Malawi is one of many countries throughout the world struggling with massive amounts of water hyacinths (Eichornia crassipes) in the country’s fresh water resources.  In nutrient-rich ecosystems where the aquatic weed has no natural enemies it will reproduce very rapidly with the consequence that lakes become overgrown, water flow in rivers is reduced, and other water organisms becomes excluded. At the same time, the plants form a good breeding place for species carrying tropical diseases for example Malaria and Bilharzia. Water hyacinths are usually more of a problem for poorer countries since there are often great economic losses caused by the weed and to control their relative abundance is costly. In Malawi, 99 % of the produced electricity is based on water resources, mainly through hydropower turbines in the main river, Shire River. Water hyacinths, aggregated as islands, floating along the river and clogging the turbines cause repeated electricity black-outs and approximately 140 megawatt power is lost every day. To counter the weed interference with the electricity supply, there are great amounts of water hyacinths harvested every day and dumped along the road, with no further disposal plan. In this report, soil from one local dumping area is analysed to determine if such places are leaching nutrients or metals to the surrounding environment.  Water hyacinths contain naturally high values of nutrients and farmers use these harvested plants as a green manure to improve soil properties on agricultural land. This paper aims to examine levels of metal in water hyacinths used as green manure. This is of interest since water hyacinths have the ability to effectively absorb substances from the water body which could pose a risk for potentially toxic elements (PTEs) to accumulate in the agricultural soil and subsequently in crops. Sampling and analyses were carried out with standard methods. Metal and nutrient levels in the analysed samples were obtained through detection with atomic absorption spectrophotometry (AAS), ion chromatography (IC) and UV/VIS spectrophotometry at the Department of Chemistry of Chancellor College in Zomba, Malawi. None of the investigated metal ions (Cr, Pb, Cd) were found in the analysed water hyacinths and since soil sampling was done during the dry season this thesis cannot determine if the dumping areas are leaching nutrients. Relatively high amounts of total phosphorus were found in the plants. Overall, the conclusion is that there is no risk of using water hyacinths harvested in Shire River as a green manure on agricultural land.

This master thesis is about mathematical modelling of the anammox process with a moving bed biofilm reactor (MBBR) for a reject water application. Specifically, the aim of my research was to find out whether the model proposed by Erik Lindblom in (Lindblom et al. 2016) is a good model for this purpose and worth continuous research and optimization. The code for the model, implemented in Matlab/Simulink, was given; although not initially functioning in the given condition. Some modifications needed to be done to make it function properly. In order to confirm that the code was working and used in a correct way some results in (Lindblom et al. 2016) were reproduced. Before starting the evaluation of the model, some much-needed optimizations of the code were done, substantially reducing the run time. A sensitivity analysis was done, and the five most sensitive parameters were picked out to be used in the calibration. The calibration improved the total fit of the model to the available measurements, although one of the model outputs could not be calibrated satisfactorily. In short, I found that although there are still problems left to solve before the model can be stated to accurately model the anammox process with MBBR, it appears promising. Most importantly, more measurement data are needed in order to make a proper validation and to do a better calibration. / CONAN

The availability to clean drinking water is something a lot of people take for granted today. Daily, there are about 1.8 billion people around the world that drinks water from a contaminated water source. Unfortunately, the deficiency is a fact, and about 361 000 children under the age of five die each year because of diarrheal disease (WHO, 2016a).  Earlier studies show that a biosand filter is an easy and efficient water purification method that cleans the water both physically, biologically and chemically. A biosand filter is often built using local material and is filled with sand, which makes the construction cheap and easy to repair is needed. Earlier studies have shown that this purification method can reduce waterborne disease by 99,9% with the help of a biofilm layer which develop in the top layer of the sand if the conditions are meet (CAWST, 2009). The purpose with this study was to build and evaluate a biosand filter as a water treatment method in Ghana. In total, three biosand filters was built with local material, each with different sand heights. The evaluation was done by studying the waters physical, biological and