One of the environmental problems today in seas, lakes and streams is eutrophication. This is often caused by nutrients such as phosphorus (P) and nitrogen (N) that leak from agricultural areas. A measure to partly prevent the nutrient discharge is to construct or restore wetlands.In order to control the efficiency of nutrient reduction of existing wetlands in the county, the administrative board in Västra Götaland wants to find different criterias for reference wetlands. These reference wetlands should represent other wetlands and be used in future evaluations of reduction of nutrients and design of constructed wetlands. According to the administrative board in Västra Götaland the reference wetlands should have a catchment area of about 50 hectare consisting of at least 70 % arable land, to represent wetlands created to remove nutrients.

Considering water quality, landuse and reducion of wetland area in the watershed of Tidan, areas witch are in need of constructions to improve the water quality are identified. Constructions are suggested to be located within the smaller streams in the watershed, so that the water is treated before it reaches the stream Tidan..

Water logistics has long been a problem in order to effectively carry out stump treatment in both thinning and final felling. It is important that the stump treatment? equipment is configured as well as a sufficient amount of water is carried out on the harvester to get a cost? effective treatment. The flow control of the equipment has improved and water can be dispensed more efficient, but still the amount of water on the machine is a crucial factor in the total cost estimate. The knowledge of the tools available to bring water as well as the internal logistics of loading and transport to the felling site is deficient. Increased focus on "smart" solutions to manage water cost is of great importance in order to combat Hetrobasidion spp in both thinning and final felling. The purpose of the study is to describe and summarize different solutions of water logistics at stump treatment in final felling.

Considering water quality, landuse and reducion of wetland area in the watershed of Tidan, areas witch are in need of constructions to improve the water quality are identified. Constructions are suggested to be located within the smaller streams in the watershed, so that the water is treated before it reaches the stream Tidan..

Regulation of rivers by dams and reservoirs is a good example where anthropogenic impact could be considerable both in the local environment, but also has major implications upstream and downstream. This study was accomplished as a literature study of the river Nile, which is extremely important for water supply. The purpose of this study was to investigate the consequences of the construction of the Aswan High Dam, to obtain a consistent flow for water supply, irrigation and power generation in Egypt. Since Egypt has a very hot and dry climate large amounts of water in reservoir is lost to the Nubian aquifer system and by evaporation. The consequences from constructing the dam are considerable.

The aim of this study was to develop a load prognosis model for Uppsala district heating system to be used as a tool for heat production optimization. The methodwas to build three models for the different customer types; housing, industry andoffices and then scale them for the total system using data from Uppsala districtheating system. The heat load consists of two parts, one that is temperaturedependent and one that is dependent of the social behavior of the customers. Thetemperature part was modelled with an ARX model using an outdoor temperatureprognosis as input signal. The social behavior part was modelled using the mean ofthe social behavior from some days before and additionally by distinguishing betweenweekdays and weekends.

It is important to construct or recreate different types of wetlands and study their retention of nutrients, since knowledge of their effectiveness in this matter is poor. In 2003 a wetland was constructed on an old meadow on the western shore of Lake Bornsjön in central Sweden. The main purpose of the wetland was to reduce the amount of phosphorus entering the lake, which is the back-up water supply for Stockholm when the city cannot obtain water from Lake Mälaren. Large areas around Lake Bornsjön consist of agricultural land and the nutrient concentrations in the inflows to the lake are usually relatively high (approx. 1 mg/l total nitrogen and 0.05-0.1 mg/l total phosphorus).

Storm water causes a number of problems in our country, particularly in city environment with its surfaces of non-absorbing ground materials. At heavy rain falls there are floods due to lack of capacity in the drain system when meeting heavy water masses over a short time. When the drain system is overloaded huge water masses reach the recipient untreated and there causing disturbances in the aquatic ecosystem. Due to emissions from mainly traffic, industries and other human activities the storm water is polluted. Earlier the problem used to be solved technically, by increasing the capacity of the tubes and by construction of reservoirs to delay the floods peaks.

Water is an essential factor for both people and animals, and access to water is therefore of great importance. The water access also largely determines the availability of food for people and feed for animals. The aim of this study was to survey the affect of water access on milk production from dairy animals. The study included nineteen farm visits that were made in the Nyando district in Kenya between February and Mars 2011. Farm visits included interviews with questions about for example number of dairy animals, milk production, water access, feed and water routines.

The purpose of the thesis was to map the hydraulic load on the Knivsta river from stormwater runoff, and build a platform for further studies of pollution loads on the rivers ecosystems. New residential areas are planned to be built in Knivsta municipality and it will have an impact on stormwater flows to Knivsta river. To examine the impact this will have, simulations were made in the area as it stands today and after expansion work. The work includes calculation of flows from the populated areas but also from the catchment area around it consisting of woodlands and fields. Because of expected climatic changes which may affect rainfall, the simulations have been performed with different return periods for rainfall data.

Hammarby Sjöstad is a new district in southern Stockholm. A main objective with the Sjöstad project was to halve the environmental impact compared to other construction work. The environmental goals involve a halved water consumption rate, a local treatment of storm water and trials aiming to extract nutrients from the waste water. Sjöstadsverket is an experimental treatment plant used for testing new treatment processes for domestic waste water from Hammarby Sjöstad. The results are to be compared with the conventional process used at Henrikdals treatment plant today.

Nanofiltration is a proper way of preparation of drinking water. The process has a lot in common with reverse osmosis where a semipermeable membrane is used to separate a pure water flow from the remaining water. A pilot plant was used to ensure that nanofiltration is a suitable technology for a specific waterworks station in Glemmingebro, Ystad. The purpose was also to find out if a pH-adjustment is needed for feed water in a possible full scale plant.  In this case nanofiltration is used mainly to remove sulphate and calcium since the raw water contains concentrations of these substances which exceed the limits for potable water. It is important to receive a high recovery (RC), otherwise the deliviery of water won?t be high enough.

The purpose of this thesis has been to develop a tool for modelling and simulating the nuclear plant Ringhals 3. The model should be used to improve the knowledge on the dynamics of the plant. Ringhals 3 is being upgraded to produce more power and a tool for analyzing the new operating conditions is needed.The work in this thesis has consisted of improving and developing an existing model of Ringhals 3 made with the modelling tool Dymola. The model has been validated by comparing the results of a simulated house load transient with data from the actual plant. Validation shows good agreement with data from the real plant.

The last decades have shown increased nitrogen leeching from soil to water recipients. This is inSweden mainly due to over-manuring of agriculture land, effectivization of drainage systems and thedeclining extent of wetlands. The accumulated amount of nitrogen in water doesn?t only make itunsuitable for use by humans and cattle, but also decreases the biological diversity as well as negativelyaffect tourism and fish industry. In the most severe cases shallow maritime grounds can be completelydepleted of oxygen due to decomposition of the increased amount algae and plankton growth.This study have the aim to describe and quantify the nitrogen leeching from the Genevad drainagebasin, located in southern Halland, Sweden.

Arlanda airport is Sweden?s largest airport. The demand for comfort cooling of the airport?s buildings is high and is mainly provided by district cooling. District cooling is based on the same principle as district heating.