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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
871

An environmentally-based systems approach to sustainability analyses of organic fruit production systems in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Sustainable Agricultural Systems at Massey University, Palmerston North, New Zealand

Page, Girija January 2009 (has links)
An environmentally-based systems approach to sustainability analyses of organic fruit production systems in New Zealand. This research introduces an approach for the assessment of the sustainability of farming systems. It is based on the premises that sustainability has an environmental bottom line and that there is very limited substitutability between natural capital and other forms of capital. Sustainability assessment is undertaken through analyses of energy and material flows of the system and their impacts on the environment. The proposed sustainability assessment approach is based on two high level criteria for sustainability: efficient use of energy and non-degradation of the environment from energy and material use. Sustainability assessment of organic orchard systems in New Zealand was undertaken to demonstrate this approach. Five indicators which address the two criteria for the sustainability of the orchard systems are the energy ratio, the CO2 ratio, changes in the soil carbon level, nutrient balances, and the leaching of nitrogen. Organic kiwifruit and organic apple systems are modelled based on their key energy and material flows and their interactions with the natural environment. The energy and material flows are converted into appropriate energy and matter equivalents based on coefficients taken from the published literature. Sustainability indicators are estimated over one growing season using two computer modelling tools, Overseer® and Stella®, in a life cycle approach. Sustainability assessment of the organic orchard systems suggests that the approach is useful for evaluating energy use and key environmental impacts that occur in soil, water and atmosphere. The results indicate that the model organic orchard systems are sustainable in terms of energy use and are a net sink of CO2-equivalent emissions. The implication of this result is that organic orchard systems potentially could trade carbon credits under the Kyoto Protocol. The findings also suggest that the sustainability assessment approach is capable of identifying the trade-offs within the sustainability indicators associated with particular management practices. Further research to improve and validate the proposed approach is essential, before it can be practically used for decision making at the orchard level and for policy making at the national level.
872

Sustainability issues in the Central Mount Lofty Ranges

Layton, Ronald A. January 2001 (has links) (PDF)
Bibliography: leaves 78-83. "The dissertation brings together discourses relating to sustainability with that of the environment, at least in terms of its meaning and responses to it being culturally constructed. The Central Adelaide Hills provides the locality for achieving this, which a peri-urban environment is subject to the power exerted by urban Adelaide as well as the tension arising out of land use conflict and attitudes to the environment."
873

