One of the biggest upcoming challenges to the international community is the problem of a changing climate. The earth’s surface temperature is rising and associated impacts on physical and biological systems are increasingly being observed. Science tells us that climate change will bring about gradual changes, such as sea level rise, and shifts of climate zones due to increased temperatures and changes in precipitation patterns. A changing climate affects the entire world but will strike hardest against the poorest as they are the ones most dependent on agriculture which is a sector that is very vulnerable to changes in temperature and precipitation patterns. One region that will be especially vulnerable and has experienced the problems of shifting climate zones before is the Sahel region that borders to the south end of the Sahara desert where problems of desertification have occurred before. This region will in large extent be affected if the Intergovernmental Panel on Climate Change’s (IPCC) predictions of a rising temperature will become a reality. This is one of the reasons why I have chosen Burkina Faso, situated in the south end of the Sahel region, as the objective for my MFS. The question of rising temperatures will be especially important here as the region is very sensitive to differences in temperature. A crucial topic in this part of the world as well as the topic of this study is the process of adapting to the new climatic situation.

To facilitate the process of setting up small scale environmental models in coastal and offshore areas a wave model and a 2D current model for the Baltic Sea have been set up with MIKE 21. The ambition is that the Baltic Sea model can serve as a source of boundary conditions for local models. The main focus in the project has been to determine which input data to use to get the best results and then to calibrate and validate the model with the best data sets available. The wave model has been tested with three different sources of wind forcing and the results with the different sources are evaluated. The wave model has been calibrated and validated against five wave buoys and the current model against three current observation stations. The comparison shows that the wave model gives good estimations of wave height, period and direction. The output of the current model coincides with observations where distinct current patterns exist. The wave model is considered a good source to extract wave statistics from for the entire Baltic Sea. The current model can be used for scenarios or areas that do not suffer from the limitations of a 2D model.

There is an extended concern for how to quantify the fluxes of greenhouse gasses (GHG) and how they are related to climate change and land use. Efforts have already been done, mostly regarding carbon (C) compounds, but there is still much to be done especially to understand regulating factors and interactions with the Nitrogen cycle. NitroEurope is a large project for the integrated European research into the N cycle. This study shares its aim, to improve the understanding the physics involved in the fluxes of the reactive N (Nr). More specifically, the patterns of some physical and biological processes related to Nr have been studied for two wetlands, one in the proximity of Edinburgh and the other in the North of Finland.   A common model setup has been used for both of them, since they are both peat soils. The differences applied to achieve appropriate performances give insights of their nature. The presence of snow is a major factor that governs the behavior of the site in Finland. The scaling of existing models for the estimation of heat transfer in the soil of the Scottish site is also critical, such as its groundwater level. The sites represent different climatic conditions, but for CO2 fluxes they showed similar behavior and response to governing meteorological conditions. Using the GLUE method in combination with a process oriented ecosystem model, some further insights have been gained for the regulation and control of greenhouse gas emissions from the two sites.

Sewage sludge is treated with the biological process of anaerobic digestion in which organic material of a substrate is degraded by microorganisms in the absence of oxygen. The result of this degradation is biogas, a mixture mainly of methane and carbon dioxide. Biochemical Methane Potential tests are used to provide a measure of the anaerobic degradability of a given substrate. This study aims to determine the methane potential in Sjöstadsverket’s sludge this will moreover determine the viability of recycling the digested sludge back into the anaerobic system for further digestion. Batch digestion tests were performed in both Sjöstadsverket’s (S1) and Henriksdal’s (H2) sludge, for a reliable comparison. An inoculum to substrate ratio of 2:1 based on VS content was used and BMP tests presented results that S1 and H2 in the 20 days of incubation produced 0.29 NLCH4/gVS and 0.33 NLCH4/gVS respectively. A second experiment considering the same amount of substrate (200ml) and inoculum (200ml) for each sample, showed that Control S1 had a higher methane potential than Control H2, 0.31 NL/gVS and 0.29 NL/gVS respectively. All the samples containing Sjöstadsverket’s inoculum presented a higher volume of total accumulated gas (measured in Normal Liters), however methane potentials are low. Results demonstrated that methane production in samples S1 and Control S1 was originating from the grams of VS in the inoculum itself after depletion of all the soluble organic material in the substrate. This suggested that Sjöstadsverket’s sludge can endure a higher organic load rate and that the digested sludge still has potential to produce biogas, hence the recycling of this can enhance the biogas production in the digestion system.

