Projektet genomfördes vid IVL Svenska Miljöinstitutet i Hammarby Sjöstadsverk i samarbete med Kungliga Tekniska Högskolan (KTH). Syftet med detta projekt är att jämföra biogas potential mellan tre olika förbehandlingsmetoder av avloppsslam före rötningen, dessa metoder är djup och lätt frysning samt uppvärmning av slammet. Rötningsprocesser kan göras vid olika temperatur, olika inmatningshastighet och olika antal steg. Oavsett exakt utformning innebär rötningen fyra steg: hydrolys, fermentering, anaerob oxidation och metanbildning. Vid rötningen produceras metangas vilken används till uppgradering för att producera fordonsbränsle, värmeproduktion, elproduktion och fackling. Det har visat sig att förbehandlingsmetoderna har en stor potential för att utöka gas produktionen genom förbehandling av avloppsvattensslam före en anaerob rötning som utfördes i laboratorieskala med hjälp av ”Automatisk Metan Potential Test System(AMPTS II). Experimentet visade på lovande resultat, det har skett en ökning av metanutbytet på två av dem testade metoderna i jämförelse med det obehandlade slammet och ett referensprov med bara inocolum. Försöket avslutades efter 35 dagarsrötning, den optimala metanpotentialen som erhålls var 0,25 Nm3 CH4/kg VS framställd av djupfrystslam och 0,21 Nm3 CH4/kg VS producerad av uppvärmt slam, detta betyder en förbättring på biogas potential med 34 respektive 16 procent men lättfryst slam procentuella minskningen av metan potential ligger på 21 procent mot det obehandlade slammet. 1 Nm3 biogas motsvarar cirka 1 liter bensin som ger lika lång körsträcka, men är något billigare, bilarna får dessutom en 5–10 dB lägre bullernivå, detta uppfattas som hälften så bullrigt som ett dieseldrivet (Stockholm Vatten, 2004) På grund av att det krävs stora anläggningar och mycket slam för att få lönsamhet i verksamheten är rötningen av avloppsslam idag koncentrerad till storstadsregionerna. Genom att röta avloppsslammet minskar mängderna som behöver gå till deponi och klimatvinster kan göras då biogas ses som klimatneutral till skillnad från fossila bränslen. Att investera i biogasutvinning innebär även en ekonomisk risk då distributionsnätet inte är helt utvecklat och konsumenters intresse för bränsleformen ur ett mer långsiktigt perspektiv är svårbedömt. Det finns dock flera goda exempel på lönsamma anläggningar, ett sådant är i Stockholm där reningsverken idag levererar biogas till SL:s bussar vilket ger tystare gator och mindre partiklar i stadsmiljön (SL, 2010). Trots att det finns en del frågetecken kring exakt hur stor potential för produktionen är och att en ökning troligen samverkar med en ökad vilja att satsa på bränslet både från myndigheter, företag och enskilda konsumenter finns det en framtid för rötningen. Rötningen av avloppsslam för att producera biogas bör inte ses som en enskild energikälla utan snarare som ett komplement och ett sätt att utnyttja de resurser vi har för att skapa ett mer hållbart samhälle. Därför är satsningar och investeringar för att utveckla produktion och distribution av biogas från rötning vid avloppsreningsverk väl motiverade och bör uppmuntras. / The project was carried out at the Swedish Environmental Research Institute in Hammarby Sjöstadsverk in collaboration with the Royal Institute of Technology (KTH). The purpose of this project is to compare the biogas production based on different methods of pretreatment of sewage sludge before digestion. The digestion process can be done at different temperature, different feed rate and different number of steps. Whatever the precise formulation involves digestion of four steps: hydrolysis, fermentation, anaerobic oxidation and methane formation. Upon digestion produced methane gas which is used to upgrade to produce vehicle fuel, heat, power generation and flaring. There is a potential to expand gas production by those methods in this project, tested for pretreatment of wastewater sludge prior to anaerobic digestion in a laboratory scale using Automatic Methane Potential Test system ( AMPTS II).The experiment showed promising results; there has been an increase in methane yield in comparison with untreated sludge and reference samples with only inoculums. The experiment ended after 35 days of digestion, the optimum methane potential obtained was 0.25 Nm 3 CH4/kg VS made of deep frozen sludge and 0.21 Nm 3 CH4/kg VS produced by the heated sludge this