Limitations to plant root growth in highly saline and alkaline bauxite residue

Kopittke, Peter Martin Unknown Date (has links)
Revegetation of bauxite residue is hampered by a lack of understanding of the limitations imposed on plant growth in highly saline and alkaline growth mediums. In this study, several of these growth limiting factors were investigated. The toxicity of the hydroxyl ion (OH-) was examined using a solution culture system developed to allow studies at high pH without nutritional limitations. Also using this solution culture system, the effect of the high Na and Mg concentrations of bauxite residue on the Ca nutrition of plants was investigated. As the toxicity of Al at high pH is not known, a study was conducted to examine the rhizotoxicity of aluminate (Al(OH)4-) and polycationic Al at high pH. The ability of plant roots to reduce rhizosphere pH in bauxite residue was also considered. A novel gypsum application method was assessed for its efficiency at improving the Ca status of bauxite residue. Manual adjustment, ion exchange resins and automated titration were examined for their suitability for nutrient solution pH control in alkaline conditions. For short-term studies, it was found that a solution without supply of Cu, Fe, Mn and Zn, and aerated with CO2 depleted air, greatly reduced nutrient precipitation at high pH, thus eliminating nutritional differences between treatments. Manual pH adjustment and the use of ion exchange resins as pH buffers were unsuitable methods of pH control. In contrast, pH control by automated titration had little effect on solution composition while maintaining constant pH. The solution culture system was used to examine OH- toxicity in mungbeans (Vigna radiata (L.) Wilczek cv. Emerald), with root length reduced at a bulk solution pH of 8.5 and greater. The effect of Ca activity ratio (CAR) and pH on Ca uptake by mungbeans and Rhodes grass (Chloris gayana cv. Pioneer) in Na dominated solution cultures and in soil was investigated. Changes in pH in the alkaline range were shown to have no effect on the critical CAR of 0.024 (corresponding to 90 % relative root length) for mungbeans grown in solution culture. Results from soil grown mungbeans confirmed those from solution culture, with a critical CAR of 0.025. A critical CAR of 0.034 was also established for soil grown Rhodes grass. However, using dilute nutrient solutions dominated by Mg at pH 9.0, root growth was found to be more limited than had been observed for Na solutions, with growth reduced beneath a critical CAR of 0.050. Using a CAR equation modified with plasma membrane binding constants (to incorporate the differing antagonistic effects of Mg and Na), new critical CAR values were calculated for Na (0.56) and Mg (0.44) dominated solutions. This modified CAR equation permits the calculation of CAR irrespective of the dominant salt present. Solubilities of various gypsum sources and size fractions in seawater were studied to investigate the effectiveness of gypsum addition to the residue sand pipeline, rather than as a direct field application. The dissolution rate constant varied with gypsum source (analytical grade (AR) > phosphogypsum (PG) > mined gypsum (MG)) due to reactivity and surface area differences, generally reaching saturation within 15 s (AR) to 30 min (MG > 2.0). The ability of bauxite residue to remove Ca from solution (due to cation exchange and precipitation) was also examined; the quantity of the total solution Ca adsorbed was found to be small (5 %). These low rates of solution Ca adsorption, comparatively rapid dissolution rates, and long pumping times (20 min), preclude the application of gypsum to the residue sand/seawater slurry as a method for residue amelioration. Dilute, alkaline (pH 9.5) nutrient solutions were used to investigate the effects of aluminate (Al(OH)4-) on mungbean root growth. Although root growth in Al(OH)4- solutions was slightly limited, the symptoms associated with this growth reduction were observed to be similar to those caused by the Al13 polycation at concentrations lower than that which can be detected. Also, when roots displaying these symptoms were transferred to fresh Al(OH)4- solutions, no root tip lesions were observed, and root hair growth on the lateral roots improved. Thus, Al(OH)4- is considered to be non-toxic, with the observed reduction in root growth in solutions containing Al(OH)4- due to the gradual formation of toxic Al13 in the bulk nutrient solution resulting from the acidification of the alkaline nutrient solution by the plant roots. The effect of Mn deficiency in Rhodes grass and of legume inoculation in lucerne (Medicago sativa L. cv. Hunter River), on the rhizosphere pH of plants grown in highly alkaline bauxite residue was investigated. In response to Mn deficiency in residue sand, Rhodes grass was observed to increase acidification of its rhizosphere (being up to 1.22 pH units lower than the bulk soil). Due to its ability to fix atmospheric N2 rather than relying on soil N (NO3-) reserves, inoculated lucerne (1.75 pH unit decrease) was also found to acidify its rhizosphere to a greater extent than non-inoculated lucerne (1.16 pH unit decrease).
874

