Because of the increasing trends in energy consumption and increased environmental awareness, greater focus has been placed on improvement and development of renewable energy sources. An already proven and accepted method is biogas production from anaerobic digestion at municipal wastewater treatment plants.In the waste water treatment process solid material and dissolved pollutants are separated from the water, forming a sludge. The sludge is separated from the process and stabilized during anaerobic digestion or aerobic aeration. Most often, mesophilic anaerobic digestion is used. Because of degradation by microorganisms, biogas with a high content of methane is formed during the digestion.

This master thesis sets out to compare the different public transport modes in Stockholm city.Both energy consumption and air pollution are compared. The chosen transport methods are car,bus and metro.Traditionally the rail industry has had environmental arguments as a strong competitiveadvantage when it comes to passenger transportation. However, in recent years the automotiveindustry has been getting more positive media attention regarding environmental issues, forexample Roger Kemp?s statement that the car is the most environmental friendly passengertransportation mode in the UK. This study will show the environmental advantages of railwaytraffic in cities.The energy sources of the world are not endless and the use of the different sources affects theenvironment in different ways.

Background and problem discussion: Sustainability reporting has recently risen in importance and a rising number of companies choose to issue voluntary stand-alone sustainability reports. Their non-regulated nature increases the opportunity for management to angle the information in these disclosures to their own advantage. Lately the focus has shifted from examining what kind of information is provided in environmental disclosures, to analyzing how the information is presented.Purpose: The purpose is to examine if managers in the energy sector use optimistic tone when issuing sustainability reports. The aim is to find out if the tone applied in environmental disclosures is in congruence with either the environmental or economic performance or if an excessively positive tone is being used to mislead readers.Limitations: This study is limited to information found in environmental disclosures from private companies in the energy sector, issued in 2012 or 2013. Environmental performance is defined as the amount of CO2e emissions and economic performance refers to annual company revenues.Methodology: The quantification of optimistic tone is conducted using a content analysis, relying on a pre-specified wordlist and a pilot study.

The idea for the project emerged when Nilorn wanted to get better control over their supplychain and improve operational efficiency. The company also want to reduce their expenses inthe continuous process of improving profitability. By choosing the right option oftransportation and mode of transport there are large potential savings for the company. Thisenables Nilorn to reduce the transportation costs and strengthen the environmentalresponsibilities by reducing their environmental impact.The flow of goods within Nilorn has over the past years increased significantly and most ofthe gods today is transported by air. The aim of this thesis is to analyse the supply chain of thecompany and evaluate the potential economic savings in this area.

Today most ice rinks in Sweden use secondary refrigeration systems with a solution of calcium chloride and water as secondary refrigerant. Due to the large amount of energy such a system uses more efficient systems would be desired.An earlier study concluded in the possibilities of using carbon dioxide as secondary refrigerant with copper tubes as the loops in the ice rink. Since then 3 ice rink refrigeration systems has been built with carbon dioxide in copper tubes. Excluding the ones being direct involved in those projects there is still very little knowledge about how these system works. This study has been made primarily with the aim of adding to the knowledge concerning availability and cost and secondary to look at possibilities for improvement.A comparison between systems with carbon dioxide, calcium chloride respective ammonium solved in water has been made by using Decision Matrix.

In this report a study is carried out with the aim to identify added values of EPC projects implemented in schools in order to increase the interest of EPC projects on the market. The report examines how the planned maintenance, supervision, maintenance and corrective maintenance is affected, how insurance premiums and terms are affected, the indoor environment and how the tasks of the operating staff is changing. A literature study of energy savings, energy use in schools, maintenance and insurance as well as how energy efficiency improvements are related to the Swedish environmental objectives has been made. Visits were carried out in Ludvika, interviews were also carried out with operation technicians and local strategists in Ludvika as well as employees of insurance companies.Schools often have neglected maintenance and problems with ventilation and indoor environment. Schools also have a large energy saving potential due to their low utilization, mainly because they are empty parts of the year.

