To develop anaerobic digestion (AD), innovative solutions to increase methane yields in existing AD processes are needed. In particular, the adoption of low energy pre-treatments to enhance biomass biodegradability is needed to provide efficient digestion processes increasing profitability. To obtain these features, hydrodynamic cavitation has been evaluated as an innovative solutions for AD of waste activated sludge (WAS), food waste (FW), macro algae and grass, in comparison with steam explosion (high energy pre-treatment). The effect of these two pre-treatments on the substrates, e.g. particle size distribution, soluble chemical oxygen demand (sCOD), biochemical methane potential (BMP) and biodegradability rate, have been evaluated. After two minutes of hydrodynamic cavitation (8 bar), the mean fine particle size decreased from 489- 1344 nm to 277- 381 nm (≤77% reduction) depending of the biomasses. Similar impacts were observed after ten minutes of steam explosion (210 °C, 30 bar) with a reduction in particle size between 40% and 70% for all the substrates treated.  In terms of BMP value, hydrodynamic cavitation caused significant increment only within the A. nodosum showing a post treatment increment of 44% compared to the untreated value, while similar values were obtained before and after treatment within the other tested substrates. In contrast, steam explosion allowed an increment for all treated samples, A. nodosum (+86%), grass (14%) and S. latissima (4%). However, greater impacts where observed with hydrodynamic cavitation than steam explosion when comparing the kinetic constant K. Overall, hydrodynamic cavitation appeared an efficient pre-treatment for AD capable to compete with the traditional steam explosion in terms om kinetics and providing a more efficient energy balance (+14%) as well as methane yield for A. nodosum.

Så här långt i bokens tredje del har angreppssätt för att hantera miljöfrågor berörts ur olika perspektiv. Det har handlat om en historisk tillbakablick, övergripande strategier och produktutveckling, men också om systemperspektiv och miljösystemanalys. Boken har i många avseende samhällsfokus, men mycket av det som berörs har stor relevans för och inverkan på enskilda företag och andra typer av organisationer. De måste ofta inom ramarna för sin verksamhet och organisation hantera miljöfrågor som berör dem. Eftersom det kan vara nyttigt att försöka se situationen ur ett företagsperspektiv beskrivs i detta kapitel kortfattat hur miljöarbete kan se ut i dag i större svenska industriföretag.

Detta sjätte kapitel inleder bokens tredje del, som handlar om olika angreppssätt för att hantera miljöproblem. Kapitlet bidrar med en kort historisk översikt för att illustrera hur både synen på miljöfrågorna och åtgärderna förändrats över tid. Avslutningsvis summeras olika strategier för att jobba med miljöfrågor.

I detta kapitel beskrivs några betydande miljöproblem av global karaktär. Det handlar närmare bestämt om klimatförändringar, uttunning av ozonskiktet, minskad biologisk mångfald och användning av naturresurser. Syftet är att du som läsare bättre ska förstå vad som kännetecknar problemen, vad i samhället som orsakar dem, rådande trender och möjliga åtgärder.

Disinfection by-products (DBPs) are potentially toxic compounds formed when drinking water is treated with disinfectants, such as chlorine or chloramine. A large proportion of the exposure to DBPs is still unknown and the health risks observed through epidemiological studies cannot be explained by DBPs known today. In this thesis, a part of the unknown DBP fraction is investigated, covering a wide range of non-volatile, chlorine/bromine-containing DBPs. The goals were to investigate how the compositions of these DBPs differ between water treatment plants, how their occurrence changes in the distribution system until reaching consumers and how new treatment techniques can reduce their formation and toxicity. To analyze unknown DBPs, a non-targeted approach adopting ultra-high-resolution mass spectrometry, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), was used, where the mass of molecules is measured with such accuracy that the elemental composition of individual DBPs can be calculated. A panel of bioassays was used to assess the combined toxic effects from these DBP mixtures. 

The results show that the formation of these DBPs to a large extent was specific to each water treatment plant and that local conditions influenced DBP formation, based on e.g., the abundance of organic material with certain chemical structures, bromide and disinfection procedure and agent (chlorine or chloramine). The DBPs were detected in both chlorinated and chloraminated water and in all tap water samples, demonstrating that they are part of human exposure. The number of DBP formulae decreased and the DBP composition changed between drinking water treatment and consumer taps, suggesting that DBP exposure to consumers is not necessarily resembling measurements at the treatment plants. Evaluation of new treatment techniques showed that suspended ion exchange and ozonation have potential to decrease the formation and toxic effects of DBPs and that the removal of organic matter can influence qualitative aspects of DBP formation, such as the proportions of chlorine-containing (less toxic) versus bromine-containing (more toxic) DBPs. Through increased knowledge about the role and relevance of non-volatile DBPs, this work can contribute to future monitoring and actions to reduce the health risks associated with DBPs in chlorinated or chloraminated drinking water. 

Disinfection by-products (DBPs) are potentially toxic compounds formed upon chemical disinfection of drinking water. Controlling the levels and characteristics of dissolved organic matter (DOM) as precursor material for DBPs is a major target to reduce DBP formation. A pilot-scale treatment including suspended ion exchange (SIX (R)), a ceramic microfilter (CeraMac (R)) with in-line coagulation and optional pre-ozonation followed by granular activated carbon (GAC) filtration was compared with a conventional full-scale treatment based on DOM removal and DBP formation using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), rapid fractionation, liquid chromatography organic carbon detection (LC-OCD), adsorbable organic halogens (AOX) and trihalomethane (THM) analysis. The new treatment combination showed different selectivity for DOM removal, compared to the conventional, leading to changes in composition of the DBPs formed. SIX (R) and GAC had the largest impacts on reducing AOX and THM formation potentials but the high adsorptive capacity of GAC affected the diversity of detected DBPs most. Chlorination and chloramination of pilot treated water with doses normally used in Sweden produced low levels of AOX compared to the full-scale treatment, but FT-ICR MS revealed an abundance of brominated DBP species in contrast with the conventional treatment, which were dominated by chlorinated DBPs. This finding was largely linked to the high DOM removal by the pilot treatment, causing an increased Br-/C ratio and a higher formation of HOBr. Potential increases in Br-DBPs are important to consider in minimizing health risks associated with DBPs, because of the supposed higher toxicity of Br-DBPs compared to Cl-DBPs.

Disinfection by-products (DBPs) are unwanted, potentially toxic compounds formed when drinking water is disinfected with chemical disinfectants such as chlorine or chloramine. The levels of DBPs produced depends on parameters, such as levels of natural organic matter (NOM) and the nature and concentration of chemical disinfectant used. In this thesis, the effects of two different types of chemical disinfectants, chlorine and chloramine, are investigated in terms of levels of DBP production. The goal was to investigate if chlorine disinfection produces similar levels and types of DBPs as in case of chloramination.

Within the thesis work was also tested a method based on a gas chromatograph coupled with halogen selective detector (GC-XSD) to determine the known DBPs in the drinking water.

The results show that the formation of DBPs at chlorine or chloramine disinfection were similar. Still, chloramine is preferably used because it produces less legally regulated DBPs.

The GC-XSD worked well for the determination of DBPs in drinking water. Since XSD is very selective and specific towards halogens and easy to operate, therefore this setup not only a potential tool for routine DBPs monitoring at drinking water facilities, but it could also be used for the determination of unknow halogenated compounds.

Through increased knowledge in the formation of DBPs and their determination with GC-XSD can contribute to the development of better methods to quantify known and identify unknow halogenated organic compounds in treated drinking water and reduce public exposure to potentially toxic halogenated organic compounds.

Poor water quality is a global health concern affecting one billion people around the world. It is important to monitor water sources in order to maintain the quality of our drinking water and to avoid disease outbreaks. Targeting Escherichia coli as a faecal indicator is a widely used procedure, but the current methods are time consuming and not adequate to prevent spreading of faecal influence.

This Master thesis demonstrates the development of a near infrared fluorescence flow cytometer sensor system targeting Escherichia coli, using fluorescently labeled chicken IgY antibodies. The near infrared light was chosen to avoid fluorescence from blue-green algae that are present in the water source.

The hardware was developed with a 785  nm laser line to detect Alexa Fluor 790 labeled antibodies, using a photomultiplier tube or two different CMOS cameras. The antibodies were labeled using a commercial labeling kit, and evaluated using antibody binding assays and the developed hardware.

The IgY antibodies were successfully labeled with Alexa Fluor 790 and the function was maintained after the labeling process. The result demonstrates the principles of the sensor system and how it solved to the problem with fluorescence from blue-green algae. An aperture was used to overcome the suboptimal laser and filter setup, and to increase the sensitivity of the system. However, only a small fraction of the cells could be detected, due to challenges with the focal depth and loss of sensitivity in the photomultiplier tube at near infrared wavelengths. Further development is required to create a working product.

