AbstractThe purpose of this study is to find out how pupils give expression of a water cycle model and if the model causes any misunderstanding. Two problems constitute the starting point for this investigation. The first question is: how do the pupils explain the water cycle with the help of the jar model (can of glass). The other question is: can the children see any similarities between the can of glass and our earth. Qualitative semi structured interviews with seven pupils in the ages of 8-9 have been used to show the pupils? own thoughts and how they express them.

In Sweden there are 1894 small-scale hydropower plants in operation, which together generate 4.3 TWh of electricity per year according to Swedish hydropower compound (SVKF, 2011). This corresponds to the annual consumption of about 860,000 Swedish households (based on an annual consumption of 5000 kWh). In the mid-1950s there were around 4000 small-scale hydropower plants in operation in Sweden before cheap fossil fuels and uranium competed with them, in the current situation only 1,894 of these are in use. If slumbering small hydropower plants once again would be taken into use and some new ones are built, we would be able to extract about 7 TWh of renewable electricity from these annually in Sweden, representing about 1.4 million households.The thesis intends to calculate and construct a hydroelectric power plant at the existing dam in Olofsfors and give suggestions on how the power station should run during the time that fish migration is greatest in Leduån.The turbine and generator to the station in Leduån at Olofsfors is designed by the height of the fall and the water flow through the dam. The turbine selected for the station is a CK-1000RM turbine with a 4-pole 250 kW generator from Cargo & power turbine Sweden AB, which is expected to deliver 1.2 GWh per year.

Global warming is a huge issue that humans have contributed to through over-exploitation of natural resources and extensive usage of fossil fuels. Now more than ever, we need to embrace a recycle thinking and reuse our waste, for example through producing biogas from our food waste. The purpose of this report was therefore to identify the energy usage and emissions resulting from the biogas chain which spans from Solna Stad to Uppsala Vatten. Furthermore, potential efficiency improvements were to be identified and proposed. This report focused mainly on the first part of the biogas chain that includes the collection of the food waste and the reloading process.

Turbiditet är ett mått på partikelinnehåll i dricksvatten samt ett sätt att beskriva vattenkvaliteten. Vattentäkten i Gäddvik, Luleå kommun, har periodvis hög turbiditet. Syftet med examensarbetet är att utreda orsaker till turbiditet i dricksvatten, från Gäddviks vattentäkt till konsumenter i Luleå kommun. Målet är att ge svar på vilken typ av partiklar som orsakar turbiditen. Analyser utfördes före och efter filtrering av dricksvatten.

Mosquitoes are found in extremely large numbers in the lower parts of the River Dalälven. In the year 2000 the mosquito nuisance was especially high, resulting in foundation of the Biological mosquito control project. Since 2001 mosquito larvae are controlled by using a biological pesticide BTI (Bacillus thuringiensis ssp israelensis). The mosquito fauna in the area is dominated by flood water mosquitoes, a group of mosquitoes that are very aggressive and form new generations of mosquitoes during every single flooding event during the summer. To be able to efficiently control the mosquitoes it is essential to know the extension and locality of the flooding.

This thesis raises the problem with acid mine drainage around the closed mine Finngruvan.The purpose of the investigation was to compare metal content in surface water in the areaand its catchments between year 2010 and 2003, also to make calculation of specific runoffand metal load, furthermore determine the recipients in the area. Surface water samplingwhere preformed at the same place as 2003 and also at a few other places of interest. Adigital elevation file were used in GIS to calculate the area of the watersheds in the region,observations in the field where also made. The collected data were used to make comparisons,calculations and conclusions. The result showed that the surface water 2010 had somewhatlower metal concentrations.

The purpose with this thesis is to analyse different factors that can explain district heating prices for energy companies in Sweden. We are further interested in examining if the prices is affected by the use of industrial waste heat in their production and the company?s ownership structure. The method applied is a multiple regression analysis using a panel data set of 50 companies over 5 years (2008-2012). The data used is yearly data obtained from the Swedish district heating association.

In recent years, existing solutions for cooling personal computer CPUs have been supplemented by a new product category, factory sealed water cooling loops. These systems, consisting of a water block with an integrated pump, a fan and a radiator, perform well compared to the air cooling solutions but are less effective than larger, custom-built water cooling systems.This project aims to explore the most important aspects of a factory sealed system and to identify possible cost-effective enhancements of the performance.The most significant differences between the different groups of water cooling loops are the block design and the pumping power. The performance of both categories is also largely dependent on the fan power, but increasing fan power has a large negative impact on the noise level.Both radiator size and fan model choice appear, in tests, to be relatively unimportant, presuming that the noise level is kept constant. The position and direction of the fan, however, has significant impact on both the temperature and the sound level.Water blocks can be designed in several different ways, both regarding the heatsink design and the flow direction. In simulation, flow with the inlet centered above the heatsink result in considerably lower pressure drop and slightly higher temperatures than flow through the block, for heatsinks with fin arrays.Creating a competitive product in this product segment certainly seems possible, as there are performance-increasing changes to be made that seemingly has little impact on the production cost.

