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Volatile Fatty Acids (VFAs) are a by-product when producing methane through anaerobic digestion (AD). Due to their many uses as building block chemicals, it is of interest to look into ways to optimize anaerobic digestion toward VFA production instead of methane generation. This report will focus on different parameters to produce VFA from food waste (FW), primary sludge (PS), and digested sludge (DS) in different ratios. In this project, three different experimental sets were run over a period of 25 days. The three different sets were 100 % FW, 100 % PS, and 50/50 % FW and PS mixture. Reactors were adjusted to an initial pH-value of 10 and then sparged with nitrogen to create an anaerobic environment. Measurements of the pH were done by sampling at each retention time. Gas chromatography (GC) was used at the end of the project to determine the concentrations of the VFA in the samples. The results showed that, with pH 10, a retention time of 15 days and using only FW, was optimal for VFA production as it gave the highest total concentration of 14.03 g VFA/L. Acetic acid was found in the highest concentration in all ratios. A mixture of FW and PS had an optimal retention time of 12 days, but did not generate as high concentrations of VFAs as only using FW, with a maximum concentration of 9.34 g VFA/L. Using only PS generated even lower concentrations, with a maximum of 5.33 g VFA/L, but did not start decreasing during the experimental run, and no clear conclusion can, therefore, be drawn.

M.Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / An enormous amount of food waste (FW) is generated worldwide. Most of this waste is discarded in landfills, where it undergoes uncontrolled anaerobic digestion (AD) process, which emits excessive amounts of greenhouse gases, (methane and carbon dioxide), thereby contributing to global warming. A controlled AD of FW is key for organic waste management with a positive impact on the environment and economy. In South Africa (SA) there is little uptake of biogas technology for FW management due to little research on biogas potential at small to large scale. Furthermore, there is an over reliance on foreign data, which leads to misfit parameters to local raw materials; consequently, producing biogas of low quality and quantity with low degradation of waste. Biogas with poor quality reduces the efficiency of biogas conversion to energy and the low production rate makes the system less feasible. Considering the challenges faced with FW management and the little uptake of the AD technology in SA, this study aimed to treat FW through AD and convert the biogas produced to electricity. A complete-mix biogas pilot plant (VUT-1000C) was designed, constructed and commissioned. The materials used for constructing the pilot plant were sourced locally to prove the applicability of the AD technology in SA. The biodigester was operated at mesophilic temperature, 37 oC, aided by a solar system. A stand-alone 1 m3 plug-flow ambient biodigester (STH-1000A) was operated semi-continuously as well as a control. Cow dung (CD) was used to inoculate the biodigesters, which were then operated semi-continuously at their optimum organic loading rate (OLR). The STH-1000A digester was operated at 0.446 kgVS/m3/day OLR, according to the manufacturer’s specification, while for VUT-1000C, the OLR was determined. The highest biogas and methane yields obtained were 582 and 332 L/kgVS/m3, respectively, at the determined optimal OLR of 1.5 kgVS/m3/day for the VUT-1000C digester this was supported by the modified Gompertz model with an R2 value of 0.9836. VUT-1000C produced 1200 L/day while STH-1000A produced 150 L/day. VUT-1000C proved to be a more effective biodigester than STH-1000A owing to the digester design and operation at mesophilic conditions. The key design findings are higher reactor working volume and high digester temperature. From the 1000 L of biogas produced from VUT-1000C, 1.8 kW of electricity was generated, which is equivalent to powering 300 6W light bulbs for 1 hour. The energy balance of the pilot plant showed that only 10 percent of the energy output was required to operate the plant. These results show that SA has a 475 GWh energy potential based on the current FW figures. Furthermore, the study has shown that biogas technology is readily available for South Africans and that the designed biogas plant was very efficient in FW-to-energy conversion.