Giardia intestinalis, Cryptosporidium spp., Entamoeba histolytica and Dientamoeba fragilis are parasitic protozoa and causative agents of gastroenteritis in humans. G. intestinalis and Cryptosporidium spp. in particular are the most common protozoa associated with waterborne outbreaks in high-income countries. Surveillance of protozoan prevalence in wastewater and evaluation of wastewater treatment removal efficiencies of protozoan pathogens is therefore imperative for assessment of human health risk. In this study, influent and effluent wastewater samples from three wastewater treatment plants in Sweden were collected over nearly one year and assessed for prevalence of parasitic protozoa. Quantitative real-time PCR using primers specific for the selected protozoa Cryptosporidium spp., G, intestinalis, E. histolytica, Entamoeba dispar and D. fragilis was used for protozoan DNA detection and assessment of wastewater treatment removal efficiencies. Occurrence of G. intestinalis, E. dispar and D. fragilis DNA was assessed in both influent (44, 30 and 39 out of 51 samples respectively) and effluent wastewater (14, 9 and 33 out of 51 samples respectively) in all three wastewater treatment plants. Mean removal efficiencies of G. intestinalis, E. dispar and D. fragilis DNA quantities, based on all three wastewater treatment plants studied varied between 67 and 87%, 37-75% and 20-34% respectively. Neither E. histolytica nor Cryptosporidium spp. were detected in any samples. Overall, higher quantities of protozoan DNA were observed from February to June 2012. The high prevalence of protozoa in influent wastewater indicates the need for continued monitoring of these pathogens in wastewater-associated aquatic environments to minimise the potential risk for human infection. (C) 2017 Elsevier B.V. All rights reserved.

Due to an increasing global population and changes in diets the impact of food consumption on the world’s ecosystems and their services has become more significant. The purpose of this project has been to investigate how the impact on ecosystem services from Swedish food consumption has changed over time and if this development is sustainable or not. A quantitative assessment of six different environmental impact factors has been carried out for each food category. The project clarifies how Swedish food consumption has developed since the 1960s, the origin of the food that has been consumed, which processes that affect the environment as well as the consequences from these impacts. The result showed that Swedish food consumption has increased considering quantity, that the consumption pattern has changed, and that the import of goods has increased since the 1960s. The average Swede eats more animal-based products such as meat, cheese and cream, along with more vegetable-based products such as fruit and berries, and vegetables. Instead, products such as milk and soured based products has decreased, while products made from flour and grains has stayed unchanged. The project shows that animal-based products, especially from ruminant animals, has a significantly higher ecological footprint in comparison with vegetable-based products, concerning most of the categories mentioned above. Considering that the swedes eat more animal-based products today than in the 1960sthefollowing conclusion, that the Swedish impact on ecosystem services has increased since the 1960s even though food production has become more efficient, could be drawn.

Linköpings Universitet har tillsammans med Pöyry och Scandinavian Biogas Fuels drivit projektet ”Etablering/effektivisering av  biogasproduktion inom svensk pappers- och massaproduktion”. Potentialen hos det organiska materialet i avloppsvatten från svensk pappers- och massaindustri (PMI) till biogasproduktion skattades vid projektstart till 100 milj. Nm3 metan per år (1 TWh). Denna rapport är en syntes av resultaten från projektet med syfte att ge visa hur de genererade resultaten kan omsättas i teknisk praktik med tillhörande ekonomiska insatser. Syftet är att ge underlag och stöd till PMI-branschen och externa intressenter, som överväger att implementera biogasproduktion inom PMI.

Substraten för biogasproduktion som återfinns i pappers- och massaindustrins avloppsvatten och slam kännetecknas av stora volymer med låga COD-halter. Detta kräver rötningstekniker, som tillåter mycket korta uppehållstider jämfört med mer traditionellt utformade biogasanläggningar för att inte tankstorleken ska bli för stor. Två tekniker, som utvecklats inom projektet, klarar detta: EGSB (expanded granular sludge bed) och CSTR (completely stirred tank reactor) med slamåterföring. Dessa tekniker har därför utvärderats för tre olika typbruk, ett CTMP-bruk, ett TMP-bruk och ett sulfatmassabruk. Resultaten från dessa experimentella studier är utgångspunkten för i utvärderingen i föreliggande rapport. För varje processkoncept har en grov kostnadsuppskattning (±20 %) gjorts för den investering som krävs för biogasproduktion.

En EGSB på ett TMP-bruk med ett totalavlopp på 1500 m³/h, där hela blekeriavloppet från peroxidblekningen och en del av det övriga avloppet behandlas i en 4000 m³ reaktor förväntas ge 2,5 milj Nm³ metan/år. Investeringskostnaden för anläggningen uppskattas till 75 milj. SEK (±20 %).

En EGSB på ett CTMP-bruk med ett totalavlopp på 170 m³/h där hela avloppet behandlas i en 3000 m³ reaktor förväntas ge 1,8 milj Nm³ metan/år. Investeringskostnaden för anläggningen uppskattas till 64 milj. SEK (±20%).

En CSTR med slamåterföring som körs på bioslam från ett sulfatmassabruk där ett bioslamflöde på 46 m³/h behandlas i en 4000 m³ reaktor förväntas ge 1,0 milj Nm3 metan/år. I denna design är strategin för den aeroba bioreningen ändrad för att producera ett bioslam optimerat för att ge högsta möjliga biogaspotential. Detta innebär produktion av större mängd slam, som i största mån kan rötas till metan, dvs mängd metan per mängd rötat organiskt material samtidigt som COD-reduktionen i vattenreningen bibehålls. Investeringskostnaden för anläggningen uppskattas till 32 milj. SEK (±20%).

Baserat på de COD-kvantiteter som når de luftade dammarna inom PMIs vattenreningssystem förbrukas årligen ca 0,8 TWh el. Införande av biogasproduktion i massaindustrins spillvattenrening skulle reducera mängden COD med mellan 30-50%, vilket får till följd att den årliga elförbrukningen i samband med den aeroba reningen går ner med ca 0,2-0,4 TWh. Detta innebär alltså ett energitillskott av 0,9 – 1,1 TWh givet att hela den tillgängliga biogaspotentialen skulle byggas ut. Till detta kommer eventuella vinster relaterade till slamhanteringen.

Den här rapporten har studerat VAKA-gruppens verksamhet med speciellt fokus på hur de som larmat VAKA upplevt hjälpen, vilka konsekvenser som kunnat undvikas genom VAKA:s stöd samt hur insatserna skulle kunna organiseras och finansieras framöver. Studien utgår från 26 intervjuer med aktörer som larmat VAKA någon gång mellan 2010 och 2015.

Sammanfattningsvis kan det konstateras att de intervjuade kommunerna upplever att VAKA erbjuder en synnerligen effektiv och professionell hjälp som bidragit till att olycksförloppen kunnat både mildras och förkortas avsevärt. Man har bistått med kvalificerad experthjälp vad gäller lägesanalys, provtagningar och analyser, bistått i organisationen av krisledningen och även förmedlat erfarenheter och kunskaper gällande media hantering samt kommunikation gentemot allmänheten. VAKA har dessutom tillgång till ett brett kontaktnät och har i de fall då man själv inte besitter rätt expertis snabbt kunnat förmedla kontakt med rätt person/instans. De intervjuade kommunerna har framhållit att man fått mental stöttning av VAKA i situationer som varit belastande för krisledningen. Att ha tillgång till erfarna människor som bollplank och som en part i diskussionen i ett kritiskt läge framhålls som otroligt viktigt för de inblandade.

Flertalet av de intervjuade bedömer att det kan finnas en viss betalningsvilja för VAKA:s tjänster på kommunal nivå men ser en överhängande risk med att vissa kommuner eventuellt avvaktar en kontakt om denna är avgiftsbelagd. I sammanhanget bör man också beakta att andra aktörer än kommuner i dagsläget är berättigade att nyttja VAKA:s tjänster varför en exklusiv kommunavgift inte framstår som en optimal lösning framgent.

Ingen av de intervjuade ser någon fördel med att VAKA verksamhet skulle organiseras på privat konsultbasis alternativt ersättas med regional kompetensutveckling. Det senare alternativet menar man känns inte realistiskt med tanke på att VAKA besitter vad som måste betraktas som nationell spetskompetens och att det skulle vara svårt att sprida denna till alla regioner.

Förslag på verksamhetens utveckling som framkommit gäller bl.a. tillgången till nödvattenutrustning där tillgängligheten skulle kunna förbättras både via tätare avstånd mellan lagren samt en koordinering av samutnyttjande av resurser mellan kommuner. Man tror även att kännedomen om VAKA skulle kunna förbättras via informationsinsatser.

Ytterligare ett förslag på verksamhetens utveckling gäller tillgång till laboratorier där man föreslår att VAKA alternativt Livsmedelsverket skulle administrera en central upphandling för att säkerställa att det alltid finns tillgång till laboratorieresurser.

Baserat på rapportens samlade bedömning rekommenderas det att VAKA gruppens verksamhet även fortsättningsvis bör bedrivas i sin nuvarande form men med en fast finansiering från näringsdepartementet som möjliggör en mer långsiktig planering av verksamheten.

Avslutningsvis bör det återigen understrykas att effekterna av framtida klimatförändringar medför att riskerna för dricksvattenförsörjningen ökar och att antalet incidenter kopplat till dricksvattenförsörjning med stor sannolikhet kommer att öka. Behovet av VAKA-gruppens tjänster blir därmed större i framtiden.

