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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.
81

Installation av grundvattenrör för användning inom undervisning

Forsgård, Maria January 2012 (has links)
Den dokumenterade nyttan med att undervisa på ett varierat vis har gjort att Uppsala universitet vill ge sina hydrologistudenter möjlighet till mera fältarbete. Detta skall göras genom att installera grundvattenrör i vilka grundvattnets nivå samt kemiska sammansättning kommer att undersökas. Detta ställer krav på att området där rören installeras har en sådan geologi och topografi så att fältarbetet blir givande. Därför eftersöks områden med egenskaper som ger variationer mellan rören. Variationer i grundvattennivå förväntas främst uppkomma av olika lagerföljder eller en lutande markyta. Variationer i grundvattnets sammansättning förväntas främst bero på huruvida man befinner sig i ett inströmnings- eller utströmningsområde. Efter en undersökning av grundvattenrör i fyra redan existerande fältområden konstateras det att flera av dessa besitter några av de eftersökta kvaliteterna. Därför kommer ett av dessa områden att utökas med flera nya rör. Det valda området ligger i Marsta cirka 10 kilometer norr om Uppsala. Marsta har flera fördelar, exempelvis en variation när det gäller lagerföljder som skapar möjligheter att jämföra grundvattennivån mellan rören och diskutera resultaten. Vidare kommer en grundvattenrörsinstallation i nämnda område att gynna flera aktörer vilket ytterligare ökar nyttan. Efter en genomförd marknadsundersökning väljs företaget Zublin Scandinavia AB till att utföra installationerna. I framtiden kan flera av de andra undersökta områdena komma att bli aktuella för användning eller utökning. Då kan denna sammanställning användas för att ge grundläggande fakta om platserna och rören. / The documented benefits of teaching in a varied manner have motivated Uppsala University to provide hydrology students with the opportunity of having more fieldwork. This will be done by installing groundwater tubes in which the groundwater level and the chemical composition will be studied. This requires that the area where the tubes are installed possesses such a geology and topography so that the field work is rewarding. Areas with features that provide variations between the groundwater tubes are therefore sought. Variations in the groundwater level are expected primarily to depend on different stratigraphies or sloping land surfaces. Variations in groundwater composition are expected to mainly depend on whether the sampling sites are located in a recharge or discharge area. After having performed an investigation of ground water tubes at field sites that already exist, it is concluded that several of them possess some of the desired qualities. Therefore one of these areas will be expanded with several new tubes. The chosen area is in Marsta, about 10 kilometers north of Uppsala. Marsta has several advantages, such as a variation in stratigraphy that creates opportunities to compare the groundwater level between the pipes and discuss the results. In addition, an installation of groundwater tubes in the region mentioned above will most possibly benefit more people, which further increases its usefulness. A marketing study was performed and the company Züblin Scandinavia AB was chosen to carry out the installations. In the future, more of the other investigated areas may be considered for use or extension. This compilation will then be used to provide basic facts about the areas and the groundwater tubes.
82

Anaerobic digestion of biological sludge from the pulp and paper industry

Karlsson, Robin January 2009 (has links)
The need for - and use of non-fossile fuels such as biogas have increased due to global warming, oil depletion and stricter environmental regulations. Organic wastes can be anaerobically digested in order to produce biogas, which can be utilized to generate heat or electricity. So far, little attention has been directed towards anaerobic digestion of organic wastes from the forest industry. Due to high sludge management costs and more rigorous environmental legislation, the demand for new and/or improved disposal methodologies has increased. Substrate treatment methods such as enzyme addition and ultrasound are of interest in order to make anaerobic digestion of organic wastes, e.g. biological sludge, economically feasible. The aim of this study is to evaluate if biological sludge from the pulp and paper industry can be used for methane production in anaerobic digestion and to investigate the effects of ultrasound pre-treatment and enzyme treatment. The aim of the study was accomplished by performing four batch experiments, during 67-110 days, and a six months laboratory-scale semi-continuous digestion experiment. Substrates were provided by a chemical and a mechanical paper mill, whereas Kemzymes® from Kemira and ultrasound equipment from Ultra Sonus were used for sludge treatment. The short term average accumulation of methane per added g VS rate increased both when ultrasound pre-treatment and enzyme treatment was applied in batch experiments. The enzyme treatment was considered to have a greater potential in larger scale and was consequently used in the semi-continuous digestion experiment. Positive effects of the treatment were however difficult to prove. Adapting the enzyme treatment to be more specific for the degradation of the sludge is recommended. It is possible that there are inhibitory interactions between ultrasound pre-treatment and enzyme treatment. 75% ultrasound pre-treatment is an alternative to complete pre-treatment and renders equivalent average accumulation of methane per added g VS. Storage of ultrasound pre-treated biological sludge at 4°C for six and 13 days does not affect the average accumulation of methane per added g VS. Enzyme treatment of biological sludge enhanced the average accumulation of methane per added g VS from indigenous material in the inoculum. It is likely that anaerobic digestion of biological sludge from the pulp and paper industry can render a stable biogas production. High viscosity and agitation problems were predominant in the semi-continuous digestion experiment and can be difficult to control in larger scale. The results from the semi-continuous digestion experiment are similar with those obtained from the batch experiments. The methane production rates in this study are lower (biological sludge from chemical pulp process) or higher (mechanical ditto) in comparison to those presented data by Puhakka et al. (1992). Different types of biological sludge were used and might explain the prevailing differences.
83

