Concentrations in Wastewater: Experiences from Two Catchments in Northern Sweden
- 2022
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Ingår i: Environments. - : MDPI. - 2076-3298. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- The detection of SARS-CoV-2 RNA fragments in feces has paved the way for wastewater-based epidemiology to contribute to COVID-19 mitigation measures, with its use in a public health context still under development. As a way to facilitate data comparison, this paper explores the impact of using alternative normalization approaches (wastewater treatment plant (WWTP) flow, population size estimates (derived using total nitrogen (TN), total phosphorus (TP) and census data) and pepper mild mottle virus (PMMoV)) on the relationship between viral wastewater data and clinical case numbers. Influent wastewater samples were collected at two WWTPs in Luleå, northern Sweden, between January and March 2021. TN and TP were determined upon sample collection, with RNA analysis undertaken on samples after one freeze–thaw cycle. The strength of the correlation between normalization approaches and clinical cases differed between WWTPs (r ≤ 0.73 or r ≥ 0.78 at the larger WWTP and r ≤ 0.23 or r ≥ 0.43 at the smaller WWTP), indicating that the use of wastewater as an epidemiological tool is context-dependent. Depending on the normalization approach utilized, time-shifted analyses imply that wastewater data on SARS-CoV-2 RNA pre-dated a rise in clinical cases by 0–2 and 5–8 days, for the lager and smaller WWTPs, respectively. SARS-CoV-2 viral loads normalized to the population or PMMoV better reflect the number of clinical cases when comparing wastewater data between sewer catchments.
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| 3. |
- Kaykhaii, Saida, 1989-, et al.
(författare)
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Stormwater treatment using ultrafiltration – Effect of cleaning chemical and backwash time on membrane efficiency
- 2022
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Konferensbidrag (refereegranskat)abstract
- Stormwater runoff is known as one of the main contributors of pollutants which is often discharged untreated to the water bodies and causes environmental risk [1]. Membrane treatment may be a good option for treatment of heavily polluted stormwater as it can also remove small particles and colloids that are not normally captured in typical stormwater facilities such as ponds, wetlands, etc. However, fouling in membranes is challenging to control. Application of a pre-treatment prior to the membrane process might help to postpone fouling [2]. In addition, a proper combination of backwash and chemical cleaning for the membrane is essential but this has not yet been studied specifically for stormwater runoff treatment with membranes. In this study, a combination of ultrafiltration PVP/PES membrane with pulsatile fluid flow was used for separation of pollutants from stormwater. Sieving was considered as pre-treatment. In addition, a combination of backwash and chemical cleaning was used to assess reversibility, flux recovery and productivity of the membrane. The results showed that by increasing backwash time from 30 to 60 s, the reversibility and flux recovery increased from 26% to 75% and 55% to 87%, on average and also resulted in 20% increase in productivity. Cleaning chemically with alkaline solution (NaOH, pH=12), followed by acidic solution (HCl, pH=2), had a good impact on removing foulants from membrane surface. According to the experiments, addition of NaOCl to the alkaline solution did not have significant effect on pure water flux recovery. From environmental point of view, using NaOCl is not recommended [3].
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| 4. |
- Klapp, Rasmus, 1990-, et al.
(författare)
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The French two-stage vertical flow constructed wetland in subarctic climate
- 2022
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Ingår i: 17th International Conference on Wetland Systems for Water Pollution Control: Conference Proceedings. - : IWA Publishing. ; , s. 579-580
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Konferensbidrag (refereegranskat)abstract
- Conventional small wastewater treatment plants in Sweden produce a sludge that needs to be collected and transported long distances to a centralised treatment facility. As many of these small plants are old and need replacement, the question arises weather a more sustainable solution is possible. The French two-stage vertical flow constructed wetland (VFCW) is a method where very little sludge handling is required, as the sludge is treated on-site. Therefore, this study aims to investigate cold climate performance of such a system in northern Sweden. A pilot-scale VFCW was built and sampled for BOD, nutrients and microplastics since November 2021. Results indicate that treatment performance is adequate and that microplastic can also be treated.
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| 5. |
- Milovanovic, Ivan, 1990-, et al.
(författare)
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Performance of a Zeolite Filter treating Copper Roof Runoff
- 2022
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Ingår i: Urban Water Journal. - : Taylor & Francis. - 1573-062X .- 1744-9006. ; 19:5, s. 499-508
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Tidskriftsartikel (refereegranskat)abstract
- Copper is a common roofing material used in urban environments, yet it poses a threat to the ecosystem. Space requirements for stormwater treatment in urban areas are often problematic. This study investigated the treatment efficiency of a filter system containing zeolite as filter medium and treatment of copper roof runoff in field conditions. Emphasis was placed on copper and zinc treatment, while the release of sodium and aluminium was also evaluated. The filter system was monitored over a period of 16 months (7 sampling events). The filter reduced the total and dissolved copper by 52–82% and 48–85%, respectively. Although the average observed treatment efficiency of copper and zinc was high, considerable decline in filter efficiency was noticed, indicating potential saturation of the filter medium. Moreover, the copper concentrations in the outlet were still high, 350–600 μg/l, and significantly higher than the concentrations recommended by the relevant authorities.