Carbon dioxide from biogas production is currently considered to be without value and isbecause of this released into the atmosphere in the biogas upgrading process. The residualgas is a potential carbon source and can create value in the biogas manufacturing process.By finding a suitable value-creating process that utilizes carbon dioxide, it can be possibleto provide both economic and environmental incentives for companies to develop theiroperations. This project explored the possibility to create value from this CO2. Through anevaluation of the technical maturity of CCU technologies, a recommendation could be givenat the end of the project. An analysis of technical barriers, such as pollutants in the gas, aswell as barriers in the form of competence and corporate culture were examined in orderto provide a reasoned recommendation. The project mapped which value-creating systemswould be suitable for biogas producers in a Swedish context. This included established methaneand carbon dioxide upgrading techniques currently in use and suitable CCU techniquesthat can interact with the selected upgrading processes and serve as value creators. Based onthis survey, it was then possible to identify common, critical variables for these systems. Thereafter,a recommendation of an appropriate CCU technology could be given depending onthe CO2 composition produced. One conclusion from the study was that carbon dioxide concentrationsfrom the residual gas was often high (approx. 97-98 %) and did not contain anycorrosive or toxic components, and that this largely depends on how the digestion reactor ishandled in the production process. Thus, questions were raised about what the actual limitationsof the CCU are, as they did not seem to be technical. CCU techniques that proved to beof particular interest were pH regulation of sewage plants, CO2 as a nutrient substrate for thecultivation of microalgae, and manufacturing of dry-ice for refrigerated transports. All of thesetechnologies currently have a sufficiently high degree of technical maturity to be installedalready today. Other CCU techniques, such as "’Power to gas”, require a high CO2 concentrationand were discarded as the literature review did not suggest the economic potential forthem as they require additional CO2 upgrading steps. Instead, CCU techniques were chosenthat could be implemented directly with the existing CO2 quality. Furthermore, it was concludedthat one reason why CCU technologies have not been widely implemented is internalbarriers between distributors and manufacturers (or users) of CCU technologies. Thus, theuse of carbon dioxide from biogas production and implementation of CCU technologies canbe promoted by eliminating barriers in companies, such as a lack of both knowledge andfinancial incentives.

Research on value pathways for organic wastes has been steadily increasing in recent decades. There have been few considerably broad overview studies of such materials and their valuation potential in the bio-based economy in part because of the vast multitude of materials and processes that can be used to produce energy carriers, chemicals, and materials of value. This article explores how automated data analysis approaches can help in analyzing large bodies of text to distill and present potential value pathways for secondary (waste) bio-based materials. The study employed multiple methods (literature collection, topic modelling, and co-occurrence analysis) on a collection of abstracts from 53,292 academic articles covering technologies, applications, and products (TAPs) for bio-based wastes. The results of both the topic modelling and co-occurrence analysis are presented as online interactive web pages. The topic modelling presented an overview of research clusters related to secondary organic resources, processes, and disciplines. The co-occurrence analysis helped to understand which TAPs are researched in relation to a broad spectrum of organic wastes. Co-occurrences were evaluated using the Normalized Pointwise Mutual Information measure to locate terms which co-occur more frequently than would be expected by chance. Through the use of detailed lists of organic wastes and TAPs, the co-occurrence method mapped out 7118 unique intersections between 473 specific wastes and 228 TAPs. This technique enables us to find seemingly non-obvious valorization pathways such as the re-use of oyster shells as catalysts for bio-diesel production and bioplastic production from brewery waste. While a proof-of-concept, this work points the way for using Big Data to suggest novel pathways for implementing the Circular Economy.

Currently Vietnam is facing several problems with waste handling. For instance, a lot of the municipal organic solid waste is dumped at landfills, which contributes to environmental difficulties such as greenhouse gas emissions. Anaerobic digestion has proven to be an adequate method for solving environmental problems such as waste treatment, where biogas can be produced. The methane content in the biogas can subsequently be used as a prosperous energy source for heating, electricity and vehicle fuel. The production and utilization of biogas in Vietnam is in a developing face. However, there are issues that should be tackled to improve and expand the biogas production and use. In Vietnam the main substrate used for anaerobic digestion is animal manure as most of the biogas digesters are placed on farms. The purpose of this master thesis was to identify additional potential substrates for biogas production, with focus on Thái Nguyên city and Sông Công city in the Thái Nguyên province. In order to find suitable substrates, interviews and literature research were carried out in Vietnam. Subsequently biochemical methane potential (BMP) tests were performed for the identified and acquired substrates. The BMP-tests were first performed at Thái Nguyên University but as the results were inconclusive, further experiments were performed at Linköping University (Sweden) where eight substrates from the Thái Nguyên province were investigated. The identified substrates used for the BMP-tests were three types of beer waste from the Vicoba brewery in Thái Nguyên city, food waste from different restaurants in Sông Công city, fruit waste from the fruit market in Thái Nguyên and household vegetable waste. The highest methane yield could be observed for household vegetable waste (543 Nml/g VS) followed by beer waste (yeast) with a methane potential of 497 Nml/g VS. Beer waste (hops boiling) had the lowest methane potential with a value of 230 Nml/g VS. Estimation of the total methane potential in both cities together from food waste from restaurants, beer waste and sewage sludge from the upcoming waste water treatment plant (WWTP) in Thái Nguyen city were made by combining data from interviews, literature values and the BMP-results. The estimation showed that from Thái Nguyên City and Sông Công city about 137,500 m³ CH₄/year can be produced from food waste from restaurants, about 1.7 millionCH₄ m³/year can be produced from sludge from the WWTP in Thái Nguyên city (under construction) and there is also a possibility to produce about 10,700 m³ CH₄/year from the beer brewery in Thái Nguyên city. Thus, the total estimated methane potential sums up to 1.8 million m³ CH₄/year. The results show that Thái Nguyên city and Sông Công city have potential wastes that preferably could be used as substrates for biogas production which could add on to the biogas produced currently at farm level in the Thái Nguyên region.

In this study, cooperation between Stockholm's transport and district heating sectors is analysed. The cooperation concerns the integration of biofuel polygeneration production. A MODEST optimisation model framework is used, assuming various energy market and transport sector scenarios for the year 2030. The scenarios with biofuel production and increased biofuel use in the region are compared with reference scenarios where all new plants introduced into the district heating sector are combined heat and power plants, and the share of biofuel used in the transport sector is the same as today. The results show that the cooperation implies an opportunity to reduce fossil fuel consumption in the sectors by between 20% and 65%, depending on energy market conditions and assumed transport sector scenarios. If we consider biomass an unlimited resource, the potential for greenhouse gas emissions reduction is significant. However, considering that biomass is a limited resource, the increase of biomass use in the district heating system may lead to a decrease of biomass use in other energy systems. The potential for reduction of global greenhouse gas emissions is thus highly dependent on the alternative use of biomass. If this alternative is used for co-firing in coal condensing power plants, biomass use in combined heat and power plants would be more desirable than biofuel production through polygeneration. On the other hand, if this alternative is used for traditional biofuel production (without co-production of heat and electricity), the benefits of biofuel production through polygeneration from a greenhouse gas emissions perspective is superior. However, if carbon capture and storage technology is applied on the biofuel polygeneration plants, the introduction of large-scale biofuel production into the district heating system would result in a reduction of global greenhouse gas emissions independent of the assumed alternative use of biomass.

This work was carried out at Biogas Research Center (BRC) and the company Biogas in Vadstena. The aim was to systematically evaluate new substrates for biogas production. In particular, this case investigated the potential of straw in co-digestion with manure and slurry from pig, chicken and dairy. Straw is interesting to evaluate since it is second generation biomass and available in a large quantity. Also, anaerobic digestion (AD) of manure is beneficial because it deals with the spontaneous methane emission and leads to a better manure handling. Goals within the EU as well as in Sweden have been set up to reduce greenhouse gas emissions from fossil fuel and to produce more renewable energy.

The methodology used is outlined by BRC in which a number of key areas, such as description of biomass, amount biomass, gas yield, technology, economy, environmental performance and energy system, competing interests and institutional factors, have been evaluated through literature studies and case study Biogas in Vadstena. Based on the results an overall judgment is done to determine the potential of straw.

The result shows that straw is not appropriate to digest solely because of high TS, high carbon content and lack of nutrients. Straw also has lignocellulosic structures, which are difficult to break down. Especially lignin limits the biodegradability. Mechanical, thermal, chemical and biological pretreatments can increase the availability and biodegradability in the straw. In some cases pretreatment can also increase the methane potential. However, straw works well as a carbon complement in co-digestion with manure, which is a nitrogen-rich substrate. There are technologies available for AD of straw and manure for the whole biogas process, from transportation and pretreatment to digestion and upgrading. Although, there is space for further development of pretreatment and upgrading technology. The economic calculations show that it is profitable to use straw with manure in a farm-based biogas plant for vehicle gas production. Furthermore, the calculations of the energy show that biogas production is energy efficient with energy input/output ratio of 18-23%. Besides production of biogas, the digestate could be used as an environmentally friendly fertilizer.

In summary, it is possible to produce biogas from straw together with manure, and this is beneficial from both an environmental and economic perspective.

Föregående kapitel bidrog med grundläggande kunskaper om stora tekniska system. Men den kunskapen som bas kan man närma sig frågan hur några av de system som finns i dag kommit till och utvecklats med tiden. Dessutom ges i detta kapitel en historisk introduktion, som på en övergripande nivå beskriver hur industrisamhället och industriella system utvecklats. Kapitlet avslutas med en utblick mot framtiden.