Livcykelanalys av golvvård : En jämförande studie av Twister™-metoden och golvvårdsmetoder med polish och vax / Life Cycle Assessment of floor care : A comparative study of the Twister™-method and floor care methods using polish and vax

Larsson, Henrik January 2009 (has links)
I dagens samhälle finns det en stor variation på golv och golvmaterial. Till dessa finns det en stor variation av de produkter och metoder som används för att hålla dessa golv funktionsdugliga. Samtliga golv och produkter ger upphov till miljöpåverkan av olika storlek och sort. Denna studie är skriven på uppdrag av avdelningen för industriell miljöteknik, Institutionen för ekonomisk och industriell utveckling (IEI) Linköpings Universitet, som vill veta vilken miljöpåverkan Twister™-metoden har. Detta sker genom en livscykelanalys. En livscykelanalys ställer en produkt eller tjänst miljöpåverkan utifrån helhetsperspektiv innefattande materialframställning, tillverkning, användning och resthantering. Som hjälp i denna studie har programvaran SimaPro 7.0 använts vari metoden Eco-indikator 99 valts. I studien ställs Twister™-metoden mot andra golvvårdsmetoder innefattande polish och vax. I analysen sker även en nedbrytning av Twister™-metoden likväl en nedbrytning av den Twister™-rondell som HTC Sweden AB tillverkar. Resultatet visar att den del av Twister™-metoden som har störst miljöpåverkan är den skurmaskin som används och den energianvändning som Twister™-metoden kräver. Resultatet visar även att Twister™-metoden har signifikant lägre miljöpåverkan än de andra golvvårdsmetoderna polish och vax. De delar av Twister™-rondellen som har störst miljöpåverkan är de industridiamanter och den rondell, som Twister™-rondellen består av.
84

Comparing C, N and P concentrations in soils in agricultural verus natural land, and across climates

Classon, Agnes January 2016 (has links)
How do concentrations of C, N and P vary between agricultural and natural land?How do C, N and P concentrations vary between climate zones? Soil organic carbon (SOC),total nitrogen (TN) and phosphorus (TP) as well as microbial C, N and P (MBC, MBN andMBP respectively) concentrations in soils were collected through a literature review, andstudied to analyze the differences between agricultural land-use and natural land, and betweendifferent climate zones. The minimum concentrations of SOC, TN, MBC, MBN and MBP werefound in the agricultural soils and the maximum concentrations in natural soils. The minimumTP concentration was the same for the two land types but the maximum concentration wasfound in agricultural soils. The mean concentrations of MBC, MBN, MBP, SOC and TN weresignificantly lower in the agricultural land than in the natural land.The highest concentrations of soil and microbial C, N and P were found in the tropical wetclimate, in the highlands, in the midlatitude climate with high temperature variations, and in themarine west coast climate. The results show that: 1. rainfall and mild to warm temperaturescould increase nutrient concentrations; 2. northern latitudes and highlands have high stocks ofnutrients, and 3: Humid subtropical climates are probably more exploited to humans due toagricultural productivity which decreases nutrient concentrations.The results clearly show the loss of nutrients following cultivation, and the importance ofresearch of nutrient status in soils; for global soil and water quality issues, for a sustainableagricultural production and for ecosystems.
85