Like many small-time companies there is a need to improve the flow of materials at HSP-Gripen AB. The company develops and manufactures hydraulic-powered grapples for the machine- and forest industry. By mapping the material flow in the current production and gathering necessary data, suggestions on how different parts of the production could be controlled is presented in this dissertation. This has been achieved by the study of relevant scientific literature. The suggested ways of controlling the production consist of 2-bin systems, hybrid material flow system as well as a cyclic product-planning.

The idea for the project emerged when Nilorn wanted to get better control over their supplychain and improve operational efficiency. The company also want to reduce their expenses inthe continuous process of improving profitability. By choosing the right option oftransportation and mode of transport there are large potential savings for the company. Thisenables Nilorn to reduce the transportation costs and strengthen the environmentalresponsibilities by reducing their environmental impact.The flow of goods within Nilorn has over the past years increased significantly and most ofthe gods today is transported by air. The aim of this thesis is to analyse the supply chain of thecompany and evaluate the potential economic savings in this area.

The idea for the project emerged when Nilorn wanted to get better control over their supplychain and improve operational efficiency. The company also want to reduce their expenses inthe continuous process of improving profitability. By choosing the right option oftransportation and mode of transport there are large potential savings for the company. Thisenables Nilorn to reduce the transportation costs and strengthen the environmentalresponsibilities by reducing their environmental impact.The flow of goods within Nilorn has over the past years increased significantly and most ofthe gods today is transported by air. The aim of this thesis is to analyse the supply chain of thecompany and evaluate the potential economic savings in this area.

A clean and affordable energy source for cooking is deficient in developing countries. People rely on fuels that contribute to environmental, social and health problems.Biogas is an alternative energy source and an increased investment in small-scale biogas production can in several developing countries be found. Several projects have started to use the technology in developing countries because of the benefits with biogas. Some cases in the establishment of biogas plants have succeeded and some have not. The study is a literature review supplemented by two field studies.

The idea for the project emerged when Nilorn wanted to get better control over their supplychain and improve operational efficiency. The company also want to reduce their expenses inthe continuous process of improving profitability. By choosing the right option oftransportation and mode of transport there are large potential savings for the company. Thisenables Nilorn to reduce the transportation costs and strengthen the environmentalresponsibilities by reducing their environmental impact.The flow of goods within Nilorn has over the past years increased significantly and most ofthe gods today is transported by air. The aim of this thesis is to analyse the supply chain of thecompany and evaluate the potential economic savings in this area.

A clean and affordable energy source for cooking is deficient in developing countries. People rely on fuels that contribute to environmental, social and health problems.Biogas is an alternative energy source and an increased investment in small-scale biogas production can in several developing countries be found. Several projects have started to use the technology in developing countries because of the benefits with biogas. Some cases in the establishment of biogas plants have succeeded and some have not. The study is a literature review supplemented by two field studies.

There is always a need for more effective ways to store energy in order to reduce the human impact on the environment. One step on the way can be the use of flywheels as kinetic energy storage devices. Low frictional losses are essential for a flywheel to be effective. To minimize these losses active magnetic bearings (AMB) can be used to keep the shaft centered instead of the more conventional ball-bearings. AMBs use actuators and a fast control system that needs correct and noise-free measurement data of the shaft position and the current in the actuators to work properly.This thesis explains the process of constructing power electronics and a current measurement system for active magnetic bearings (AMB).

The aim of this study was to investigate whether a dietary change, physical activity or a combination of both gave the best result when treating obesity, concerning weight loss and BMI. Excessive weight and obesity are today a big health-issue and it is estimated that 10 % of the men and 12 % of the women in Sweden have a BMI over 30, i.e. are suffering from obesity. The corresponding number for children is 3 %. No one can say for sure what causes obesity but there are many theories.

The idea for the project emerged when Nilorn wanted to get better control over their supplychain and improve operational efficiency. The company also want to reduce their expenses inthe continuous process of improving profitability. By choosing the right option oftransportation and mode of transport there are large potential savings for the company. Thisenables Nilorn to reduce the transportation costs and strengthen the environmentalresponsibilities by reducing their environmental impact.The flow of goods within Nilorn has over the past years increased significantly and most ofthe gods today is transported by air. The aim of this thesis is to analyse the supply chain of thecompany and evaluate the potential economic savings in this area.