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  • 1.
    Andersson, Erik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Nilsson, Martin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Tillskottsvatten i spillvattennät: Underlag för framtida åtgärder i Fengersfors2015Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Wastewater contains elevated levels of nitrogen and phosphorus which the treatment plants are forced to deal with. If the purification in the plant are substandard these substances is emitted in lakes and streams, which can lead to eutrophication. The small village of Fengersfors, in the province of Dalsland, uses two small stabilization pounds to cleanse their wastewater. These stabilization pounds do not meet the authorities’ treatment requirements, which have led the municipality to upgrade the facility. Before expanding the treatment plant, today’s volumes of extraneous water must be reduced to be able to dimension the new pounds, in proportion to the size of Fengersfors. Extraneous water is clean water that reaches the treatment plants in addition to water from baths, showers, washing machines and toilets. Examples of additional water can be storm water and groundwater. It is desired to minimize the percentage of extraneous water in wastewater systems to avoid costly purification processes.

    The purpose of this study is to reduce the flow of extraneous water which transports to the stabilization pounds. What sources to extraneous water is there in Fengersfors and which actions should the municipality take to achieve their goal of reduced flow of extraneous water to the stabilization pounds?

    To identify seepage of extraneous water in wastewater systems is a time consuming job. To address the problem, without being forced to duplicate the system, it is important to first build an image of the area. In this study this is done by four examinations: field inventory of residential areas, field inventory of transfer schemes, investigation of groundwater levels and dye tracing of bad connections. These steps are easy to preform, requires no large financial means and need not to be performed by individuals with special skills. The survey is completed in two overview maps, Fengersfors Norra and Fengersfors Södra. These are then used for basic calculations to point out areas which are contributing large volumes of groundwater, trough foundation drainage, to the treatment plant.

    Several properties in Fengersfors have their roof surfaces connected to the wastewater system. Simple measures, such as switching to drain spouts with dense water deflector, can reduce the volume of rainwater that reaches the stabilization pounds. General for the area is that ditches have been neglected for a long time, resulting in drums and wells clogged. A functioning ditch system is necessary for transport of storm and drainage water to the recipient. During the dye tracing process parts of previously unknown storm water systems were found. Sewer system maps can now be updated and become an important part of future actions. The study provides an indication of which areas need to be addressed or further investigated by the municipality.

  • 2.
    Berggren, Christian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Dig or no dig?: En jämförelse mellan schaktfria tekniker och konventionell schakt vid VA-produktion.2015Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Sweden's public water and sewer system consists of 191 000 km of water- and sewer pipelines. Annually is it about 380 km of pipelines which not is reconditioned even if it should if the renovation rate should keep up with the ageing of the pipelines. The renovation costs large sums of money which is supposed to be one of the biggest reasons that some of the renovations are absent. In order to keep production going in Sweden’s water and sewer - sector is it required that both finance and time is to be reviewed.

    This study compares the economics of various methods of producing water and sewer lines. The work also includes a study of pollution in form of carbon dioxide during the production of pipelines. The methods that have been raised are conventional excavation, directional drilling and relining. In directional drilling has two methods been examined, JT and AT drilling. For relining the examined methods are slip-lining and closed -fit.

    The work has been done for Skanska Väg och Anläggning Väst , which is part of Skanska Sverige AB. The comparison has been performed with a literature study to complete the theory behind the background. The result in the comparative study of economics and environment is based on calculations from completed and ongoing projects within Skanska, as well as interviews with various contractors.

    The results show that trenchless technologies emit less carbon dioxide than conventional excavation which is not surprising since the excavation handled much larger land masses. In regards to the economy can be said that the basis of the result is substandard but a fact is still that what is most effective due to cost varies depending on the project. A generalization can be made for trenchless methods. These tend to be more profitable, the deeper and longer works, and the fewer connections and the ramifications it is on line. Directional drilling is limited by the drilling mud that is an out coming waste during the production. For bigger line sizes will the disposing of the sludge be a major expense which in some cases can make it unprofitable to drill. Generally drilling bigger sizes with god profit demands objects worthy of protection above ground.