The Effects of Erosion-control Structures and Gully Erosion on Groundwater Dynamics Along the Kromrivier, Eastern Cape, South Africa

de Haan, Vincent January 2016 (has links)
The Palmiet wetlands located along the Kromrivier in the Eastern Cape province of South Africa have experienced severe degradation through gully erosion during the past decennia which has been threatening the water quality and water security of large towns in the Nelson Mandela Metropolitan hub. Water scarcity is a growing problem in this region as a result of land degradation and growing erratic rainfall patterns. The main causes of wetland degradation are argued to be land use and land cover change. With the aim of protecting the wetlands along the Kromrivier a total of eleven large gabion and concrete erosion-control structures were constructed between the 2002 and 2013 by the government initiate Working for Wetlands. This study aims to map the groundwater table in order to derive how erosion-control structures and gully erosion affect groundwater dynamics along the Kromrivier. This was achieved by several steps. Firstly, water table elevations were measured along several transects by installing a series of piezometers which allowed do investigate how the structures affected the water table. This also allowed for a comparison in groundwater dynamics between eroded and non-eroded reaches so that effects of gully erosion could be identified and potential causes discussed. Secondly, the analysis of aerial images allowed for the development of the aerial extent of the Palmiet wetland and gullies to be seen over a ten year period and longitudinal profiles provided specific characteristics of the wetland and gullies. Lastly, particle size distribution and organic matter content were analyzed as groundwater flow and gully erosion can vary greatly depending on soil characteristics. The hydraulic gradient was highest in proximity to the structures as a result of the created potential induced by the drop in surface water elevation. The radius of influence to where the structures were affected the water table was estimated to be approximately 40 m from the channel. Further away from the channel, the gradual slope of the water table indicated that the porous gabion side walls of the structures did not affect the water table. The groundwater flow is determined by Darcy's Law and the relatively flat water table along the non-eroded reaches of site A displayed local drainage points, thereby indicating variations in the local flow direction. In May the water table along the non-eroded reaches was sloping away from the channel resulting in an area of groundwater discharge with respect to the channel. Not only was the water table generally higher during August, the regime had also changed, indicating a potentially large seasonal variability. Along the eroded reaches downstream from the structures the water table was above the gully bottom during both months resulting in an area of groundwater recharge with respect to the channel. Also here the regime had changed from an approximately constant hydraulic gradient sloping towards the channel during May to a water table with a divide in flow direction. Since their implementation in 2003, the structures have been effective with respect to preventing the headcut in the main channel from migrating further upstream. However, the gullies downstream of the structures had significantly increased in width between 2003 and 2013 and the Palmiet wetland had also slightly decreased in size during the same period. However, it was unclear whether this decrease was part of the longer term ongoing trend or part of a shorter term cycle and/or seasonal fluctuation. For a gully bank to collapse, the shear strength of the slip surface needs to be exceeded and this often occurs because of an increase in pore water pressurewhich causes a reduction in shear strength. A large gully height of up to 4 m with nearly vertical slopes, a water table above the gully bottom and an increase in moisture content between May and August indicated that it is not unlikely that a high pore water pressure. played a significant role in the slumping of the gully walls. The two structures together were responsible for an surface water elevation difference of 7.76 m. Through damming this resulted in an elevated water table in the upstream Palmiet wetland, thereby increasing the saturation and promoting diffuse flow across the wetland. However, the structures also trap most of the sediment in upstream direction which appears to have resulted in the de-stabilization of the downstream streambed at site A as these eroded reaches now receive a significantly lower sediment load. By increasing the retention volume in the wetland, the structures also facilitated in ensuring flood retention as the wetland could now hold more water during high flows, thereby cutting off the peak flow. As gully erosion is known to occur during periods of high flow it is not unreasonable to argue that slumping of the gully walls would have been more severe without the structures in place. In this sense the structures increase the water quality and decrease the flux of sediment where the latter leads to a decrease in the sedimentation rate of the downstream Churchill Dam. Consequently, this contributes to securing the fresh water supply to towns in the Nelson Mandela Metropolitan hub. The discovery of Palmiet rests up to 2.6 m below the surface indicated that cycles of gully erosion followed by the re-establishment of Palmiet have been occurring in this valley for thousands of years. However, it seemed that land use and land cover changes had accelerated gully erosion during the past decades resulting in a loss of Palmiet wetland at a rate which was beyond 'natural'. Even though the structures could be seen as disruptions of long term natural cycles, they are in favor of the well-being of mankind as they protect the wetlands to a certain extent. The main results of this study provided a basic understanding of how the water table behaves in response to the structures and along eroded and non-eroded reaches of the Kromrivier. Furthermore, this study discussed the larger scale affects of the structures and showed how the gullies and the aerial extent of the Palmiet wetland have evolved since the implementation of the structures in 2003. In order to manage these Palmiet wetlands more effectively in the future, it is highly important that groundwater dynamics, gully erosion and the size and health of the wetland are annually monitored in order to get a more accurate idea of how effective these structures are. This new obtained knowledge could also assist in managing other peat lands in South Africa more effectively.
86