Stora tekniska system fyller en viktig funktion i många människors vardag och de har också en stor miljömässig betydelse. Det gäller dels systemen själva, dels många delsystem i form av produkter och tjänster vars miljöpåverkan till stor del kan avgöras av de stora systemen. I kapitlet introduceras stora tekniska system. Fokus ligger på systemens framväxt och miljökoppling, viktiga komponenter och aktörer, och hur systemen kan utvecklas och förändras.

The pulp and paper industry is a large producer of wastewater and sludge, putting high pressure on waste treatment. In addition, more rigorous environmental legislation for pollution control and demands to increase the use of renewable energy have put further pressure on the pulp and paper industry’s waste treatment, where anaerobic digestion (AD) and the production of methane could pose a solution. Kraft pulping makes up 80% of the world production of virgin wood pulp, thus, the wastewaters from this sector represent a large unused potential for methane production.

There are three main types of substrates available for AD at pulp and paper mills, the wastewaters, the primary sludge/fibre sludge, and the waste activated sludge. AD treatment of these streams has been associated with several challenges, such as the presence of inhibiting compounds or low degradability during AD. The aim of this thesis was to experimentally address these challenges and potentials, focusing on wastes from kraft mills.

Methane potential batch tests showed that many wastewater streams still posed challenges to AD, but the alkaline elemental chlorine-free bleaching stream and the condensate effluents had good methane potentials. Further, the methane potential of kraft mill fibre sludge was high, and co-digestion of kraft mill fibre sludge and waste activated sludge was feasible in stirred tank reactors with sludge recirculation. By increasing the organic loading in a pilot-scale activated sludge facility and thereby lowering the sludge age, the degradability of the waste activated sludge was improved. The higher wastewater treatment capacity achieved by this method provides an opportunity for the mills to increase their pulp and paper production. Further, by dewatering the digestate after AD and returning the liquid to the activated sludge treatment, costs for nutrient supplementation can be reduced.

In conclusion, the thesis shows that AD of wastes from the kraft pulp and paper industry was feasible and carried many benefits regarding the generation of methane as a renewable energy carrier, improved wastewater treatment and reduced costs. Different strategies on how AD may be implemented in the kraft pulp and paper industry were formulated and discussed.

Most pharmaceutical residues in wastewater treatment plants (WWTPs) end up in the hydrosphere where they cause negative effects on the aquatic life and might disrupt ecosystems. By implementing an ozonation step (treatment with ozone) in the wastewater treatment process, these pharmaceutical residues can be reduced.  The purpose of this project was to verify that the ozonation process works in full-scale, thereby verifying a pilot study conducted in 2014 at Tekniska Verken i Linköping AB (TVAB). Additionally, the purpose was to investigate which parameters influence the ozone demand in order to formulate a model for the ozone demand. The initial phases during this thesis were a pre-study and a literature study. This was followed by the multivariate analysis and model construction based on different data from the pilot study. Measurements were performed on the wastewater in the full-scale facility in order to verify the results from the pilot study. Moreover, measurements were performed to find new ozone consuming parameters. The reduction of pharmaceutical residues was similar to the pilot study, although slightly lower. Several parameters and factors that were different between pilot study and new measurements affected the reduction of pharmaceutical residues. For example, DOC and nitrate concentrations have increased since the pilot study in 2014. Also, factors such as the growth in population in Linköping and the differences in design between the pilot plant and the full-scale facility have influenced the reduction of pharmaceutical residues. A control strategy based on a linear relationship between ozone sensitive Ultra Violet Absorption (UVA) left and remaining pharmaceutical residues after ozonation could potentially be used. Moreover, three models were constructed and the Multivariate Analysis 1 (MVA1)-model was deemed as the best, this model includes ozone residual, nitrite, turbidity, simulated Chemical Oxygen Demand (COD(sim)) and ozone dose. The variations in the dose compared to the input parameters for the validation data show that the model predict the ozone dose well. However, in future other interesting parameters can be included in the model to further improve the accuracy in the ozone dose predicted by the model.

The feasibility of using bench-scale biotrickling filter reactors inoculated with the fungus UBAF004, isolated from soil in Tahuapalca, for treatment of water contaminated with cypermethrin was investigated. Wood chips, gravel and ceramics were tested as packing materials for the reactors in batch experiments in small glass flasks. Wood proved to be the material on which the fungus grew best and was thus chosen as the packing material for the reactors. It was determined that UBAF004 had quite low competitive strength compared to other microorganisms when growing on wood and gravel but not necessarily on ceramics. UBAF004 grew slowly in the reactors leading to poor degradation performance. The results obtained indicate that it will be challenging to use UBAF004 for treatment of water contaminated with cypermethrin in Tahuapalca. The single largest issue is to find a way to establish a stable population of the fungus in the reactor and to protect it from being out competed by other microorganisms.

Development of new pharmaceutical compounds is crucial to advancing the field of medicine and finding new ways to treat different ailments. It is, however, also necessary to study how both newly synthesized pharmaceuticals and existing compounds impact other organisms in nature, to be certain that the negative effects of these do not outweigh the positive. Imidazole is a molecule whose derivatives often can be used as antifungal agents to treat infections in medicine or fungicides used to control plant disease in agriculture. These imidazole derivatives have previously been proven to act as competitive antagonists of the protein calmodulin. Calmodulin (CaM) is highly conserved across different species of eukaryotes and is involved in various cellular processes such as regulating enzymes and transduction pathways, among others. This study uses Drosophila melanogaster (D. melanogaster ) as a model organism, where CaM is responsible for regulating the olfactory system of D. melanogaster among other processes. The fact that CaM is highly conserved across species is important since an external molecule affecting the protein in one species is very likely to have a similar effect in many other species, leading to the possibility of a single molecule, perhaps such as a pharmaceutical compound or a pesticide, impacting whole ecosystems. This study focuses on exploring whether or not imidazole derivatives have a negative effect on non-target organisms, such as D. melanogaster. The C-domain of calmodulin from D. melanogaster (CaM_c^drm ) was characterized by using biological measurement techniques such as Circular Dichroism (CD) and nano Differential Scanning Fluorimetry (nanoDSF). Bioinformatic tools, such as modelling and docking, were used to study the structure of CaM_c^drm as well as the interaction between CaM_c^drm and potential ligands, such as miconazole and other derivatives of imidazole. This was used in combination with nanoDSF and fluorescence spectroscopy as the selected measurement techniques to investigate if miconazole binds to CaM_c^drm. The effects of miconazole were also studied on an organismal level by conducting an in vivo toxicity analysis with D. melanogaster and measuring the olfactory index after exposure to miconazole. Bioinformatic tools and CD both confirmed that CaM_c^drm mainly consists of α-helices. Bioinformatic tools also predicted that binding between miconazole and CaM_c^drm is likely to occur. This was confirmed by nanoDSF and fluorescence spectroscopy, since both methods displayed a change in signal upon addition of miconazole. The toxicity analysis revealed that flies that had consumed miconazole exhibited a lower olfactory index than the flies used for control, suggesting that the olfactory system of the flies had been affected negatively. These results indicate that miconazole is able to bind to CaM_c^drm and has a disruptive effect on the activity of CaM in D. melanogaster. Because of the fact that CaM is involved in multiple processes and that it is similar between species, the results suggest that miconazole can alter the function of many other cellular processes across a wide range of species, making contamination of miconazole a threat to the survival of non-target organisms.

An elevated level of Arsenic (As) in aquifers from India and Bangladesh affecting the human health has been widely reported since the late 1980s. The thesis aim is to investigate the present status of As contamination and biogeochemical cycling with direct role of diverse indigenous bacterial communities in As cycling in the Bengal Delta Plain (BDP) aquifers in Nadia district, West Bengal (India). The As(III) oxidizing bacterial communities were predominant in grey sand aquifers (GSA), but were characteristically absent in brown sand aquifers (BSA). Rainwater recharge containing inorganic and organic dissolved compounds played an important role in shaping the different groups of bacterial phenotypes. It included thearsenite-oxidizing bacteria as revealed by the aioA and 16S rRNA phylogeny. These bacterial communities in BDP groundwater were assumed to utilize the dissolved and sedimentary organic carbon (DOC and SOC) as the primary carbon source for respiration, and remobilization/immobilization of As involving reductive dissolution of iron oxyhydroxides. Hence, sediment and groundwater of these aquifer waters were characterized for their different inorganic constituents (metals) and organic compound classes. There were notable differences between the groundwater DOC and SOC pools. The only similarity between these carbon pools is presence of petroleum-derived hydrocarbons. The SOC in BSA has good correlation with the clay and silt-rich fraction. Notably, As formed complexes with iron, but not manganese. Biomarker characterization in sediments showed presence of terrigenous inputs along with petroleum-derived hydrocarbons. However, these hydrocarbons were absent in BSA sediments, and so were the arsenite oxidizing bacterial communities. Although DOC in groundwater plays an important role in sustaining the microorganisms, the contrasting character of SOC in BSA and GSA strongly influence the shaping of microbial community structure and biogeochemical cycling of As. This particularly affects the natural ‘safe’ drinking water capacity. Overall, the study gives a new directionfor long-term research on As biogeochemical cycling in the contaminated BDP aquifers.