Manganese compounds have a high potential for treating wastewater, both for utilizing its oxidation, flocculation ability and catalyst ability in anaerobic nitrification. The promising use of manganese compounds (such as permanganate and manganese dioxide) is regarded as an effective method of treating organic compounds in wastewater from municipal and industrial wastewater. Now it is newly realized possibilities to combine manganese compounds with Microbial Fuel Cell technology. Aiming at reusing the biomass in anaerobic digested sludge for degrading organic pollutants and simultaneously recovering electric energy, Single-chamber Microbial Fuel Cell (SMFC) system was developed and investigated during the main experimental part. Considering the electricity generation rate and characteristics of cathode, MnO2 was used as the reactant on the cathode electrode; meanwhile, the substrate types in anode compartment also were investigated and then extra sodium acetate was added to investigate the power generation performance. Two parts of the research were carried out during the whole project. The chemical treatment part was mainly designed to find out the best dosage of KMnO4 in flocculation when concurrent reacted with magnesium and calcium compounds when treating reject wastewater from digester at Hammarby Sjöstadsverk. The other part was studied to see whether it is possible to improve electricity generation by degrading organic pollutants when MnO2 was used as a cathodic reactant in sediment microbial fuel cell which consisted of anaerobic digested sludge from UASB.

The management of the organic fraction of municipal solid waste has become a major issue lately in the province of Québec, Canada. Most of it is landfilled today, which increases the burden on landfills and is environmentally unsound. In order to comply with new government guidelines, municipalities have to develop solutions to recover and recycle organic waste. In this context, this study examines two solutions for treating organic waste: home-composting and a separate biodegradable waste collection system combined with large-scale composting. The two scenarios are compared in terms of costs and environmental performance to a reference scenario where all waste is landfilled, using as a case study a fictional city of 50 000 inhabitants. Results indicate that a centralized collection system, combined to large-scale composting, has greater environmental benefits than home-composting. It cuts greenhouse gas emissions by 240% compared to the reference scenario, while emissions from home-composting remain at the reference level. However, when compared to the reference scenario, home-composting reduces waste management costs by 15% while they represent an increase of 4% with large-scale composting. The study concludes that separate biodegradable waste collection combined to large-scale composting is the best way for a municipality to achieve high environmental goals, despite a slight increase of municipal costs. The participation rate of citizens is suggested to be a crucial parameter for the success of organic waste management in the two scenarios and it should be enhanced by different means to ensure the successful implementation of the chosen solution.

Microbial fuel cell (MFC) has become one of the energy-sustainable technologies for wastewater treatment purpose in the recent years. It combines wastewater treatment and electricity generation together so as to achieve energy balance. By inoculating microorganism in the anode chamber and filling catholyte in the cathode chamber, and also with the help of a proton exchange membrane (PEM) between them, the MFC can transfer protons and produce power. Microbial desalination cells (MDC) are based on MFC’s structure and can fulfill desalination function by the addition of a middle chamber and anion exchange membrane (AEM). This study focuses on ammonium removal and electricity generation in MDC system. Mainly two types of liquid were tested, a solution of Hjorthorn Salt and filtrated supernatant. The experiments were performed at Hammarby Sjöstad research station and laboratory of Land and Water Resources department, Stockholm. It consists of a preparation stage, a MFC stage and a MDC stage. Until the end of MFC stage, biofilm in the anode chamber had been formed and matured. After that, solutions of different initial concentrations (1.5, 2.5, 5, 15 g/L) of Hjorthorn Salt and also filtrated supernatant have been tested. Ammonium removal degree can be obtained by measuring the initial concentration and cycle end concentration, while electricity generation ability can be calculated by voltage data which was continuously recorded by a multimeter. Results showed that this MDC system is suitable for ammonium removal in both of Hjorthorn Salt solutions and supernatant. The removal degrees in Hjorthorn Salt solution at desalination chamber were 53.1%, 52.7%, 60.34%, and 27.25% corresponding to initial NH4+ concentration of 340.7, 376, 376 and 2220 mg/L. The ammonium removal degrees in the supernatant were up to 53.4% and 43.7% under 21 and 71 hours operation, respectively. In power production aspect, MDC produced maximum voltage when potassium permanganate was used in the cathode chamber (217 mV). The power density in solutions of Hjorthorn Salt was relative low (46.73 - 86.61 mW/m3), but in the supernatant it showed a good performance, up to 227.7 and 190.8 mW/m3.

