Bringing back the nutrients from the city to the country is becoming increasingly important, as the world?s stores of nutrients get more exhausted. Sewage sludge is an unapplied resource, rich in plant nutrients, which could replace parts of the commercial fertilizers used in Sweden today. Sewage sludge may contain large amounts of pathogens, such as Campylobacter and Salmonella, why use can cause severe spreading of infections, both to animals and humans. These pathogens have the ability to survive for a long time in soil and water and therefore some sort of treatment of the sludge is recommended before use.

The purpose of the project has been to work out recommendations that reduce the energy-related costs and environmental impact of HPW Fresh & Dry Ltd., a fruit drying factory in Ghana. The factory produces electricity with diesel and biogas but also purchases electricity from the national electricity company. Heat for the drying process is produced from biogas, kerosene and solar panels. In the project the energy system was analyzed by measuring production and consumption of heat and electricity. The project results show that the factory can become self-sufficient on heat if the available energy is used more efficient. The production units for both electricity and heat have low efficiencies.

Individual cellulose ?bers were studied to identify the transport and absorbtion phenomena as well as the in?uence of drying. A Chalmers University of Technologydeveloped method within ESEM (Enviromental Scanning Electron Microscope) has been used in this study. The results from the laborations gave the following conclu-sions: The transport of water occurs in ?bers in the ?ber wall surface and the lumen.

Göteborg Energi has a surplus of district heating during spring, summer and fall. The heat surplus is due to a constant production of waste heat from oil refineries and heat from waste incineration over the year. It would be desirable to increase the demand for heat and the uptime for the newly built combined heat and power generation plant, Rya Kraftvärmeverk. One alternative could be to integrate Rya Kraftvärmeverk with a pellet production facility. By producing heat, electricity and pellet in a joint process the energy use can be decreased.

The purpose of this study has been to make an inventory of combustible waste in the region around Norrköping and to investigate the composition of domestic waste, industrial waste and two different types of sludge. The work was performed at the request of Norrköping Miljö & Energi, due to the planning of an incineration plant. The inventory of the waste was performed through inspection of environmental impact reports, from waste disposal plants in a number of local government areas in the region. The quantities were also compared to another inventory, carried out in a different way. The characterisation of the wastes was compared to the fuel specification determined by Norrköping Miljö & Energi.

This thesis describes the redesign ofequipment designed for drying bags thatis used in Fresenius Kabis´manufacturing of their nutritionmedicine in Uppsala. The need of thistask arise during the start of thedevelopment of a new packaging line werethis equipment were meant to be used. Anevaluation of the bagdryers capacity andcapability was necessary.The work started with gathering ofinformation from suppliers of the usedcomponents and from the responsibleengineers for this equipment. Aneducation to learn how the equipmentworked and how to operate it were taken.That was followed by the creation of astudy plan were the tests were plannedto test different parameters effect onthe drying result and to see if thebagdryer managed to handle the bags ofthe correct format in the pace that theequipment should be designed for.The test results detected a need ofdesigning a unit with a function thatholds the bags in place while passingthrough the dryer in order to attainhigh quality results. The results werelater used for optimization of thedesign.

Timber floating operations in Scandinavia during the 19th and 20th centuries has contributed to severe negative impacts on riverine ecosystems. Increase in water velocity and lack of stream bed heterogeneity as a result of stream channelization lead to increased bed load transport. Since availability and recruitment of new suitable spawning substrate in Scandinavian watercourses is sparse, spawning habitats for salmonids has become a scarce commodity. Lately, increasingly more attention has been given to the recreation and improvement of brown trout (Salmo trutta) spawning habitats in restoration projects. While much of the research on spawning habitat has been focused on evaluation of the influence that the constructed spawning grounds have on fish populations, few studies have been conducted to evaluate the persistence of these constructions over time. I evaluate erosion of constructed spawning beds as an effect of sediment transport attributable to water discharge.

The corn plant came to Europe with Christopher Columbus in the 14th century and have ever since bin cropped here, but corn haven?t bin very common in Scandinavia until recently. The mainly use for this crop silage but even corn for grain is cropped in Europe. Corn for grain is a common part of feed in beef and chicken farming. In Sweden corn for grain is pretty rare but almost 1000 hectares are used for this crop, Lantmännen Sverige is the biggest buyer of corn at the moment.