The coupled role of organic matter (OM) and microbial activity is widely acknowledged in arsenic (As) biogeochemical cycling in sedimentary environments. However, little is known about OM characteristics particularly the dissolved fraction in the Bengal Delta Plain aquifers – one of the worst As impacted regions in the world. Ongoing investigations in As-rich aquifers in Nadia district (West Bengal, India) indicate presence of arsenite As(III) oxidizing bacterial communities in the Grey Sand Aquifers (GSA), but absent in Brown Sand Aquifers (BSA). In this study, we investigate the key differences in dissolved organic carbon (DOC) characteristics and its relationship with differences in elemental concentrations, distribution of biomarkers, and utilization of DOC by in situ microbial communities in BSA and GSA. We demonstrate a new approach using ENVI™ C-18 DSK discs to pre-concentrate DOC from large volumes of water, and further extract the OM and separate it into different lipid fractions using the solid phase extraction technique. The aquifers show marked heterogeneity in terms of their DOC characteristics and elemental profiles irrespective of their grey or brown color. DOC indicates variable inputs of terrestrial derived OM sources, and OM derived from decomposition and/or microbial cellular components. DOC in the aquifers consist of predominantly n-alkanoic acids (∌80%) followed by n-alkanes and n-alcohols. The GSAs indicate high iron (Fe) and manganese (Mn) concentrations, and presence of mature petroleum derived hydrocarbons in DOC. BSA has comparatively lower concentrations of Fe and Mn, and shows absence of mature hydrocarbons in DOC. Experiments in presence of indigenous bacteria from groundwater with DOC lipid extracts as the sole carbon source indicate higher growth in the GSA samples implying preferential use of DOC. The potential availability of DOC in these aquifers can influence the community composition of indigenous heterotrophic microbial flora, which in turn can affect elemental cycles including that of As.

This article presents a framework from a systems’ perspective to benchmark biomethane supply chains consisting of biogas upgrading, biomethane distribution, and refilling in the context of Western Europe.

Compressed biomethane is already widely adopted as a vehicle fuel, whereas liquefied biomethane is also a vialble alternative. Distribution in gas grids is a feasible option only in short distances and large scale, whereas trucks with composite swap bodies is the preferable alternative otherwise. As a whole, liquefied biomethane supply chains manifests better attributes from both climate and cost perspectives, whereas compressed biomethane supply chains imply better energy intensity.

Biomass is a valuable and limited resource that should be used efficiently. The potential of replacing fossil-based products with bio-based ones produced in biobased industrial systems is huge. One important aim of increasing the share of biobased products is to improve the sustainability of systems for production and consumption. Therefore, it is important to evaluate what solutions are available to improve the sustainability performance of bio-based industrial systems, and if they also bring negative impacts. The thesis focuses on assessing the role of biogas solutions in developing sustainable bio-based systems. Such assessments are often quite narrow in their scope and focus on quantitative environmental or economic aspects. This thesis aims at also including feasibility related aspects involving the contextual conditions that are assessed more qualitatively. Biogas solutions are identified as a versatile approach to treat organic materials which are generated in large volumes in bio-based industrial systems. The results show that biogas solutions in bio-based industrial systems (i) improve circular flows of energy and nutrients, (ii) are especially viable alternatives when the quality of the by-product streams become poorer, and (iii) may improve the profitability of the bio-based industrial system. To perform better assessments of these systems, it seems valuable to broaden the set of indicators assessed and include feasibility-related indicators, preferably through the involvement of relevant stakeholders as they contribute with different perspectives and can identify aspects that influence the sustainability in different areas. Future studies could benefit from applying those broader assessments on more cases to build on a more generalisable knowledge base.

This project investigated the bacteria in water entering and leaving the slow sand filters at Ringsjö Water Works using flow cytometry. The purpose was to explore the possibility of utilising flow cytometry as a monitoring method for optimising water production using slow sand filters. Data describing the bacterial community in water was collected over seven weeks and analysed with FlowJo, flow cytometric image comparison and Minitab. The total cell count, intact cell count and the percentage of high nucleic acid bacteria were analysed. These parameters were highly dependent on scraping events, water entering the filters and season. The results indicated that flow cytometry has great potential for use as a monitoring method, although more data should be collected to establish expected trends and secure baseline values for routine comparisons.

I det här kapitlet introduceras begreppet miljöproblem. Vidare berörs flera viktiga globala utvecklingstrender som ligger bakom problembilden. Tanken är att bidra med information som underlättar förståelsen av kommande kapitel.

Energisystemet är oerhört viktigt på många sätt, bland annat för att vår vardag ska fungera - tänk bara på alla problem vi upplever när det är strömavbrott även en kortare tid. När du läste de andra delarna i boken noterade du säkert och att energi har stor betydelse för många miljöproblem. I det här kapitlet beskrivs vad vi menar med energisystemet och viktiga aspekter och delar av systemet ur ett miljöperspektiv.

Produktionen av biogas är en viktig komponent för skapandet av ett fossilfritt samhälle. Rötning av det matavfall som uppstår i hushållen är en central källa till att producera biogas och biogödsel. Regeringen har satt upp etappmålet att till 2018 sortera ut minst 40 % av matavfallet från hushåll, storkök, butiker och restauranger så att energi kan utvinnas eller att 50 % av matavfallet samlas in så antingen energi kan utvinnas eller växtnäring tas till vara på.

Det här examensarbetet utfördes på initiativ av Tekniska verken i Linköping AB med syftet att studera och kartlägga hur olika fastighetsnära insamlingssystem för matavfall påverkar biogasproduktion med avseende på mängd och kvalitet på biogas och biogödsel. Det har dessutom studerats om det finns andra faktorer som påverkar insamlad mängd och renhet på matavfallet. Rapporten är tänkt att utgöra beslutsunderlag för Tekniska verken inför en eventuell omställning av rådande insamlingssystem.

Resultaten i studien visade att system där matavfall läggs i ett separat fack eller kärl har något högre utsorteringsgrad av matavfall jämfört med optisk sortering. Detta innebär att en omställning till fyrfackskäl eller separata kärl skulle kunna ge högre utsorteringsgrad än dagens optiska sortering. Därför konstateras det i studien att insamlingssystemet troligtvis har en påverkan på utsorteringsgraden av matavfall. Renhetsgraden är hög för samtliga studerade system, därför är det troligt att en omställning av insamlingssystem för villor i Linköping kommun kan genomföras utan att kompromissa med renheten på matavfallet. Det konstateras även i studien att det finns yttre faktorer som påverkar mängd och renhet på det matavfall som samlas från hushållen. Litteraturstudier och intervjuer med utvalda kommuner med hög utsorteringsgrad visade att faktorer som informationskampanjer och användarvänlighet kring matavfallsinsamling har en påverkan på insamlingsresultatet. Dock kan det inte bestämmas till vilken grad de yttre faktorerna påverkar resultatet.

För framtida studier rekommenderas att inkludera fler plockanalyser för att få en tydligare bild av hur resultatspridningen ser ut för de olika insamlingssystemen. Detta skulle leda till en större säkerhet i slutsatserna om hur de olika insamlingssystemen påverkar insamlingsresultatet för matavfall. Vidare är det möjligt att en strukturerad intervjustudie med fokus på enstaka utvalda faktorer skulle kunna avgöra vilken påverkan en isolerad yttre faktor har på insamlingsresultatet.

"Miljöproblem handlar nästan bara om avfall och avfall är skräp..." - så har nog många äldre generationer tänkt på avfallsfrågorna när miljöproblem diskuterats. Men i dag vet vi bättre och efter att du har läst kapitlet har du förhoppningsvis en ännu djupare förståelse för avfallssystemets funktion och roll i samhället. I kapitlet behandlas uppkomsten och hanteringen av avfall i Sverige. Efter en kort inledning om olika huvudtyper av avfall läggs fokus på hushållsavfallet eftersom det är den typ av avfall som det finns mest dokumentation om och som de flesta av oss enklast kan relatera till. Mycket av det som behandlas i kapitlet, såsom behandlingsmetoder och miljöpåverkan från avfallshantering, är dock i allra högsta grad relevant även för andra typer av avfall.

Hydrodynamic cavitation is a pre-treatment method that has shown promising results regarding biodegradability and biogas production in anaerobic digestion. In this thesis, its specific impacts on digestate dewatering, with the potential to reduce operational costs and to achieve higher solid content in the dewatered fraction was assessed. Several methods of evaluating dewaterability were investigated, including capillary suction time and the novel parameter C/N•ash. Two semi-continuous anaerobic digestion reactors were operated for 91 days processing mixed wastewater sludge - primary sludge, biosludge and recirculated digested sludge from a municipal wastewater treatment - under mesophilic conditions. Hydrodynamic cavitation was applied to the biosludge alone in reactor 1 and to biosludge together with the recirculated digested sludge in reactor 2. In terms of digestibility, hydrodynamic cavitation showed limited benets with higher benets when pre-treating biosludge and digested sludge together, with a 3% higher specic biogas yield compared to when only pretreating the biosludge. On the contrary, clear eect of the pre-treatment on dewaterability was observed causing an increment of capillary suction time-values up to 60% when pre-treating both biosludge and digested sludge. Applied to commercial scale, such behaviour could potentially result in signicant economic savings due to reduced polymer dosing.

