Detta arbete utreder möjligheten att säkra vattentillgången i Mönsterås kommun med hjälp av en avsaltningsanläggning för bräckvatten från östersjön. Det är högst troligt ett sådant vattenverk skulle kunna uppföras i kommunen och dessutom ge ett vatten med lägre halter av oönskade ämnen än vatten renat med konventionella metoder från yt- och grundvatten till en marginellt högre kostnad. I arbetet redovisas kortfattat principen för avsaltning med RO (Reverse osmosis).  Uppbyggnaden av två vattenverk som använder den tekniken och likt Mönsterås ligger i Kalmarsund beskrivs. Med information från sjökort och kartor har troliga råvattentillgångar i kommunen identifierats och utifrån dessa grundar sig förslagen för placering. Med hjälp från ett flertal kontakter i branschen har en enklare projektering gjorts för ett vattenverk med kapacitet på 3000 kubikmeter dricksvatten per dygn. I resultatet redovisas några förslag på placering av ett vattenverk. / This work investigates the possibility of securing the water supply in Mönsterås municipality with the help of a desalination plant for brackish water from the Baltic Sea. It is highly likely that such a waterworks could be built in the municipality and also provide water with lower levels of unwanted substances than water purified by conventional methods from surface and groundwater at a marginally higher cost. In the work, the principle of desalination with RO (Reverse osmosis) is briefly presented.  The construction of two waterworks that use this technology and, like Mönsterås, is located in Kalmarsund is described.  With information from nautical charts and maps, probable raw water resources in the municipality have been identified and based on these, the proposals for placement are based. With the help of several contacts in the industry, a simpler design has been made for a water treatment plant with a capacity of 3000 cubic meters of drinking water per day. The result presents some suggestions for placement of a desalination plant.

There are today thousands of active and disused landfills around Sweden. New landfills have to meet high standards to prevent spreading of contaminants from the landfill, and the more hazardous the waste is, the higher the requirements. This study investigates how contaminants from the landfill Ullnatippen can spread around the area. Ullnatippen is a landfill that today only is used for inert waste, which is waste that does not release hazardous contaminants. The landfill has been used since the 1950s and there is some information that suggests that more hazardous waste has been left on the landfill in the past. Ullnatippen has a control program, consisting of 6 groundwater pipes where samples have been taken every year for many years. The purpose with the control program is to discover contaminants spreading from the landfill. This study also investigates whether the control program is designed in such a way that contaminants measured in the pipes actually derive from the landfill.  To be able to investigate this a groundwater model was built with the program Modflow. From this model, a particle tracking to see the possible routes for contaminants to spread was performed. The result showed that the groundwater from the landfill is moving towards the lake Ullnasjön. The model also confirmed that possible contaminants from the landfill are measured by the control program, but that there is room for improvement since the pipes are located with such long distances. The study also discusses general uncertainties with groundwater modeling and which improvements that have to be done to establish the result from this study.

