| 1. |
- Ask, Anna, et al.
(författare)
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Studenters uppmärksamhet under föreläsningar
- 2009
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Ingår i: Proceedings utvecklingskonferens 09 Lunds Universitet. - 9789197797429 ; , s. 112-120
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Konferensbidrag (refereegranskat)abstract
- Föreläsningar är vanlig undervisningsform på Lunds Tekniska Högskola (LTH). Deras stora fördel är att information överförs ekonomiskt och effektivt till många studenter samtidigt men de har även sina begränsningar. Kritiker menar att information överförs till passivt mottagande studenter och att bristande uppmärksamhet och engagemang hos studenterna begränsar mängden kunskap som faktiskt tas emot. En intervju- och litteraturstudie har genomförts för att dels inventera vilka metoder som finns för att hålla studenternas uppmärksamhet uppe och dels vilka som tillämpas av föreläsare vid LTH. Variation och olika former av aktivering framstår såväl i litteraturen som i intervjuerna som viktiga metoder. I artikeln presenteras även inspiration kring hur man kan använda variation, och andra aktiviteter för att engagera och aktivera studenterna samt hur man kan strukturera en föreläsning. De flesta av de intervjuade föreläsarna uppger att de utvecklat sina strategier genom erfarenhet medan knappt hälften nämner pedagogiska kurser.
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| 2. |
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| 3. |
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| 4. |
- Frühwald, Eva, et al.
(författare)
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Teachers’ view on combining assessment elements into a holistic assessment concept
- 2008
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Ingår i: [Host publication title missing].
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedAssessments of students’ knowledge and skills are sometimes habitually performed, but the design of proper assessment concepts – beneficial to both teaching and learning – ought to be a central issue for all course planners in higher education. The main purpose of this paper is to discuss a variety of assessment elements, as well as ways in which to combine them. It uses experiences from Lund University’s Faculty of Engineering (LTH) to provide suggestions and advice for course planners. The discussion is based on the combination of a literature review in the field of teaching and learning, of empirical material obtained from surveys and group discussions with 22 teachers at LTH, and of the authors’ own experiences in their capacity as course leaders and teachers. The study reveals a preference for projects and written assessment, as compared with the less preferred individual oral assessment. The paper indicates potential for quality enhancements through the adapted tailoring of assessment elements into holistic assessment concepts.
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| 5. |
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| 6. |
- Jakobsson, Anna, et al.
(författare)
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Tungmetaller och PAH i ett efterbehandlingssystem för vägdagvatten i Gårda
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I detta projekt har processer för transport och avskiljning av partiklar och föroreningar i vägdagvatten studerats i en ny typ av sedimentationsanläggning vid Odinslund i Gårda, Göteborg. Anläggningen består av sju seriekopplade brunnar, placerade under jord, med en total lagringsvolym av 122 m3, som töms till Mölndalsån efter en uppehållstid på 40 timmar. Vid kraftiga regn bräddar orenat vatten ut till Mölndalsån. Gårdaanläggningens effektivitet för att avskilja dagvattenföroreningar från den hårt trafikerade motorväg E6 genom Göteborg, har beräknats genom massbalanser för partiklar, tungmetaller och PAH. Beräkningarna har baserats på dagvattenvolymer och föroreningarnas koncentrationer i inkommande och utgående vatten under flera regntillfällen. Förekomst av PAH och tungmetaller i de olika brunnarnas sediment, samt föroreningarnas koppling till sedimentens karaktäristik, har studerats för att få en fördjupad förståelse för de processer och mekanismer som styr anläggningens effektivitet. Även yttre miljöbetingelser som kan ändra processer och mekanismer för transport av föroreningar i anläggningen, och som på så sätt kan påverka avskiljningens effektivitet, har studeras genomlaboratorieförsök. Projektet har givit ökade kunskaper och förståelse om vilka faktorer som styr avskiljningen av föroreningar i Gårdaanläggningen, samt grundläggande kunskaper om hur anläggningen kan utvecklas och förbättras.Resultaten visar att sedimentet i första brunnen bestod av större partiklar, 80 % i kornstorleksfraktionen > 0,125 mm. I denna brunn var vattenhalten i sedimenten 30 %, och halten organiskt material endast 5 %. Densitetsmätningar visade att sedimentet i första brunnen liknar en ren mineraljord, eftersom sedimentet till största delen består av oorganiskt mineralmaterial. I den sista (sjunde) brunnen bestod sedimentet av mycket fina partiklar, 94 % ikornstorleksfraktionen
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| 7. |
- Kain, Jaan-Henrik, 1960, et al.
(författare)
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Multi-Criteria Decision Aids for Sustainable Water Management
- 2007
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Ingår i: Proceedings of the Institution of Civil Engineers: Engineering Sustainability. - 1478-4629 .- 1751-7680. ; 160:2, s. 87-93
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Tidskriftsartikel (refereegranskat)abstract
- This article evaluates three multi-criteria decision aid (MCDA) methods—Regime, Novel Approach to Imprecise Assessment and Decision Environments (Naiade) and Strategic Advisor (Strad)—from a process facilitation perspective. This research shows that Strad has many advantages over the other tools regarding knowledge management, pluralism, functionality, transparency and participation. Concluding recommendations are as follows. (1) Agree explicit aims with stakeholder participation and if the aims change during the process, this is to be communicated. (2) Match methodology with the aims of the process since it is not always necessary to base the ranking on complex mathematical calculations. (3) Participatory processes should be conducted with care as they are resource consuming. Select cases thoughtfully and design them with a reflective attitude. The systematic structure of going through one criterion at a time is perceived as more important than software aggregation of multiple criteria at the end. It was further concluded that MCDAs have to be transparent and software must be flexible with an understandable user interface.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
- Persson, Jesper, 1966, et al.