  • 3. Govindarajan, Venkatesh
    Changes in material flows, treatment efficiencies and environmental load-shifting in the wastewater treatment sector Part II: Case study of Norway2009In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 30, no 11, p. 1131-1143Article in journal (Refereed)
  • 4.
    Govindarajan, Venkatesh
    Norwegian University for Science & Technology, Norway.
    Cost-benefit analysis: Leakage reduction by rehabilitating old water pipelines: Case study of Oslo (Norway)2012In: Urban Water Journal, ISSN 1573-062X, Vol. 9, no 4, p. 277-286Article in journal (Refereed)
  • 5.
    Govindarajan, Venkatesh
    Norwegian University of Science & Technology, Trondheim.
    Malaysian Water tariff influences water-saving habits2011In: Journal - American Water Works Association, ISSN 0003-150X, E-ISSN 1551-8833, Vol. 103, no 7, p. 32-34Article in journal (Other (popular science, discussion, etc.))
  • 6.
    Govindarajan, Venkatesh
    Norwegian University for Science & Technology, Norway.
    Sisyphean struggle or Pyrrhic victory ?2014In: Problemy Ekorozwoju, ISSN 1895-6912, E-ISSN 2080-1971, Vol. 9, no 2, p. 73-77Article in journal (Refereed)
  • 7.
    Govindarajan, Venkatesh
    Norwegian University for Science & Technology, Norway.
    Testing different rehabilitation options in the drinking water pipeline network in Oslo using the Dynamic Metabolism Model2014In: Vatten, ISSN 0042-2886, Vol. 70, no 4, p. 215-224Article in journal (Other academic)
  • 8.
    Govindarajan, Venkatesh
    Norwegian University of Science & Technology, Trondheim, Norway.
    The EU TRUST project: Coming together to seek common solutions for water utilities2012In: Journal - American Water Works Association, ISSN 0003-150X, E-ISSN 1551-8833, Vol. 104, no 11, p. 52-54Article in journal (Refereed)
    Abstract [en]

    TRUST is an acronym for Transition to the Urban Water Services of Tomorrow. Just into its second year, this four-year European Union project consists of a consortium that is split into eight work areas (which in turn are segmented into many work packages), focusing on different aspects of the project. These eight work areas are not islands of expertise working in isolation in different countries in Europe, but cooperating and collaborating team members actively exchanging and sharing information among themselves to ensure that progress toward the end goals is ensured and expedited.

  • 9.
    Govindarajan, Venkatesh
    Norwegian University for Science & Technology, Norway.
    Urban Water System metabolism assessment using WaterMet(2) model2014In: 12TH INTERNATIONAL CONFERENCE ON COMPUTING AND CONTROL FOR THE WATER INDUSTRY, CCWI2013 / [ed] Brunone, B; Giustolisi, O; Ferrante, M; Laucelli, D; Meniconi, S; Berardi, L; Campisano, A, Elsevier, 2014, Vol. 70, no 1, p. 113-122Conference paper (Refereed)
  • 10.
    Govindarajan, Venkatesh
    Norwegian University of Science & Technology, Trondheim, Norway.
    Wastewater treatment in Norway: An overview2013In: Journal - American Water Works Association, ISSN 0003-150X, E-ISSN 1551-8833, Vol. 105, no 5, p. 92-97Article in journal (Refereed)
    Abstract [en]

    The challenges of providing services to growing populations multiply, as demonstrated by the trials faced in Norway as it searched for effective ways of addressing a growing wastewater treatment problem.