means that deep freezing enhances the biogas potential with 34 % and the heating of the sludge by 16 % but easily frozen sludge had less methane potential than the untreated sludge by 21 %. Because of the need for a large facilities and much sludge to get a profitable operation, the anaerobic digestion of sewage sludge is now concentrated in the metropolitan areas. By digesting sewage sludge reduces the amounts that need to go to landfill and climate gains can be achieved when biogas is seen as carbon neutral, unlike fossil fuels. Investing in biogas production also involves a financial risk when the distribution network is not fully developed, and consumer interest in fuel form from a longer term perspective is difficult to assess. However, there are several good examples of profitable plants; one is in Stockholm, where treatment plants currently supply biogas to SL's buses for quieter streets and less particles in the urban environment. Although there are some questions about how exactly great potential for production and that an increase is likely interacts with an increased willingness to invest in the fuel from authorities, companies and individual consumers, there is a future for digestion. Anaerobic digestion of sewage sludge to produce biogas should not be viewed as a single energy source, but rather as a supplement and a way to exploit the resources we have for creating a more sustainable society. Therefore, initiatives and investments to develop the production and distribution of biogas from anaerobic digestion at wastewater treatment plants well justified and should be encouraged.

Due to the impoundment of the Three Gorges Dam a decrease in sediment flow has been a major factor for erosion on the riverbed further downstream in the Yangtze River. This rapport studies the water flow conditions in the Nanjing reach. It also examines the effect of building a diversion dike at the head of the reach as a measure to redistribute some of the water flow to the northern branch. This branch suffers from a declining water flow, largely as a consequence from the erosion in the southern branch. By constructing a numerical model model with the software SMS, the current conditions of the reach were simulated. The simulated diversion dike having best effect on diverting water was able to improve the split ratio with 4.3 percentage points.

Every year around 270 million tonnes of plastic are produced worldwide. As a result of poor waste management in many countries, a large amount of it ends up in the world’s oceans where it degrades into micro particles. The degrading plastic particles release toxic chemicals, which can bioaccumulate in bodies of oceanic life and subsequently travel through the nutrition chain. Hence it is of great importance to find solutions to this problem. In this report, the composition and scale of plastic marine debris is investigated using data collected from fieldwork performed by the authors in a number of countries around the world, as well as through examining and combining reports from the International Coastal Cleanups organized by Ocean Conservancy. The combined data is used to create a top ten ranking of the most common plastic marine debris and its corresponding plastic type. The most common items were determined to be e.g. beverage bottles and plastic bags and the most common plastic type was estimated to be PP, LDPE and PET. According to the data collected through the fieldwork, the total plastic share of the marine debris was estimated to range between 67.4% and 86.3%. Further, the possible economic gains of conventional material recycling, incineration for energy recovery and microwave pyrolysis as a material recovery process are investigated. The study is executed partly by reviewing several scientific articles on the subject as well as by practical laboratory work with microwave pyrolysis of polystyrene. The study shows that conventional recycling is not a sufficient treatment, due to the photo degradation of the polymers in the oceans. Furthermore, end products from incineration give a greater economical gain and provide for a less complicated and time-consuming procedure than microwave pyrolysis when considering the composition of plastic marine debris. However, microwave pyrolysis is a more environmentally friendly option than incineration due to the greenhouse gas emissions caused by incineration.