(författare)
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Svenska dagvattendammar: om provtagning, avskiljning och dammhydraulik
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sedan början av 1990-talet har intresset för öppna system för omhändertagande av dagvatten ökat dramatiskt, vilket har resulterat i en stor mängd nyanlagda dammar. Enligt en studie från SGI (Vägverket 2003) uppskattas det finnas cirka 400 dammar längs det svenska allmänna vägnätet. Anläggandet av nya dammar har sedan dess fortsatt att öka i oförminskad takt. Men trots att huvudsyftet med dessa åtgärder är att rena vattnet är kunskapen om avskiljningseffektiviteten dålig. Det finns såväl teoretisk kunskap som genomförda datasimuleringar, men relativt få experimentella studier som verifierar teori och simuleringar, och det finns ännu färre studier kring hur dammarnas utformning påverkar avskiljningen.Syftet med denna studie är dels att utifrån befintliga teorier om avskiljning och dammhydraulik, empiriskt granska kopplingen mellan avskiljningseffektivitet och dammhydraulik, och dels att inventera och analysera genomförda vattenprovtagningar. Målsättningen med studien är primärt att resultatet skall ligga till grund för en framtida uppdatering av Vägverkets råd vid dimensionering och utformning av dammar för vägdagvatten.För att få fram så mycket data som möjligt var ambitionen att samla in alla genomförda provtagningar som gjorts i Sverige. I sökarbetet användes SGI:s nationella inventering; databasen Libris; en inventering gjord av SLU (finansierad av Formas); samt intervjuer av personal från sex av Vägverkets regionkontor och från tolv kommuner. För att få ett större underlag användes även provtagningar från dagvattendammar som även tar emot vatten från t ex bebyggelse.Inventeringen kunde påvisa 51 fall i Sverige där man undersökt dagvattendammar. Av dessa utgjorde 27 fall där det tagits prov på in- och utgående vatten i syfte att bestämma dammarnas avskiljningsfunktion. Resterande fall utgjordes av rena sedimentprovtagningar. Vid genomgång av de 27 fallen visade det sig att cirka 70 % av provtagningarna inte har använt en metodik som gjort det möjligt att säga något om dammens avskiljningskapacitet, trots att det var syftet. I 16 fall utgjordes provtagningen av stickprov och i 13 fall saknades flödesmätning. Resultaten var med andra ord nedslående. De provtagningsresultat som genomfördes på ett korrekt sätt, visar att dammar med olika specifika dammytor (d.v.s. kvoten mellan dammarea och avrinningsområdets hårdgjorda yta) kan ge såväl dåliga som bra avskiljningsresultat. Det gick därför inte direkt att påvisa ett samband mellan avskiljning och specifik dammarea. Resultaten stödjer emellertid tumregeln att dammar bör ha en specifik area runt ca. 200-250 m2/ha. I de fall man endast räknar med den ”verkliga” dammarean, som inte innehåller döda zoner eller större recirkulationszoner, kan denna rekommendation även yttryckas som att effektiv specifik area bör vara större än 100-150 m2/ha.Resultaten påvisar att hydrauliken spelar en stor roll. Däremot kan denna studie inte tydligt visa på i vilken omfattning. Sambandet mellan föroreningsavskiljning och specifik dammarea blir emellertid bättre om man korrigerar värdena på dammytorna, så att bara den effektiva delen av dammen inkluderas. Vad som också framträder är att hydrauliken spelar mindre roll om systemet är ”överdimensionerat”, dvs. en dålig spridning av inkommande vattnen får en stor betydelse om den specifika dammarean är 100 m2/ha jämfört med en area på 300 m2/ha.Studiens slutsatser kan formuleras i fyra punkter:•Provtagningen av dagvatten är bristfällig och bör förbättras genom bättre kompetens hos beställare och utförare.•Det finns en liten mängd användbar data över dammars föroreningsavskiljning och hydraulik.•Sambandet mellan avskiljning och dammens specifika dammarea är oklar.•Dammens specifika area och hydraulik spelar en stor roll för avskiljningen.Av slutsatserna kan följande rekommendationer ges:•En enkel kvalitetshöjande åtgärd är att låta en oberoende expert granska provtagningsprogram och tolkning av resultaten. Denna ”3:e part” kan utgöras av en konsult eller forskare inom eller utanför Vägverket.•Det är mycket kostsamt att genomföra korrekta provtagningar av dagvattendammar. Det är därför bättre om resurser samlas för att genomföra korrekta provtagningar.•Mer forskning behövs. Ett alternativt ställningstagande är att övergå till att bara mäta halter i syfte att avgöra vattnets ecotoxitet, och därmed ge upp ambitionen att få fram ett tydligt kvantitativt samband kring avskiljningseffektiviteten.•Det är viktigt att dammen inte underdimensioneras, men också att dammarnas form granskas med avseende på hydraulisk effektivitet. Alla dammritningar bör ses över med avseende på dammhydraulik för att undvika att allt för dåliga lösningar genomförs.
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| 12. |
- Pettersson, Thomas, 1966
(författare)
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Characteristics of suspended particles in a small stormwater pond
- 2002
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Ingår i: In: Proc. 9th International Conference on Urban Storm Drainage, Portland, Oregon, USA, 8-13 September 2002.
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Konferensbidrag (refereegranskat)abstract
- Polluted urban stormwater contains a number of hazardous constituents, such as heavy metals and polycyclic aromatic hydrocarbons (PAH). These pollutants are to a considerable extent associated with solids and can therefore be removed from the stormwater through sedimentation and particle encounter on aquatic vegetation. Due to this fact, stormwater ponds have frequently been used as a method for the treatment of stormwater. Information regarding particlecharacteristics and associated pollutants in stormwater is therefore of great importance to engineers involved in the design of ponds. This study investigates the inflow particle characteristics (such as particle size distribution, total and volatile suspended solids content and heavy metal content) of a small stormwater pond that predominantly receives stormwater drainage from a highway. Flow measuring devices and two automatic samplers were installed at the inlet and outlet of the pond. Measurements of particle characteristics and pollutant loads at the pond inflow and outflow for several storm events are carried out. The results show the particle volume in the stormwater (particle volume per stormwater volume) predominately consists of very fine particles and that the smallest particles comprise most of the surface area. Densities of particles in the inflow stormwater are presented. The stormwater pollutants exhibit strong correlation with particle characteristics, which is of great importance for pond design.
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| 13. |
- Åström, Johan, 1977, et al.