The goal of this master thesis project was to develop computer models of some plausiblepretreatment techniques and to assess the potential benefits/costs of using pretreatment andanaerobic digestion for waste management of organic waste from a system perspective. Forthis purpose a computer program called ORWARE has been used. ORWARE (organic wasteresearch) is a program for making life cycle assessments of waste management. As the mainpart of the project work the ORWARE system has been provided with three new models ofpretreatment techniques. The additions consist of: One model of pretreatment with ultrasound,one model of thermal hydrolysis and one model of a screw press.

Hammarby Sjöstad is a new district of southern Stockholm built with focus on reduced environmental impact by recirculation of materials and sustainability. The environmental goals aim to cut the water consumption by half and a separate storm water treatment. Thus, the wastewater will be more concentrated and will originate from the households only. The Sjöstad project includes the idea of a local treatment plant for the household wastewater. To evaluate this possibility, Sjöstadsverket, an experimental treatment plant was constructed.

In the next few years the pollutants loading at the Slottshagen wastewater treatment plant in Norrköping is going to increase due to the reason that one of the waste water treatment plant in the district will be shut down.A survey of how these different pollutants are divided in the treatment process is therefore necessary for mapping out both the loading and treatment efficiency.This can be achieved by studying mass balances.Mass balances were carried out for the water treatment process for the mechanical/chemical,biological and the chemical stage.The mass balance studies show that the treatment efficiency was very good. However in order for the mass balances to be quite consistent and to ensure complete coverage of results and conclusions i.e. more reliable results, sludge samples should be collected and taken at different times per day and the influent rate should be investigated.In this work mass balance has been set up in order to illustrate and identify the factors that should be considered and taken care of for further estimation using mass balances in the future. Furthermore this survey results in a calculating model for the mass balances at thisplant.This calculating model is used as a tool to facilitate future calculations for mass balances for the water treatment process at Slottshagens wastewater treatment plant.Moreover it provides a basis for carrying out further estimation of the treatment process in the near future.In this project the importance of some operating parameters was also taken in consideration.This calculating model can be modified so that calculations of such operating parameters i.e. sludge loading and sludge age can be easily performed.Such information can be used further to evaluate different operation alternative in order to ensure an optimal use of the treatment process with in the plant..

Hallsta paper mill uses large amounts of water during the pulp and paper making processes. The wastewater is treated in two separate activated sludge processes referred to as BIO 1 and BIO 2. The main aim is to reduce the organic substance content, measured as COD (Chemical Oxygen Demand) before the wastewater is released into the environment. Since the effluent produced is very rich in organic substances, the addition of nitrogen (N) and phosphorus (P) are necessary to give satisfactory treatment results. Problems with sludge bulking sometimes occur which lead to increased levels of suspended matter and nutrients in the effluent.

Biogas is a renewable energy source that is produced by anaerobic digestion of organic mate-rial. In Sweden, biogas predominately comes from sewage water sludge and landfills or from organic waste of households and industries. Small scale digestion plants at farms are espe-cially expected to contribute to increased biogas production in the future. Biogas can be ob-tained directly in it?s raw form and used as fuel in a combustion chamber.

This thesis describes the redesign ofequipment designed for drying bags thatis used in Fresenius Kabis´manufacturing of their nutritionmedicine in Uppsala. The need of thistask arise during the start of thedevelopment of a new packaging line werethis equipment were meant to be used. Anevaluation of the bagdryers capacity andcapability was necessary.The work started with gathering ofinformation from suppliers of the usedcomponents and from the responsibleengineers for this equipment. Aneducation to learn how the equipmentworked and how to operate it were taken.That was followed by the creation of astudy plan were the tests were plannedto test different parameters effect onthe drying result and to see if thebagdryer managed to handle the bags ofthe correct format in the pace that theequipment should be designed for.The test results detected a need ofdesigning a unit with a function thatholds the bags in place while passingthrough the dryer in order to attainhigh quality results. The results werelater used for optimization of thedesign.

The purpose with this study is to compare different systems of grain storage from a financial point of view. Grain that is supposed to be fed to laying hens. The systems that were compared were different airtight storage of grain and a system of conventional storage. To make this case study I choose to compare four different systems. In the case study there was one system with bin drying of the grain, two systems with airtight storage of the grain and one system where you buy dried grain during the season. I made several of capital investment appraisal where I found the cost of each system, then I took the cost and divided it with the total grain use and calculated the cost for each kilogram of grain, and also the cost of the feed. Then I compared the cost from my case study with the cost of buying feed. All the systems except for one, gave a lower cost for the hen feed than buying feed from a dealer The best system, witch were bin drying lower the cost with about 80 000:- SEK.