Limitations to plant root growth in highly saline and alkaline bauxite residue

Kopittke, Peter Martin Unknown Date (has links)
Revegetation of bauxite residue is hampered by a lack of understanding of the limitations imposed on plant growth in highly saline and alkaline growth mediums. In this study, several of these growth limiting factors were investigated. The toxicity of the hydroxyl ion (OH-) was examined using a solution culture system developed to allow studies at high pH without nutritional limitations. Also using this solution culture system, the effect of the high Na and Mg concentrations of bauxite residue on the Ca nutrition of plants was investigated. As the toxicity of Al at high pH is not known, a study was conducted to examine the rhizotoxicity of aluminate (Al(OH)4-) and polycationic Al at high pH. The ability of plant roots to reduce rhizosphere pH in bauxite residue was also considered. A novel gypsum application method was assessed for its efficiency at improving the Ca status of bauxite residue. Manual adjustment, ion exchange resins and automated titration were examined for their suitability for nutrient solution pH control in alkaline conditions. For short-term studies, it was found that a solution without supply of Cu, Fe, Mn and Zn, and aerated with CO2 depleted air, greatly reduced nutrient precipitation at high pH, thus eliminating nutritional differences between treatments. Manual pH adjustment and the use of ion exchange resins as pH buffers were unsuitable methods of pH control. In contrast, pH control by automated titration had little effect on solution composition while maintaining constant pH. The solution culture system was used to examine OH- toxicity in mungbeans (Vigna radiata (L.) Wilczek cv. Emerald), with root length reduced at a bulk solution pH of 8.5 and greater. The effect of Ca activity ratio (CAR) and pH on Ca uptake by mungbeans and Rhodes grass (Chloris gayana cv. Pioneer) in Na dominated solution cultures and in soil was investigated. Changes in pH in the alkaline range were shown to have no effect on the critical CAR of 0.024 (corresponding to 90 % relative root length) for mungbeans grown in solution culture. Results from soil grown mungbeans confirmed those from solution culture, with a critical CAR of 0.025. A critical CAR of 0.034 was also established for soil grown Rhodes grass. However, using dilute nutrient solutions dominated by Mg at pH 9.0, root growth was found to be more limited than had been observed for Na solutions, with growth reduced beneath a critical CAR of 0.050. Using a CAR equation modified with plasma membrane binding constants (to incorporate the differing antagonistic effects of Mg and Na), new critical CAR values were calculated for Na (0.56) and Mg (0.44) dominated solutions. This modified CAR equation permits the calculation of CAR irrespective of the dominant salt present. Solubilities of various gypsum sources and size fractions in seawater were studied to investigate the effectiveness of gypsum addition to the residue sand pipeline, rather than as a direct field application. The dissolution rate constant varied with gypsum source (analytical grade (AR) > phosphogypsum (PG) > mined gypsum (MG)) due to reactivity and surface area differences, generally reaching saturation within 15 s (AR) to 30 min (MG > 2.0). The ability of bauxite residue to remove Ca from solution (due to cation exchange and precipitation) was also examined; the quantity of the total solution Ca adsorbed was found to be small (5 %). These low rates of solution Ca adsorption, comparatively rapid dissolution rates, and long pumping times (20 min), preclude the application of gypsum to the residue sand/seawater slurry as a method for residue amelioration. Dilute, alkaline (pH 9.5) nutrient solutions were used to investigate the effects of aluminate (Al(OH)4-) on mungbean root growth. Although root growth in Al(OH)4- solutions was slightly limited, the symptoms associated with this growth reduction were observed to be similar to those caused by the Al13 polycation at concentrations lower than that which can be detected. Also, when roots displaying these symptoms were transferred to fresh Al(OH)4- solutions, no root tip lesions were observed, and root hair growth on the lateral roots improved. Thus, Al(OH)4- is considered to be non-toxic, with the observed reduction in root growth in solutions containing Al(OH)4- due to the gradual formation of toxic Al13 in the bulk nutrient solution resulting from the acidification of the alkaline nutrient solution by the plant roots. The effect of Mn deficiency in Rhodes grass and of legume inoculation in lucerne (Medicago sativa L. cv. Hunter River), on the rhizosphere pH of plants grown in highly alkaline bauxite residue was investigated. In response to Mn deficiency in residue sand, Rhodes grass was observed to increase acidification of its rhizosphere (being up to 1.22 pH units lower than the bulk soil). Due to its ability to fix atmospheric N2 rather than relying on soil N (NO3-) reserves, inoculated lucerne (1.75 pH unit decrease) was also found to acidify its rhizosphere to a greater extent than non-inoculated lucerne (1.16 pH unit decrease).
875

Evaluation of Potentially Eco-Efficient Solutions: Functional Sales and Industrial Ecology / Evaluation of Industrial Ecology, Eco-Efectiveness and Functional Sales under a framework of Eco-Efficiency

González Ocón, Santiago January 2009 (has links)
<p>Design of products permits to yield goods and services to produce satisfaction on customers, which is measured as value. However, it is at this stage in which most of the environmental impact, from a lifecycle perspective, is added to the product. Eco-design aims at increasing value of products while reducing the burdens on the environment by means conscious design towards efficient use of resources. That efficiency, referred to as eco-efficiency, can be increased in a number of manners within environmental engineering. Traditionally, different fields have tackled materials, energy flows and products from different angles or approaches. In this thesis we describe Functional Sales (FS) and Industrial Ecology (IE) as examples of these. Within this latter, we put emphasis on Industrial Symbiosis (IS) and Eco-effectiveness. We consider these approaches are suitable to work in the framework of eco-design to increase ecoefficiency. By adding services to material products, and managing material and energy flows with a more ecological consciousness, we expect to increase value of products while reducing the impact on the environment.</p><p>To analyse this potential improvement, we developed a method involving a new eco-efficiency index (VERI), that recursively intends to ease decisions on possible eco-efficient alternatives. This index and its method are applied to a case study on management of olive oil supply in region of Murcia, Spain. Here, we propose three scenarios that will involve the implementation of FS and IE to compare the outcomes in value and environmental performance against an idealised current supply chain. The results obtained, although not accurate, suggest that FS and EI should be more taken into account in eco-design and, this latter, to also consider holistic viewpoints to find more eco-efficient alternatives for a product development.</p>
876