Sverige har en stor problematik med övergödning, ett miljöproblem som bland annat orsakas av näringsämnesläckage från jordbruksmark till akvatiska miljöer som kan leda till negativa effekter på den biologiska mångfalden. Ett sätt att rena vattnet från näringsämnen är att anlägga våtmarker eller en mindre typ specialutformad för att fånga partiklar och fosfor som kallas för fosfordammar. Syftet med detta examensarbete har av den anledningen varit att studera 47 dammar anlagda med LOVA-bidrag med utgångspunkt från faktorerna: placering, storlek, utformning, näringsretention (särskild inriktning på fosfor) och kostnadseffektivitet. Detta för att ta reda på hur optimala några av de redan befintliga fosfordammarna i Sverige är utifrån ett rening- och kostnadsperspektiv. Via uppgifter från Länsstyrelsen och belastningskartor från SLU kunde fosfordammarna modelleras i GIS. Utifrån detta framställdes näringsbelastning, avrinningsområde, vattenytans storlek och vattnets väg genom dammarna. Vidare beräknades näringsretentionen, kostnadseffektiviteten och hydrauliska formen utifrån redan befintliga ekvationer. Av dammarna noterades det att 13 dammar hade ett primärt syfte av att begränsa flödet uppströms för att motverka höga flöden nedströms och att det inte blir stående vatten på åkermark. Resterande 34 dammar var fosfordammar som hade primärt syfte att rena vattnet från näringsämnen med fokus på fosfor. Resultatet visade att 60 % av fosfordammarna hade en bra placering då de påvisade en hög fosfor- och kväveretention (>50 kg/ha och år respektive >500 kg/ha och år). De flesta av de undersökta fosfordammarna hade däremot en hög hydraulisk belastning i jämförelse med värdet på den optimala belastningen (100 m/år). Detta innebär att de flesta av de undersökta fosfordammarna är mindre än de bör vara för att effektivt rena fosfor. Därutöver hade alla fosfordammar en hög hydraulisk form, vilket visar på att de är bra utformade för näringsretention. Kostnadseffektiviteten hos 13 % av fosfordammarna var även mindre än schablonvärdet (726 kr/kg renat fosfor och år) och resultat från tidigare studier. Majoriteten av fosfordammarna hade däremot en högre kostnad per kg renat fosfor än vad schablonvärdet säger. Metodvalet att använda höjddata för att bestämma avrinningsområdet kan i vissa fall ha orsakat felaktiga områden eftersom det inte tar hänsyn till bland annat dränering. Näringsretentionen beräknades med erhållna ekvationer som var baserade på mätdata. Detta innebar att näringsbelastningar som låg utanför mätdata intervallet kan ha haft en annan näringsretention i verkligheten. Det finns även osäkerheter i beräkningen av kostnadseffektiviteten, eftersom detta gjordes med ett par antaganden som fosfordammens livstid på 20 år och sedimentrensning var 10:e år på 10 000 kr. / Sweden has a major problem with eutrophication, an environmental problem caused by nutrient leakage into aquatic environments which can result in negative effects on biological diversity. One way to purify the water from nutrients is to construct wetlands, of which one type is specially designed to reduce phosphorus. The purpose of this master thesis has therefore been to study 47 wetlands constructed with LOVA grants based on the factors: location, size, design, nutrient retention (special focus on phosphorus) and cost effectiveness. This is to find out how optimal some of the already existing phosphorus wetlands are in Sweden from a nutrient reduction and cost perspective. Using data from the County Administrative Board and nutrient load maps from SLU, the phosphorus ponds could be modeled in GIS. Based on this, the nutrient load, catchment area, size of the water surface and the path of the water through the wetlands were produced. Furthermore, nutrient retention and cost effectiveness were calculated based on already existing equations. In addition, the shape of the wetlands was evaluated by calculating the hydraulic shape. Of the wetlands, it was noted that 13 dams had a primary purpose of limiting the flow upstream from forest to counteract high flows downstream and prevent standing water on agricultural land. The remaining 34 dams were phosphorus dams whose primary purpose was to purify the water from nutrients with a focus on phosphorus. The result showed that 60 % of the phosphorus wetlands had a good location as they demonstrated a high phosphorus and nitrogen retention (>50 kg/ha and year and >500 kg/ha and year respectively). Most of the examined phosphorus wetlands, on the other hand, had a high hydraulic load compared to the value of the optimal load (100 m/year). This means that most of the investigated phosphorus wetlands are smaller than they should be to effectively reduce phosphorus. In addition, all phosphorus wetlands had a high hydraulic form, indicating that they are well designed for nutrient retention. The cost-effectiveness of 13 % of the phosphorus wetlands was also less than the standard value (726 SEK/kg reduced phosphorus and year) and results from previous studies. However, most of the phosphorus wetlands had a higher cost per kg of reduced phosphorus than the standard value. The method choice of using elevation data to determine the catchment area may in some cases have caused incorrect areas because it does not consider drainage, among other things. Nutrient retention was calculated using obtained equations that were based on measurement data. This meant that nutrient loads that were outside the measured data range may have had a different nutrient retention. There are also uncertainties in the calculation of the cost-effectiveness, as this was made with a couple of assumptions such as the phosphorus pond's lifetime of 20 years and sediment cleaning every 10 years at SEK 10,000.

