| 1. |
- Andersson, Anna, et al.
(författare)
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Waterworks-specific composition of drinking water disinfection by-products
- 2019
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Ingår i: Environmental Science. - Cambridge : Royal Society of Chemistry. - 2053-1400 .- 2053-1419. ; :5, s. 861-872
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Tidskriftsartikel (refereegranskat)abstract
- Reactions between chemical disinfectants and natural organic matter (NOM) upon drinking water treatment result in formation of potentially harmful disinfection by-products (DBPs). The diversity of DBPs formed is high and a large portion remains unknown. Previous studies have shown that non-volatile DBPs are important, as much of the total toxicity from DBPs has been related to this fraction. To further understand the composition and variation of DBPs associated with this fraction, non-target analysis with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed to detect DBPs at four Swedish waterworks using different types of raw water and treatments. Samples were collected five times covering a full year. A common group of DBPs formed at all four waterworks was detected, suggesting a similar pool of DBP precursors in all raw waters that might be related to phenolic moieties. However, the largest proportion (64–92%) of the assigned chlorinated and brominated molecular formulae were unique, i.e. were solely found in one of the four waterworks. In contrast, the compositional variations of NOM in the raw waters and samples collected prior to chemical disinfection were rather limited.This indicated that waterworks-specific DBPs presumably originated from matrix effects at the point of disinfection, primarily explained by differences in bromide levels, disinfectants (chlorine versus chloramine) and different relative abundances of isomers among the NOM compositions studied. The large variation of observed DBPs in the toxicologically relevant non-volatile fraction indicates that non-targeted monitoring strategies might be valuable to ensure relevant DBP monitoring in the future.
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| 2. |
- Anh Nguyen, Viet, et al.
(författare)
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Design and performance of a coarse media, high hydraulic load polishing wetland for steel industry wastewater
- 2019
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Ingår i: Water Science and Technology. - : IWA PUBLISHING. - 0273-1223 .- 1996-9732. ; 80:1, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design of a constructed wetland (CW) system in an area with limited land availability, resulting in high hydraulic loads. The CW was constructed to act as a buffering/polishing step after stabilization ponds for steel industry wastewater post-treatment. A pilot test with two different filter media (50-100 mm vs 40-60 mm diameter) indicated that a flow rate increase from 49.5 m(3)/h to 122.4 m(3)/h would lead to a head loss increase from 2.9 cm to 8.7 cm, and more than double that for the finer gravel. This was substantially higher than the calculated theoretical values, though the relation with flow rate was similar. Four full scale wetland cells (CW1, CW2, CW3 and CW4) were constructed using the coarser gravel. A design value of total head loss of 1.01 m over the total system length, with a design flow of 36,000 m(3)/day, was expected based on pilot test results. During the first operation year (September 2017 to July 2018), the pond-CW system has received wastewater already meeting required discharge standards. The effluent from the CWs had consistently lower concentrations of all measured variables, and met the predicted values for biochemical oxygen demand (BOD5), total nitrogen (TN) and NH4+-N. Highest removal efficiencies were achieved for NH4+-N (amp;gt; 90%), Mn (amp;gt; 60%) and Fe (45%) with removal efficiencies for TN (14%), BOD5 and chemical oxygen demand (COD) (around 30%). Concentrations of phenol, CN- and Cr6+ were below 10, 4 and 3 mu g/l, respectively, in in- and outflows. An appreciated benefit of the wetland was the green element in the industrial landscape.
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| 3. |
- Bobbert, Peter A., et al.
(författare)
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Operational Stability of Organic Field-Effect Transistors
- 2012
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag. - 0935-9648 .- 1521-4095. ; 24:9, s. 1146-1158
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Tidskriftsartikel (refereegranskat)abstract
- Organic field-effect transistors (OFETs) are considered in technological applications for which low cost or mechanical flexibility are crucial factors. The environmental stability of the organic semiconductors used in OFETs has improved to a level that is now sufficient for commercialization. However, serious problems remain with the stability of OFETs under operation. The causes for this have remained elusive for many years. Surface potentiometry together with theoretical modeling provide new insights into the mechanisms limiting the operational stability. These indicate that redox reactions involving water are involved in an exchange of mobile charges in the semiconductor with protons in the gate dielectric. This mechanism elucidates the established key role of water and leads in a natural way to a universal stress function, describing the stretched exponential-like time dependence ubiquitously observed. Further study is needed to determine the generality of the mechanism and the role of other mechanisms.