  • 11.
    Govindarajan, Venkatesh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. Norwegian University of Science & Technology.
    WaterMet2: A tool for integrated analysis of sustainability-based performance of urban water systems2014In: Drinking Water Engineering and Science Discussions, ISSN 1996-9473, E-ISSN 1996-9481, Vol. 7, no 1, p. 63-72Article in journal (Refereed)
    Abstract [en]

    This paper presents the "WaterMet2" model for long-term assessment of urban water system (UWS) performance which will be used for strategic planning of the integrated UWS. WaterMet2 quantifies the principal water-related flows and other metabolism-based fluxes in the UWS such as materials, chemicals, energy and greenhouse gas emissions. The suggested model is demonstrated through sustainability-based assessment of an integrated real-life UWS for a daily time-step over a 30-year planning horizon. The integrated UWS modelled by WaterMet2 includes both water supply and wastewater systems. Given a rapid population growth, WaterMet2 calculates six quantitative sustainability-based indicators of the UWS. The result of the water supply reliability (94%) shows the need for appropriate intervention options over the planning horizon. Five intervention strategies are analysed in WaterMet2 and their quantified performance is compared with respect to the criteria. Multi-criteria decision analysis is then used to rank the intervention strategies based on different weights from the involved stakeholders' perspectives. The results demonstrate that the best and robust strategies are those which improve the performance of both water supply and wastewater systems.

  • 12.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Azrague, Kamal
    SINTEF Bldg & Infrastruct, Water & Environm Res Grp, N-7465 Trondheim, Norway.
    Bell, Stig
    Municipal Oppegard, Water Wastewater & Renovat Sect, N-1412 Sofiemyr, Norway.
    Eikebrokk, Bjornar
    SINTEF Bldg & Infrastruct, Water & Environm Res Grp, N-7465 Trondheim, Norway.
    Triple bottom line assessment of raw water treatment: Methodology and application to a case study in the municipality of Oppegard in south-eastern Norway2015In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 36, no 15, p. 1954-1965Article in journal (Refereed)
  • 13.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Brattebo, Helge
    Norwegian University for Science & Technology, Norway.
    Analysis of chemicals and energy consumption in water and wastewater treatment, as cost components: Case study of Oslo, Norway2011In: Urban Water Journal, ISSN 1573-062X, Vol. 8, no 3, p. 189-202Article in journal (Refereed)
    Abstract [en]

    Adopting a systems-approach to an urban water and wastewater system, while applying a triple bottom line strategy to management, entails a careful analysis of all the sub-systems and components thereof with a view to improving service levels, optimising expenditure, augmenting investments, and also reducing the life-cycle environmental impacts associated with setting up, maintaining and operating the system. The scope for optimising expenses is system-wide, though it varies from one sub-system to another, depending on inherent lock-ins and external factors beyond the direct control of the water and wastewater utility. Optimising the consumption of energy and chemicals and improving the cost-efficiency thereof, is always on the agenda of water treatment plants (WTPs) and wastewater treatment plants (WWTPs). This paper analyses the consumption of and the expenditure on chemicals and energy at Oslo's WTPs and WWTPs over time. Energy and chemicals for water and wastewater treatment, on an average account for 10.8% of the total operational expenses in the water supply sub-system and 13.7% for the wastewater handling sub-system. There is a perceptible increase in this share from 5.2% in 2004 to 14.9% in 2009 for water and 12.3% to 14.2% for wastewater. Chemicals cost more than energy for the WWTPs, while it was the other way round for the WTPs. The total real cost of energy and chemicals per cubic metre, in year-2007 currency, was between 4 and 5.2 Euro cents for the WTPs, and between 1 and 4.5 Euro cents for the WTPs. The total (WTP + WWTP) per-capita real costs of energy and chemicals, expressed in year-2007 currency, rose from around 10 Euros in year 2000 to about 12.2 Euros in year 2007.

  • 14.
    Govindarajan, Venkatesh
    et al.
    Norwegian University of Science and Technology, Trondheim, Norway.
    Brattebo, Helge
    Norwegian University of Science and Technology, Trondheim, Norway.
    Changes in material flows, treatment efficiencies and shifting of environmental loads in the wastewater treatment sector.: Part I: Case study of the Netherlands2009In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 30, no 11, p. 1111-1129Article in journal (Refereed)
    Abstract [en]