chemical properties before and after the filtration, which then was compared to the water quality standards from the World Health Organization (WHO) and Sweden. The results show that none of the three filters could produce water which met the standards for drinking water, which might be caused by the high flow of water through the filter which prevented the biofilm to grow. With the help from the results in Ghana, a new design of a water filter has been made to reduce the flow of water through the filter. Which gave a new biosand filter design with a diameter of 42 cm that, sand height of 80 cm and gravel height of 15 cm. / Tillgången till rent dricksvatten är idag något som många tar som en självklarhet. I dagsläget är det omkring 1.8 miljarder människor i världen som dagligen dricker vatten från en kontaminerad vattenkälla. Dessvärre är bristen på rent dricksvatten ett faktum, vilket gör att det årligen dör cirka 361 000 barn under fem års ålder på grund av diarrésjukdomar världen över (WHO, 2016a).  Tidigare studier har visat på att biosandfilter är en enkel och effektiv vattenreningsmetod för att rena vatten både fysiskt, biologiskt och kemiskt. Ett biosandfilter är ofta byggt med lokala material och fylld med sand, vilket gör konstruktionen billig och enkel att reparera vid behov. Tidigare studier har visat på att vattenreningsmetoden kan reducera vattenburna sjukdomar med upp till 99.9% med hjälp av ett biofilmslager som utvecklas i sandlagrets övre skikt om förhållandena är gynnsamma (CAWST, 2009).  Syftet med denna studie var att bygga och utvärdera biosandfilter som vattenreningsmetod i Ghana. Totalt byggdes tre biosandfilter av lokala material med olika sandhöjder. Utvärderingen gjordes utifrån att studera vattnets fysiska, kemiska och biologiska egenskaper före och efter filtrationen, som sedan jämfördes med vattenkvalitetsstandarder från World Health Organization (WHO) och Sverige. Resultaten visade på att ingen av de tre sandfiltret kunde producera vatten med en drickvattenstandard, detta tros bero på det höga flödet genom filtret som hindrat biofilmstillväxten. Med hjälp av resultat från Ghana har en ny design av ett biosandfilter tagits fram för att minska flödet genom filtret. Vilket gav en filterdiameter som är ungefär 42 cm som sedan är fylld med 80 cm sand och 15 cm grus.

Landfills are potential sources for PFASs and treatment techniques for landfill leachate are urgently needed. Foam fractionation is an aeration technique which utilizes the tendency of PFASs to escape the liquid phase and build foam. The foam is harvested and with it the contamination. Landfill leachate from Hovgården, Uppsala Sweden contained PFASs of higher concentration than desired and investigations into whether foam fractionation could reduce PFASs amounts were initiated. Landfill leachate containing sum PFASs of 5500 ng/L on average were aerated in two different aeration foam collection pilot set-ups for the research. The pilot set-ups were divided into two models: a batch pilot and a continuous pilot. The batch pilot was run for 60 minutes testing parameters such as column volume, air flow rate, dilution and using additives as NaCl, FeCl3 and dish soap. The continuous pilot used contact times of 5, 10 and 20 minutes with constant air flow rate and column volume and no additives. All batch experiments showed reduced concentrations of PFASs, from 62 up to 91%, with an average sum PFASs removal efficiency of 77%. Air flow rates of 4 and 6 L/min were more effective than 2 L/min to reduce the amount of PFASs. Smaller volumes got higher removal efficiency. The dilution experiments showed mixed and somewhat contradictory results, where the nondiluted experiment had removal efficiency of sum PFASs of average 77% while the 50% diluted had an average sum PFASs removal efficiency of 84%. The experiment with the greatest dilution (75%) had the lowest average sum PFASs removal efficiency as suspected, at 68%. Regarding additives, the experiments with added 0.155 and 0.313% NaCl in the leachate were most effective at removing PFASs. The dish soap and FeCl3 additives also contributed to higher PFASs reduction. The experiment with the addition of dish soap had an average sum PFASs removal efficiency of 88% compared to 77% without additives, and the highest concentration of FeCl3 (0,09% of the leachate) had an average sum PFASs removal efficiency of 85%. All continuous experiments showed reduced reduced PFASs concentrations with sum PFASs removal efficiencies ranging from 72 up to 94%, with an average of 86%. The majority of the PFASs were reduced within the first time steps for all experiments, but for the last amount to be removed the contact time needed to be longer. The column contact time of 20 min had the highest average sum PFASs removal efficiency. The conclusion is that PFASs are reduced during the treatment in the pilots and that the reduction is dependent on the chain length and functional groups of the substances, and increased with additives and increased air flow rate. The volume treated and the concentration of raw water also influenced the removal efficiency.