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| 6. |
- Okwori, Emmanuel, 1988-, et al.
(författare)
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Using centrality measures, network cross k-function and geographically weighted regression as decision support for operational issues and redesigning sewers.
- 2022
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Ingår i: 10th International Conference on Sewer Processes and Networks.
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Konferensbidrag (refereegranskat)abstract
- The topology of Sanitary Sewer Networks (SSNs) can play an influential role in the occurrence and magnitude of operational failures such as blockages and basements flooding (Reyes-Silva et al., 2020). For example, meshed (grid-like) topologies are reported to be less vulnerable to failures compared to branched (tree-like) topologies (Zhang et al., 2017). However, in reality, most SSNs are reported to have a predominantly branched topology (Reyes-Silva et al., 2020). Therefore, it could be argued that the spatial behaviour of operational failures may be related to the topological properties of SSNs. This study explored this argument by investigating the spatial association between the location of recurrent blockages and the location of influential nodes within the network. Graph theory–centrality measures (Ganesan et al., 2020) and the network cross-K-function (Okabe and Sugihara, 2012) were the methods used. Secondly, the question of which structural, hydraulic or environmental factors may explain the identified spatial associations was also explored using geographically weighted regression (Fotheringham and Charlton, 2009). In lieu of robust properly calibrated hydraulic models, results from centrality measures and network cross k-function can support the discovery of influential locations within the topology of SSNs that may propagate recurrent blockages. Such influential locations may also be inception points for remedial actions such as redesigning, which may be more cost-effective in the long term compared to conventional approaches like flushing. Results from a preliminary application of centrality measures and network cross-function to the SSN of one municipality (total network length 500 km, ≈40 people/km) using its historical blockage data are presented.
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| 7. |
- Panasiuk, Oleksandr, 1986-, et al.
(författare)
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Identifying sources of infiltration and inflow in sanitary sewers in a northern community: comparative assessment of selected methods
- 2022
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 86:1, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- Infiltration and inflow (I/I) into sanitary sewers causes numerous negative effects on the whole wastewater management system and ultimately, on the receiving waters. Consequently, a number of methods have been developed to analyse the performance of sewer systems with respect to I/I, including: distributed temperature sensing (DTS), closed-circuit television (CCTV) inspections, flow and conductivity measurements, automatic or grab sampling of ammonium, smoke testing, and visual inspection of manholes. Such methods were compared in an application to sanitary sewers in a small community and assessed with respect to their accuracy and ability to identify locations of sources of I/I, as well as temporal and spatial resolutions of the obtained results. Furthermore, different approaches to ammonium sampling during I/I monitoring campaigns were discussed. It was concluded that among the methods tested in this study, DTS had the highest temporal and spatial resolutions, while ammonium grab sampling showed promise for initial screening of large catchments.
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| 8. |
- Sami, Mashreki, et al.
(författare)
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Removal of Microplastics from Greywater Using a Green Wall Treatment System
- 2022
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Ingår i: 17th International Conference on Wetland Systems for Water Pollution Control: Conference Proceedings. ; , s. 505-508
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Konferensbidrag (refereegranskat)abstract
- A green wall with four filter media - pumice, biochar, hemp, and compost soil - was investigated with regard to the removal of microplastics from real greywater. Nine polymers were analysed using thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS). The results showed the presence of polyvinylchloride (PVC), polystyrene (PS), poly-ethylene-terephthalate (PET), polypropylene (PP), and polyamide (PA) in the influents and effluents. High concentration of PS (22 μg/l) and PET (73 μg/l) were observed in the influent but were removed efficiently in the green wall with effluent concentrations of <2 μg/l from all filter materials except for hemp. The effluent from one hemp replicate showed higher concentrations of PVC (58 μg/l) and PET (114 μg/l) than the influent. During the sampling period, all filter materials removed TSS, BOD and TOC by >90%.