    The material that is separated from wastewater in wastewater treatment plants has to be transferred from the water phase to the atmosphere, lithosphere, and/or biosphere (and also the technosphere). After the initial discharges into the different environmental media (and the technosphere), there are further 'inter-sphere' leakages or redirections. However, these happen over protracted periods of time and have not been accounted for in this paper. The paper presents a case study on the wastewater treatment plants in the Netherlands, examines how the degree of separation of COD (BOD), nitrogen, phosphorus and heavy metals from the wastewater have increased over time, and studies the changes in proportions separated out to the atmosphere and lithosphere. The hydrosphere has benefited from a decline in the degree of eutrophication and marine/fresh water toxicity, owing to the favourable combination of higher degrees of separation, over time, and source control, especially in the industrial sector. Global warming is a major concern owing to the increasing conversion of COD to carbon dioxide (and methane). Heavy metal and nitrogen emissions have been curbed thanks to source reduction within industries. Technologies have, of course, enabled some mitigation of the problems associated with atmospheric (global warming and toxicity) and lithospheric (toxicity) pollution, though these are beyond the scope of this paper, which assumes a hypothetical worst-case scenario in this regard for the study period 1993-2005.

  • 15.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Brattebo, Helge
    Norwegian University for Science & Technology, Norway.
    Environmental impact analysis of chemicals and energy consumption in wastewater treatment plants: Case study of Oslo, Norway2011In: Water Science and Technology: Water Supply, ISSN 1606-9749, E-ISSN 1607-0798, Vol. 63, no 5, p. 1081-1031Article in journal (Refereed)
  • 16.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Brattebo, Helge
    NTNU, Norway.
    Sægrov, Sveinung
    NTNU, Norway.
    Behzadian, Kouroush
    University of Exeter, UK.
    Kapelan, Zoran
    Metabolism-modelling approaches to long-term sustainability assessment of urban water services2015In: Urban Water Journal, ISSN 1573-062X, p. 1-12Article in journal (Refereed)
    Abstract [en]

    There is a discernible need for a holistic, long-term and sustainability approach in decision-making in water and wastewater utilities around the world. Metabolism-based modelling, which can quantify various flows within an urban water system (UWS), has shown its effective usability for a more comprehensive understanding of the impacts of intervention strategies and can be used by any water utility for future planning of UWS. This study presents the main principles of a holistic Sustainability Assessment Framework which can be simulated by using two analytical, conceptual, mass-balance-based models to quantify relevant key performance indicators (KPIs) associated with the metabolic flows of the urban water cycle. These two models are WaterMet2 (WM2) and dynamic metabolism model (DMM), developed recently under the aegis of the EU TRUST (Transitions to the Urban Water Services of Tomorrow) project. There are clear differences between the two models which make them useful in different contexts and circumstantial situations. DMM is a mass-balance consistent model which quantifies and presents annually-aggregated performance values for system wide energy consumption, emissions, environmental impacts and costs for the entire UWS though it is also possible to derive corresponding indicators for individual sub-systems (e.g. water distribution and wastewater transport). WM2 is the opposite of this, it is a distributed metabolism model which simulates water related and other resource flows throughout the UWS components with a higher resolution both spatially (e.g. multiple water resources and service reservoirs) and temporally (e.g. daily and monthly), and thereby is useful in contexts where utilities would like to focus on further details of the UWS metabolism with the aim to understand and solve specific problems. Overall, these two complementary metabolism-based approaches enable any water utility to quantitatively explore and understand the influences of different external drivers and intervention strategies on future performance profiles linked to any physical, environmental and economic criteria.

  • 17.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Didi, Mohamed Ahmed
    Norwegian University for Science & Technology, Norway.
    Mujthaba, Ahmed
    Norwegian University for Science & Technology, Norway.
    Male makes the most of limited land and freshwater2011In: Journal - American Water Works Association, ISSN 0003-150X, E-ISSN 1551-8833, Vol. 103, no 5, p. 44-50Article in journal (Other academic)
  • 18.
    Govindarajan, Venkatesh
    et al.
    Norwegian university of science and technology, Trondheim, Norway.
    Hammervold, Johanne
    Brattebo, Helge
    Norwegian university of science and technology, Trondheim, Norway.
    Combined MFA-LCA for analysis of wastewater pipeline networks: Case study of Oslo (Norway).2009In: Journal of Industrial Ecology, ISSN 1088-1980, E-ISSN 1530-9290, Vol. 13, no 4, p. 532-550Article in journal (Refereed)
    Abstract [en]

    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.