Designing stormwater systems and reservoirs correctly is important to prevent floods, pollution emissions, and unnecessary costs. This work has investigated different types of rainfall based on their impact on stormwater reservoirs, aiming to recommend which rainfall data should be used for designing reservoirs. The work was conducted using the MIKE+ modelling tool, where models of stormwater systems were run with various rainfall data. Five models were used, including three existing models from Gustavsberg, Lund, and Malmö. The compared design rains were CDS rains and constant-intensity rains with a return period of ten years and varying durations. The models were also run with historical rainfall series from eight locations in Sweden. The focus was on the water levels of the reservoirs, flooding events, and critical durations. The CDS rain with a duration of six hours gave the highest water levels in the reservoirs. The number of floods exceeded expectations, and rains that caused flooding in different reservoirs had different durations. Critical rainfall durations were identified for each reservoir, which represented the durations leading to the highest water levels in the reservoirs. A suggested key indicator was developed for each reservoir in an attempt to explain the variations in critical durations. The suggested key indicator was based on the reservoirs' reduced area and outflow. A certain correlation between the reservoir's critical durations and a suggested key indicator was observed and described by a trend curve, where higher values of the key indicator were associated with higher critical durations. The recommended design rain was the CDS rain with a duration of six hours if the critical duration for the reservoir was shorter than six hours. The trend curve presented in the study can be used to estimate the critical rainfall duration for a reservoir during the dimensioning process. Knowledge of the critical duration can then simplify the selection of the duration for the design storm, and it can also enhance the validation step in designing stormwater reservoirs. / Korrekt dimensionering av dagvattensystem och magasin är avgörande för att förhindraöversvämningar, föroreningsutsläpp och onödiga kostnader. I detta arbete har olika typer avregn undersökts utifrån deras påverkan på dagvattenmagasin, med syfte att kunnarekommendera vilken regndata som bör användas vid dimensionering av dessa anläggningar.Arbetet har genomförts med modelleringsverktyget MIKE+ där modeller av dagvattensystemhar belastats med olika regndata. Fem modeller har använts, varav tre var befintliga modellerfrån Gustavsberg, Lund och Malmö. Typregnen som jämfördes var CDS-regn och blockregnmed en återkomsttid på tio år och varierande varaktigheter. Modellerna belastades även medhistoriska regnserier från åtta mätstationer i Sverige. Fokus låg på magasinens vattennivåer,överbelastningar och kritiska regnvaraktigheter.Resultaten visade att CDS-regn med sex timmars varaktighet gav de högsta vattennivåerna imagasinen. Antalet överbelastningar översteg förväntningarna, och regn som översvämmadeolika magasin hade olika varaktigheter. Kritiska regnvaraktigheter identifierades för varjemagasin vilket motsvarade den varaktighet som bidrog till högst vattennivåer i magasinen. Iarbetet togs även ett föreslaget nyckeltal fram för varje magasin i ett försök till att förklaravariationerna i kritiska varaktigheter. Nyckeltalet baserades på magasinens reducerade area ochstrypflöde. En viss korrelation mellan magasinens kritiska varaktigheter och det föreslagnanyckeltalet konstaterades och beskrevs med en trendkurva. Förhållandet visade att höganyckeltal för magasin gav högre kritiska varaktigheter. Det typregn som tillslutrekommenderades var CDS-regn med sex timmars varaktighet, under förutsättning att denkritiska varaktigheten för magasinen är kortare än sex timmar. Med hjälp av trendkurvan sompresenterades i arbetet kan den kritiska regnvaraktighet uppskattas för ett magasin som skadimensioneras. Vetskap om den kritiska varaktigheten kan därefter underlätta valet avvaraktighet för det typregn som är dimensionerande och det kan även underlättavalideringsteget vid dimensionering av dagvattenmagasin.