Plastproduktionen och användningen av plast ökar varje år i hela världen och detta är ett av världens största problem. Plaster är ett svårnedbrytbart ämne och processen kan ta hundratals år. Detta leder i sin tur till att plastackumuleringen orsakar skadlig påverkan på klimat, miljö och människor. Ett av alternativen som har stor potential för hanteringen av detta problem är att minska användningen av plast och i stället öka produktionen och användningen av bioplastereller biopolymerer som är nedbrytbar. Bioplaster har kortare nedbrytningstid än vanliga plaster och därför är bioplast ett bra alternativ istället för att använda vanliga plaster. Det finns tre olika grupper av bioplaster, nämligen dem som är biobaserade, bionedbrytbara och de som är både biobaserade och bionedbrytbara. Entyp av bioplast som är biologiskt nedbrytbar och biobaserad är polyhydroxialkanoater (PHA)som används i olika branscher då PHA är en av de biopolymerer som visar störst potential attersätta plast i framtiden. Forskning pågår på Högskolan i Borås med målet av att bilda en ny process för produktion och återvinning av PHA. Processen baseras på produktion av PHA från flyktiga fettsyror som produceras från acidogen jäsning. Acidogen jäsning är en modifierad process av anaerobmatsmältning som används idag för produktion av biogas från avfall. Den kan vara den rättaprocessen för återvinningen av PHA-baserade avfall och för att producera ett billigt substrat, nämligen flyktiga fettsyror för PHA produktion. Det här projektet handlar om en del av processen, nämligen produktion av PHA med bakterier. Forskningsgruppen på Högskolan iBorås har en bakteriestam som inte har undersökts för produktion av PHA. Innan bakterien kan studeras för produktion av PHA från flyktiga syror behövs medelinnehållet optimeras för bakterietillväxt. Syftet med detta arbete är att undersöka effekten av olika glukoskoncentrationer som kollkälla och olika mängder av ammoniumsulfat som används vid tillväxt av den bakterien Bacillusmegaterium för produktion av PHA. En jämförelse mellan det definierade mediet som användsi detta arbete och dess ersättning med nutrient broth, ett komplext medium som normalt används för bakterietillväxt genomfördes också för att utvärdera lämpligheten hos mediet underutveckling för att framgångsrikt stödja bakterietillväxt. Under detta arbete användes flera olika analytiska tekniker såsom pH mättning, Högupplösande vätskekromatografi (HPLC),Spektrometer (OD mättning), och Fourier-transform infraröd spektroskopi (FTIR) för att utvärdera bakterietillväxt och produktion av PHA samt analysera sammansättningen av PHAs. Mängden av ammoniumsulfat påverkade glukosförbrukningen, där koncentrationer av 3 g/Loch 7 g/L visades att leda till en snabbare glukosförbrukning jämfört med 5 g/L. Därför valdes3 g/L ammoniumsulfat då det innehåller mindre kemikalier användning och påverkar inte celltillväxten på ett negativ sätt. Under experimentet med användning av 3 g/Lammoniumsulfat med 10 g/L glukos, konsumerades glukosen fullständigt vid 72 timmar av bakterietillväxt och den maximala PHA-produktionen var på 13–14% baserad på torr cell vikt. Tillväxtmedelet som utvecklades i det här projektet visade att vara lämplig för bakterietillväxt eftersom användning av nutrient broth som används normalt för bakterietillväxt ledde till långsammare glukosförbrukning. Initial glukoskoncentration (5, 10 och 20 g/L) påverkade inte glukosförbrukningen och får studerats vidare för att öka cellkoncentrationen och följaktligen produktionen av PHA. En av det mest studerade i PHA-familjen är polyhydroxibutyrat (PHB). Under detta arbete visade det sig att genom användning av FTIR att PHB framställdes. / Plastic production and use of plastic are increasing every year throughout the world and this is one of the world's biggest problems. Plastic is a persistent substance, and its biodegradation process can take hundreds of years. This in turn leads to the accumulation of plastic causing harmful effects on the climate, the environment, and people. One of the alternatives that has great potential when it comes to dealing with this problem is to reduce the use of plastics and instead increase the production and use of bioplastics or biopolymers that are biodegradable. Bioplastics have a shorter biodegradation time than plastics and therefore bioplastics are a good alternative instead of using ordinary plastic. There are three different groups of bioplastics, namely those that are bio-based, those that are biodegradable and those that are both bio-based and biodegradable. One type of bioplastic that is biodegradable and bio-based is Polyhydroxyalkanoates (PHA) which are used in various industries as PHA is one of the biopolymers that shows the greatest potential to replace plastic in the future. Research is underway at the University of Borås with the goal of developing a new process for the production and recycling