(författare)
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Avloppsutsläpp och mikrobiologisk påverkan i råvattentäkten Göta älv
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Hälsosäkert dricksvatten är en angelägenhet svenska kommuner måste prioritera, då vattenburna sjukdomsutbrott ofta är förknippade både med stora samhällskostnaderoch förlorat konsumentförtroende. Världshälsoorganisationen WHO förespråkar idag riskanalys som verktyg för att effektivt förebygga risken för vattenburen smitta. Riskanalysen startar med en kartläggning av mikrobiologiska spridningskällor inom avrinningsområdet. Faroidentifiering inom råvattentäkten följs sedan av motsvarande genomgång av risker inom vattenberedning och distribution. När väl en identifiering och kvantifiering av patogenkällor i råvattnet genomförts, kan vattenberedningen anpassas så att risken för vattenburen smitta kontrolleras till en av samhället accepterad nivå.I denna rapport ges ett exempel på hur en kartläggning av mikrobiologiska spridningskällor i en ytvattentäkt för 700 000 personer kan gå till. Fallstudien har alltså omfattat Göta älv, och fokus ligger på avloppssystemen, något som motiveras av att flera tidigare vattenburna utbrott i Sverige kunnat kopplas till avloppsförorening. Kartläggningen har tagit sin utgångspunkt i de miljörapporter som kommunerna sammanställer vad gäller utsläpp av såväl renat som orenat (bräddat) avloppsvatten till recipient. Rapporter från 2004 har granskats och beskrivningen har utökats med mer detaljerade utsläppsdata som kommunerna internt registrerat.Till råvattentäkten Göta älv förs avloppsvatten från omkring 100 000 personer genom det kommunala avloppssystemet. Insamlade uppgifter från Göteborg, Ale, Kungälv, Lilla Edet, Trollhättan och Vänersborg, vilka varit av varierande kvalitet och detaljeringsgrad, har sammanställts för att beskriva den totala avloppsbelastningen till Göta älv. Utsläpp i form av volym per dygn har jämförts med den mikrobiologiska haltvariationen vid två nedströms liggande kontrollstationer. Även betydelsen av nederbörd och flöde studerades. Jämförelsen har omfattat traditionella fekala indikatororganismer (E. coli, sulfitreducerande clostridier, colifager) samt patogena bakterier (E. coli O157/EHEC och Campylobacter), virus (noro- och enterovirus) och parasiter (Giardia och Cryptosporidium).Resultaten visar att mikrobiologiska halter i älven i hög grad samvarierar med utsläpp av avloppsvatten; bräddningar, nödavledningar, samt utgående från avloppsreningsverken. Vid nederbörd var bräddning mer regel än undantag i flertalet kommuner. De högsta patogenhalterna i råvattnet, och därmed förhöjda riskerna för dricksvattnet, kan alltså väntas vid regniga förhållanden. På goda grunder kan man hävda att åtgärder för att minska patogenutsläppen från de kommunala avloppssystem avsevärt skulle minska patogenhalterna i hela Göta älv. Rapporten visar också på den stora variationen både vad gäller utsläppsmängder och grad av kontroll på patogenspridande avloppsflöden. Denna kartläggning kan utökas på många sätt, och fortsatt forskningsbehov finns kring patogenhalter i bräddavlopp, modellering av mikrobiologisk transport samt betydelsen av andra patogenkällor.
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| 14. |
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| 16. |
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| 17. |
- Kvarnström, Elisabeth, et al.
(författare)
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Sanitation Planning : A Tool to Achieve Sustainable Sanitation?
- 2007
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Ingår i: Proceedings of Water Supply and Sanitation For All.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The global sanitation crisis and its importance to the Millennium Development Goals (MDGs) is reflected in the specific sanitation target adopted in 2002. An enormous amount of funds will need to be invested in sanitation over the coming years in order to meet the MDGs. It is important that these funds are invested in sustainable sanitation systems, since providing sanitation systems that are not sustained is a very costly shortterm solution that may contribute to long-term problems. The authors strongly believe that sanitation planning is one key to sustainable sanitation. Recent planning frameworks for sustainable sanitation systems suggest the utilization of a number of steps: (i) recognizing the existence of different domains across the city, (ii) analysis of the interests driving desire for the sanitation system and services for the stakeholders across the domains, (iii) analysis of external drivers and context that impact behaviour in each domain (iv) analysis of technical options, in relation to findings on context and criteria, (v) analysis of management requirements for proposed technical options, (vi) critical assessment whether the proposed system is fit for the purpose. This paper will discuss the merits and challenges of these planning methodologies in reference to experience from West Africa and Sweden. The intent is to illustrate the potential of these methods for increasing sustainable sanitation, but also to raise some key questions that may be missing from the frameworks.
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| 18. |
- McConville, Jennifer R., 1978-
(författare)
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Assessing sustainable approaches to sanitation planning and implementation in West Africa
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The challenge of achieving global sanitation targets is that it requires application of both technology that is appropriate and a supporting organizational structure. The interactions between the two begin during the planning/decision-making process and continue throughout the system lifetime. During the last decade, strategic planning frameworks have emerged in the water and sanitation sector that reflect a shift from traditional, top-down planning to a more participatory, bottom-up approach. Despite this shift and in light of the continuing challenge of achieving widespread sanitation in the world, it is necessary to question if a knowledge gap exists between the global sanitation frameworks and local stakeholder priorities. This licentiate thesis presents the first phase of a research project whose objective is to study the global models and compare them with existing local planning and decision-making conditions. It focuses on establishing the global context with regard to strategic planning tools and perspectives on sustainable sanitation. In general, there is close agreement on methodology and processes recommended by international planning frameworks; however the use of the term “sustainable sanitation” is highly variable. In general, the findings of this thesis show that improving sanitation conditions requires tools based on participation, social marketing, and process approaches for planning, capacity development, and feedback. Continuation of this research will investigate the local context regarding current planning practices and perspectives on sustainable sanitation in order to assess potential differences between the global and local context and make recommendations for improving adaptation of planning strategies for bringing sanitation to scale.
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| 19. |
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| 20. |
- Pettersson, Thomas, 1966, et al.