  • 19.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Nersund Larsen, Hogne
    Energy and Environment, AsplanViak, Trondheim, Norway.
    Water-energy nexus in urban water utilities: A brief Norwegian outlook2015In: Vatten, ISSN 0042-2886, Vol. 71, no 2, p. 101-109Article in journal (Other academic)
  • 20.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Ramprakash, Govindarajan
    Norwegian University for Science & Technology, Norway.
    Metabolism: beyond the preserve of biological sciences2014In: Journal - American Water Works Association, ISSN 0003-150X, E-ISSN 1551-8833, Vol. 106, no 7, p. 44-48Article in journal (Refereed)
  • 21.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Saegrov, Sveinung
    Norwegian University for Science & Technology, Norway.
    Brattbo, Helge
    Norwegian University for Science & Technology, Norway.
    Dynamic metabolism modelling of urban water services - demonstrating effectiveness as a decision-support tool for Oslo, Norway2014In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 61, no 1, p. 19-33Article in journal (Refereed)
  • 22.
    Govindarajan, Venkatesh
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. NTNU.
    Ugarelli, Rita
    NTNU, SINTEF.
    Kristiansen, Per
    Oslo VA.
    Oslo consumers willing to pay more for improved services: Interview with Per Kristiansen, Chief of Oslo VAV2010In: Journal of American Water Works Association, ISSN 0003-150X, Vol. 102, no 11, p. 26-29Article in journal (Other (popular science, discussion, etc.))
  • 23.
    Graversgaard, Morten
    et al.
    Aarhus University, Denmark.
    Hedelin, Beatrice
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Smith, Laurence
    SOAS University of London, UK.
    Gertz, Flemming
    SEGES, Landbrug & Fødevarer F.M.B.A., Denmark.
    Højberg, Anker Lajer
    Geological Survey of Denmark and Greenland (GEUS), Denmark.
    Langford, John
    University of Melbourne, Australia.
    Martinez, Grit
    Ecologic Institute, Germany.
    Mostert, Erik
    Delft University of Technology, The Netherlands.
    Ptak, Emilia
    Aarhus University, Denmark.
    Peterson, Heidi
    University of Minnesota, MN, USA; International Plant Nutrition Institute, MN, USA.
    Stelljes, Nico
    Ecologic Institute, Germany.
    van den Brink, Cors
    Royal Haskoning DHV, The Netherlands; Groningen University, The Netherlands.
    Refsgaard, Jens Christian
    Geological Survey of Denmark and Greenland (GEUS), Denmark.
    Opportunities and barriers for water co-governance: A critical analysis of seven cases of diffuse water pollution from agriculture in Europe, Australia and North America2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 5, article id 1634Article in journal (Refereed)
    Abstract [en]

    Diffuse Water Pollution from Agriculture (DWPA) and its governance has received increased attention as a policy concern across the globe. Mitigation of DWPA is a complex problem that requires a mix of policy instruments and a multi-agency, broad societal response. In this paper, opportunities and barriers for developing co-governance, defined as collaborative societal involvement in the functions of government, and its suitability for mitigation of DWPA are reviewed using seven case studies in Europe (Poland, Denmark, Sweden, The Netherlands and UK), Australia (Murray-Darling Basin) and North America (State of Minnesota). An analytical framework for assessing opportunities and barriers of co-governance was developed and applied in this review. Results indicated that five key issues constitute both opportunities and barriers, and include: (i) pressure for change; (ii) connected governance structures and allocation of resources and funding; (iii) leadership and establishment of partnerships through capacity building; (iv) use and co-production of knowledge; and (v) time commitment to develop water co-governance