<p>Fresh groundwater quality and availability in coastal areas is affected by seawater intrusion into coastal aquifers, and coastal water quality and ecosystem status may be significantly affected by groundwater pollutants that are transported into coastal waters by submarine groundwater dis-charge (SGD). This thesis uses an overall regional perspective for investigating: i) seawater intru-sion and its possible control in sustainable coastal groundwater management; ii) SGD and its relevant quantification as one interacting part among the diverse main regional pathways of freshwater and tracer/pollutant inputs from land to sea; and iii) the integrated system functioning of both i) and ii) as main components of the same coastal groundwater system.</p><p>Results show that intensive pumping rates may be maintained for a long time before major re-gional seawater intrusion problems are recognized by too high salinities in pumped groundwater. After such late recognition, pumping wells are no longer useful and a common strategy of mov-ing groundwater pumping further upstream from the coast only increases the extent of the salt-water intrusion zone into the aquifer. An alternative strategy may be to control seawater intrusion through artificial groundwater recharge, for instance by sufficiently treated wastewater, which may considerably reduce long-term trends of salinity increase in pumped groundwater, even for small artificial recharge rates compared to pumping rates. In general, account for natural spatial-temporal variability and randomness may be essential for relevant prediction of groundwater dynamics for management purposes. Spatial and temporal randomness effects, however, may not be additive, but rather largely overlapping, with either spatial or temporal randomness being the dominating part that must be accounted for in predictive groundwater dynamics calculations. Aquifer depth is identified as an important control parameter in this context, yielding much greater temporal randomness effects in shallow than in deep aquifers.</p><p>Combined simulation results suggest a simple, approximately linear regional relationship between total SGD and its hydrologically determined freshwater component. Tidal oscillation may signifi-cantly affect such linear dependence of steady-state SGD, but primarily for low SGD conditions. High SGD appears to depend mainly on a dominant freshwater component, which effectively counteracts density-driven flow of seawater into the aquifer and thus decreases also effects of sea-level oscillation on the seawater component of total SGD. Comparative analysis between different SGD estimation methods in different reported high-SGD regions of the world indicates possible anomalously large regional SGD estimation from tracer concentrations in coastal waters, by confusing different main pathways of groundwater flow and pollutant inputs to the sea.</p>

Fresh groundwater quality and availability in coastal areas is affected by seawater intrusion into coastal aquifers, and coastal water quality and ecosystem status may be significantly affected by groundwater pollutants that are transported into coastal waters by submarine groundwater dis-charge (SGD). This thesis uses an overall regional perspective for investigating: i) seawater intru-sion and its possible control in sustainable coastal groundwater management; ii) SGD and its relevant quantification as one interacting part among the diverse main regional pathways of freshwater and tracer/pollutant inputs from land to sea; and iii) the integrated system functioning of both i) and ii) as main components of the same coastal groundwater system. Results show that intensive pumping rates may be maintained for a long time before major re-gional seawater intrusion problems are recognized by too high salinities in pumped groundwater. After such late recognition, pumping wells are no longer useful and a common strategy of mov-ing groundwater pumping further upstream from the coast only increases the extent of the salt-water intrusion zone into the aquifer. An alternative strategy may be to control seawater intrusion through artificial groundwater recharge, for instance by sufficiently treated wastewater, which may considerably reduce long-term trends of salinity increase in pumped groundwater, even for small artificial recharge rates compared to pumping rates. In general, account for natural spatial-temporal variability and randomness may be essential for relevant prediction of groundwater dynamics for management purposes. Spatial and temporal randomness effects, however, may not be additive, but rather largely