The ever-increasing population in the metropolis of Accra, Ghana resulting in con-cerns for finding lasting solutions to manage large volumes of waste produced can be tackled through composting for urban agriculture. With insanitary land filling serving as the major disposal option in the metropolis, plans to build the first ever sanitary landfill facility in the metropolis calls for measures to be taken in order to prolong the lifespan of the facility. This therefore necessitates the need to look into an alternative means of diverting organic waste from landfills. The objective of this research is to re-view the Municipal Solid Waste (MSW) management situations in Accra Metropolitan Assembly upon which an investigation is made into the various process steps involved in aerobic windrow composting and also finding out the possibility for integrating composting with urban agriculture. The study relied mainly on secondary data obtained from books, published articles, governmental documents, internet, and master thesis reports on related topics. By the help of a causal loop diagram, the interdependence of various policy actions and sys-tem elements in the waste management process are linked to illustrate the possibility of a composting programme for urban agriculture. Even though the metropolis for some time back has been operating a centralized composting facility, the facility is confirmed to be closed down due to problems ema-nating from financial inadequacy, power failure and mechanical breakdown. The study delve into the process steps in windrow composting and finally identified potentials for composting in the metropolis but however enumerated constraints ranging from human and environmental health, financial, institutional, policy directives, to public and leadership attitudes as stumbling blocks to the implementation of a centralized composting scheme. It finally concluded that the metropolis has the potentials to embark on composting for urban agriculture however, until measures are taken to overcome these constraints, implementing a centralized composting scheme in the metropolis may not be a sustainable option. It is further recommended that whiles the city authorities continue to tackle the constraints to pave way for the implementation of the program, efforts must be made in promoting small scale composting that rely on manually operated tools to help reduce organic waste loads in the municipal waste stream.

In the last decade, several novel and cost-effective biological nitrogen removal technologies have been developed. The discovery of anaerobic ammonium oxidation (Anammox), about 15 years ago, has resulted in new opportunities for research and development of sustainable nitrogen removal systems. Compared to conventional nitrification/denitrification, Anammox eliminates necessity of external organic carbon source, has a smaller production of excess sludge, reduces energy demand for aeration (up to 60-90%) and CO2 emissions (up to 90%). Systems based on Anammox can be of great help to comply with stricter wastewater discharge regulations and reduce environmental problems caused by nutrients discharges (e.g. eutrophication). This thesis investigates the partial nitritation/Anammox in one stage system under oxygen limited condi-tions (also called CANON or Deammonification) and with the Moving Bed Biofilm Reactor (MBBR™) technology. Anammox process coupled with partial nitritation can be particularly suitable to treat ammo-nium-rich wastewater with low content of biodegradable organic matter, such as the reject water from dewatering of digested sludge, which is usually recirculated back to the main stream of wastewater treat-ment plants, accounting for the 15-20% of the total nitrogen load. Partial nitritation/Anammox process was successfully tested on a pilot plant scale for four months at 25°C, in a 200 L Continuous Stirred Tank Reactor (CSTR), filled with 40% of Kaldnes media (model K1). At an Ammonium Surface Load (ASL) of 3.45 gN m-2d-1, the removal rate was about 2.85 gN m-2d-1. Removal efficiencies of 95%, 85% and 83% were respectively achieved for NH4+-N, inorganic nitrogen, and Total Nitrogen (TN). Bacteria activity was followed by batch tests such as Specific Anammox Activity (SAA), Oxygen Uptake Rate (OUR) and Nitrate Uptake Rate (NUR), which revealed an increase in activi-ty for Nitrosomonas and Anammox bacteria within the biofilm. Dissolved oxygen concentration in the bulk liquid was a crucial parameter, whereas pH and conductivity turned out to be two useful monitoring tools. Two laboratory-scale reactors were previously run for two months each, in order to evaluate the one-stage partial nitritation/Anammox process with a lower ASL. One reactor was fed with diluted reject water, whereas the other one treated the effluent from UASB (Up-flow Anaerobic Sludge Blanket) reactor after sand filtration. Fairly good efficiency (>75%) were reached but, however, in the last case the low ammo-nium nitrogen load could represent a problem for a stable full-scale installation and long-term growth of Anammox bacteria. Some suggestions for full-scale implementation and further research are proposed in the last chapter of this master thesis.