少数主桁橋梁と従来型橋梁のライフサイクル環境負荷とコストの比較研究

伊藤, 義人, ITOH, Yoshito, 梅田, 健貴, UMEDA, Kenki, 西川, 和廣, NISHIKAWA, Kazuhiro 03 1900 (has links)
No description available.
877

Biophilic Design at Pomona College: An Analysis of the New Sontag and Pomona Residence Halls

Hasse, John W 01 May 2012 (has links)
The Leadership in Energy and Environmental Design for New Construction (or LEED-NC) has become one of the most commonly used green building standards during the turn of the 21st century. While many champion LEED-NC, certain architects and academics believe that its low-environmental impact design approach toward green building isolates people from nature and thus cannot achieve sustainable development over the long-term. Pomona College’s green buildings, including its newest LEED Platinum certified Sontag and Pomona Residence Halls, exemplify this fact, as their designs fail to communicate their sustainable goals or inspire sustainable behavior. By examining the LEED-NC standards, the history of environmental conservation, Modern architecture, biophilia, and the Living Building Challenge, this thesis seeks to provide recommendations for how Pomona College can alter its existing green buildings as well as improve its green building policies for future projects so that its built environment better fosters positive human-nature interactions.
878

Development of a procedure for power generated from a tidal current turbine farm

Li, Ye 11 1900 (has links)
A tidal current turbine is a device functioning in a manner similar to wind turbine for harnessing energy from tidal currents, a group of which is called a farm. The existing approaches used to predict power from tidal current turbine farms oversimplify the hydrodynamic interactions between turbines, which significantly affects the results. The major focus of this dissertation is to study the relationship between turbine distribution (the relative position of the turbines) and the hydrodynamic interactions between turbines, and its impact on the power from a farm. A new formulation of the discrete vortex method (DVM-UBC) is proposed to describe the behavior of turbines and unsteady flow mathematically, and a numerical model is developed to predict the performance, the unsteady wake and acoustic emission of a stand-alone turbine using DVM-UBC. Good agreement is obtained between the results obtained with DVM-UBC and published numerical and experimental results. Then, another numerical model is developed to predict the performance, wake and acoustic emission of a two-turbine system using DVM-UBC. The results show that the power of a two-turbine system with optimal relative position is about 25% more than two times that of a stand-alone turbine under the same conditions. The torque such a system may fluctuate 50% less than that of a stand-alone turbine. The acoustic emission of such a system may be 35% less than that of a stand-alone turbine. As an extension, a numerical procedure is developed to estimate the efficiency of an N-turbine system by using a linear theory together with the two-turbine system model. By integrating above hydrodynamic models for predicting power and a newly-developed Operation and Maintenance (O&M) model for predicting the cost, a system model is framed to estimate the energy cost using a scenario-based cost-effectiveness analysis. This model can estimate the energy cost more accurately than the previous models because it breaks down turbine’s components and O&M strategies in much greater detail when studying the hydrodynamics and reliability of the turbine. This dissertation provides a design tool for farm planners, and shed light on other disciplines such as environmental sciences and oceanography.
879

