Emissions of insufficiently treated wastewater, mainly blackwater (i.e. wastewater from toilets), contributes to the eutrophication of lakes and seas. At the same time, blackwater is a fraction with a low content of heavy metals and, after sanitization, it can recirculate plant nutrients to arable land using the liquid composting treatment method. Liquid composting means that organic material is degraded under aerobic conditions. For sanitization, the blackwater needs to be treated together with energy-rich complementary material. A requirement for the sanitization in a liquid compost is that the substrate is energy rich, that the energy content is high enough and that the material is well dispersed and pumpable. The aim of this master thesis has been to find appropriate complementary material for treating blackwater in the wet compost treatment plant located in Karby, Norrtälje municipality, Sweden. An inventory was made of the organic waste produced in Norrtälje municipality and two nearby municipalities. Samples of the organic waste were collected and analysed for dry matter (as an indicator of energy content), plant nutrients, heavy metals and biochemical oxygen demand (BOD7). The suitability and availability of different organic waste fractions as complementary material was decided upon analyses results, calculations of estimated amounts of organic waste as well as some assumptions. Food waste is a relative clean fraction with a high energy content that would be a good complementary material for liquid composting. Fruit, vegetables and bread from stores are also clean fractions, but the availability is uncertain and depends on different factors. Based on results from this project, grease from grease trap is an uncertain fraction that is not recommended for complementary material for the liquid compost. The results show that Norrtälje municipality has enough organic waste to make it possible to use the whole capacity of the liquid compost plant in the future and to treat larger quantities of blackwater than today. The quantities of blackwater that can be treated are uncertain because a number of assumptions have been made and also because availability varies between different fractions of organic waste. Before it will be possible to add new organic waste fractions and more black water into the liquid compost plant, some kind of pretreatment plant is needed.

<p>Wastewater treatment is increasingly controlled by the Swedish environmental quality objectives, adopted by the Swedish parliament. There is a need for a sewage system that can fulfill stringent requirements concerning the environment, recycling and resource use and hygiene. Additional environmental aspects in recent years are the impact of climate change, new knowledge about the effects of pharmaceuticals in water, the need for improved wastewater treatment and increased recycling of nutrients to agriculture.</p><p> </p><p>This report has, from a future scenario of the year 2050, analyzed seven different systems for wastewater treatment and treatment of compostable biowaste from households in Eskilstuna. A future scenario was chosen based on that within a forty year period new challenges may arise which can result in higher demands on sewage treatment than those we see today. Another reason why the future scenario was established is that changes in wastewater treatment systems are slow to establish.</p><p> </p><p>The analysis is mainly focused on the economical aspects but environmental aspects such as emissions to receiving waters and potential recycling of plant nutrients has also been evaluated briefly. The economical analysis was made from a new construction perspective. The economy model is constructed in Microsoft Office Excel and named URWARE Eko. The report also includes a section based on results from previous system studies.</p><p> </p><p>A target image of Eskilstuna 2050 was initially created. Seven systems were then analyzed based on this target image. The seven different systems could be divided in to three main categories: conventional sewage system that were modified, source separated blackwater systems and a sewage plant with improved treatment technology in the form of membrane technology and reverse osmosis.</p><p> </p><p>The results showed that it differed a factor of 1.9 between the cheapest system (sludge recovery to productive land) and the most expensive (separated blackwater treated in a central treatment facility). All systems have a big recycling potential of phosphorus. Blackwater systems and wastewater plants with membrane technology and reverse osmosis are the best systems for recycling of other nutrients such as nitrogen, potassium and sulfur.</p><p><em> </em></p>