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| 4. |
- Bohman, Anna
(författare)
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I vått och torrt? : En studie av nationell vattenkatastrofgrupp VAKA : Underlag till den statliga dricksvattenutredningen
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den här rapporten har studerat VAKA-gruppens verksamhet med speciellt fokus på hur de som larmat VAKA upplevt hjälpen, vilka konsekvenser som kunnat undvikas genom VAKA:s stöd samt hur insatserna skulle kunna organiseras och finansieras framöver. Studien utgår från 26 intervjuer med aktörer som larmat VAKA någon gång mellan 2010 och 2015.Sammanfattningsvis kan det konstateras att de intervjuade kommunerna upplever att VAKA erbjuder en synnerligen effektiv och professionell hjälp som bidragit till att olycksförloppen kunnat både mildras och förkortas avsevärt. Man har bistått med kvalificerad experthjälp vad gäller lägesanalys, provtagningar och analyser, bistått i organisationen av krisledningen och även förmedlat erfarenheter och kunskaper gällande media hantering samt kommunikation gentemot allmänheten. VAKA har dessutom tillgång till ett brett kontaktnät och har i de fall då man själv inte besitter rätt expertis snabbt kunnat förmedla kontakt med rätt person/instans. De intervjuade kommunerna har framhållit att man fått mental stöttning av VAKA i situationer som varit belastande för krisledningen. Att ha tillgång till erfarna människor som bollplank och som en part i diskussionen i ett kritiskt läge framhålls som otroligt viktigt för de inblandade.Flertalet av de intervjuade bedömer att det kan finnas en viss betalningsvilja för VAKA:s tjänster på kommunal nivå men ser en överhängande risk med att vissa kommuner eventuellt avvaktar en kontakt om denna är avgiftsbelagd. I sammanhanget bör man också beakta att andra aktörer än kommuner i dagsläget är berättigade att nyttja VAKA:s tjänster varför en exklusiv kommunavgift inte framstår som en optimal lösning framgent.Ingen av de intervjuade ser någon fördel med att VAKA verksamhet skulle organiseras på privat konsultbasis alternativt ersättas med regional kompetensutveckling. Det senare alternativet menar man känns inte realistiskt med tanke på att VAKA besitter vad som måste betraktas som nationell spetskompetens och att det skulle vara svårt att sprida denna till alla regioner.Förslag på verksamhetens utveckling som framkommit gäller bl.a. tillgången till nödvattenutrustning där tillgängligheten skulle kunna förbättras både via tätare avstånd mellan lagren samt en koordinering av samutnyttjande av resurser mellan kommuner. Man tror även att kännedomen om VAKA skulle kunna förbättras via informationsinsatser.Ytterligare ett förslag på verksamhetens utveckling gäller tillgång till laboratorier där man föreslår att VAKA alternativt Livsmedelsverket skulle administrera en central upphandling för att säkerställa att det alltid finns tillgång till laboratorieresurser.Baserat på rapportens samlade bedömning rekommenderas det att VAKA gruppens verksamhet även fortsättningsvis bör bedrivas i sin nuvarande form men med en fast finansiering från näringsdepartementet som möjliggör en mer långsiktig planering av verksamheten.Avslutningsvis bör det återigen understrykas att effekterna av framtida klimatförändringar medför att riskerna för dricksvattenförsörjningen ökar och att antalet incidenter kopplat till dricksvattenförsörjning med stor sannolikhet kommer att öka. Behovet av VAKA-gruppens tjänster blir därmed större i framtiden.
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| 5. |
- Bäckström, Magnus, et al.