Concentrations and riverine massflows of geothermal arsenic. : Case study: Jemez River, NM, USA / Koncentrationer och massflöden av geotermal arsenik. : Fallstudie; Jemez River, NM, USA

Hansson, Lina January 2016 (has links)
Geothermal arsenic (As) and its inorganic species transformation in river systems are of global concern, since As has a potential negative impact on human health and ecosystems. Periods of increased precipitation may change As concentrations and As partitioning in streams, due to elevated water tables, increased runoff generation, dilution, and interactions with sediment.In this study we investigate hydrological conditions of Jemez River, located along the Jemez fault in NM, USA, during the monsoon months June, July and August of 2015. We aim at determining how different hydrological conditions in the Jemez River during the monsoon months might affect the concentrations and riverine mass flows of geothermally derived (total) As and As III discharging in a travertine- and hot spring area called Soda Dam. Water and sediment from the river and hot springs sites, as well as streamflow measurements along a 22 km river reach were collected. The chemical composition of water and sediment was determined using Inductively Coupled Plasma-Optical Emission Spectrometry/Mass Spectrometry (ICP-OES/MS); and Ion Chromatography (IC) as well as a High Performance Liquid Chromatograph (HPLC) coupled to an ICP-MS for further water analysis. Discharge and mass flows as well as element inputs and outputs to/from Soda Dam was computed. The measurement months were characterized by a median discharge of 1642 L/s. During the measurement campaigns peak flows occurred with discharges of 2.5×104 to 6.1×104 L/s during the measurement campaigns. Arsenic concentrations were between 1.3 and 107 μg/L in river water, between 167.3 and 6707 μg/L in hot spring waters, and between 0.37 and 13.1 μg/kg in river bed sediment. Arsenic III was found in hot springs water and river water. Infiltration and subsurface flows induced by fault-associated fractures and permeability structures were found to be likely to divert water at Soda Dam, as reflected in large discharge differences along the reach (470 to 1305 L/s). These flows also had an impact on As concentrations in riverine and hot spring water since they mobilize As from bedrock and sediment. Changing mass flows of As can only in a few cases be explained by dilution processes by Jemez River, which has previously been assumed to be the main control on As mass flows along the stretch. Instead, our findings are likely to reflect changes in chemical composition of the mixed geothermal waters discharging at Soda Dam, due to changing mixing ratios of ground waters of different compositions. The present study hence provides a refined interpretation of the hydrological pathways in Soda Dam and Jemez River, and calls for more discharge and geochemical investigations during a longer study period, to properly investigate the driving forces behind the fate of the As from geothermal fluids.
87

Undersökning av näringsläckage till akvatiska miljöer : Kartläggning av näringsstatusen i vattenmiljön för området kring Byssträsket, Lycksele kommun

Larsson, Simon January 2015 (has links)
During the summer of 2013 the environmental office at Lycksele Municipality received a complaint, regarding algal blooms at the stream outlet between the lakes Kalven and Byssträsket in the southern parts of Lycksele Municipality. No deeper studies were made to ensure what could have caused the bloom. The purpose of this report was to examine if there was a specific source contributing to high levels of nutrients in the stream, mainly focusing on clear-cuts and a small dam by the stream inlet, and if the nutrient status differed along the stream flow. Therefore, suitable sites were picked for examination, following the stream flow between the two lakes, and in a stream not affected by clear-cuts for reference. Water samples were picked at each site, determining the status of the parameters total-nitrogen, total-phosphorus, nitrate, ammonium, pH and conductivity. The result showed quite high levels of total-phosphorus (ranging from 40-50 µg/l) and total-nitrogen (ranging from 350-450 µg/l), but low levels of ammonium and nitrate. The results showed no sign of a nutrient input from a specific location. The conclusion of this study is that the present nutrient levels could be high enough to result in a bloom, though probably dependent on contributing factors, such as warmer weather and lower water levels. An alternative explanation is that the nutrient levels could have been higher 2013, deriving from new clear-cuts, but that these clear-cuts stopped leaching nutrients due to older age. Hence, due to lack of previous studies no exact assumption can be made
88

Impact of irrigation development and climate change on the water level of Lake Urmia, Iran