The upflow anaerobic sludge blanket (UASB) reactor is widely used around the world to treat variety of domestic andindustrial wastewater with three main advantages: production of biogas as renewable energy, no need of support structure for development of microorganisms and high rate treatment efficiency with low rate of biomass production. This study evaluates the effect of temperature on biogas production and CODtotal removal in Line 4-UASB system treating domestic wastewater in Hammarby Sjöstadsverk. Eight parameters were examined including the following: Influent and effluent temperature, pH, influent CODtotal, influent rate, effluent CODtotal, volatile fatty acids, biogas production rate and methane concentration. There are eight set temperature and each is stabilized for seven days. The biogas production analysis is focus on UASB 1. Temperature rising from 19°C to 35°C achieves a general benefit result in methane yield rate and CODtotal removal efficiency. The best methane yield rate and CODtotal removal rate are 0.167l/gCODtotal and 56.84% respectively at highest working temperature 33.4°C with OLR 3.072gCODtotal/(l*day) and HRT 4.2h. / Den ökande energiförbrukningen i världen och utsläpp av växthusgaser (GHG) gör det nödvändigt att söka nya hållbara energikällor för att matcha efterfrågan på energi i framtiden. Rötningsteknik med organiskt avfall som förnybar energikälla, ger biogas som i genomsnitt består av 78% CH4, 22% av CO2och spår av H2S (<0.5%), är en idealisk kostnadseffektiv metod. Den Uppåt flödande anaeroba slambäddsreaktorn(UASB) med största fördelarna: biogasproduktion som förnybar energi, hög belastning och hög behandlingseffektivitet med låg produktion av biomassa, inget behov av stödstruktur för utveckling av mikroorganismer, är den viktigaste typen för anaerobt reningssystem. Det finns flera faktorer som påverkar UASB-reaktorns prestanda, såsom temperatur, pH, HRT, Uppåtriktat flödeshastighet, OLR, SRT och VFA. I denna studie är huvudsyftet att med fokus på utvärdering av temperaturpåverkan på biogasproduktion och CODtotal avlägsnat i UASB-systemet Linje 4 som behandlar hushållsspillvatten i Hammarby Sjöstadsverk. Analysen avbiogasproduktionen fokuserades på UASB reaktor 1. Åtta parametrar övervakades för att kontrollera skick inklusive inflöde och utflöde, temperatur, pH, CODtotal inflöde, strömningshastighet för inflöde, CODtotal utflöde, flyktiga fettsyror VFA, biogasproduktionstakt och metankoncentration. Försöken utfördes vid åtta inställda temperaturnivåer och varje nivå stabiliserades i sju dagar. pH och VFA-värde var stabilt under hela försöket. Resultatetvisar att temperaturen har en större inverkan på metanavkastningen och CODtotal avlägsnat än belastningen, OLR. Då temperaturen höjs från 19°C till 35°C erhålls en större metanavkastning och större CODtotal avlägsnat. Den största metanavkastningen och CODtotal avlägsnat är 0,167l/g CODtotal respektive 56.84% vid den högsta arbetstemperaturen 33.4°C med OLR 3.072g CODtotal/(l * dag) och HRT 4.2h. Energibalansen vid olika arbetstemperaturer visaratt det finns en stor skillnad i energibehov för uppvärmning och utbyte avenergi i form av biogas. För att minska klimatpåverkan och nå balans mellan input och output av energi måste energibehovet för uppvärmning reduceras. Energiåtervinning från utflöde till inflöde liksom drift av UASB vid låg temperatur är ämnen som kan studeras vid fortsatt arbete.