  • 24.
    Johansson, Emma
    et al.
    Karlstad University.
    Govindarajan, Venkatesh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Wastewater treatment plants as energy producers: Comparison of status quo in Sweden and India2018In: Vatten, ISSN 0042-2886, Vol. 73, no 151, article id 160Article in journal (Other academic)
    Abstract [en]

    As the population of the world rises and economies grow, both energy and water will be needed in ever-increasing quantities. There is a delicate balance between these two resources called the energy-water (or the water-energy) nexus. One way to reduce the energy consumption associated with wastewater treatment is to use the sludge produced during the process to generate biogas. In most countries in the developed world, the coverage, standards and reliability of wastewater treatment are high.  But as the countries in the developing world are striving towards the living standards of those in the developed world, even as they combat population pressure, it is  imperative that they  learn from the experiences (the mistakes which occurred during the ‘learning-by-doing’ process) of the developed world. In this paper, Sweden has been used as a proxy for the developed world with a well-functioning sanitation infrastructure and reliable power supply; and India (the home country of one of the coauthors) is a proxy for the developing world which lacks the same. A very important starting point for development would be to educate people about the long-term socio-economic and environmental benefits of wastewater treatment

     

  • 25.
    Naqvi, Salman Raza
    et al.
    Univ Twente, Fac Engn Technol, Enschede, Netherlands; Natl Univ Sci & Technol, Islamabad, Pakistan.
    Tariq, R.
    Natl Univ Sci & Technol, Islamabad, Pakistan.
    Hameed, Z.
    Natl Univ Sci & Technol, Islamabad, Pakistan.
    Ali, I.
    King Abdulaziz Univ, Dept Chem, Rabigh, Saudi Arabia; King Abdulaziz Univ, Dept Mat Engn, Rabigh, Saudi Arabia.
    Taqvi, S. A.
    Univ Teknol PETRONAS, Dept Chem Engn, Seri Iskandar, Malaysia; NED Univ Engn & Technol, Chem Engn Dept, Karachi 75270, Pakistan.
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Niazi, M. B. K.
    Natl Univ Sci & Technol, Sch Chem & Mat Engn, Islamabad, Pakistan.
    Noor, T.
    Natl Univ Sci & Technol, Sch Chem & Mat Engn, Islamabad, Pakistan.
    Farooq, W.
    KFUPM, Dept Chem Engn, Dhahran, Saudi Arabia.
    Pyrolysis of high-ash sewage sludge: Thermo-kinetic study using TGA and artificial neural networks2018In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 233, p. 529-538Article in journal (Refereed)
    Abstract [en]

    Pyrolysis of high-ash sewage sludge (HASS) is a considered as an effective method and a promising way for energy production from solid waste of wastewater treatment facilities. The main purpose of this work is to build knowledge on pyrolysis mechanisms, kinetics, thermos-gravimetric analysis of high-ash (44.6%) sewage sludge using model-free methods & results validation with artificial neural network (ANN). TG-DTG curves at 5,10 and 20 °C/min showed the pyrolysis zone was divided into three zone. In kinetics, E values of models ranges are; Friedman (10.6–306.2 kJ/mol), FWO (45.6–231.7 kJ/mol), KAS (41.4–232.1 kJ/mol) and Popescu (44.1–241.1 kJ/mol) respectively. ΔH and ΔG values predicted by OFW, KAS and Popescu method are in good agreement and ranged from (41–236 kJ/mol) and 53–304 kJ/mol, respectively. Negative value of ΔS showed the non-spontaneity of the process. An artificial neural network (ANN) model of 2 * 5 * 1 architecture was employed to predict the thermal decomposition of high-ash sewage sludge, showed a good agreement between the experimental values and predicted values (R2 ⩾ 0.999) are much closer to 1. Overall, the study reflected the significance of ANN model that could be used as an effective fit model to the thermogravimetric experimental data. © 2018 Elsevier Ltd