of PHAs. The process is based on the production of PHAs from volatile fatty acids produced from acidogenic fermentation. Acid fermentation is a modified process of anaerobic digestion; the latter is used nowadays to produce biogas from waste and can be the right process for recycling PHA-based waste and for producing a cheap substrate, namely volatile fatty acids for PHA's production. This project is about a part of the process, namely the production of PHAs with bacteria. The research group at the University of Borås has a bacterial strain that has not been yet investigated for the production of PHAs. Before this bacterium can be studied for the production of PHAs from volatile fatty acids the compositionoptimization of the cultivation medium for bacterial growth is needed. The purpose of this work is to investigate the effect of different glucose concentrations as a source of carbon and different amounts of ammonium sulphate in the growth of the bacterium Bacillus megaterium and the production of polyhydroxyalkanoates. A comparison between the defined medium under development in this project with nutrient broth, a complex medium normally used to grow bacteria, was also carried out in order to evaluate the suitability of the defined medium to support bacterial growth. During this work several different analytical techniques have been used such as pH measurement, High-Performance Liquid Chromatography (HPLC), Spectrometer (for optical density (OD) measurement), and Fourier-Transform Infrared Spectroscopy (FTIR) to evaluate bacterial growth and production of PHA as well as PHAs composition. The amount of ammonium sulphate affected glucose consumption rate, where concentrations of 3 g/L and 7 g/L were shown to lead to a faster glucose consumption compared to that at 5 g/L. Therefore, 3 g/L ammonium sulphate was chosen as it represents less chemical consumption while not affecting cell growth negatively. During bacterial cultivation in a medium containing 3 g/L ammonium sulphate, 10 g/L glucose, among other compounds, glucose was completely consumed after 72 hours of bacterial growth and the maximum PHA production was 13-14% based on cell dry weight. The cultivation medium developed in this project was shown to be suitable for bacterial growth since the use of nutrient broth, normally used for bacterial growth, led to slower glucose consumption. Initial glucose concentration (5, 10 and 20 g/L) did not affect glucose consumption rate and should be further studied to increase cell concentration and consequently the production of PHA. One of the most studied polymers in the PHA family is polyhydroxybutyrate (PHB). During this work, it was found, through the use of FTIR, that PHB was produced.

Uppsatsen är en fallstudie utförd på uppdrag av Arla ostmejeri i Kalmar med syfte att undersöka om en minskning av den höga vattenförbrukningen på anläggningen är genomförbar. För att svara på studiens frågeställning har samtal med systemtekniskt kunnig personal på mejeriet tillsammans med egen efterforskning och studiebesök utförts. Fokus har lagts på att undersöka möjligheten att öka användningen av biprodukten produktkondensat som vattenresurs, vilket redan används till en nyttjandegrad upp till ca 50%. Ökningen är tänkt att ske bland annat genom att använda produktkondensatet i ostrecepten vilket gör att kondensatet måste vara fritt från bakterier och orenheter. Tanken är att det ska uppnås med hjälp av avancerad filterteknik, så som omvänd osmos och ultrafiltrering. Även undersökning kring fullständig vattenåterföring genom total vattenrening har undersökts som alternativ, det visade sig vara ett kostsamt projekt med behov av större utbyggnader. Arbetet är aktuellt då många kommuner i Sverige kämpar med att hålla vattenförsörjning till invånare och industrier under särskilt torra somrar. / This is a case study commissioned by Arla cheese dairy in Kalmar, Sweden, with the purpose to examine if a decrease of the high water consumption on the dairy is possible. To answer the question formulation of the study dialogues with experienced personnel of the dairy together with research and visit at an adjacent water treatment plant. The research has focused on the possibility to increase the use of the bi product ”product condensate” as a water resource, which is used up to 50% today. The increase is supposed to be achieved with the use of product condensate in the cheese recipes which means that the condensate needs to be free from bacteria and impurities. To reach this cleanliness of the water advanced filter technique like reversed osmosis and ultrafiltration must be used. Total water recirculation with no water discharge in the factory was examined but it showed to be an expensive project with the need of big investments.This study is important today since a lot of areas in Sweden is struggling with high water consumption, especially warm and dry summers.