The heavy metal pollution from a former solid waste disposal site in Dar es Salaam, Tanzania, that is currently used for urban farming was investigated. The pollution was assessed by measuring the content of copper, lead, zinc and chromium in soil, plants and leachate from the site as well as in the adjacent river. The safe daily intake of onsite cultivated vegetables, in regard to the heavy metal content, was calculated. The analysis showed that there is a health risk connected to consuming vegetables in volumes greater than 100 g cowpea leaves, 70 g pumpkin leaves or 1700 g maize grains for someone with a body weight of 80 kg due to the concentration of Pb. The heavy metal content in leachate exceeded the Swedish limits for leachate discharge to water recipient. The river water contained too high levels of Cr to be within the FAO standards set for irrigation water. Measures are urgently needed to cover the site with a final layer and collecting the leachate for purification. To stop further contamination from the Vingunguti dumpsite the bottom and sides of the dump need to be covered to ensure a fully enclosed site. The local community also needs to be informed of the risks connected to urban farming in the area.

The purpose of this bachelor degree thesis is to analyze technical issues associated with an implementation of a low sloping trash rack with narrow spacing. A hydropower plant in Umeälven was used as a case study. The basis for the study was a model where trash racks were dimensioned for inclinations between 25 and 45 degrees. Corresponding head loss, durability and water speed through the rack were then determined for each inclination. Necessary measures are thereafter discussed for the installation. Finally some of the estimated costs and incomes regarding the installation are presented. An implementation of a narrow spaced trash rack (10 mm) with an inclination of 30 degrees will cause an exceeding of the tolerance speed through the rack 15 percent of the operational time when there is no clogging. Furthermore, the change of intake screens result in an increase of the head loss of 4.8 millimeters, which corresponds to an income loss of 25000 SEK annually due to reduced production. Complimentary measures include supporting beams, new lower attachment point and an extension of the intake walls. The final cost is strongly dependent on how the installation work is done. A high cost may occur due to an interruption in the production and when extensive arrangements for the implementation are needed, such as the construction of a cofferdam. In total a replacement of trash racks will cost at least 8 184 000 SEK, in addition to 216 000 SEK/day due to loss of production. Moreover expenses for the supporting beams and extension of the intake are added as well. / Syftet med detta kandidatarbete är att analysera tekniska spörsmål kopplade till en installation av låglutande fingaller. Som fallstudie används ett kraftverk i Umeälven. Grunden för underlaget utgörs av en beräkningsmodell där intagsgaller dimensioneras för lutningar mellan 25 och 45 grader. För varje lutning bestäms tillhörande fallförluster, erforderlig hållfasthet samt vattenhastighet genom gallret. Därefter diskuteras vilka kompletterande åtgärder som krävs för installationen. Slutligen belyses en del av de intäkter och kostnader som är relaterade till installationen. En installation av ett fingaller med 10 millimeters spaltbredd och 30 graders lutning i kraftverket kommer leda till att toleransnivån för normalhastigheten 0.5 m/s genom gallret överskrids 15 procent utav drifttiden då ingen igensättning råder. Gallerbytet medför vidare att fallförlusterna ökar med minst 4.8 millimeter, vilket motsvarar ett intäktsbortfall på lägst 25 000 SEK årligen på grund av minskad produktion. Igensättning av gallret är en faktor som inte bidrar nämnvärt till ökade kostnader, varken för rensning eller i form av minskad produktion. Vid utebliven rensning hotas dock den ekologiska funktionen då toleransnivån för normalhastighet genom gallret överskrids i högre utsträckning. Ekologiska spörsmål blir således aktuella tidigare än de tekniska. Kompletterande åtgärder innefattar stödjande balkar, ny nedre fästpunkt och utbyggnad av aggregatintagsväggarna. Omfattningen av dessa är direkt kopplade till hur mycket gallret lutas. Den slutgiltiga kostnaden är starkt beroende av hur åtgärderna genomförs. En hög kostnad uppstår ifall omfattande kringåtgärder som uppförande av fångdamm med fullständigt produktionsstopp krävs. Totalt kommer ett gallerbyte som lägst kosta 8 184 000 SEK där produktionsstopp på i genomsnitt 216 000 SEK/dag samt kostnader för utbyggnad av aggregatintagsväggarna och stödanordningar tillkommer.