  • 26. Osorio, Andrea Diaz
    et al.
    Govindarajan, Venkatesh
    Integrated Management Spells Success for Medellin, Colombia's, Water and Wastewater Utility2013In: Journal - American Water Works Association, ISSN 0003-150X, E-ISSN 1551-8833, Vol. 105, no 3, p. 78-82Article in journal (Refereed)
    Abstract [en]

    The city of Medellin is the second largest urban area in Colombia. The state-owned company, Empresas Publicas de Medellin E.S.P. (EPM), provides water supply and wastewater treatment services to more than 3.5 million people in the city and nine other smaller towns in the conurbation. EPM also provides public services other than water supply and wastewater treatment. Eduardo Cadavid Restrepo, director of the department of water management at EPM, described the current status, challenges, and future plans for the water supply and sanitation system in Medellin in this interview (conducted by e-mail in Spanish and later translated to English) with Andrea Diaz Osorio and Govindarajan Venkatesh.

  • 27.
    Ugarelli, Rita
    et al.
    Bologna university, Bologna, Italy.
    Govindarajan, Venkatesh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Brattebo, Helge
    Norwegian university of science and technology, Trondheim, Norway.
    Di Federico, Vittorio
    Bologna university, Bologna, Italy.
    Saegrov, Sveinung
    Norwegian university of science and technology, Trondheim, Norway.
    Historical analysis of blockages in wastewater pipelines in Oslo and diagnosis of causative pipeline characteristics.2010In: Urban Water Journal, ISSN 1573-062X, Vol. 7, no 6, p. 335-343Article in journal (Refereed)
    Abstract [en]

    The city of Oslo is evaluating strategies for the selection of appropriate materials for the pipelines and manholes of its wastewater network. The overarching motive is to minimise construction-related failures over the system lifetime and also ensure that it is able to avert flooding events. This paper analyses the blockage records of the last 16 years (1991-2006) in the wastewater pipeline network of Oslo. For the purpose of the analysis, the pipeline stock is categorised on the basis of pipe diameter, material of fabrication, slope and age. Proneness to blockages is studied and attempts are made to correlate the same to the size, material, slope and age. The analyses performed confirm that older and small diameter sewage pipelines made of concrete, laid almost horizontal to the ground surface are the high-priority candidates, and more importantly enables one to compare among the different categories and classes of pipelines.

  • 28.
    Ugarelli, Rita
    et al.
    Bologna University, Bologna, Italy.
    Govindarajan, Venkatesh
    Norwegian university of technology and science, Trondheim, Norway.
    Brattebø, Helge
    Norwegian university of technology and science, Trondherim, Norway.
    Di Federico, Vittorio
    Bologna university, Bologna, italy.
    Sægrov, Sveinung
    SINTEF, Trondheim, Norway.
    Asset management of urban wastewater pipeline networks2010In: Journal of Infrastructure Systems, ISSN 1076-0342, E-ISSN 1943-555X, Vol. 16, no 2, p. 112-121Article in journal (Refereed)
    Abstract [en]

    Pipelines account for the lion’s share of the lifetime costs of any typical urban wastewater collection. While the deterioration of pipeline is the obvious “frontline” reason to adopt asset management practices, a more overarching driver is the need to gravitate toward sustainable development and set short- and long-term objectives encompassing economic, social, and environmental goals. Optimizing the expenses and providing the required levels of service to customers are the twin targets of wastewater utilities. Oslo Vann og Avløpsetaten—the water/wastewater utility in the Norwegian capital, considered as case study in this paper, is sprucing up its data bank, rightly realizing that a very effective information management system is the spine of asset management.

  • 29.
    Ugarelli, Rita
    et al.
    Bologna university, Italy.
    Govindarajan, Venkatesh
    Norwegian University of Science and Technology, Trondheim, Noraway.
    Brattebø, Helge
    Norwegian University of Science and Technology, Trondheim, Norway.
    Sægrov, Sveinung
    SINTEF, Trondheim, Norway.
    Importance of investment decisions and rehabilitation approaches in an ageing wastewater pipeline network.: A case study of Oslo (Norway)2008In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 58, no 12, p. 2279-2293Article in journal (Refereed)
    Abstract [en]

    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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