Flooding from extreme rainfall is already taking place today in Sweden's urban areas. In order tocreate sustainable stormwater management that reduces the risk of flooding, various factorsshould be taken into account such as the choice of method for management. Bottlenecks in thestormwater system mean wells with undersized outlet pipes. A bottleneck area in Bollnäs urbanarea has already caused flooding. The aim of this study is to investigate if there are more similarareas and to contribute to sustainable stormwater management for Helsinge Vatten. Themethods chosen for the study were a literature study and a case study with simulation andcalculations. The literature study was conducted to see how stormwater is handled and what theclimate looks like. The case study was conducted to evaluate the flows that occur during heavyrains. In the case study, a terrain model was first made that showed drainage directions andwater dividers. The calculations in the case study were based on the rational method forcalculating design flow. The climate is changing and as the temperature rises, so does therainfall. The risk of extreme weather increases as the annual average temperature rises and aglobal increase in rainfall intensities has occurred. In Bollnäs, the annual average temperaturehas risen since the measurements began in 1969. In the future, the average temperature can beexpected to rise to 3-5 degrees until the end of the century in Gävleborg. In heavy rain, floodscan occur, they are called pluvial floods and can cause major damage to properties and roads,among other things. There are many methods for developing and making the stormwatersystem more sustainable. Among other things, there is something called blue-greeninfrastructure and this involves green surfaces in the management of stormwater. There, forexample, the water is allowed to infiltrate, evapotranspire or slowly pass on into the system.These solutions also have other benefits, they meet several social needs and can bring ecosystemservices. After the simulation that was carried out, 37 catchment areas could be observed andcalculations for design flow were made based on, among other things, the area in thesecatchment areas. Sustainable stormwater management can be introduced in Bollnäs urban area,when new guidelines and greater cooperation between Helsinge vatten and Bollnäs municipalityare needed. Sustainable stormwater management could reduce the risk of floods in bottlenecks.However, it is not possible to locate any bottlenecks in Bollnäs urban area due to missinginformation about the storm sewers in Bollnäs urban area. More studies would be needed tolocate bottlenecks. / Översvämningar från extrem nederbörd sker redan idag i Sveriges tätorter. För att skapa hållbardagvattenhantering som minskar översvämningsrisken bör olika faktorer tas i beaktning somexempelvis val av metod. Flaskhalsar i dagvattensystemet innebär brunnar medunderdimensionerade utloppsledningar. Ett flaskhalsområde i Bollnäs tätort har redan orsakatöversvämningar. Detta arbete går ut på att undersöka om det finns fler liknande områden ochbidra till hållbar dagvattenhantering för Helsinge Vatten. Metoderna som valdes för arbetet varen litteraturstudie och en fallstudie med simulering och beräkningar. Litteraturstudiengenomfördes för att se hur dagvatten hanteras och hur klimatet ser ut. Fallstudien genomfördesför att utvärdera vilka flöden som uppkommer vid kraftiga regn. I fallstudien gjordes först enterrängmodell som visade dräneringsriktningar och vattendelare. Beräkningarna i fallstudienutgick från rationella metoden för beräkning av dimensionerande flöde. Klimatet förändras ochnär temperaturen stiger så stiger också nederbörden. Risken för extremväder ökar till följd avatt årsmedeltemperaturen ökar och en global ökning av nederbördsintensiteter har skett. IBollnäs har årsmedeltemperaturen ökat sedan mätningarna började 1969. I framtiden kanmedeltemperaturen väntas öka upp mot 3-5 grader fram till slutet av seklet i Gävleborg. Vidkraftiga regn kan översvämningar uppstå, de kallas pluviala översvämningar och kan orsaka storaskador på bland annat fastigheter och vägar. Det finns många metoder för att utveckla och göradagvattensystemet mer hållbart. Bland annat finns det något som kallas blågrön infrastruktur (BGI) och detta involverar gröna ytor i hanteringen av dagvatten. Där får vattnet till exempelinfiltrera, evapotranspirera eller långsamt ledas vidare i systemet. Dessa lösningar har ocksåandra fördelar, de tillgodoser flera sociala behov och kan medföra ekosystemtjänster. Efter densimulering som utfördes kunde 37 avrinningsområden observeras och beräkningar fördimensionerande flöde gjordes utifrån bland annat arean på dessa områden. I Bollnäs tätort kanhållbar dagvattenhantering införas, då behövs nya riktlinjer och ett större samarbete mellanHelsinge Vatten och Bollnäs kommun. Hållbar dagvattenhantering skulle kunna minska riskenför översvämningar vid flaskhalsar. Däremot går det inte att lokalisera några flaskhalsar i Bollnästätort på grund av saknad information om dagvattenledningarna i Bollnäs tätort. Fler studierskulle behövas för att lokalisera flaskhalsar.