Tillämpning av GIS-analyser i MKB / Application of GIS-analyses in EIA

Wall, Erik January 2006 (has links)
The reason for performing an Environmental Impact Assessment (EIA) is to incorporate environmental concern in different kinds of plans and projects. The purpose of such an assessment is to identify and describe direct, indirect and cumulative environmental impacts. Geographical Information System (GIS) is a tool that can be used to combine spatial extension of both sensitive areas and different environmental impacts in a quick and easy way. Because of that, descriptions of environmental impacts and motivation of different standpoints on a specific issue can be more correct and easier to make if GIS is used as a tool. Hence, GIS can contribute to improve the quality of Environmental Impact Assessments. If the benefits of using GIS are to out weight the costs, geographical information of satisfactory detail, actuality and accuracy need to be available at reasonable prices. In this paper, case studies are carried out for three different geographical analyses to investigate the use of GIS as a tool in EIA. From these case studies, more general conclusions about the benefits and limitations of using GIS for Environmental Impact Assessments are also drawn. The criteria, after which benefits and limitations of GIS have been estimated, are data availability, time consumption for performing the analyses and how the results from the performed analyses can make impact assessments easier, motivate different standpoints and increase the comprehensiveness of the EIA-report. The three different GIS-analyses includes calculation of pollution load in a catchment area, estimation of the visual impact from planned buildings and generation of alternative locations for underwater pipes. These analyses have been applied on one ongoing EIA for a freight terminal and one ongoing EIA for an underwater wastewater transmission pipe. The analyses in these case studies have been undertaken with ArcGIS software using the extensions “Spatial Analyst” and “3D Analyst”. It is shown in this study that due to uncertainty in available model values and the time consuming data manipulation, it is unlikely that calculations of pollution loads with GIS will be used to any larger extent in EIA. To carry out visual assessments with help of GIS to estimate visual impacts is on the other hand assumed to be useful in EIA-work. Both to assess impacts and to estimate how changes in building design can alter those impacts. To use GIS to produce alternative locations for underwater pipes is also considered valuable in EIA-work, even though there is a considerable lack of data to predict the environmental class of marine areas and the connections between available data and real environmental values are weak. However, the risk of damaging vulnerable and high valued marine areas should decrease when applying this type of analyse. / Miljökonsekvensbeskrivningar (MKB) genomförs för att möjliggöra att hänsyn om miljön tas vid olika typer av exploateringsprojekt och exploateringsplaner. Syftet med en miljökonsekvensbeskrivning är att identifiera och beskriva direkta, indirekta och kumulativa miljöeffekter. Geografiska informationssystem (GIS) är ett verktyg som kan användas för att snabbt och enkelt kombinera rumslig utsträckning av både känsliga områden och olika miljökonsekvenser. GIS kan därför användas för att underlätta beskrivningar av miljökonsekvenser och motivera olika ställningstaganden. Därigenom kan GIS bidra till bättre grundade och mer rättvisande miljökonsekvensbeskrivningar. Men för att vinsterna av att genomföra GIS-analyser ska överstiga kostnaderna krävs att geografisk information av tillräcklig detaljeringsgrad, aktualitet och säkerhet finns att tillgå till rimliga kostnader. Syftet med denna studie har varit att genom fallstudier undersöka om tre olika GIS-analyser kan användas som verktyg i miljöbedömningar med idag tillgänglig data, samt att utifrån fallstudierna dra mer allmänna slutsatser om vinster och begränsningar av att använda GIS i miljökonsekvensbeskrivningar. De kriterier som har använts för att bedöma vinster och begränsningar är tidsåtgång för analyserna, tillgång på data samt hur analyserna kan vara ett stöd i MKB-arbetet genom att underlätta beskrivningar av konsekvenser, motivera ställningstaganden som görs och öka rapportens begriplighet. De tre genomförda GIS-analyserna innefattar beräkning av föroreningsbelastning inom ett avrinningsområde, bedömning av byggnaders landskapspåverkan genom synlighetsanalys samt generering av förslag till alternativ ledningsdragning för en undervattensledning. Dessa analyser har tillämpats på en pågående MKB för en detaljplan för en partihall och en pågående MKB för en avloppsvattenledning under vatten. Analyserna i fallstudierna har genomförts i programmet ArcGIS med tilläggen ”Spatial Analyst” och ”3D Analyst”. Studien visar att det på grund av osäkerheter i tillgängliga schablonvärden och tidsåtgång för databehandling är osannolikt att beräkning av föroreningsmängd inom ett avrinningsområde med GIS kommer att användas till någon större utsträckning i MKB. Att med GIS genomföra synlighetsanalyser för att utvärdera landskapspåverkan bedöms däremot kunna användas i MKB, både för att bedöma påverkan och för att utvärdera hur en förändring i en byggnads utformning kan förändra den påverkan. Även att med GIS generera förslag till alternativa ledningsdragningar under vatten bedöms kunna fylla en funktion i MKB trots att tillgången på data för att kunna beskriva olika marina områdens naturvärden är klart bristfällig och kopplingen mellan tillgängliga data och verkliga naturvärden är osäker. Denna typ av analys bör ändå minska risken att värdefulla och skyddsvärda marina områden skadas vid lednignsdragning.
880