(författare)
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Draining function of porous asphalt during snowmelt and temporary freezing
- 2000
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Ingår i: Canadian journal of civil engineering (Print). - : Canadian Science Publishing. - 0315-1468 .- 1208-6029. ; 27:3, s. 594-598
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Tidskriftsartikel (refereegranskat)abstract
- Urban runoff creates problems with flooding and pollution of receiving waters. Furthermore, cold climate conditions have a degenerating effect on stormwater systems and road constructions. Porous asphalt has been used as a wearing course on highways and in porous pavement constructions all around the world. The main focus of this study was to evaluate the function of porous asphalt in cold climates. Measurements of the draining function of porous asphalt were carried out in a climate room with adjustable temperature in the range -10%C to +20%C. At freezing point, the infiltration capacity of porous asphalt was approximately 50% of the infiltration capacity at +20%C. When the porous asphalt was exposed to alternating melting and freezing during 2 days, conditions similar to the snowmelt period, the infiltration capacity was reduced by approximately 90%. Based on the results of this study and previous studies, the infiltration capacity of porous asphalt was estimated to be 1-5 mm/min for snowmelt conditions.
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| 6. |
- de Araujo, Kleiton R., et al.
(författare)
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Carbon dioxide (CO2) concentrations and emission in the newly constructed Belo Monte hydropower complex in the Xingu River, Amazonia
- 2019
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Ingår i: Biogeosciences. - Gottingen : Copernicus Gesellschaft MBH. - 1726-4170 .- 1726-4189. ; 16:18, s. 3527-3542
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Tidskriftsartikel (refereegranskat)abstract
- The Belo Monte hydropower complex located in the Xingu River is the largest run-of-the-river (ROR) hydroelectric system in the world and has one of the highest energy production capacities among dams. Its construction received significant media attention due to its potential social and environmental impacts. It is composed of two ROR reservoirs: the Xingu Reservoir (XR) in the Xingu's main branch and the Intermediate Reservoir (IR), an artificial reservoir fed by waters diverted from the Xingu River with longer water residence time compared to XR. We aimed to evaluate spatiotemporal variations in CO2 partial pressure (pCO(2)) and CO2 fluxes (FCO2) during the first 2 years after the Xingu River impoundment under the hypothesis that each reservoir has contrasting FCO2 and pCO(2) as vegetation clearing reduces flooded area emissions. Time of the year had a significant influence on pCO(2) with the highest average values observed during the high-water season. Spatial heterogeneity throughout the entire study area was observed for pCO(2) during both low-and high-water seasons. FCO2, on the other hand, only showed significant spatial heterogeneity during the high-water period. FCO2 (0.90 +/- 0.47 and 1.08 +/- 0.62 mu mol m(2) d(-1) for XR and IR, respectively) and pCO(2) (1647 +/- 698 and 1676 +/- 323 mu atm for XR and IR, respectively) measured during the high-water season were on the same order of magnitude as previous observations in other Amazonian clearwater rivers unaffected by impoundment during the same season. In contrast, during the low-water season FCO2 (0.69 +/- 0.28 and 7.32 +/- 4.07 mu mol m(2) d(-1) for XR and IR, respectively) and pCO(2) (839 +/- 646 and 1797 +/- 354 mu atm for XR and IR, respectively) in IR were an order of magnitude higher than literature FCO2 observations in clearwater rivers with naturally flowing waters. When CO2 emissions are compared between reservoirs, IR emissions were 90% higher than values from the XR during low-water season, reinforcing the clear influence of reservoir characteristics on CO2 emissions. Based on our observations in the Belo Monte hydropower complex, CO2 emissions from ROR reservoirs to the atmosphere are in the range of natural Amazonian rivers. However, the associated reservoir (IR) may exceed natural river emission rates due to the preimpounding vegetation influence. Since many reservoirs are still planned to be constructed in the Amazon and throughout the world, it is critical to evaluate the implications of reservoir traits on FCO2 over their entire life cycle in order to improve estimates of CO2 emissions per kilowatt for hydropower projects planned for tropical rivers.
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| 7. |
- Dienus, Olaf, et al.