The desire for value addition to the organic waste management chain at Högbytorp using the Black Soldier Fly (BSF) process, as well as the problem of the escalating demand for protein in livestock feed motivated this study. Good quality crop land is devoted to growing feed for animals at the expense of human food, and ironically with a full understanding of the associated environmental footprints. Black Soldier Fly Larvae (BSFL) feed on organic waste voraciously while building their body composition of 40% protein and 30% fat. Their protein can be used in animal feedstock and pet food, replacing the more expensive but nutritionally comparable fishmeal, while their fat can be used for biodiesel production. They can also reduce a waste pile significantly, minimizing possible pollution. In this study, the process was tried on various waste streams (fruits, manure and ‘slurry reject’) at Högbytorp. Biomass conversion, larval fat and protein content, compost by-product characteristics and residence time requirements for each stream were assessed. The study involved literature review, chemical analyses and experimental design (rearing BSFL on waste through their lifecycle). The study yielded waste reduction up to 83% and fat and protein contents up to 42% and 41% respectively, depending on the waste stream. The residence time depended on the age at which the larvae started feeding, but ranged between 8-11 days. If applied in organic waste management chain, the process could contribute to greener energy provision (biodiesel) as well as sustainable protein provision to the animal, fish and pet industries. It could further reduce waste amounts significantly and generate income while contributing to the saving of Earth’s limited resources.

Avloppsreningsverket i Hallsberg kommun är beläget i direkt anslutning till Hallsberg, med Ralaån som recipient. Tekniken på reningsverket bygger på principerna för en klassisk aktivslamanläggning med mekanisk rening, kemisk rening, biologisk rening och en slambehandling där rötning av primär- och sekundärslam används för utvinning av biogas. Hallsberg ARV har under en längre tid haft problem med kvävereningen. Under senaste åren har man överskridit riktvärdet för kväveutsläpp vid ett flertal tillfällen och under 2009 överskreds även gränsvärdet. Riktvärdet för Hallsberg ARV är i dagsläget satt till 10mg NH4-N/l som medelvärde per månad, gränsvärdet är satt till 10 mg NH4-N/l som medelvärde per kalenderår. Då Hallsberg ARV inte drivs vid full kapacitet antas en minskning av kväveutsläppen vara möjlig att genomföra genom trimning av befintligutrustning och processer på verket. Detta antagande låg till grund för det här examensarbetet som syftar till att optimera kvävereningen på Hallsberg ARV. I optimeringen ingick en teknisk, ekonomisk och miljömässig utvärdering av olika alternativa lösningarna för att förbättra funktionen hos anläggningen. Extra hänsyn togs till energi- och kemikalieåtgång i syfte att få en så effektiv drift av verket som möjligt. Arbetet genomfördes genom en initial litteraturstudie på området, vartefter en provtagningsserie om fyra veckor realiserades på verket. Data som ligger till grund för slutsatserna i projektet har också inhämtats från onlinemätare på verket samt från äldre externt analyserade prover. Efter analys av insamlad data antas orsakerna till Hallsberg ARV:s höga utsläpp av kväve bero på en kombination av flera faktorer: -Vid vår och höst kan brunnsslamintaget vara så stort att bräddning sker ut till verket. Detta leder till att kvävebelastningen höjs så kraftigt att nitrifierarna inte hinner acklimatisera sig och får förhöjda kväveutsläpp till följd. -Mycket kväve följer med slammet från simultanfällningen till rötningen. Detta kan påverka halten kväve i rejektet från rötkamrarna som i sin tur kan leda till störningar i kvävereningen. -Centrifugens rejekt innehåller mycket kväve och körs idag endast under ett par dagar i veckan vilket leder till stora variationer i inkommande kvävehalt. -En hög förfällning av fosfor och organiskt material har bidragit till en låg halt av organiskt material i denitrifikationen. Sammantaget föreslås att vidare studier bör genomföras av ovan nämnda områden för att driften på Hallsberg ARV ska kunna drivas med så låga miljömässiga och ekonomiska kostnader som möjligt. / The waste water treatment plant in Hallsberg municipal is situated adjacent to Hallsberg, with Ralaån as a recipient. The technique at the waste water treatment plant is based on the principles for a classical activated sludge treatment plant and includes mechanical treatment, chemical treatment, biological treatment, and a sludge treatment