overlapping, with either spatial or temporal randomness being the dominating part that must be accounted for in predictive groundwater dynamics calculations. Aquifer depth is identified as an important control parameter in this context, yielding much greater temporal randomness effects in shallow than in deep aquifers. Combined simulation results suggest a simple, approximately linear regional relationship between total SGD and its hydrologically determined freshwater component. Tidal oscillation may signifi-cantly affect such linear dependence of steady-state SGD, but primarily for low SGD conditions. High SGD appears to depend mainly on a dominant freshwater component, which effectively counteracts density-driven flow of seawater into the aquifer and thus decreases also effects of sea-level oscillation on the seawater component of total SGD. Comparative analysis between different SGD estimation methods in different reported high-SGD regions of the world indicates possible anomalously large regional SGD estimation from tracer concentrations in coastal waters, by confusing different main pathways of groundwater flow and pollutant inputs to the sea. / QC 20101012

<p>New possibilities of nutrients removal by additions of magnesium compounds were studied in primary treatment and supernatant of side stream in wastewater treatment. The precipitation product from this method is magnesium ammonium phosphate (MAP) socalled struvite. High efficiencies on NH4-N and PO4-P removals have been demonstrated up to over 90 % respectively in side stream from dewatering of digested sludge. In order to find out the nutrient removal efficiency in raw wastewater and the feasibility of MAP recycling in wastewater treatment, the postulations of combining MAP and nitrification-denitrification process, and MAP and partial nitritation-anmmox process were carried out by experimental works in the laboratory at Land and Water Resources Department, KTH. It was found that 92-97 % of PO4-P and 57 % of NH4-N were removed from raw wastewater by Mg2+ addition at pH10 to pH10.5. The research work revealed that recycling of MAP by nitrification-denitrification and partial nitritation-anmmox processes may be a feasibly process combination. In MAP and nitrification -denitrification process, the released ammonium was mostly oxidized to nitrate in nitrification phase and ready for denitrification. Based on presented results on MAP and partial nitritation-anmmox process, it was found that the released ammonium was consumed by anammox bacteria.</p>

<p>Land use/cover has shown significant changes during the past three decades in Ethiopia especially in the highlands of the country. That resulted in changes in streamflows and other hydrological processes. The existing land and water resources system of the area is adversely affected due the rapid growth of population, deforestation, surface erosion and sediment transport. The main objective of this study is to evaluate the impact of land use/cover changes in the hydrology of <em>Beles</em> Basin, Ethiopia. The physically based hydrologic model, SWAT, was developed for the <em>Beles</em> basin, Ethiopia by combining geospatial and climatic data. ArcGIS has been used to process geospatial data which includes the Digital Elevation Model (DEM) which has a resolution of 90 m, land use/cover and soil maps. A simple Interpolation technique has been used to fill in the missing precipitation data. The GIS interface version of SWAT (ArcSWAT) has the capability to utilize ArcGIS to facilitate input data preparation and output data generation. Idrisi Andes in cooperation with ArcGIS 9.2 used to generate landuse/cover maps from Landsat data of three different years. Three SWAT models were set up using the three generated land use/cover maps and used to evaluate the land use/cover change and its impacts on the streamflow of study basin. The primary hydrological model was evaluated through sensitivity analysis, model calibration, and model validation for realistic prediction of the different hydrological components in the basin. Out of twenty six flow parameters sixteen parameters were found to be sensitive. But the most sensitive ten parameters were selected and used for model calibration. The model calibration was carried out using observed streamflow data from 01 January 2001 to 31 December 2002 and a validation period from 01 January 2003 to 31 December 2004. The coefficient of determinations (<em>R2</em>) was 0.74 and the Nash-Sutcliffe simulation efficiency (<em>NSE</em>) was 0.62which indicated that the model was able to predict streamflow with reasonable accuracy. However, the hydrograph of the cumulative hydrographs of the calibration and validation periods showed significant discrepancies between the observed and the simulated data of each period.  