(författare)
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Evolution on Pollutant Removal Efficiency in Stormwater Ponds due to Changes in Pond Morphology
- 2006
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Ingår i: 8th Highway and Urban Environment Symposium, Nicosia, Cyprus, 12-14 June 2006, Alliance for Global Sustainability Bookseries, Springer, Editors: Morrison, G.M., Rauch, S.. - 9781402060090 ; 12
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Konferensbidrag (refereegranskat)abstract
- Ponds are frequently used to remove pollutants from urban runoff, but only a few accurate studies have been carried out to determine the long-term pollutant removal efficiency, and almost none on changes in removal over time. Removal efficiency will be affected by changes in pond morphology, vegetation growth and sediment accumulation. This study presents the evolution of pollutant removal efficiency over a seven-year period.The results showed that vegetation growth and increased sediment thickness affected copper, zinc, and nitrogen removal efficiency nega-tively. Concluding recommendations are removal of vegetation in the au-tumn and sediment removal after approximately seven to ten years in op-eration.
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| 21. |
- Wik, Torsten, 1968, et al.
(författare)
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Model based control of external carbon dose rate in a full-scale predenitrification system
- 2004
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Ingår i: Water Intelligens Online, IWA Publishing.
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Tidskriftsartikel (refereegranskat)abstract
- In wastewater treatment plants (WWTPs) with biological nitrogen removal it is commonthat large amounts of an easily biodegradable carbon source have to be added for completedenitrification. At the Rya WWTP in Göteborg, which is a predenitrification system with postnitrifyingtrickling filters (NTFs) in the recirculation stream, this occurs during periods of loworganic loads and after nitrate chock loads after flooding and back washing of the NTFs. In thisstudy, this costly control problem is regarded as an uncertain dynamic system. A model based feedforward loop, using biased information about the recirculated nitrate flow is combined with a robustPI feed back controller that applies large stability margins and ensures that these are fulfilled for alllikely operating points of the system. Different feed forward strategies to deal with possible overdosagedue to lack of past information in periods when full denitrification has occurred withoutexternal carbon, are assessed by simulation. After evaluation of the controllers by simulation usinga simplified activated sludge model a controller was implemented at Rya WWTP with good results.
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| 22. |
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| 23. |
- Govindarajan, Venkatesh, 1972-, et al.
(författare)
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Combined MFA-LCA for analysis of wastewater pipeline networks : Case study of Oslo (Norway).
- 2009
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Ingår i: Journal of Industrial Ecology. - Malden, MA, USA : Wiley-Blackwell. - 1088-1980 .- 1530-9290. ; 13:4, s. 532-550
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Tidskriftsartikel (refereegranskat)abstract
- Oslo's wastewater pipeline network has an aging stock of concrete, steel, and polyvinyl chloride (PVC) pipelines, which calls for a good portion of expenditures to be directed toward maintenance and investments in rehabilitation. The stock, as it is in 2008, is a direct consequence of the influx of pipelines of different sizes, lengths, and materials of construction into the system over the years. A material flow analysis (MFA) facilitates an analysis of the environmental impacts associated with the manufacture, installation, operation, maintenance, rehabilitation, and retirement of the pipelines. The forecast of the future flows of materials-which, again, is highly interlinked with the historic flows-provides insight into the likely future environmental impacts. This will enable decision makers keen on alleviating such impacts to think along the lines of eco-friendlier processes and technologies or simply different ways of doing business. Needless to say, the operation and maintenance phase accounts for the major bulk of emissions and calls for energy-efficient approaches to this phase of the life cycle, even as manufacturers strive to make their processes energy-efficient and attempt to include captive renewable energy in their total energy consumption. This article focuses on the life cycle greenhouse gas emissions associated with the wastewater pipeline network in the city of Oslo.
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| 24. |
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| 25. |
- Persson, Magnus, et al.
(författare)
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A small-scale matric potential sensor based on time domain reflectometry
- 2006
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Ingår i: Soil Science Society of America Journal. - 0361-5995. ; 70:2, s. 533-536
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of soil matric potential (Psi) are needed in many soil science applications. In the present study, a small matric potential sensor having a length of 30 mm and a diameter of 9.6 mm was developed. The sensor consists of two coils made of lacquer-coated copper wires embedded in gypsum. The dielectric constant of the gypsum (K-gypsum) was measured with time domain reflectometry (TDR). The gypsum probes were tested in a sandy loam soil using a pressure extractor to obtain the relationship between K-gypsum and Psi, allowing inference of the soil Psi in equilibrium with the sensor. It was shown that the gypsum probe could give Psi estimates with a root mean square error (RMSE) of around 50 kPa in the range of -20 to -1500 kPa. Most of the sensitivity of the sensor was in the -50- to -1000-kPa range.
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| 26. |
- Persson, Magnus, et al.
(författare)
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Time-domain reflectometry probe for water content and electrical conductivity measurements in saline porous media
- 2004
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Ingår i: Vadose Zone Journal. - 1539-1663. ; 3:4, s. 1146-1151
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Tidskriftsartikel (refereegranskat)abstract
- A new coated time-domain reflectometry (TDR) probe design is described and evaluated. In contrast to previous coated TDR probes, our probe may be used to measure both the dielectric constant (K-a) and bulk electrical conductivity (sigma(a)) in saline porous media. This was made possible by attaching two coaxial cables to a 0.27-m three-rod with a coated central rod. The shield of the first cable was to one of the outer rods and the conductor was connected to the coated central rod. The conductor and shield of the other coaxial cable were connected to each of the two outer rods, respectively. Thus, our probe consists of two unbalanced, two-rod probes. The probe is called coated-uncoated probe (CUP). Four prototypes with two different coating materials (i.e., polyolefin and kynar heat-shrink tubes) were evaluated. The probes were calibrated in several fluids having different K-a and sigma(a). The K-a measurement of the coated part the probe was successfully fitted to target K-a using a two-phase dielectric mixing model. Due to signal attenuation, measurements of K-a were not possible for sigma(a) higher than 9 dS m(-1) for the polyolefin-coated probes whereas the upper limits for the kynar-coated probes and the uncoated probe were 5 and 2.5 dS m(-1), respectively. Measurements of sigma(a) are only possible with the uncoated part. Measurements of K-a and sigma(a) were also taken during three upward infiltration experiments in sand using soil solution electrical conductivities of 0.01, 6.31, and 12.03 dS m(-1). For the uncoated part, K-a could not be measured when sigma(a) was higher than about 2 dS m(-1), whereas K-a measurements were possible using the coated part even when sigma(a) was 3 dS m(-1).