The purpose of the report is to study whether and how the municipalities in budget and annual reports describe the management, status and maintenance and development of fi xed assets within water and sewer from a life cycle perspective.

There are several ways to improve biogas production in anaerobic digestion processes and a number of strategies may be chosen. Increased organic loading in existing plants will in most cases demand the introduction of new substrate types. However, to substantially increase the Swedish biogas production new, large-scale biogas plants digesting new substrate types need to be established.

Better utilization of existing digester volumes can be linked to: 

• Increase of organic loading rates and/or reduced hydraulic retention time
• Optimizing the anaerobic microbial degradation by identifying rate-limitations, its causes and possible remedies such as:
• Nutrient and trace element balances
• Needs and availability of trace element
• Process design aiming at an increase of the active biomass (e.g. recirculation of reactor material, two stage processes)
• Process inhibition (enzymatically regulated product inhibition and toxicity)
• Improved pre-treatment to increase degradation rates and VS-reduction
• Mixing and rheology
• Better monitoring and control
• Co-digestion with more high-potential substrates

The present report reviews a number of fields that are linked to improvements in the biogas production process as based on the bullets above.

A well-working, active biomass is a prerequisite for efficient biogas production processes, why factors affecting microbial growth are crucial to obtain stable processes at the highest possible organic load/lowest possible hydraulic retention time.

The microorganisms need nutrients, i.e. carbon, nitrogen, phosphorus, calcium, potassium, magnesium and iron as well as trace elements such as cobalt, nickel, manganese, molybdenum, selenium and tungsten for growth. The need of nutrients and trace elements varies with the substrate digested, the organic loading rate, the process design (e.g. the reactor configuration, the degree of recirculation etc). In addition, the complexity of the chemical reactions controlling the bioavailability of the trace metals is wide, why optimal addition strategies for trace elements needs to be developed.

Substrates as food wastes, sewage sludge, cattle manure, certain energy crops and algae are good bases to obtain processes with good nutrient- and trace element balances. These kinds of substrates can often be implemented for “mono-substrate” digestion, while substrates dominated by carbohydrates or fats needs to be co-digested or digested in processes modified by  e.g. nutrient- and trace element additions, sludge recirculation, etc. Protein-rich substrates often include enough nutrients, but can give other process problems (see below).

Iron, cobalt and nickel are the nutrients/trace elements given most attention so far. However, molybdenum, selenium and tungsten have also, among others, been shown effective in different AD applications. The effects have, however, mainly been shown on turnover of VFAs and hydrogen (resulting in increased methane formation), while just a few studies have addressed their direct effect on rates of hydrolysis, protein-, fat- and carbohydrate degradation. Selenium- and cobalt-containing enzymes are known to be involved in amino acid degradation, while selenium and tungsten are needed in fat- and long chain fatty acid degradation. Enzymes active in hydrolysis of cellulose have been shown to be positively affected by cobalt, cupper, manganese, magnesium and calcium. This implies that trace element levels and availability will directly affect the hydrolysis rates as well as rates and degradation pathways for digestion of amino acids, long chain fatty acids and carbohydrates. However, their effect on hydrolysis seems neglected, why studies are needed to map the metals present in active sites and co-factors of enzymes mediating these primary reactions in AD. Further investigations are then needed to elucidate the importance of the identified metals on the different degradation steps of AD aiming at increased degradation rates of polymeric and complex substrates. It should also be noted that the degradation routes for amino acid degradation in AD-processes, factors governing their metabolic pathways, and how ATP is gained in the different pathways seem unknown. The different routes may result in different degradation efficiencies, why a deeper knowledge within this field is called for.

Trace metals added to biogas reactors have positive effects on the process only if they are present in chemical species suitable for microbial uptake. Interaction of biogenic sulfide with trace metals has been identified as the main regulator of trace metal speciation during AD. Fe, Co and Ni instantaneously form strong sulfide precipitates in biogas reactors but at the same time show very different chemical speciation features. The soluble fraction of Co widely exceeded the levels theoretically possible in equilibrium with inorganic sulfide. The high level of soluble Co is likely due to association with dissolved organic compounds of microbial origin. Fe and Ni speciation demonstrated a different pattern dominated by low solubility products of inorganic metal sulfide minerals, where their solubility was controlled mainly by the interactions with different dissolved sulfide and organic ligands. To our knowledge, the information about chemical speciation of other trace metals (Se, Mo, and W among others) and its effects on the bioavailability in anaerobic digestion environments is rare. Providing information on the metal requirements by processes linked to their bioavailability in biogas reactors is identified as a key knowledge needed for maximizing the effect of metals added to biogas reactors. Further research is also needed for development and design of proper metal additive solutions for application in full scale biogas plants. A practical approach is to supplement trace metals in specific chemical forms, which are either suitable for direct bio-uptake or will hamper undesirable and bio-uptake-limiting reactions (e.g. mineral precipitation).

Recirculation of reactor material as a way to enrich and maintain an active microbial biomass (and, thus, an increase in the substrate turnover rate) in tank reactors has been tested for digestion of fat within BRCs project DP6. The methane yield increased from 70 to 90% of the theoretical potential at a fat-loading rate of 1.5 g VS/L and day. The same strategy has been successful during digestion of fiber sludge from the pulp and paper industry, i.e. the recirculation has been crucial in establishment of low hydraulic retention times. Also degradation of sewage sludge (SS) would likely be improved by recirculation as the retention time of the solid SS is prolonged in such a system. However, this remains to be tested. The recirculation concept also needs to be evaluated in larger scale reactors to form a base to include extra costs and energy consumption vs. the benefits from increased yields.

To divide the anaerobic digestion process into two phases, where the hydrolytic/acidogenic and the syntrophic/methanogenic stages of anaerobic digestion are separated, might be a way to enhance degradation of lignocellulosic materials as the hydrolysis of these compounds may be inhibited by the release of soluble sugars. It should be noted that the natural AD of ruminates is phase-separated and improvements in AD can likely be achieved using these natural systems as a starting point. Also the degradation of aromatic and chlorinated species is likely enhanced by phase separation. One way to obtain such systems is to combine a leached bed for hydrolysis of insoluble material with a methanogenic reactor treating the leachate. Plug flow reactors might be another possibility as well as membrane reactors, which physically separates the hydrolyzing and methanogenic phases.

Inhibition caused by toxic levels of ammonia (protein- and ammonia rich substrates), fat-rich substrates and long chain fatty acids (LCFAs), aromatic compounds, salts etc. have been reported in many cases and some remedies are suggested. Ammonia can be stripped off as a measure to overcome too high levels. Another option is to adjust pH of the reactor liquid by addition of acid shifting the ammonia-ammonium balance in the system towards less free ammonia. A decrease in alkalinity by acid addition might also affect the availability of trace elements as solubility of trace metal mineral phases is generally higher at lower pH. LCFA degradation has been shown to benefit from periodic additions of fat and is, thus, an effective strategy to minimize inhibition by the release of the LCFA. Adsorption to zeolites has also been shown to abate the inhibition by LCFA. The best way to avoid inhibition is, however, to keep the processes nutritionally well balanced and using concepts suitable for the actual substrate mix digested (i.e. sludge recirculation, phase separation etc.) in order to obtain the highest possible degradation rate for problematic compounds, thus, avoiding accumulation of inhibitory components such as LCFA and aromatics. High ammonia and salt levels can often be regulated by the substrate mix.

The hydrolysis is often reported as rate limiting in digestion of complex polymers in balanced anaerobic digestion systems, while the methanogensis is regarded as rate-limiting for more easily degraded substrates. As mentioned above the effect on methane formation rates by the addition of trace elements have been shown in numerous studies, while their effect on the hydrolysis and acidogenic AD steps are much less studied. Thus, the effects of the trace elements on the early steps in the AD-chain need to be investigated further.

To obtain high-rate hydrolysis, effective and energy efficient pre-treatment methods are crucial for a large number of substrates. The rate of hydrolysis is to a large extent dependent on the properties of the organic compounds in the substrate e.g. carbohydrates, proteins, fat or lignocellulosic material as well as particle size and pre-treatment methods applied. The establishment and colonization by sessile microorganisms and biofilms is highly important for efficient and high rate hydrolysis. Microbial formation of organic compounds and the availability of surfaces are factors influencing these key processes, which in turn are tightly coupled to the growth conditions for the hydrolyzing microorganisms. This is an area recently brought up as an issue for detailed research.

Mixing is mostly needed for effective high-rate biogas production, but too extensive mixing can destroy the syntrohpic interactions necessarily taking place during AD. However, the efficiency of the mixing system design in relation to colonization, presences of dead zones, changes in viscosity/rheology, etc. seem unclear and this area thus calls for further attention. 

In high-loaded efficient processes a monitoring program following parameters e.g. organic loading rate, gas-production, VS-reduction, pH and VFA-levels is needed. This can be achieved through sampling and analysis off line, but there are of course benefits with on-line monitoring. A number of different methods have been suggested and tested, and some titration- and spectroscopic methods are applied, but none seems commonly in use. The reasons for the low interest to apply these methods may be the need for expertise on calibration, validation and multivariate analysis of most on-line methods, high maintenance demands (cost and time), and l functional problems related to fouling, gas bubbles, sensor location, disturbing particles etc.