BackgroundEnvironmental issues have become relevant all over the world. This has led to customers putting high demands on company that manufactures the product they purchase, to ensure that it’s been manufactured in an environmentally friendly manner. One way for companies to reduce their environmental impact is to improve the organizations energy efficiency. There is, however, a lack of knowledge of what truly affects the companies’ incentives to implement these investments. The research has not yet succeeded in mapping out whether the companies’ perception of the driving forces can be explained by means of its corporate characteristics. ObjectivesThe objective of this study is to contribute with knowledge of what is affecting the companies’ incentives to invest in energy efficiency improvements. The purpose is to study which driving forces affect the companies most when they have the opportunity to implement an energy-efficient property- technical investment. Furthermore, the intention is to investigate whether the proximity of large Swedish manufacturing companies to the end customer influences their perception of the importance of these driving forces. The result of the study can be used as an aid for suppliers of energy-efficient systems as they through this research can gain knowledge of what their customers value in order to adapt their marketing accordingly. MethodsThe study was carried out using a quantitative analysis where primary data was collected through a questionnaire sent out by e-mail. In order to ensure a high reliability and validity in the study, the questionnaire was designed with the help of already tested and validated secondary data. This questionnaire was then sent out to large manufacturing companies in Sweden and a collection of 121 replies was made. The collected material was processed in SPSS using relevant analyzes and tests in order to answer the research questions of the study. ResultsOnly the importance of one driving force differed between companies that had different proximity to the end customer. Deeper analysis, on the other hand, reviled that the importance of 11 driving forces differed between companies that had different energy intensities. ConclusionsThe perception of the importance of government subsidies when investing in energy-efficient systems differs between companies that have different proximity to the end customer. An increased understanding of the difference in perceived significance can be obtained if consideration is also given to the company’s energy intensity.

In concomitance with the growing developments around the circular economy concept in the region, the resource recovery and recycling of industrial production residues is increasingly being envisaged in the European Union and its member states. The role of the recycling industry has become ever important in this context. The shredding industry is based on shredding discarded products such as end-of-life vehicles, and municipal white goods, and subsequent retrieval of (primarily) metals. Shredder fines (or fines) is a heterogeneous fine-granular production residue of this industry, which is currently disposed of. Shredder fines presents, and will continue to do so in the foreseeable future, several challenges that need to be addressed. It creates a disposal problem given the shrinking landfill availability and incurs handling costs to the shredding industry. Furthermore, it reduces our resources efficiency in general. This thesis aims to contribute knowledge on the challenges of facilitating the valorisation of shredder fines in the context of Sweden. In doing so, the current situation concerning fines and its management was investigated by addressing the research questions; 1) What is the resource potential of fines generated at the studied shredding plant, and 2) Why is the current disposal-oriented management of shredder fines sustained in Sweden. There, a systems perspective was employed, where the research questions were addressed on the material, actor, and institution levels, based on three scientific articles, which are appended. The studied material carries a certain amount of potentially recoverable resources, nevertheless shows a significant need for upgrading pertaining to the user requirements and regulatory standards of different recovery applications. The full recovery of fines requires integrated processes that could simultaneously harness these resource opportunities and resolve the material constraints. When it comes to the current practice of managing fines in Sweden, the utilisation in landfill covering offers the shredding companies a secure outlet for the material, given it is a well-established practice that has evolved over decades of operations and there is still a significant demand for landfill cover materials. Additionally, it provides shredding companies with a legislatively-compliant low-cost disposal option for managing fines. On the other hand, the complex materiality, lack of marketability of secondary raw materials (SRMs), and unfavourable governmental regulation of waste recovery create strategic disincentives for shredding companies in opting for fines valorisation. Fines valorisation calls for change in the well-established current practice of utilising the material in landfill covering. Thus, drastic policy measures such as phasing out landfilling and mandating resource recovery and recycling of fines are required to remove the incentives for fines disposal and compel the shredding industry to seek valorisation alternatives for its management. In order to ensure long-term sustenance, applications based on fines valorisation need favourable and more predictable circumstances and settings on different societal levels. There, secure outlets for potential fines-derived SRMs is one of the essential elements. Governmental interventions to create demand and alleviate valorisation investments via market and financial instruments play a significant role in that regard. The other primary requirement to facilitate fines valorisation in the long term is to set clear market and regulatory playing rules. Established supply and demand structures would enable clear pricing mechanisms for fines-derived SRMs and accurate economic assessments of fines valorisation, thus reducing the investment risk for shredding companies. On the other hand, clear regulatory standards and favourable regulatory practices would reduce the uncertainty of the realisation of valorisation applications and gain trust among actors.