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| 27. |
- Rigon, Riccardo, et al.
(författare)
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Manuale utente Trento_P
- 2006
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 28. |
- Ugarelli, Rita, et al.
(författare)
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Importance of investment decisions and rehabilitation approaches in an ageing wastewater pipeline network. : A case study of Oslo (Norway)
- 2008
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Ingår i: Water Science and Technology. - London : IWA Publishing. - 0273-1223 .- 1996-9732. ; 58:12, s. 2279-2293
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Tidskriftsartikel (refereegranskat)abstract
- As Oslo Vann og Avlopsetaten (VAV, meaning Water and Sewage Department) looks into the future, it is faced with a quandary-to replace old pipelines or to continue maintaining them. The primary goal is to improve the level of service. The secondary goals are to rejuvenate the system and stem the decline in capital value. In 1991-2006, the Operation and Maintenance expenses (O&M) were far higher than the investments, and the network aged as its capital value plummeted. However, if the funds are insufficient, the self-financing Oslo VAV would have to turn to the consumers for help. Will the consumers pay more to have a 'younger' system? What if they are happy with the 'status quo' and are unconcerned about the falling capital value? Should the pipelines be depreciated over a longer period than the 40 years which is adopted now? Should the economic method be replaced by a more engineering-based method, whereby the pipes are assessed 'on merit'-on the basis of their service lives? There are numerous issues and a good decision will ease the road ahead. This paper, using Life Cycle Costing Analysis (LCCA) and scenarios therein, looks at how Oslo VAV could strike a balance between expending on O&M, investing in upgrading the network, and decelerating the ageing of the network while augmenting the capital value, and what is the best attainable set of targets they could aim for, at the end of the next 20 years. The two approaches mentioned above are compared with each other. It is seen that a rehabilitation programme based on the pipes performance approach is preferable to one guided by an economic lifetime approach, when the motive is to optimise expenditure and also improve the level of service.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Tikkanen, Toni
(författare)
-
3. Waste management and nutrient flows in the city of Turku : A detailed N and P flow study to estimate the capacity of biowaste sorting to contribute to nutrient recycling
- 2003. - 1
-
Ingår i: Urban Environmental Management. - Uppsala : Baltic University Press. - 9197001759 ; , s. 27-41
-
Bokkapitel (populärvet., debatt m.m.)abstract
- A detailed quantitative study of flows of nitrogen and phosphorus in all organic waste in Turku was made to evaluate the potential of recycling of nutrients. Both inputs and outputs in all municipal and private sewerage, nutrient-containing fluent and solid waste flows were estimated. These included municipal and private sewerage, municipal solid waste, and municipal as well as private composting. The volume or weight of each of these was measured as well as their content of N and P either measured or estimated using reference values from literature. The total flows for the 170,000 inhabitants and their animals were found to be 3,074 kg of N and 583 kg of P per day. 64% of the inputs were found in the municipal wastewater, 11% in private sewarage, 10% in solid organic waste sent to incineration and 7% in organic waste sent to landfill. The major flows of output nitrogen included 53% (1,647 kg/day) to surface waters and 23% (765 kg/day), to sludge, while for phosphorus 15% (90 kg/day) went to surface waters and 61% (368 kg/day) to sludge. Only 1% of the nutrients were recycled for new agricultural production. If separate sorting of biowaste is achieved (planned for 2005) this figure will increase to 7% and with maximum recycling amount to 15-16%.
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| 33. |
- Adamsson, Åsa, 1970, et al.
(författare)
-
Measurement and three-dimensional simulation of flow in a rectangular detention tank
- 2005
-
Ingår i: Urban Water Journal. - 1744-9006 .- 1573-062X. ; 2:4, s. 277-287
-
Tidskriftsartikel (refereegranskat)abstract
- There are two main ways to obtain better knowledge of the hydraulics of ponds, namelymeasurements and simulations. In this study, the applicability of using three-dimensionalsimulations as an engineering tool in stormwater pond design was investigated. To dothis, three-dimensional simulations were compared with measurements of flow patternand residence time in a large physical model of a detention tank (13 x 9x 1 m). Theagreement between measurements and simulations concerning both flow pattern andresidence time distribution curves was found to be good for high flow rates.
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| 34. |
- Adamsson, Åsa, 1970, et al.
(författare)
-
Simulation of temperature influence on flow pattern and residence time in a detention tank
- 2006
-
Ingår i: Nordic Hydrology. - 0029-1277. ; 37:1, s. 53-68
-
Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional simulations were used to model how a temperature difference between the incoming water and tank water influences the flow pattern and residence time in a detention tank. Buoyant, neutrally buoyant and negatively buoyant incoming jets were simulated. The simulations were compared with measurements for neutrally buoyant jets in a large-scale model of a detention tank (13 × 9×1 m). The results show that a negatively buoyant jet gives slightly less effective volume, defined as the time when 50% of added tracer has passed the outlet divided by the nominal residence time, than a neutrally buoyant jet. The flow pattern for a negatively buoyant jet at low densimetric Froude numbers consists of a current that travels along the bottom towards the outlet and a counter current at the surface towards the inlet, while the neutrally buoyant jet excites a surface jet with two large eddies on each side of the jet. This implies that the short-circuiting will decrease when a negatively buoyant jet at low densimetric Froude number occurs in the tank. The difference between the flow pattern excited by a buoyant jet and a neutrally buoyant jet is small.
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| 35. |
- Addie, Graeme, et al.
(författare)
-
Pipeline design characteristics of some industrial paste-like slurries
- 2005
-
Ingår i: Conference Proceedings - First Extractive Metallurgy Operators' Conference. - : The Australian Institute of Mining and Metallurgy. ; , s. 147-154
-
Konferensbidrag (refereegranskat)abstract
- There is a wide variety of industrial pastes or non-settling slurries pumped in mining, dredging and reclamation projects as products, refuse and tails. The types and/or names of some of the common ones are alumina red mud, phosphate clays, tar sands mature fine tails, tar sands (CT) consolidated clays and fly ash. The pipeline performance or friction of these varies dramatically with the type, its concentration and the particulars of the actual slurry making it difficult to select pumping equipment and to design associated pipelines. The GIW Hydraulic Laboratory in Grovetown Georgia has tested a number of these slurries over the last 30 years for various mining customers. Where available in the public domain and/or where permission has been obtained, the results of those tests are presented in this paper in a form usable for pipeline and pump system designers and users.