The average yearly flow volume of the observed streamflow on the cumulative hydrograph of the calibration period has exceeded the simulated streamflow. On the other hand on the cumulative hydrograph of the validation period the average yearly flow volume of the simulated streamflow was higher than the observed streamflow. The simulated result of the streamflow data from different land use/cover maps revealed that the change in the land use/cover classes of the basin throughout the study periods.</p> / QC 20100707

<p>År 2000 startades ett samarbete mellan Wuhan i Kina och Borlänge Energi i Sverige. De två parterna bestämde år 2005 tillsammans med IVL, Svenska Miljöinstitutet, att samarbeta inom följande områden; hållbar energiproduktion, hållbar avfallsproduktion samt grundandet av ett miljöteknikcentrum i Wuhan. Miljöteknikcentrumet är till för att vara en plattform för svensk miljöteknik och expertis. Som ett första steg inför grundandet av ett miljöteknikcentrum gjordes en undersökning för att se inom vilka sektorer svensk miljöteknik kan etableras.</p><p>Undersökningen var inriktat på industriell avloppsvattenrening i Wuhan; bedömning av vilka typer av industrier/företag som har problem med avloppsvattenreningen och i vilken utsträckning det finns svenska tekniklösningar på problemen. Undersökningen genomfördes genom intervjuer med myndigheter och en del utvalda företag. Det var svårt att få fram information om vilka företag som inte följer de kinesiska gränsvärdena, varför en del besök gjordes till företag som lever upp till gränsvärdena. På grund av detta togs även andra problem med miljön som företagen hade upp. Några kommunala reningsverk besöktes och intervjuades också för att få en bättre bild av den kommunala vattenreningssituationen. En generell beskrivning av Wuhans miljösituation utfördes också samt en beskrivning av de viktigaste miljömyndigheterna och institutionerna.</p><p>Wuhans största utmaning är att konstruera reningsverk till alla de 3.5 miljoner som fortfarande släpper sitt avloppsvatten rätt ut till sjöar och floder, snarare än att ytterligare rena det industriella avloppsvattnet. Behandlingsgraden av det industriella avloppsvattnet har nått 97 % medan behandlingsgraden av det kommunala avloppsvattnet endast nått 70 %.</p><p>Besök vid de utvalda företagen och kommunala reningsverk ledde till slutsatsen att svensk teknik och expertis kan införas i följande områden: hantering av slam från reningsverk, byggandet av förbränningsanläggningar för sopor och hur man löser problemet med att rena luften från gaser som SO2 och dioxiner. De flesta företagen kunde följa de kinesiska gränsvärdena för utsläpp av avloppsvatten men mycket kan göras för att förbättra företagens tekniker ytterligare. Detta utförs dock nästan aldrig eftersom det är en ekonomisk fråga. Det är möjligt för Wuhan att sätta lokala, hårdare gränsvärlden för att tvinga företagen att förbättra sina reningstekniker ytterligare.</p> / <p>In 2000 a co-operation between Wuhan in China and Borlänge Energi in Sweden started. The two parts decided in 2005 together with IVL, the Swedish Research Institute, to co-operate in the fields of sustainable energy production, sustainable waste management and the establishment of an Environmental Technology Centre, supplying Swedish environmental expertise to companies in Wuhan. As a first step for the establishment of an Environmental Technology Centre in Wuhan, an investigation was made to find out in which sectors Swedish environmental technology could be established.</p><p>The investigation took aim at observing the industrial wastewater treatment in Wuhan and to see which types of companies that have problems with the wastewater treatment and if there existed Swedish technology that could solve the problems. The investigation was performed through interviews with the authorities and some selected companies. It was difficult to get information about companies that did not comply with the National Chinese wastewater standards. This meant that some of the visits were made to companies that comply with the standards, also taking into consideration other problems with the environment that the companies might have. Visits were also paid to municipal wastewater treatment plants to get an overview over the municipal wastewater treatment situation. An overall survey of the environmental situation in Wuhan was also made and a presentation of the most important environmental departments and institutions is given.