Society has depended on fossil-based fuel for a long time, which has led to a fundamental increase of greenhouse gases in the Earth?s atmosphere. To tackle this problem the international community has agreed that action is necessary. Focus is now directed towards local extraction of energy from renewable sources such as biogas.Utö is participating in the Green Island project, which aims to investigate the possibility of making the island climate neutral. This report has been implemented on behalf of Skärgårdsstiftelsen, the main partner responsible for the Green Island project in Sweden.

Sewage sludge contains plant nutrients and has earlier been utilised as fertilizer to cropland. Unfortunately not only plant nutrients but also heavy metals, pathogens and organic contaminants tend to accumulate in sludge. The suitability to use sewage sludge in agriculture has therefore been subject to several discussions over the years. The Swedish food industry does no longer accept sludge as fertiliser for Swedish producers. In 1999 the Swedish parliament accepted several objectives for environmental protection. In order to prevent environmental pollution and further exploitation of the earth crust, one of these objectives confirm that phosphorous from sewage shall be recirculated to arable land.

Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off.

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.

The aim of this study was to in laboratory experiments investigate how addition of urea, ECOX and structural materials can optimize sanitization during composting of sewage sludge. Today we strive for a sustainable society and the importance of closing the nutrient loop increases. It has therefore become even more important to safely reuse plant nutrients from human excreta to agricultural land. Partly because it increases the sustainability of society as the world's supply of many nutrients are finite, partly because it promotes human health, both by reducing disease transmission and by increasing Agricultural production. An untapped resource such as sewage sludge that is rich in nutrients and humus-forming materials could replace parts of the commercial fertilizers used in Sweden today. owever, sewage sludge contains undesirable substances such as heavy metals and drug residues, and pathogenic microorganisms.

Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off.

The purpose of this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

The purpose of this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

The purpose of this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

The purpose of this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

The purpose of this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

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 this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

The purpose of this degree-project was to investigate the possibilities for primary air preheating into the two smallest waste incineration boilers of Halmstad Energy and Environment. The investigation is a pre-study which has the primary goal to evaluate technical and financial offers from companies that manufacture primary air preheater, and investigate if it is technically and financially profitable to do a purchase on primary air preheaters in the future.In the pre-study it is proposed that it is most efficient to have individual primary air preheater, one for each incineration boiler and the primary air are also proposed to be preheated by hot water in the pre-study. Further in the pre-study it is proposed that the heat-exchanger should have plain tubes instead of finned tubes, to avoid getting dirty fast. The space in the boiler-room is limited, and therefore the major problem was to fit in the primary air preheaters into the boiler-room. By comparing the different offers from the companies, the result in the pre-study shows that the offer from the company C.A.

The purpose of this essay was to identify the primary stakeholder in aid organisations, by which we mean whom they make their annual report for, and to analyse if there were any differences considering the design of their annual reports depending on which their primary stakeholder is. The method we used to explain the choice of primary stakeholder and the differences in the annual reports was a multiple case study. The collected data came from telephone interviews with 23 representatives from aid organisations and a review of annual reports. The results were analysed through pattern matching. We found that aid organisations do not have a primary stakeholder as in incorporated organisations.