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| 36. |
- Addie, Graeme R., et al.
(författare)
-
A first slurry standard and some implications for paste application
- 2007
-
Ingår i: Paste 2007. - Perth : Australian Centre for Geomechanics. - 975675656 ; , s. 153-162
-
Konferensbidrag (refereegranskat)abstract
- The Hydraulic Institute has just completed the task of developing a new ANSI/HI standard on Rotodynamic (Centrifugal) Slurry Pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of all the different types of pumps available and has an extensive section on definitions. Slurries and their effect on performance and wear are covered. A slurry service class is established which then is used to limit velocities and head produced per pump to give acceptable wear. A special section deals with mechanical seals and a new method for determining flange loads is presented and guidelines are given for commissioning, start-up etc.The head limits and the performance derating are of special interest when centrifugal slurry pumps are applied to thickened tailings and paste-like slurries. For Newtonian liquids, the Hydraulic Institute's Viscosity Correction Method (ANSI/HI 2004) provides a procedure widely used for viscous effects on the performance. For the homogeneous flow of viscous slurries, the new slurry standard refers to an applicable viscosity to use with the method and to "consult the pump manufacturer for guidance regarding non-Newtonian slurry pump performance."Experimental performance results are presented here and applied to the viscosity correction method for a simulated tailings product slurry characterized by a fully sheared yield stress of about 100 Pa, evaluated from pipeline data. The pump was a GIW-LCC type three-vane all metal unit with a 0.3m-diameter impeller having an open shroud with a simple auger-like inducer. Results are also given for an underground hydraulic fill product characterized by a Newtonian kinematic viscosity which is 1300 times that for water. The different results obtained here point out the strong influence the rheological behavior has on the choice of pump size and the power requirement.
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| 37. |
- Addie, Graeme R., et al.
(författare)
-
The new ANSI/HI centrifugal slurry pump standard
- 2007
-
Ingår i: South African Institute of Mining and Metallurgy. - 0038-223X. ; 107:6, s. 403-409
-
Tidskriftsartikel (refereegranskat)abstract
- The Hydraulic Institute has completed the task of developing a new ANSI/HI standard 12.1-12.6 (2005) for Rotodynamic (Centrifugal) Slurry Pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of the different slurry pump types and contains an extensive section on pump and slurry definitions. The effect of slurry on pump performance is covered along with the pumping of froth. Reference is also made to ANSI/HI standard 9.6.7 (2004), which contains a new method for pump performance correction when handling viscous fluids.Classification of slurry services is established and then is used to determine limitations on velocities and total head per pump in order to obtain acceptable wear performance. The new service class, head per stage and other limits are directly related to capital and other cost considerations that will affect solids transport system economics. The writers review the contents of the new standard, highlight the main points, and discuss the reason for the slurry classification, corresponding limits and expected implications, particularly with respect to operating costs of the pumps in solids transport systems.
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| 38. |
- Addie, G.R., et al.
(författare)
-
Weir Minerals North America
- 2007
-
Ingår i: Hydrotransport 17. - : South African Institute of Mining and Metallurgy. - 9781920211028 - 9781855980846 ; , s. 205-218
-
Konferensbidrag (refereegranskat)abstract
- The Hydraulic Institute has completed the task of developing a new ANSI/HI standard 12.1-12.6 (2005) for rotodynamic (centrifugal) slurry pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of the different slurry pump types and contains an extensive section on pump and slurry definitions. The effect of slurry on pump performance is covered along with the pumping of froth. Reference is also made to ANSI/HI standard 9.6.7 (2004), which contains a new method for pump performance correction when handling viscous fluids. Classification of slurry services is established and then is used to determine limitations on velocities and total head per pump in order to obtain acceptable wear performance. The new service class, head per stage and other limits are directly related to capital and other cost considerations that will affect solids transport system economics. The writers review the contents of the new standard, highlight the main points, and discuss the reason for the slurry classification, corresponding limits and expected implications, particularly with respect to operating costs of the pumps in solids transport systems
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| 39. |
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| 40. |
- Agustin, Sanchez-Arcilla, et al.
(författare)
-
Introduction
- 2008
-
Ingår i: Journal of Hydraulic Research. - 0022-1686. ; 46:2, s. 179-182
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 41. |
- Ahlberg, Jesper, et al.
(författare)
-
Distributed snow modelling integrating ground penetrating radar data for improved runoff predictions in a Swedish mountain basin
- 2009
-
Ingår i: EGU General Assembly 2009.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Operational forecasts of snow melt runoff in Sweden are currently running with precipitation and temperature as the main input variables and calibrated with runoff data, and there is an interest to make better use of new measurement systems for distributed snow data. At the same time, various data assimilation techniques are becoming more frequently used in hydrological modeling, in order to reduce uncertainties related to both model structure errors and errors in input and calibration data. Thus, it is important to address not only what type of snow data that can be used to improve the model predictions, but also what type of input data and model structures that are optimal in relation to the available snow data. The objective of this study is to investigate to what extent the runoff predictions can be improved by assimilation of temporal and spatially distributed snow data, and if the improvements depend on the choice of model structures, for instance the use of energy balance or day-degree snow models. In order to achieve these objectives a new distributed snow model has been implemented into the hydrological modeling framework HYSS/HYPE. This model can easily be setup with either an energy balance model or a day-degree model for the snow pack calculations, and it is easy to run the model with different spatial resolutions. In the fully distributed case, snow drift processes are implicitly included in the model through a precipitation distribution model, based on topographical information and wind direction. The model was applied to a mountain basin in northern Sweden used for hydropower production, where extensive snow measurements were taken during the last two winters 2007-2009. A climate station is located at the outlet of the regulation lake, including automated point measurements of snow depth, snow mass (snow pillow), snow wetness and snow temperature. Distributed snow cover data was sampled using ground-penetrating radar from snow mobiles. Measurements were taken at the time of the maximum snow cover, providing a data set with snow depth, snow density, snow water equivalent along 20 km long transects in representative areas of the basin. The precipitation distribution model was calibrated using the distributed SWE data from the GPR measurements. Application of the calibrated model to previous years without available snow data show that the runoff predictions was improved compared to calibrations without the distributed snow data, however the improvements were larger for the energy balance compared to the day-degree model. Further developments will include assimilation of the temporal and spatial snow data to adjust the distribution of various input variables, for instance air temperature and wind speed.