where the digestion of primary and secondary sludge is used for extraction of biogas. Hallsberg waste water treatment plant has during some time had problems with the nitrogen removal with high nitrogen emissions as a consequence. The target value has been exceeded a couple of times during the last years and in 2009 the limit value was exceeded as well. The target value for Hallsberg waste water treatment plant is 10 mgNH4-N/l as an average value per month, the limit value is set to 10 mg NH4-N/l, as an average value per year. Since the waste water treatment plant in Hallsberg not is operating at full capacity, a lowering of the nitrogen emissions is assumed to be possible though a trimming of the existing equipment and of the processes on the site. This assumption formed the basis for this thesis, designed to optimize the nitrogen removal at the waste water treatment plant in Hallsberg. A technical, economical and environmental evaluation was included in the optimization to improve the function of the plant. Extra evaluations were made in the energy- and chemical consumption in order to streamline the operations at the plant as much as possible. The project was carried out through an initial literature-investigation followed by a four week period of sampling and analyzing at the site. The data that form the conclusion in this project has also been collected through online measurements at the plant as well as through analyses of older samples. After analyzing the collected data, the reasons for the high emissions of nitrogen is thought to be due to a combination of reasons: -During the spring and the autumn the external intake of well sludge can lead to a direct release of sludge in to the plant. The change of nitrogen content will not give enough time for the nitrifying bacteria to acclimatize, with elevated emissions of nitrogen as a consequence. -The usage of simultaneous precipitation could lead to an irregular concentration of nitrogen released to the treatment plant from the digesters. This in turn could contribute to higher nitrogen emissions. -The irregularities of the usage of the centrifuge contribute to nitrogen irregularities and contribute to the difficulties of acclimatization of the nitrifying bacteria. -A high pre-precipitation of phosphorus and organic matter has contributed to a level of organic material in the denitrifikation below what is recommended. To sum up, further investigations are suggested in the above mentioned areas to make the operations at the plant carried trough at the lowest possible environmental and economically cost.

Industries are becoming more aware of how they use water in their production process. In many cases, they release wastewater back into the water supply untreated, which can cause adverse side effects to the ecosystem. A sustainable environment requires efficient water purification. One approach to purify wastewater uses rotating bed reactors. An impeller filled with catalyst pellets that absorb the pollutants spins in the contaminated fluid. The inertial forces from the spinning impeller propel the contaminated water through the packed bed and purify it. In this study, we used one of these rotating bed reactors. However, the motors that drive these impellers can be bulky and may not be compatible with some tanks or environments. To solve this problem, we designed, constructed, and tested a container around the impeller that provides maximal outflow, using only the impellers pumping capability. We also developed a CFD simulation of the container to analyze the internal flows and forces. Because the flow generated by the rotating impeller displaces the fluid in a radial direction, the design works as a custom-made centrifugal pump. We constructed the container using plastic and wood with an outlet nozzle made of metal. The container's pump capability was around 2.5 liters per second when the impeller spun at 300 RPM. The developed CFD simulations gave a higher flow rate at 3.1 liters/second but overall helped shed light on the internal forces happening inside the container during high RPM testing. The design could generate a sufficient outflow of fluids, converting kinetic fluid energy to fluid pressure energy at the outlet, causing a pump effect. Overall, the design proved sturdy and could handle the forces occurring inside the container. The implementation of this design could allow industries to more efficiently and ergonomically utilize the purifying capabilities of the RBR in otherwise complex scenarios. By purifying wastewater before releasing it back into the water supply, we can take immediate action in achieving a sustainable environment.