The purpose of this thesis has been to determine experimentally how good a peltierelement is to convert waste heat from wood burning. Three different peltier elementswere used in a comparison study. The comparison was mainly done to know howmuch power could be obtained from each element. Even, a circuit with a step-upfunction has been created to give a higher output voltage than the peltier elementitself. The result of the experiments was a low output power, the highest valuereached 2.18W.

In this study is being examined how cities can be planned in the face of rising water levels and extreme weather, due to the changing climate. The starting point has been to investigate how the problems can be tackled and how the positive sides of water in the city can be strengthened, and synergy effects and greater sustainability be achieved thereby. The method has been literature studies and case studies containing interviews and visits. Göteborg, Kristianstad and Arvika have been studied for discussions and ideas about adaptation. Today, building near water is very popular which brings both advantages and disadvantages.

Each year, the coffee machines at Ericsson in Kista produce around 100 tons of ground coffee waste.The companies Coor Service Management, Löfbergs Lila and Selecta are all responsible for differentstages in the logistical chain in delivering coffee and, together with Ericsson, they want to increasetheir environmental benefit. The plan is to produce biogas through anaerobic digestion instead ofincinerating the coffee waste in a heating plant. The results are to be presented as different businesscases in which different biogas plants are compared with the reference case (heating plant),comparing costs and environmental impacts.There are two major environmental benefits from producing biogas; reduced carbon dioxideemissions from when fossile fule is replaced by carbon neutral biogas, and reduced emissions fromreturning digestate from the bio reactor to farmland instead of using industrial fertelizer.In order to determine the biogas potential in coffee waste, a couple of properties had to bedetermined in a laboratory. Properties such as the dry substance content, heating value, moisturecontent and ash content. The results show that 100 tons coffee waste could produce around 16 500Nm3 biogas which would contain 163 MWh.The biogas reactor and upgrade plant both need energy gas to function and uses around 14 MWh ofthe produced gas.

The access to good sanitary facilities is an important factor that elevates the experienced living standard as it improves hygiene and reduces the transmission of deseases. The ratification of the millennium goals by 189 countries demonstrates that this is an important international issue. Together the countries have taken upon themselves that the proportion of the population that lacked access to sustainable safe drinking water and sanitary facilities in the year 2000 will have been reduced by half by the year 2015. In Peru, the construction of sewage pipe networks to transport the sewage out of the direct human environment is progressing. The safety and sustainability of these systems can be questioned, since in Peru the sewage seldom receive any treatment before being emitted to a recipient. This is taking place in Picota and sorrunding villages as well. In the last 25 years several systems implementing small-scale onsite treatment have been introduced throughout Latin America in an attempt to give more people access to sustainable and safe sanitary facilities, reducing water consumption and taking advantage of the agricultural values of the sewage fractions while protecting the environment from its negative impact. In this study three different sanitary systems and the effects of different population growths were compared.

Severe floods caused by heavy autumn rains in year 2000 raised the question whether measures to reduce the damage from high water levels, in the area surrounding lake Glafsfjorden and along the river Byälven down to lake Vänern, are possible. One option is to reduce flow resistance along the river and thereby lower the maximum water level a given inflow would cause. Good knowledge of hydraulic and hydrological conditions is necessary in order to estimate the effect of such flow-reducing measures. In order to quantify such effect a 1-dimensional hydraulic flow model has been set up for the river Byälven using the software package MIKE 11. The model is more detailed, especially concerning topography and bathymetry, than earlier models used for studies of the river.

Increasing attention is being given to acid sulphate soils wherever they occur. The problems that leaching sulphate soils gives with significant lowerings of pH and mobilization of heavy metals influence large spectra of our society from fisheries to agriculture to construction. Mapping these soils is consequently of great importance and the methods of doing this is very much lacking in function and precision. This study was therefore carried out to investigate whether conductivity in running water can be used as a simple instrument to identify acid sulphate soils in the catchment. 31 coastal streams in the county of Västerbotten were analyzed for different catchment properties such as occurence of marine sediments and basic water chemistry including conductivity and sulphate.

Drain water heat recovery is an uncommon measure in multi-unit residential buildings. There istechnology available for the purpose but the knowing and experience of the heat recovery systems islittle. The purpose of this thesis is to evaluate the future potential of drain water heat recovery inmulti-unit residential buildings.A major part of the multi-unit residential buildings in Sweden were built during modernismen andrekordåren (1940?1975). Many of the buildings have worn out drain and water supply systems andmany are in need of a general refurbishment.