Periods of hypoxia are a recurring issue in Brunnsviken. Main factors that trigger hypoxia in Brunnsviken are eutrophication  due to anthropogenic emission of nutrients, stratification in the water column due to salinity and temperature differences  that prevents mixing and a sill inlet that prevents water exchange. As an attempt to improve the oxygen levels, bottom water is pumped from Brunnsviken causing aerated surface water to flow back into the basin.  The objective of this Master?s thesis was to study the change in dissolved oxygen levels due to pumping.

Hazel (Corylus avellana L.) is a common feature of meadows and pastures where it can grow in large populations and become very old. Is it possible to use the size of hazel stools for age determination and is it possible to use the size distribution of a population to provide information about how the land has been used? Hazel populations on ground where the lake-water level had been lowered, has been studied to validate an already developed growth model of hazel clones. Different hazel populations, on wooded meadows affected by mowing or grazing or overgrown meadows, were studied to evaluate the method utilizing hazel as land use indicator. The growth model was used to compare the size distributions of hazel populations with historical periods, which has been important for changes in agriculture or demography.

In times of increased flooding, enhanced by climate change, polluted stormwater poses an increased threat to the environment through contaminated water entering waterways. Bioretention utilizes natural processes in soil and vegetation to treat pollutants and combat this threat. Biochar produced through pyrolysis, has a high cation exchange capacity (CEC) and could therefore increase treatment in bioretention systems. This research applies a literature review, interview, and a model to explore the benefits and disadvantages of biochar in order to specify a soil-mix through an understanding of the production process and preferred application rate. High purification through CEC, increased water holding capacity, and carbon sequestration being the benefits discussed.

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).

Drinking water from drilled wells has a high content of iron and other minerals in many places in Sweden. Questions about the association between the quality of drinking water and the health of dairy cows are regulary asked both by advisers and dairy farmers. There are so far not many studies published about the relevance for high iron content in water and dairy cow health and production. Therefore, the aim of this study was to investigate if there is a connection between the iron content in water and the health of dairy cows. Initially a literature study was made about iron and it´s function in ruminants.

This examination work on studies and research in articles is mostly from other countries. The purpose of the examination work have been to find out if there are any means you can work with to find out when its time to start irrigation, how they works and if they are credible. In Sweden there is not many means for decide when it?s time to irrigate and how much water you should appear. Swedish farmers think they have so much experience that they don?t need techniques like this.

The thesis deals with three document retrieval models based on logic: the Boolean model,the fuzzy model and the Van Rijsbergen model.In Chapter 1, the author presents the purpose of the thesis. This is to give the logical foundationof the models, to describe them and to examine them critically. In Chapter 2, some importantnotions in document retrieval are presented. Chapter 3 is devoted to the Boolean model, Chapter4 to the fuzzy model and Chapter 5 to the Van Rijsbergen model.These three chapters are organized in the same way. First, the logical foundation of the modelis given.

Denna rapport beskriver arbetet med utvecklingen av en ny modell för kaplanturbiner. Utvecklingen bygger på två kopplade differentialekvationer som under arbetets gång anpassats och implementerats i turbinmodellen.Modellen beskriver hur vattenflöde och turbinmoment påverkas av avvikelsen från den optimala kombineringskurvan för vinklarna på turbinens ledskena och löphjul, och är anpassad för ett referensaggregat med tillgängliga provdata. Även övriga enheter i vattenkraftaggregatet modelleras och sätts samman med frekvensregulator och elnät för att simulera aggregatets reglerstabilitet i önätsdrift.Verifieringen av turbinmodellen sker genom försök att återskapa de befintliga verkningsgradskurvorna med hjälp av modellen. Resultatet visar en god följning av de verkliga kurvformerna, dock med något lägre maximal verkningsgrad.Verifieringen av önätmodellen sker genom att prova stabiliteten i nätfrekvens och turbineffekt vid stegpålastningar. Resultatet ger en stabilare reglerstabilitet än i verkligheten, men uppfyller ändå förväntningarna på en fungerande modell.This report describes the development of a new kaplan turbine model.

This thesis aims to present the essential background on how to perform climate changeimpact assessments, and to present the results from a climate impact assessment on waterbalance and nitrate leaching for an arable Swedish soil. The soil is a sandy soil in southwesternSweden, grown with spring cereals. This study is meant to be a benchmark example,and cannot be seen as a regional or national assessment for Sweden, rather as an approachto present and analyze the most important parts of these kinds of assessments.A dynamical simulation model (COUP, Jansson and Karlberg, 2004) was used for thisstudy. The model was parameterized and calibrated against data from an experimental site,located in Mellby in Hallands county, south western Sweden. Measurements were carriedout between 1st of April 1988 and 1st of April 1991.

The purpose of this essay is to illustrate the debate of water politics and privatisation of water distribution. My method is debate analysis and qualitative idea analysis and for my essay I used three books that try to persuade the reader that his or her idea is the best for this water crisis. My main question is to illustrate the debate concerning water privatisations. I will also look at the arguments for or against privatisations and finally determine how the authors think the state should act towards this subject. The first book I used was Vandana Shivas ?Water Wars? that when published started an international discussion about the water privatisations.

This report is commissioned by the Water and Sewage Agency in The City of Mariehamn, Åland. The basic aim is to investigate positive or negative effects of a relocation of the sewage pipe from a wastewater treatment plant, Lotsbroverket. The environmental licence of Lotsbroverket is to be revised and The Environmental Appeal Board at Åland?s Government and Administrative Board has made demands that several possible locations in an outer water area should be examined. The present location of the sewage pipe is in Svibyviken, which has been classified as an ?inner water area?.The objective of this work is to study to which extent the nutrient loading from Lotsbroverket influence the environmental conditions in Svibyviken, and to investigate the suitability of different locations of the wastewater pipe from Lotsbroverket.The way a coastal area looks, i.e., its morphometry, determines to a large extent its ecological characteristics.

The European Union is struggling to maintain democracy and tries to increase the participation among the citizens in Europe. The European Citizens? Initiative, ECI, is a platform established by the European Commission to allow citizens to propose new legislation. ?Water and sanitation are a human right! Water is a public good, not a commodity!? is the first ECI that has met the requirements.

The river Bivaröd is one of the river Helgeån tributaries which has the highest and the fastest increase in water colour. The reason behind this increase is unclear but several factors have been suggested to affect this pattern. In this work, I studied the role of land use, iron and precipitation for water colour increase in river Bivaröd for the period 1976 -2011. Data from a field study along with data from SRK for river Helgeån were used for the analyses. The results showed that both water colour and iron concentration increase and that there is a strong correlation between these two variables.

This diploma work covers an investigation over the heat - and hot water systems of thetenant-owner's association, Bogården. The heat - and hot water needs of Bogården aresatisfied by both district heating as well as three heat pumps. Implemented investigationshows that the heat pumps are not used in a profitable way. Apart from that, the reservepossibilities are small. There is also a risk of the growth of Legionella bacterium in thehot water system.Since the heat pumps are already installed, HSB-Gävleborg (responsible for Bogården)has a wish to investigate possible proposed actions for optimization of existing plant.After completed investigation, a new proposed action is presented.

The report begins with a general inventory of possible technical faults in a hydropower plant and of possible fault indicating measurements. Then an investigation is made concerning a few different faults. Based on this investigation a choice on seal box condition and water leakage is made as problem for a more thorough examination, in which it is concluded that the turbine water leakage is larger when the turbine is put into operation. The examination ultimately results in a computer alarm for faults related to the seal box. Finally a few things are mentioned about flow measurement and pressure measurement in relation to the project as a whole..