Beygi, Heydar January 2015 (has links)
Lake Urmia, located in the north-west of Iran, is one of the largest hypersaline lakes in the world. In recent years, there has been a significant decrease in the lake’s area and volume by 88% and 80% respectively. An integrated water balance model of the Lake Urmia Drainage Basin (LUDB) and Lake Urmia was developed to identify these main drivers of the significant changes, and to investigate the possible future evolution of the lake under effects of projected climate change and land use change. We used an energy balance method to estimate the evaporation from the lake and the Turc-Langbein method to estimate the evapotranspiration from the drainage basin of the lake. Agricultural irrigation water was introduced to the model as an extra precipitation over the irrigated fields, after being subtracted from the surplus runoff (precipitation−evapotranspiration). The agricultural land development was assumed to be linear that changed from 300000 ha at 1979 to 500000 at 2010, which is consistent with the best available data on the actual irrigation development in the basin. We estimated the annual evaporation over the Lake Urmia and the evapotranspiration over its drainage basin as 932 mm and 287 mm respectively. Our results showed that decreased precipitation and increased temperature over the basin since 1995 could explain 68% of the observed lake level decrease. Irrigation developments during the last four decades were found to be responsible for 32% of the observed lake level decrease. Thus the future lake level of the Lake Urmia is very likely to continue to decrease unless the current climate condition will be followed by a period of increased precipitation. If the current climate conditions will prevail also in the future, even a 20% decrease in the irrigated land area, which is actually quite ambitious, will not make the lake recover to its ecological level at the end of 2020.
89

Water budget estimation on a data limited wetland : The case of the Ciénaga Grande de Santa Marta, Colombia

Hylin, Anna January 2014 (has links)
At the end of the 20th century, the combination of climatic and anthropogenic events resulted in hyper salinity conditions in the coastal wetland Ciénaga Grande de Santa Marta (CGSM), Colombia. Although salinity concentrations are generally related to the type and quantity of water entering and exiting a wetland and to its internal hydrological dynamics, there have been no up to date hydrological studies on the CGSM. Here we show how a water budget can be used as a first-order of approximation to describe the CGSM's hydrology, despite data limitations. We collected hydroclimatic data to calculate and analyze the fluxes of water entering and exiting CGSM and their corresponding uncertainties. We find that the water budget is mostly affected by the precipitation regime, a result connected to studies of regional El Niño/La Niña effects. Scenario analyses show that contribution of freshwater from the streams coming down from the Sierra Nevada Mountain Range on the eastern side of CGSM is currently larger than that of the channels draining from Magdalena River to the west, in contrast to the general focus on the western side. However, Monte Carlo simulations suggest that the eastern freshwater inflow is insignificant in affecting the hydrological response of CGSM. These results outline the need to (1) increase understanding of the internal connectivity and circulation of CGSM and (2) further investigate the effect of agriculture on the eastern side of CGSM.
90

Geostatistical analysis of the Gorran water protection area in Nynäshamn municipality

Zedek, Rfet Alla Ali January 2014 (has links)
Groundwater level models have an important role in the development and application of water management and policies. Understanding the temporal and spatial variations of groundwater levels in the Gorran water protection area in Nynäshamn is important for developing management strategies. Geostatistical analysis with several different methods was used to compare groundwater level records for 13 observation wells in Gorran from 1994 to 2012. The performance of the different methods was evaluated by using mean absolute error (MAE) and root mean square error (RMSE) metrics. The results showed that geostatistical methods had a higher general accuracy when utilizing the Empirical Bayesian kriging (EBK) method in Gorran. EBK was the best method with highest precision and lowest mean absolute error. Cross-validation was also applied to evaluate the best (smallest) root mean square error (RMSE). A predicted potentiometric groundwater level was estimated from the basis of the available digital elevation model to extend the observation area within the same geological specification. / Grundvattennivåns modeller har en viktig roll i utvecklingen och tillämpningen av vattenförvaltning och politik. Genom att förstå de tidsmässiga och geografiska variationer grundvattennivån i Gorran skyddat område är viktigt för att utveckla hanteringens strategier.Geostatistical analys med olika modeller som Inverse Distanse Weighted, Radial Basic Funktion och kriging modeller användes för att jämföra grundvattennivåns rekord under 13 observations brunnar 1994 till 2012. Prestandan hos metoder utvärderades med hjälp av medelabsolutfelet (MAE) och rot medelkvadratfelet (RMSE). Resultatet visade att geostatistiska metoder hade högre noggrannhet och Empirical Bayesian kriging (EBK) var den bästa metoden med högsta precision och lägst medelabsolutfel. Cross-validering applicerades också för att utvärdera de bästa minsta kvadratiska medelvärdet (RMSE). Förutsatt potentiometrisk grundvattennivå genomfördes från digital höjdmodell för att förlänga observations område inom samma geologiska specifikation.

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