Avloppsvattenbehandling med membranbioreaktor : En jämförande systemanalys avseende exergi, miljöpåverkan samt återföring av närsalter

Hessel, Cecilia January 2005 (has links)
In the pilot plant at Hammarby Sjöstad, Sjöstadsverket, several new methods are tested in order to achieve a good use of resources. When a new technique is considered it is often the performance of the technique itself, under given conditions, that is evaluated. However, in order to evaluate the overall function the whole picture is needed. With a system analysis it becomes possible to make a comparison where all the positive aspects are put up against the negative ones, for the technique itself as well as its requirements. In this way the influence that minor components have on an entire system can be considered. This report presents a system analysis of an anaerobic membrane reactor (MBR) with a VSEP-membrane (Vibratory Shear Enhanced Process). The MBR is tested at the research treatment plant at Hammarby Sjöstad. In the analysis presented two different treatment techniques treating two different types of wastewaters are compared. The considered techniques are conventional (represented by an active sludge process) and the MBRtechnique. The waters treated are a mixed wastewater and wastewater from a separating system where closet water is separated from greywater and mixed with food waste from waste disposers. The system analysis has been carried out with the URWARE (URban WAter REsearch) system analysis tool. A new URWARE-model that describes the anaerobic reactor and the VSEP membrane was created in order to generate the system structures needed for the analysis. The model consists of two submodels, which as the other URWARE-models are mass-flow, steady-state models based on yearly average-values. The model was tested and calibrated from the test-results at the Hammarby Sjöstad pilot plant. In the study the systems are compared considering energy, exergy and recirculation of nutrients. The VSEP-technique has some advantages compared to the conventional system as it ensures that a large part of the nutritional content in the wastewater can be retained. The advantage is more obvious with the separated system, where food waste is mixed with closet water. Also the global warming potential of the new technique is lower. However, conventional treatment is better from an exergy-perspective. This is mostly due to the high energy consumption as a result of the reversed osmosis (RO) required for post treatment. / I försöksanläggningen vid Hammarby Sjöstad, Sjöstadsverket undersöks flera olika metoder för att uppnå största möjliga resursutnyttjande. När en ny teknik utprovas är det i allmänhet funktionen hos den givna metoden under givna förutsättningar som undersöks. För att få ett helhetsperspektiv krävs emellertid att den sätts in i sitt sammanhang. En systemanalys gör det möjligt att få en bild av alla för- och nackdelar, såväl av tekniken i sig som av de förutsättningar den kräver. Även effekter som små delar har på ett helt system kan då belysas och dess betydelse för helheten fastställas. Föreliggande studie möjliggör en systemanalytisk utvärdering av en anaerob membranbioreaktor (MBR) kopplad till ett VSEP-membran (Vibratory Shear Enhanced Process) som är under utprovning vid Sjöstadsverket. Studien jämför två vattenreningstekniker för behandling av två olika typer av avloppsvatten. Dels rör det sig om konventionell teknik (aktiv slam-rening liknande den behandlingsmetod som används idag), dels den nya MBRtekniken. De vatten som behandlas är blandat avloppsvatten respektive sorterat klosettvatten blandat med matavfall från avfallskvarnar. Systemanalysen har utförts med hjälp av systemanalysverktyget URWARE (URban WAter REsearch). För att kunna bygga upp önskade systemstrukturer har en ny modell för att beskriva den anaeroba reaktorn och VSEP-membranet skapats inom ramen för detta examensarbete. Modellen består av två delmodeller, som liksom övriga modeller i URWARE är substansflödesmodeller där beräkningar är baserade på årsmedelvärden. Modellen har utprovats och kalibrerats mot mätresultat från pilotförsöken vid Sjöstadsverket. I studien jämförs systemen med avseende på energi, exergi och återföring av närsalter. Utifrån systemanalysen konstateras att MBR-tekniken ger vissa fördelar gentemot konventionell teknik då en stor del av näringsinnehållet från avloppsvattnet kan fångas upp. Detta gäller speciellt då tekniken används i kombination med ett separerat avloppssystem där matavfall blandas med klosettvatten. Även växthuspotential för den nya tekniken är lägre totalt sett. Ur exergisynpunkt är konventionell teknik emellertid mer fördelaktig. Till stor del beror detta på hög energiförbrukning pga. den efterbehandling med omvänd osmos (RO) som systemet i dess nuvarande utformning kräver.

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