New substrates with the highest potential for use in existing or new biogas plants seem to be forestry-based biomass, certain energy crops and macro-algae. Both the energy crops and the macro-algae can be chosen to give nutritionally well balanced AD-processes, while AD on forestry biomass demands nutrient supplements. For both the energy crops and the macro-algae sustainable cultivation systems need to be developed. Crop rotation systems should be employed to minimize tillage as well as fertilization- and pesticide utilization at highest possible TS-yields. System analyses aiming at sustainability and economy of TS and methane yields per ha including needs of nutrient supplements should therefore be performed.

In all three cases (forestry biomass, energy crops and algae) pre-treatment methods to create high internal surface areas are needed. However, the pre-treatment methods chosen need to be highly energy- and resource efficient to obtain sustainable systems (a positive energy balance). New plants will for profitability likely need to be large with highly developed infrastructure for substrates supply and distribution of the produced biogas/electricity nearby. Process concepts aiming at highest possible loading rates at shortest possible retention time will be needed, which likely are met by including both phase-separated process systems and systems for sludge recirculation.

It should also be noted that the lignin in substrates from forestry biomass needs to be used for production of e.g. polymeric materials or as a fuel to obtain reasonable energy balances for AD of lignocellulose. Pre-treatment methods obtaining separation of lignin is therefore needed. A substantial research and development is in progress within this field.

The possibilities for AD within the pulp and paper industry are interesting, especially if specific effluents within the pulp- and paper production units are selected and the raw material for the pulp and paper production is chosen considering the biogas yields of the residues.

This study investigated the combination of biochar derived from carbonized local feedstock and Moringa oleifera seed extract-based flocculant, a novel combination in the context of greywater treatment missed in the previous studies, with a focus on the removal of organic contaminants (caffeine, chloramphenicol, trimethoprim, carbamazepine, diclofenac, and bisphenol A) and heavy metals (Cr(VI), As(III), Co(II), Ni(II), Cu(II), Zn(II), and Pb(II)). The research focused on the optimization of dosage, application procedure, and relevance to greywater (presence of humic acids, clay, and surfactants).

The order of application was found to impact organic compound removal, with the initial application of the flocculant, followed by biochar, being the more effective approach. The combined use of biochar and flocculant positively impacted the removal of heavy metals but impeded the removal of organic pollutants. The presence of humic acids, clay, and surfactants affected the flocculation process, which impeded the removal of heavy metals and organic pollutants.

The Swedish pulp and paper industry is the third largest exporter of pulp and paper products worldwide. It is a highly energy-demanding and water-utilising industry, which generates large volumes of wastewater rich in organic material. These organic materials are to different extents suitable for anaerobic digestion (AD) and production of energy-rich biomethane. The implementation of an AD process within the wastewater treatment plant of a mill would increase the treatment capacity and decrease the overall energy consumption due to less aeration and lower sludge production and in addition produce biomethane. Despite the many benefits of AD it is only applied at two mills in Sweden today. The reason for the low implementation over the years may be due to problems encountered linked to the complexity and varying composition of the wastewaters. Due to changes in market demands many mills have broadened their product portfolios and turned towards more refined products. This has increased both the complexity and the variations of the wastewaters´ composition even further, as the above changes can imply an increased pulp bleaching and utilisation of more diverse raw materials within the mills.

The main aim of this thesis was therefore to generate knowledge needed for an expansion of the biomethane production within the pulp and paper industry. As a first step to achieve this an evaluation of the biomethane potential and the suitability for AD of wastewaters within a range of Swedish pulp and paper mills was performed. Thus, around 70 wastewater streams from 11 different processes at eight mills were screened for their biomethane potential. In a second step, the impact of shifts in wood raw material and bleaching on the AD process and the biomethane production was investigated and further evaluated in upflow anaerobic sludge bed (UASB) reactors.

The screening showed that the biomethane potential within the Swedish pulp and paper industry could be estimated to 700 GWh, which corresponds to 40% of the Swedish biomethane production during 2014. However, depending on the conditions at each specific mill the strategy for the establishment of AD needs to differ. For mills producing kraft pulp the potential is mainly found in wastewaters rich in fibres, alkaline kraft bleaching wastewaters and methanol-rich condensates. The biomethane potential within thermo-mechanical pulp- (TMP) and chemical thermo-mechanical pulp (CTMP) mills is mainly present in the total effluents after pre-sedimentation and in the bleaching effluents as these holds high concentrations of dissolved organic material. The screening further showed that the raw material used for pulp production is an important factor for the biomethane potential of a specific wastewater stream, i.e. hardwood (HW) wastewaters have higher potentials than those from softwood (SW) pulp production. This was confirmed in the lab-scale UASB reactor experiments, in which an alkaline kraft bleaching wastewater and a composite pulping and bleaching CTMP wastewater were used as substrates. AD processes were developed and maintained stable throughout shifts in wastewater composition related to changes in the wood raw materials between SW and HW for the kraft wastewater and spruce, aspen and birch for the CTMP wastewater. The lower biomethane production from SW- compared to HW wastewaters was due to a lower degradability together with a higher ratio of sulphuric compounds per TOC for the SW case. The impact of shifts between bleached and unbleached CTMP production could not be fully  evaluated in the continuous process mainly due to technical problems. However, due to the large increase in dissolved organic material when bleaching is applied, the potential biomethane production will increase during the production of bleached pulp compared to unbleached pulp. Based on the biomethane potentials obtained for one of the included CTMP mills, their yearly production of biomethane was estimated to 5-27 GWh with the lowest and the highest value corresponding to the production of unbleached spruce pulp vs. bleached birch pulp.

Thus, the results of the investigations presented in this thesis show that the UASBreactor is suitable for AD of wastewaters within the pulp and paper industry. The results also show that challenges related to variations in the organic material composition of the wastewaters due to variations in wood raw materials could be managed. The outcome of the thesis work also imply that the production of more refined products, which may include the introduction of an increased number of raw materials and extended bleaching protocols, could increase the potential biomethane production, especially if the pulp production will make use of more HW.

Kapitlet introducerar området miljödriven produktutveckling. Inledningsvis beskrivs produktutvecklingens roll och därefter berörs produktutveckling i ett historiskt perspektiv. Avslutningsvis beskrivs hur miljörelaterade krav kommer in i bilden.

The paper presents a case study of market formation for biogas in Sweden and analyses the case with concepts derived from literature on socio-technical transitions and business-to-business marketing. Based on the case study analysis, the paper outlines two different models that describe market formation processes for renewable energy technologies: a local model and a global model. Different perspectives on the market offer, different actors involved, and different institutional dynamics characterize these models. The models do not necessarily describe different stages in the market formation process. Rather, they describe different patterns by which the market for renewable energy alternatives may grow. 

Abstract It has become increasingly clear that a transition to low-carbon energy systems, including a widespread diffusion of renewable energy technologies (RETs), is necessary for the world to handle the challenges of climate change. Previous innovation system oriented research has identified barriers to development and early-stage diffusion of RETs, but more research is needed to understand what kind of institutional frameworks and governance tools are needed to achieve effective large-scale diffusion at a stage when technologies are commercially available and new demand-side actors become involved. The purpose of this paper is, therefore, to identify the main challenges faced by adopters of renewable electricity technologies under different institutional frameworks as well as their strategies for overcoming them. Results based on a qualitative multiple case study of 28 adopters in France and in Sweden show that adopters were faced with system-level challenges, such as market-structure obstacles and lack of institutional routines, as well as actor-level challenges, such as lack of resources or behavioral characteristics. The study also highlights the difference between blocking and restraining challenges and proposes that barriers are better thought of as challenges that can be overcome. It shows the importance for policy makers to consider not only system-level diffusion challenges, but also to understand actor-level contexts, including the behaviors of adopters who contribute to the transition. A further understanding how new entrants have managed to overcome existing challenges may provide new policy tools to facilitate the adoption for new adopters, for instance by encouraging the use of networks or by supplying specific information to potential adopters who lack it.

This study investigated the potential of using biochar and Moringa oleifera seed proteins for sustainable greywater treatment in rural Kenya. Greywater samples from washing clothes were collected from households in the Kenyan counties of Kwale and Siaya. Two treatment methods, batch stirring and filtration, were used to assess the effectiveness of using biochar and Moringa oleifera seed protein extract together to treat greywater at a household level. Both methods achieved a significant reduction in contaminants: colour was reduced by up to 43% in Kwale and 67% in Siaya, turbidity decreased by 91–98%, and surfactant levels were lowered by 89–93%. There were increases in total organic carbon and total dissolved solids post-treatment, but both methods effectively reduced levels of phosphates, nitrates and iron. This research highlights the potential of using locally available materials for greywater treatment and provides insights into sustainable water management nature-based solutions in the Global South.