(författare)
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Norovirus Dynamics in Wastewater Discharges and in the Recipient Drinking Water Source: Long-Term Monitoring and Hydrodynamic Modeling
- 2016
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:20, s. 10851-10858
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Tidskriftsartikel (refereegranskat)abstract
- Norovirus (NoV) that enters drinking water sources with wastewater discharges is a common cause of waterborne outbreaks. The impact of wastewater treatment plants (WWTPs) on the river Gota alv (Sweden) was studied using monitoring and hydrodynamic modeling. The concentrations of NoV genogroups (GG) I and II in samples collected at WWTPs and drinking water intakes (source water) during one year were quantified using duplex real-time reverse-transcription polymerase chain reaction. The mean (standard deviation) NoV GGI and GGII genome concentrations were 6.2 (1.4) and 6.8 (1.8) in incoming wastewater and 5.3 (1.4) and 5.9 (1.4) log(10) genome equivalents (g.e.) L-1 in treated wastewater, respectively. The reduction at the WWTPs varied between 0.4 and 1.1 log(10) units. In source water, the concentration ranged from below the detection limit to 3.8 log(10) g.e. L-1. NoV GGII was detected in both wastewater and source water more frequently during the cold than the warm period of the year. The spread of NoV in the river was simulated using a three-dimensional hydrodynamic model. The modeling results indicated that the NoV GGI and GGII genome concentrations in source water may occasionally be up to 2.8 and 1.9 log(10) units higher, respectively, than the concentrations measured during the monitoring project.
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| 8. |
- Drangert, Jan-Olof, et al.
(författare)
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Addressing urban water scarcity: reduce, treat and reuse - the third generation of management to avoid local resources boundaries
- 2017
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Ingår i: Water Policy. - : IWA PUBLISHING. - 1366-7017 .- 1996-9759. ; 19:5, s. 978-996
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Tidskriftsartikel (refereegranskat)abstract
- Urban growth leads to geographically concentrated demand for water and food -and to growing volumes of wastewater and organic waste. Left unattended by city authorities, both local and planetary resources boundaries for water and nutrients will be transgressed. A novel partly dynamic flexible water balance is developed to explore ways to address a looming water crisis. A systems-based flow chart shows how rainwater, groundwater and recycled water interact. Measures from supply-, demand-, and reuse management are combined to manipulate the water flows. Water management in Bangalore, India, focused on supply management over the period 1964 to 2015, tapping distant rivers. This mind-set was challenged by a Water Disputes Tribunal and international financiers. Residents and industry were losing faith in the erratic water supply, and met part or all their water needs by digging or drilling wells. The flexible water balance is tested on Bangalore for the year 2050 when the population has increased from 8 to 20 million. New housing complexes can provide opportunities for effective arrangements to recycle water and nutrients, save energy, and reduce water pollution and air emissions. The flexible water balance indicates that Bangaloreans can get enough household water without tapping river water and still recharge groundwater.
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| 9. |
- Drangert, Jan-Olof
(författare)
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Urban water and food security in this century and beyond: Resource-smart cities and residents
- 2021
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Ingår i: Ambio. - : SPRINGER. - 0044-7447 .- 1654-7209. ; 50:3, s. 679-692
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Tidskriftsartikel (refereegranskat)abstract
- The urban world population will increase from 3 to 8.5 thousand million in the 21st century. Cities become hot spots of both demand for water and global food and for disposed used water and nutrients. Sustainability requires that resource flows through our cities are co-managed and connected to agriculture. Reduced use of harmful chemicals in consumer products facilitates treatment to a quality that allows reuse/recycling of water and nutrients. A solid and liquid waste hierarchy can assist in ordering measures. A novel flexible water balance can guide city infrastructure and keep toilet water separate. New water-saving equipment can substantially reduce water use without losing personal comfort. The combination of these new approaches ascertains access to safe urban water, and that recovered nutrients from cities can substitute half of chemical fertilisers needed in food production. Now, thousands of new cities and suburbs provide unique opportunities to develop resource-smart and sustainable flows.
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| 10. |
- Ekstrand, Eva-Maria, et al.
(författare)
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High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation
- 2016
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 56, s. 166-172
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Tidskriftsartikel (refereegranskat)abstract
- Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for thebiogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibresludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation.Two lab-scale reactors (4L) were run for 800 days, one on fibre sludge (R1), and the other on fibre sludgeand activated sludge (R2). Additions of Mg, K and S stabilized reactor performance. Furthermore, theCa:Mg ratio was important, and a stable process was achieved at a ratio below 16:1. Foaming was abatedby short but frequent mixing. Co-digestion of fibre sludge and activated sludge resulted in more robustconditions, and high-rate operation at stable conditions was achieved at an organic loading rate of 4 gvolatile solids (VS) L1 day1, a hydraulic retention time of 4 days and a methane production of230 ± 10 Nm L per g VS.
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