Wastewater treatment is increasingly controlled by the Swedish environmental quality objectives, adopted by the Swedish parliament. There is a need for a sewage system that can fulfill stringent requirements concerning the environment, recycling and resource use and hygiene. Additional environmental aspects in recent years are the impact of climate change, new knowledge about the effects of pharmaceuticals in water, the need for improved wastewater treatment and increased recycling of nutrients to agriculture.   This report has, from a future scenario of the year 2050, analyzed seven different systems for wastewater treatment and treatment of compostable biowaste from households in Eskilstuna. A future scenario was chosen based on that within a forty year period new challenges may arise which can result in higher demands on sewage treatment than those we see today. Another reason why the future scenario was established is that changes in wastewater treatment systems are slow to establish.   The analysis is mainly focused on the economical aspects but environmental aspects such as emissions to receiving waters and potential recycling of plant nutrients has also been evaluated briefly. The economical analysis was made from a new construction perspective. The economy model is constructed in Microsoft Office Excel and named URWARE Eko. The report also includes a section based on results from previous system studies.   A target image of Eskilstuna 2050 was initially created. Seven systems were then analyzed based on this target image. The seven different systems could be divided in to three main categories: conventional sewage system that were modified, source separated blackwater systems and a sewage plant with improved treatment technology in the form of membrane technology and reverse osmosis.   The results showed that it differed a factor of 1.9 between the cheapest system (sludge recovery to productive land) and the most expensive (separated blackwater treated in a central treatment facility). All systems have a big recycling potential of phosphorus. Blackwater systems and wastewater plants with membrane technology and reverse osmosis are the best systems for recycling of other nutrients such as nitrogen, potassium and sulfur.

Ett stort antal bristfälliga avlopp i Sverige bidrar till övergödningsproblematiken och behöver åtgärdas, ett särskilt problem i omvandlingsområden. Om kretsloppsanpassade avlopps-system implementeras när dessa åtgärdas utnyttjas avfallet som en resurs och näringsämnena återförs till jordbruksmark. För att åstadkomma denna systemförändring och uppnå ett fungerande kretslopp krävs acceptans hos och involvering av användarna. På grund av att tidigare forskning till stor del fokuserat på de tekniska aspekterna med avloppssystemen, finns ett behov av att utreda hur kommunikation med användarna bör ske och hur den är relaterad till acceptans. Syftet med studien är därför att genom en fallstudie förstå hur kommunikation kan bidra till användares acceptans för ett nytt avloppssystem samt att ta fram en kommunikationsplan för användning vid införande av kretsloppsanpassade vatten- och avloppssystem. Studien bygger på en dokumentstudie samt intervjuer med ansvariga för en kretsloppsanpassad systemförändring och boende i området där förändringen genomförs. Data analyseras kvalitativt och en SWOT-analys av det kretsloppsanpassade systemet genomförs. Studien kopplar samman acceptans, kommunikation och lärande, främst genom ett ramverk som bygger på att kommunikation kan påverka medvetenhet och intresse, förståelse, attityder, intentioner och handlingsutlösning. Resultatet visar att systemets olika aspekter och kommunikationen kring dem, kan utgöra både hinder och möjligheter för acceptans. Genomtänkt och välplanerad kommunikation anpassad efter målgruppen och med fokus på motiven bakom förändringen, kan dessutom minska motstånd och möjliggöra att information hos individen blir till kunskap, som i sin tur kan öka acceptansen. I studien belyses även att demografiska faktorer påverkar acceptansen, men svårligen låter sig påverkas av kommunikation, vilket tyder på att acceptans är både komplext och individuellt / A large number of insufficient on-site wastewater treatment systems in Sweden are contributing to the problems with eutrophication and are therefore in need of replacement. This is especially a problem in transition areas, where former summer house areas are becoming permanent. By implementing nutrient recycling systems in these areas, the waste is utilized as a resource and the nutrients are recycled as fertilizer. In order to achieve this system change and close the nutrient loop, social acceptance is necessary and the users need to be involved. Since previous research has focused mainly on technical aspects of wastewater systems, there is a need to investigate how communication with users should be handled and the relation between communication and acceptance. The aim of the study is therefore to, through a case study, understand how communication can contribute to user acceptance of a new wastewater system and to develop a plan for communication in nutrient recycling waste water projects. The study consists of a document study, interviews with professionals responsible for a nutrient recycling system change as well as interviews with residents affected by the change. Data is qualitatively analyzed and a SWOT-analysis of the system is conducted. The study connects acceptance, communication and learning through a framework stating that communication can affect awareness and interest, understanding, attitude, intention and readiness to act. The result shows that aspects of the system and communication regarding them can work either as an obstacle or as an enhancer of acceptance. Strategic communication adapted for the targeted group and with a focus on the motives for change, can also reduce resistance as well as facilitate learning, which in turn is needed for acceptance. The study also discusses acceptance related factors which are hard to affect with communication. Hence, the study concludes that acceptance is both complex and individual.