Rapporten identifierar befintliga återvinningsmetoder för litiumbatterier och analyserar två avmetoderna på djupare nivå, en hydrometallurgisk metod och en pyrometallurgisk metod.Analysen är avgränsad till att utvärdera metoderna med Sverige som systemgräns och utifrånett ekologisk hållbarhets- och ekonomiskt lönsamhetsperspektiv. Verktyg som använts är enSWOT-analys som baseras på en litteraturstudie och intervju där kriterier identifierats. Dekriterier som valts för att utvärdera ekologisk hållbarhet är elkonsumtion, behov avkemikalier samt farligt avfall. De ekonomiska lönsamhets aspekterna har utvärderats medavseende på återvinningsmetodernas kapacitet, återvinnings- och reningsgrad,investeringskostnader samt metodkomplexitet. Analysen resulterar i att denpyrometallurgiska metoden är mest lämpad för Sverige i dagsläget eftersom den har högkapacitet och överensstämmer med befintlig infrastruktur. Andra slutsatser som dragits är attval av återvinningsmetod är kontextbaserat med stor vikt vid geografiskt område och tillgångtill batterimaterial. / The report identifies existing recycling methods for lithium batteries and analyzes two of themethods, a hydrometallurgical method and a pyrometallurgical method, on a deeper level.The analysis is limited to evaluating the methods with Sweden as a system boundary basedon environmental sustainability and economic profitability. Tools used are a SWOT analysisbased on a literature study and interview where criteria were identified. The criteria chosenfor evaluating environmental sustainability are energy consumption, the need for chemicalsand hazardous waste. The economic profitability aspects have been evaluated with respect tothe capacity of the recycling methods, recovery and purification, investment costs andmethod complexity. The analysis concludes that the pyrometallurgical method is mostsuitable for Sweden today as it has high capacity and conforms with existing infrastructure.Other conclusions drawn are that the choice of recycling method is context-based with greatemphasis on geographical location and access to battery material.

Täby kommun har sommaren 2013 infört en för Sverige ny dagvattenreningsteknik i form av en flytande våtmark, som har anlagts i Rönningesjön. Tekniken kan förklaras som en hybrid, där de biologiska reningsprocesserna liknar en naturlig våtmark, medan anläggningen hydrologiskt fungerar mer som en sedimentationsdamm. Att våtmarken är den första i Sverige gör det extra intressant att utvärdera. I och med denna rapport har dels en specifik undersökning av anläggningen gjorts, med särskild vikt vid det begränsande näringsämnet fosfor. Vidare ges en bredare överblick av tekniken som sådan och dess framtidsutsikter i Sverige. För att bedöma anläggningens reningseffekt har flödesmätningar och provtagningar vid in- och utlopp gjorts under en period mellan vecka 15-24 2014. Analysen har sedan gjorts med avseende på fosfor, pH, konduktivitet och turbiditet. Utifrån undersökningen har beräknats att det vid utloppet till anläggningen skett en minskning av medelkoncentrationen totalfosfor med 9,4 %. Denna relativt låga reningseffekt förklaras utifrån en förhållandevis låg fosforhalt överlag vilket skulle kunna göra att våtmarken inte når sin maximala effektivitet, samt att anläggningens unga ålder gör att den ännu inte är fullt utvecklad. En ytterligare förklaring kan vara att det i denna begränsade studie har behövt göras ett antal förenklingar och antaganden, vilket innebär osäkerheter i resultatet. Reningseffekten bör därmed snarare ses som en riktlinje än ett absolut värde. För en mer komplett bild av våtmarkens reningskapacitet bör ytterligare analyser göras, och även på parametrar som denna undersökning ej tar hänsyn till, som exempelvis rening av kväve och tungmetaller. Vad gäller teknikens framtidsutsikter i Sverige finns det flera fördelar som talar för en fortsatt etablering. Tekniken är billig och i princip underhållsfri. Dessutom lämpar den sig väl att använda som komplement till redan befintliga anläggningar. Å andra sidan är det Svenska klimatet inte optimalt i och med långa vintrar med låg biologisk aktivitet vilket skulle kunna göra att effektiviteten i Sverige blir lägre än i varmare länder där tekniken använts tidigare. / The municipality of Täby has in the summer of 2013 introduced a storm water treatment technology, new to Sweden, in the lake Rönningesjön. The technology, which is called floating treatment wetlands (FTWs), can be explained as a hybrid system, where