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| 42. |
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| 43. |
- Ahlman, Stefan, 1973
(författare)
-
Modelling of Substance Flows in Urban Drainage Systems
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stormwater is recognised as a large contributor of toxic substances to receiving waters. Different measures to manage stormwater quality have been proposed, including structural and non-structural best management practices (BMPs). Computer models have become useful tools for the analysis, evaluation and design of these BMPs. The main objective of this study was to develop a modelling framework that enables an analysis of the pollutant sources in urban drainage systems. In the modelling framework the sources of pollutants from different activities in the urban area were separated according to their origin, e.g. material corrosion, brake wear and tyre wear.The model was named SEWSYS® and was developed in MATLAB/Simulink. SEWSYS simulates substance flows in urban drainage systems. At present the model contains 20 different substances, including nutrients, heavy metals and organic pollutants. The model can simulate both stormwater and domestic wastewater flows, in either combined or separate sewer systems. In the stormwater quality module, the pollutants from sources such as atmospheric deposition, traffic and construction materials are generated and accumulated on impervious surfaces during dry weather until they are washed away during rainfall. Validation studies of the SEWSYS model were carried out using measurements of stormwater flow and quality. Calibration and validation were performed using a split-sample technique, i.e. with independent data sets for calibration and validation. The hydrological part of the model performed well in the validation but the quality part produced less reliable results.Uncertainty analysis of the stormwater module in SEWSYS was carried out for the model outputs runoff volume, pollutant concentrations (EMCs and SMC), and pollutant load of heavy metals for an uncalibrated and calibrated model. Uncertainty assessment methods included Monte Carlo simulations, multi-linear regression and a Markov-Chain Monte Carlo method for parameter calibration. The results of the uncertainty analysis showed that predictions made with an uncalibrated model were associated with a considerable amount of uncertainty. It was also shown that by means of calibration this uncertainty could be reduced to an acceptable level.The application of the SEWSYS model in different types of scenario studies has been an important part of the model development. The results from the application studies demonstrate that the model is a useful tool for simulating and evaluating pollutant source control measures.
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| 44. |
- Ahmed, K. Matin, et al.
(författare)
-
Arsenic enrichment in groundwater of the alluvial aquifers in Bangladesh : an overview
- 2004
-
Ingår i: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 19:2, s. 181-200
-
Tidskriftsartikel (refereegranskat)abstract
- Arsenic in the groundwater of Bangladesh is a serious natural calamity and a public health hazard. Most groundwater from the shallow alluvial aquifers (<150 m), particularly in the Holocene plain lands, are vulnerable to As-enrichment. Delta plains and flood plains of the Ganges-Brahmaputra river system are moderately to severely enriched and more than 60% of the tube wells are affected. Shallow aquifers in the Meghna river basin and coastal plains are extremely enriched with more than 80% of the tube wells affected. Aquifers in the Pleistocene uplands and Tertiary hills are low in As. The vertical lithofacies sequence of the sediments from highly enriched areas of the country show two distinct lithofacies associations-a dominantly sandy channel-fill association and a fine-grained over bank association. The sediments can be grouped into 4 distinct lithofacies, viz. clay, silty clay, silty sand and sand. Thin section petrography of the As-enriched aquifer sands shows that the sands are of quartzolithic type and derived from the collision suture and fold thrust belt of the recycled orogen provenance. Groundwater is characterized by circum-neutral pH with a moderate to strong reducing nature. The waters are generally of Ca-Mg-HCO3 or Ca-Na-HCO3 type, with HCO3- as the principal anion. Low SO42- and NO3-, and high dissolved organic C (DOC) and NH4+ concentrations are typical chemical characteristics of groundwater. The presence of dissolved sulfides in these groundwaters indicates reduction Of SO4. Total As concentration in the analyzed wells vary between 2.5 and 846 mug l(-1) with a dominance of As(III) species (67-99%). Arsenic(III) concentrations were fairly consistent with the DOC and NH4+ contents. The HNO3 extractable concentrations of As (As-NO3) in the sediments (0.5-17.7 mg kg(-1)), indicate a significant positive correlation with Fe-NO3, Mn-NO3, Al-NO3 and P-NO3. The concentrations Of S-NO3 (816-1306 mg kg(-1)) peaked in the clay sediments with high organic matter (up to 4.5 wt.%). Amounts of oxalate extractable As (As..) and Fe (Fe x) ranged between 0.1-8.6 mg kg(-1) and 0.4-5.9 g kg(-1), respectively. Arsenic(ox) was positively correlated with Fe-ox, Mn-ox, and Al-ox in these sediments. Insignificant amounts of opaque minerals (including pyrite/arsenopyrite) and the presence of high As contents in finer sediments suggests that some As is incorporated in the authigenically precipitated sulfides in the reducing sediments. Moreover, the chemical extractions suggest the presence of siderite and vivianite as solid phases, which may control the aqueous chemistry of Fe and PO43-. Reductive dissolution of Fe oxyhydroxide present as coatings on sand grains as well as altered mica (biotite) is envisaged as the main mechanism for the release of As into groundwater in the sandy aquifer sediments.
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| 45. |
- Al-Najjar, Nasik, et al.
(författare)
-
Cost-Effective Water Supply and Sanitation
- 2008
-
Ingår i: 2nd-Environmental Conference-Water (KECW007), Dohuk Kurdistan Region in Iraq.