As an alternative to energy intensive physical methods, enzymatic treatment of sludge produced at wastewater treatment plants for increased hydrolysis and biogas production was investigated. Several hydrolytic enzymes were assessed with a focus on how enzyme activity and life time was influenced by sludge environments. It could be concluded that the activity life time of added enzymes was limited (amp;lt;24 h) in both waste activated sludge and anaerobic digester sludge environments and that this was, for the majority of enzymes, due to endogenous protease activity. In biogas in situ experiments, subtilisin at a 1% mixture on basis of volatile solids, was the only enzyme providing a significantly increased biomethane production of 37%. However, even at this high concentration, subtilisin could not hydrolyze all available substrate within the life time of the enzyme. Thus, for large scale implementation, enzymes better suited to the sludge environments are needed. (C) 2016 Elsevier Ltd. All rights reserved.

Loading macroalgae into existing anaerobic digestion (AD) plants allows us to overcome challenges such as low digestion efficiencies, trace elements limitation, excessive salinity levels and accumulation of volatile fatty acids (VFAs), observed while digesting algae as a single substrate. In this work, the co-digestion of the brown macroalgae Saccharina latissima with mixed municipal wastewater sludge (WWS) was investigated in mesophilic and thermophilic conditions. The hydraulic retention time (HRT) and the organic loading rate (OLR) were fixed at 19 days and 2.1 g l-1 d-1of volatile solids (VS), respectively. Initially, WWS was digested alone. Subsequently, a percentage of the total OLR (20%, 50% and finally 80%) was replaced by S. latissima biomass. Optimal digestion conditions were observed at medium-low algae loading (=50% of total OLR) with an average methane yield close to [Formula: see text] and [Formula: see text] in mesophilic and thermophilic conditions, respectively. The conductivity values increased with the algae loading without inhibiting the digestion process. The viscosities of the reactor sludges revealed decreasing values with reduced WWS loading at both temperatures, enhancing mixing properties.

To date, there is no analytical approach available that allows the full identification and characterization of highly complex disinfection by-product (DBP) mixtures. This study aimed at investigating the chemodiversity of drinking water halogenated DBPs using diverse analytical tools: measurement of adsorbable organic halogen (AOX) and mass spectrometry (MS)-based target and non-target analytical workflows. Water was sampled before and after chemical disinfection (chlorine or chloramine) at four drinking water treatment plants in Sweden. The target analysis had the highest sensitivity, although it could only partially explain the AOX formed in the disinfected waters. Non-target Fourier transform ion cyclotron resonance (FT-ICR) MS analysis indicated that only up to 19 Cl and/or Br-CHO formulae were common to all disinfected waters. Unexpectedly, a high diversity of halogenated DBPs (presumed halogenated polyphenolic and highly unsaturated compounds) was found in chloraminated surface water, comparable to that found in chlorinated surface water. Overall, up to 86 DBPs (including isobaric species) were tentatively identified using liquid chromatography (LC)-Orbitrap MS. Although further work is needed to confirm their identity and assess their relevance in terms of toxicity, they can be used to design suspect lists to improve the characterization of disinfected water halogenated mixtures.

Geochemical and microbiological evidence indicates that viable microorganisms produce and consume volatile organic acids (VOA) in the Yegua formation. Acetic and propionic acid concentrations in mudstones range from 200 to 1270 and 20 to 38 nmol·gdw−1 respectively, whereas concentrations in sands are 50–200 and less than 20 nmol·gdw−1. VOA concentrations in sediments and in laboratory incubations suggest net production of VOAs by microorganisms in mudstones, and net consumption of VOAs by SO4 reducing bacteria (SRB) in sands. Notably, SRB activity is mostly confined to aquifer sands. Vertical diffusion and advection were modeled to estimate acetic acid transport from aquitard to aquifer. Assuming that SRB completely respire the acetic acid transported into the aquifer (3.2 μmol·l−1·m·a−1), the CO2 production rate in the aquifer sands is 5.3 μmol·l−1·a−1. This slow mineralization rate of in situ organic matter is within the range for deep aquifers, and probably accounts for the long-term survival of microorganisms in oligotrophic environments. Finally, the microbial communities in Yegua sediments appear to exhibit a loose commensalism, with microorganisms in aquitards providing VOAs for respiratory processes (i.e., SO4 reduction) in aquifers.

Van Stone lead-zinc mine in Washington is a possible contamination source of Columbia River water. Breaching of an old tailings pond, seepage of contaminated water, and surficial transport of mine tailings have increased trace-element (TE) concentrations in the Onion Creek water and sediments. Chemical analyses of water and sediment samples indicate high TE levels near the breached tailings pond. TE contamination indices for sediments indicate high values of Pb, Zn, and other TE’s which decrease downstream. High Kd values (> 104) for several TE’s (e.g., Al, Cd, Fe, Mn, Pb, V, and Zn) suggest their enrichment in the solid phase. TE concentrations in Onion Creek water and sediment sharply attenuate downstream due to: (1) enhanced carbonate dissolution, thereby increasing pH and immobilizing TE’s; (2) sorption to oxides; and (3) change in lithology from carbonate to granite. Speciation model MINTEQA2 was used to study the effect on TE dispersion due to dissolution-precipitation reactions and adsorption to ferrihydrite. In addition to the field and chemical data, the model also supports the hypothesis that Onion Creek sediments are the major sink for TE’s at VSM. Model runs indicate precipitation of Al, Ba, Ca, Fe, Mg, and Mn minerals from oversaturation, whereas TE’s with low concentrations (Cr, Cu, Ni, Se) or geochemically more mobile (As, Mo, Sb) remain dissolved in water. Near the tailings ponds, high pH and abundance of sorption sites in sediments contribute to the complete adsorption of Pb and Zn species. Because ambient conditions result in the sorption of most Pb and Zn ions, Onion Creek water quality meets EPA regulatory standards. These species will persist in Onion Creek sediments as sorbed or insoluble complexes, and without drastic pH changes (< 4.0) they will remain immobilized. However, continued TE enrichment in sediments will prove hazardous to filter feeding and aquatic organisms.

A balanced supply of micronutrients, including metals such as iron (Fe), cobalt (Co), and nickel (Ni), is required for the efficient and stable production of biogas. During biogas formation, the uptake of micronutrient metals by microorganisms is controlled by a complex network of biological and chemical reactions, in which reduced sulfur (S) compounds play a central role. This thesis addresses the interrelationship between the overall chemical speciation of S, Fe, Co, and Ni in relation to the metals bio-uptake processes. Laboratory continuous stirred tank biogas reactors (CSTBR) treating S-rich grain stillage, as well as a number full-scale CSTBRs treating sewage sludge and various combinations of organic wastes, termed co-digestion, were considered. Sulfur speciation was evaluated using acid volatile sulfide (AVS) extraction and S X-ray absorption near edge structure (XANES). The chemical speciation of Fe, Co, and Ni was evaluated through the determination of aqueous metals and metal fractions pertaining to solid phases, as well as kinetic and thermodynamic analyses (chemical speciation modelling). The relative Fe to S content in biogas reactors, which in practice is regulated through the addition of Fe for the purpose of sulfide removal or prior to the anaerobic digestion of sewage sludge, is identified as a critical factor for the chemical speciation and bio-uptake of metals. In the reactors treating sewage sludge, the quantity of Fe exceeds that of S, inducing Fe(II)-dominated conditions under anaerobic conditions, while sulfide dominates in the co-digestion and laboratory reactors due to an excess of S over Fe. Under sulfide-dominated conditions, chemical speciation of the metals is regulated by hydrogen sulfide and the formation of metal sulfide precipitates, which in turn restrict the availability of metals for microorganisms. However, despite the limitations set by sulfide, aqueous concentrations of different Co and Ni species were shown to be sufficient to support metal acquisition by the microorganisms under sulfidic conditions. Comparatively, the concentrations of free metal ions and labile metal-phosphate and -carbonate complexes in aqueous phase, which directly participate in bio-uptake processes, are higher under Fe-dominated conditions. This results in an enhanced metal adsorption on cell surfaces and faster bio-uptake rates. It is therefore suggested that the chemical speciation and potential bioavailability of metals may be controlled through adjustments of the influent Fe concentration in relation to S content. The results also indicated that the pool of metal sulfides in the biogas reactors could be regarded as a source of metals for microbial activities. Thus, the recovery and utilisation of this fraction of metals may be considered as a measure with which to minimise the metal dosing concentrations to CSTBRs.

The effects of sulfide removal by addition of Fe on chemical speciation of Co and Ni and how it may affect the microbial metal uptake processes in biogas reactors were assessed. The influent Fe concentration was increased in a semi-continuous stirred tank biogas reactor fed with sulfur-rich stillage. Performance of the reactor, turnover kinetics of volatile carboxylic acids as well as changes in the chemical speciation of Co and Ni were investigated. The results demonstrated that approximately 95% decrease in gaseous hydrogen sulfide content of the biogas, which was caused by addition of Fe, had no apparent effects on methane production and process stability, while it enhanced the short-term turnover time of propionate. Sulfide removal decreased the overall solubility of Co and Ni partially by 1) lowering the formation of the dominant Co- and Ni-sulfide complexes in the aqueous phase and 2) by promoting processes such as adsorption and coprecipitation of Co and Ni with FeS(s). Combination of chemical speciation and bio-uptake models suggested that a higher concentration of free Co and Ni ions is achieved at low sulfide concentrations which favors the active bio-uptake of these metals. However, it was argued that the decrease in soluble metal concentrations, which was induced as a result of the addition of Fe, demotes potential diffusion-driven, passive metal uptake by microorganisms.