the biological treatment mechanisms are similar to the ones of a natural wetland, while the facility hydrologically behaves like a retention pond. This report is the result of a first examination of the water purification capacity, where the removal capacity of phosphorus has been of particular importance. Furthermore, the techology and its future prospects is being discussed in a wider perspective. To evaluate the removal capacity, a series of flow measurements and collection of water samples has been executed in a period between week 15-24 in the year of 2014. The analysis has subsequently been done in regard to the parameters total phosphorus, pH, conductivity and turbidity. The results show a reduction of mean total phosphorus betwen inflow and outflow by 9,4 %. This relatively low efficency may depend on the overall low concentrations of phosphorus, while the wetland reaches its maximum capacity at higher concentrations. Furthermore, the wetland may not be fully developed due to the youth of the facility why an improvement of efficiency could be expected over time. A further explanation could be that in this limited study, some simplifications and assumptions has been neccesary to do, and these provides some incertainty in the results. The removal efficiency should thereby rather be seen as a guideline. To provide a complementary view of the FTW removal capacity, further analysis should be executed, and also in parameters such as nitrogen and metal removal, which this study has not taken into account. Regarding the future prospects of the technology in Sweden there a several advantages proposing a continued establishment. The technology is inexpensive and requires a low maintenance. It is also suitable to use as a complement to existing facilities. On the other hand long winters in Sweden with low bioactivity may reduce the efficency compared to other countries where the technology previously has been used.

This master thesis firstly includes a theory part describing, the conventional municipal wastewater treatment plant (WWTP) and especially the conventional activated sludge (CAS) process. As Stockholm municipality want to retrofit the current activated sludge system at Henriksdal into a membrane bioreactor (MBR), an extensive description of the MBR and its advantages and disadvantages are included. Fouling is considered a really important issue for the operation of an MBR since it reduces an MBR’s productivity over time. Therefore, description of the fouling mechanisms and the potential foulants is included as well as a description of the membrane cleaning procedures. Sludge composition is considered a very important parameter which contributes to membrane fouling and thus this master thesis aims to identify the effects of varying sludge quality on the membranes operation. Precipitation chemicals used for phosphorus chemical precipitation and especially ferrous sulphate which is examined in this master thesis are also affecting the sludge quality and the membranes operation. The report includes description of Henriksdal reningsverk and line 1 of the pilot MBR at Hammarby Sjöstadsverk where the experimental work was performed. The following chapter describes the experimental work performed in the laboratory including the determination of total suspended solids (TSS), volatile suspended solids (VSS), sludge volume index (SVI) and sludge’s filterability. The filterability was determined by performing the time to filter (TTF) method and the sludge filtration index (SFI) method. Furthermore, the samples were also examined in the optical microscope to determine their bulkiness and their filaments content. The iron content in the sludge was also measured from Eurofins Environment Testing Sweden AB. In the results section, the different parameters measured are illustrated in charts and they are compared to each other in order to define which factors contribute positively or negatively to the sludge’s filterability and thus affect the sludge quality and the membranes operation. The results indicate that SFI is a more reliable method for measuring filterability compared to TTF. Furthermore, the iron content in the sludge is proportional to the permeability as well as the filaments content observed during microscopy is proportional to the SFI or TTF. Finally, this master thesis includes recommendations for future research which basically include more analyses to identify the sludge biology and more samples taken for longer time periods.