-
Konferensbidrag (refereegranskat)abstract
- Water supply and sanitation have about the same goals all over the world. The needs for safe water supply and sanitation are obvious although not generally implemented. This depends often on the economical situation and bad management. Additional factors are effects of war actions and natural disasters as flooding of rivers and tsunamis. The strategies are, however, similar independent of the actual conditions. In this paper the strategies as developed in Sweden are described related to practical implementation of technology and management strategies. The experiences have shown on both mistakes and successful handling. Today, Sweden is involved in both adjusting policies according to European Union rules (as EU Water Framework Directive) and also in sharing experiences to facilitate international implementation of cost-effective methods.
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| 46. |
- Al-Najjar, Nasik
(författare)
-
FRAMTIDA VATTENFÖRSÖRJNING FÖR VÄXJÖ KOMMUN : BEDÖMNING AV OLIKA ALTERNATIV
- 2008
-
Ingår i: Vatten. - : Föreningen Vatten. - 0042-2886. ; 63:4, s. 299-311
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Water supply in Växjö municipality has since 1887 been based on surface water from Helga lake. A water treatment plant was built in 1957 and was extensively reconstructed in 1969 but there are still problems to accomplish with drinking water quality, mainly related to temperature, smell and taste, managanese and aluminum rest. Present water consumption periodically approached the water treatment plant maximum capacity. A performed risk analysis showed that catastrophic consequences for the water supply could occur due to an accident in a nearby traffic route or discharges from an industrial area.In 1997 Växjö municipality decided to perform a comprehensive investigation of different alternatives for future water supply. Seven alternatives were evaluated including remedial measures at the present water treatment plant. The chosen alternative was based on supply and conveying ground water from Berga esker at Ljungby municipality. Re-infiltration of ground water will be used to guarantee required water quality and quantity and will be implemented in autumn 2008 with a planned supply of 200 l per second delivered to about 70.000 persons in the municipalities of Växjö and Alvesta. The article describes the different alternatives, motives for the chosen alternative and the evaluation procedure.
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| 47. |
- Al-Najjar, Nasik
(författare)
-
The future water supply of Växjö municipality – evaluation of different alternatives
- 2007
-
Ingår i: Vatten. - : Föreningen Vatten. - 0042-2886. ; 63:4, s. 299-312
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The water supply in Växjö municipality has since 1887 been based on surface water from Lake Helgasjön. A water treatment plant was built in 1957 and was extensively reconstructed in 1969 but there are still problems to accomplish with drinking water quality, mainly related to temperature, smell and taste, manganese and aluminium rest. The present water consumption has periodically approached the water treatment plant maximum capacity. A performed risk analysis showed that catastrophic consequences for the water supply could occur due to an accident in a nearby traffic route or discharges from an industrial area. In 1997 Växjö municipality decided to perform a comprehensive investigation of different alternatives for future water supply. Seven alternatives were evaluated including remedial measures at the present water treatment plant. The chosen alternative was based on supply and conveying ground water from the Berga Esker in Ljungby municipality. Re-infiltration of ground water will be used to guarantee the required water quality and quantity and will be implemented in autumn 2008 with a planned supply of 200 l per second delivered to about 70,000 persons in the municipalities of Växjö and Alvesta. The article describes the different alternatives, motives for the chosen alternative and the evaluation procedure.
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| 48. |
- Al-Najjar, Nasik, et al.
(författare)
-
The water and wastewater situation in Iraq – problems and possibilities for counter-measures
- 2004
-
Ingår i: Vatten. - : Föreningen Vatten. - 0042-2886. ; 60:4, s. 269-274
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A summary is given of the water and wastewater situation in Iraq before the Gulf War 1991, the situation after the Gulf War and the recent effects of the conflict in 2003. The access of safe water was halved in certain governorates after March 2003 and half of the sewage works were out of function with a discharge of untreated wastewater into rivers and channels. The supply of electricity was less than 4 hours per day in January 2004 and caused discharges of untreated sewage on streets etc. The leakage from the water net was estimated at 60%. The wastewater system in 3 out of 5 schools was estimated to be out of function and epidemics have especially affected children and caused increased mortality. Special issues like the illegal openings of water pipes and security have worsened the situation. The Swedish knowledge of water and wastewater handling may have an important role in rebuilding water and wastewater handling in Iraq and different possibilities are exemplified.
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| 49. |
- Al-Najjar, Nasik, et al.
(författare)
-
VA - SITUATIONEN I IRAK : PROBLEM OCH MÖJLIGHETER TILL MOTÅTGÄRDER
- 2004
-
Ingår i: VATTEN: Tidskrift för vattenvård. - : Föreningen Vatten. - 0042-2886. ; 60:4, s. 269-274
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A summary is given on the water and wastewater situation in Iraq before the Gulf war 1991, the situation after the Gulf war and the recent effects of the conflict 2003. The access of safe water was halved in certain counties after March 2003 and half of the sewage works was out of function with a discharge of untreated wastewater to rivers and channels. The supply of electricity was less than 4 hours per day in January 2004 and caused discharges of untreated sewage on streets etc. Leakage from the water net was estimated to 60%. The wastewater system in 3 out of 5 schools was estimated to be out of function and epidemics have especially affected children and caused an increased mortality. Special issues as illegal openings of water pipes and security have worsened the situation. Swedish knowledge in water and wastewater handling may have an important role in rebuilding water and wastewater handling in Iraq and different possibilities are given.
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| 50. |
- Al-Najjar, Nasik, et al.
(författare)
-
Water management and technology in Swedish municipalities. : Assessment of possibilities of exchange and transfer of experiences.
- 2009
-
Ingår i: An International Perspective on Environmental and Water Resources Conference.
-
Konferensbidrag (refereegranskat)abstract
- The water and wastewater infrastructure began to be developed in Sweden more than one hundred years ago. Much attention was given, in the beginning, to fire prevention and hygienic problems with water borne diseases. Somewhat later storm sewers (combined system) were constructed to remove storm water and wastewater and then successively more efficient wastewater treatment plants were developed. Today water and wastewater handling is seen as a multidisciplinary subject where also attention is given to possible effects of climate changes and possibilities for resources recovery.Implementation of advanced water and wastewater systems involves not only different technologies but also effective administration and legislation. The implementation may be on national (also involving EU directives), regional and local scale. As a case study, the local implementation will be illustrated for the municipality Växjö in South Sweden with about 80,000 inhabitants.
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