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| 9. |
- Vidal, Brenda, 1987-
(författare)
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Small Sanitation Systems – Treatment Efficiency, Sustainability and Implementation
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current socio-technical wastewater system paradigms are being challenged by emerging global issues such as climate change, environmental degradation and scarcity of resources. Thus, exploration of innovative new urban water management solutions is required that enable closure of resource loops. On-site and decentralised wastewater systems are seen as emerging solutions, partly because of their flexibility, as they increase the potential for recovery and reuse of resources like nutrients. At the smallest scale, on-site wastewater treatment systems are widely present in rural and peri-urban areas globally. However, they often do not meet acceptable levels of nutrient and bacterial discharge, thereby contributing to environmental degradation and health risks. The overall aim of this doctoral dissertation is to improve knowledge and understanding of small sanitation systems in terms of treatment processes and efficiency, their sustainability and implementation. At a greater scale, the dissertation explores the historical and current contexts that have shaped, and are shaping, the existing wastewater sector, dominated by large-scale centralised mixed wastewater collection and treatment, and barriers to implementation of alternative, innovative sanitation solutions with higher resource recovery capacities, like source separating systems.Sixteen full scale on-site facilities for wastewater treatment in Sweden were investigated in the research the thesis is based upon, including sand filters and package plants. Sand filters followed by alkaline phosphorus filters showed good removals of organic matter and high P-removal capacity (>92%). Six (of 11) investigated package plants showed >78% phosphorus removal (including chemical precipitation and alkaline phosphorus filters as treatment steps). Nitrogen removal was generally low in the package plants, likely because of the low average temperatures, and appeared to be mainly mediated by sedimentation of particulate organic nitrogen. Denitrification was observed to a limited extent in facilities with effective water/sludge recirculation. High densities of indicator bacteria were found in the effluent of most facilities as the removal rates were low, often exceeding the EU Bathing Water Directive’s limits for excellent water quality in terms of intestinal enterococci and Escherichia coli. Levels of pharmaceuticals detected in the effluent of package plants were within the range or higher than previously reported in effluents from conventional wastewater treatment plants, and included anti-inflammatories, β-blockers, ACE inhibitors, anticonvulsants and antidepressants. Effluent concentrations of phthalates were below those previously reported in the literature.A scenario analysis comparing nine on-site sanitation options suggested that source separation of greywater and blackwater and urine diversion were the most sustainable options when nutrient removal and recycling were highly prioritised. A conventional sand filter or drain field were the most sustainable options when nutrient removal and recycling were less prioritised and, (in combination with chemical P-removal) when CO2 emissions and energy use and recovery were important aspects.When planning wastewater services for a given area, results of interviews with water professionals confirmed the general trend to opt for a centralising approach, whenever technically feasible, by installing pumping stations and connecting sewer pipes to a main treatment plant, in contrast to building decentralised systems. Reasons mentioned by the interviewees included the robustness of the system, simplicity of operation and maintenance and protection of the receiving waters. Identified barriers hindering implementation of alternative sanitation solutions with focus on resources recovery included factors categorized as legislative factors (lack of requirements and law interpretation), technical factors (immature technologies, uncertainties), organizational factors (lack of initiative, competence and experience) and economic factors (financial limitation, lack of incentives). From a historical perspective, strong governmental control and continuous enforcement of environmental requirements drove the expansion and strengthened the domination of the large-scale centralised sanitation system. Alternative sanitation systems with higher resource recovery capacities have received less attention and institutional support, and their shortcomings were constantly highlighted during the period covered by a historical review (1974-2015).
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| 10. |
- Öhrn Sagrelius, Pär, et al.
(författare)
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Environmental impacts of stormwater bioretention systems with various design and construction components
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 359
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Tidskriftsartikel (refereegranskat)abstract
- Nature-based blue-green infrastructure for urban stormwater management, such as bioretention systems, is considered to provide multiple benefits compared with conventional stormwater runoff quantity and quality control. There are a range of bioretention systems and design and construction can vary widely. Studies comparing environmental impacts between different stormwater bioretention systems with various design elements and construction components have been lacking and hence, this study aims to address this gap. Various designs of stormwater bioretention systems with differing construction components and filter media mixtures have for the first time been compared using a life cycle assessment approach. Environmental impacts related to the production, transportation, and installation phases (i.e. before operation) of four types of bioretention systems, encompassing 11 configurations, have been assessed. The various construction components and filter media mixtures used incur differing degrees of environmental impacts. The filter media mixtures requiring longer transportation distances were associated with the highest environmental impacts. In this analysis, the bioretention systems built with more kerb stone, without geotextile and a filter media with sand, soil and gravel incurred the lowest environmental impacts. Whereas the bioretention systems constructed with the most concrete and with filter media that included pumice incurred the highest environmental impacts in all categories, up to 9–24 times greater than the systems with less concrete and no pumice. When means of transportation and distances were considered further in the sensitivity analysis, the concrete intensive structures incurred the highest environmental impacts. These findings can improve design choices and selection of construction components for stormwater bioretention systems where environmental impacts are considered important.
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