</p><p>The greatest challenge for Wuhan is to construct wastewater treatment plants for the around 3.5 million people that still discharge their wastewater directly to rivers and lakes, rather than to improve the industrial wastewater treatment further. The treatment rate of the industrial wastewater has reached 97%, but the municipal wastewater treatment rate has only reached 70%.</p><p>After the visits to the selected companies and municipal wastewater treatment plants the conclusion was made that Swedish technologies and expertise can be applied to the following areas; handling sludge from the wastewater treatment plants, construction of waste incineration plants and handling flue gas and dioxins. Most of the visited companies could follow the wastewater standards. Although much can be done to improve their technologies further, this is not done since it is too expensive. It is possible for Wuhan to apply stricter local wastewater treatment standards. This could be used as a tool to make companies invest more money in improvements of their technologies.</p>

<p>This master's theses was carried out on assignment from Stockholm Vatten AB as a part of a project developing new waste water treatment techniques. The goal of the theisis has been to evaluate an anaerobic membrane bioreactor for treatment of waste water from Hammarby Sjöstad. The bioreactor has not been heated and the main interest has been to study the gas production, power consumption and the reduction of organic matter and nutrients.</p><p>The system has been completed with a reverse osmosis unit and a total of four batch runs have been made with good results. The use of reverse osmosis allows nutrient in the waste water to be reintroduced into circulation as the reverse osmosis concentrate can be used as crop nutrient.</p><p>The membrane unit is of VSEP ("Vibratory Shear Enhanced Processing") type and an extensive membrane test has been conducted. This so called L-test helped determine the most suitable type of membrane for the system to allow a higher ±ux and thus lower power consumption. The L-test gave good results and a new membrane with a poresize diameter of 0,45 μm was used.</p><p>The organic load on the bioreactor has been more or less constant, around 0,7 kg COD/day, during the seven weeks of testing. The reduction over the entire system including reverse osmosis has been large, around 99 % regarding organic matter and phosporus and 93 % for nitrogen, making the system suitable for waste water treatment except for high power consumption, around 2 kWh/m3. The production of methanegas has worked although it has been quite low, with average values of 0,13 m3 CH4/kg reduced COD.</p> / <p>Examensarbetet är utfört på uppdrag av Stockholm Vatten AB som en del av det pilotprojekt som utvärderar nya tekniker för avloppsvattenrening för Hammarby Sjöstad. Målsättningen med studien har varit att utvärdera ett system bestående av en anaerob membranbioreaktor för behandling av avloppsvatten från Hammarby Sjöstad. Bioreaktorn har inte varit uppvärmd och det som har studerats är reningseffekten, biogasproduktionen samt energiåtgången.</p><p>Systemet har även innefattat en omvänd osmosanläggning och totalt har fyra försök med denna gjorts med goda resultat. Analyser har koncentrerats till att utvärdera reduktion av organiskt material över membranbioreaktorn och av närsalter och metaller över omvänd osmos anläggningen. Bakgrunden till att använda omvänd osmos är att öka återföringen av näringsämnen från avloppsvatten. Resultatet av försöken med omvänd osmos gav ett koncentrat med högt näringsinnehåll och låg halt av tungmetaller vilket ger möjligheten att sprida det på åkermark.</p><p>Membranenheten är av typen VSEP ("Vibratory Shear Enhanced Processing") och ett membrantest har även utfötts för att finna det membran som passar systemet bäst med avseende på flöde och energiförbrukning. Det så kallade L-testet var omfattande och gav en klar bild över vad som skulle vara det bästa membranet. Det membran som visade sig passa systemet bäst var ett membran med en porstorlek på 0,45 μm. Belastningen av organiskt material på reaktorn under försöksperiodens sju veckor har varit mer eller mindre konstant och låg, cirka 0,7 kg COD/dygn. Reduktionen över hela systemet inklusive omvänd osmosanläggningen med avseende på organiskt material och fosfor har varit mycket hög, omkring 99 %. Reduktionen av kväve var som högst 93 %. Gasproduktionen har fungerat och har i genomsnitt varit omkring 0,13 m3 CH4/kg reducerad COD.</p><p>Energiförbrukningen för systemet i motsvarande fullskala blev omkring 2 kwh/m3.</p>