The production of volatile fatty acids (VFAs) from waste stream is gaining high attention because of their high market value and wide range of applications. In this study, the production of VFA from co-fermentation of primary sludge from wastewater treatment plant and food waste without pH control was evaluated using a pilot-scale reactor in a semi-continuous mode of operation. In addition, the influence of substrate and inoculum on VFA production and composition was assessed using a batch fermentation experiment. The pilot-scale reactor was operated at a retention time of 7 days and 10 days in phase 1 (126 days) and phase 2 (25 days) respectively. A maximum VFA production of (687 mg COD/g VS) was obtained when the pilot-scale reactor was operated at a retention time of 7 days on day 107. The change in retention time from 7 to 10 days led to a higher hydrolysis rate; however, no improvement in VFA production was observed. The most abundant VFA produced after the reactor stabilized was caproic acid (50 %), followed by acetic acid (23%) and butyric acid (20%). Higher amount ammonium nitrogen (1.3 to 14.32 mg/g VS) compared to soluble phosphorus (0.69 to 7 mg/g VS) was released during the co-fermentation process. Furthermore, the loss of the VFA due to the production of methane was highly reduced because the pH of the reactor adjusted by itself in the range of (5 – 5.7). The batch fermentation experiment revealed that VFA production without pH control is highly influenced by the type of substrate and inoculum used. While the distribution of VFAs, is highly influenced by the inoculum type compared to the substrate used. Finding from this study indicates that there is a potential to produce VFA from co-fermentation of primary sludge and food waste without pH control. / Lättflyktiga fettsyror (VFA; eng. Volatile Fatty Acids) är viktiga byggstenar för produktionen av en mängd kommersiellt viktiga kemikalier. VFA produceras för närvarande från icke-förnybara petrokemiska källor, som kan orsaka miljöproblem på grund av utsläpp av växthusgaser. VFA kan också produceras som en mellanprodukt vid den anaeroba nedbrytningsprocessen. Produktionen av VFA från avfallsströmmar har i nuläget fått stort intresse på grund av dess höga marknadsvärde och breda applikationsområde jämfört med biogas. Det mesta av forskningen som hittills genomförts har dock baserats på justeringen av pH genom tillsatts av HCl eller NaOH. Denna metod har dock mindre storskalig praktisk användning på grund av hög konsumtion av kemikalier. I denna studie undersöktes produktionen av VFA från samjäsning av primärslam och matavfall utan pH-kontroll med hjälp av en pilotskalereaktor i ett semikontinuerligt driftläge. Dessutom mättes den påverkan substrat och inokulum hade på produktion och av VFA genom batchjäsningsexperiment. Pilotskalereaktorn drevs med uppehållstid på 7 dagar respektive 10 dagar i fas 1 (126 dagar) och fas 2 (25 dagar). Maximal VFA produktion (på 687 mg COD/g VS) uppnåddes på dag 107, när pilotreaktorn hade en uppehållstid på 7 dagar. Ändringen i uppehållstid från 7 till 10 dagar ledde till en högre hydrolystakt; dock observerades ingen förbättring i VFA-produktion. Det vanligast förekommande VFA som produceras efter att reaktorn stabiliserades var caproinsyra (50%), följt av ättiksyra (23%) och smörsyra (20%). Högre mängd ammoniumkväve (1,3 till 14,32 mg/g VS) jämfört med löslig fosfor (0,69 till 7 mg/g VS) erhölls under samjäsningsprocessen. Förlusten av VFA på grund av produktion av metan minskade markant eftersom pH i reaktorn justerade sig själv i intervallet 5 – 5,7. Batchjäsningsexperiment genomfördes i 15 dagar med användning av endast primärslam, endast matavfall och en blandning av primärslam och matavfall. Två inokulum med ursprung från en anaerob rötkammare och dels från pilotskalereaktorn användes i experimentet. Resultaten visade att VFA-produktion utan pH kontroll påverkas betydligt av vilket slags substrat och inokulum som används. Sammansättning av VFA påverkas mer av vilket slags inokulum som användes jämfört med vilket substrat som används. Sammanfattningsvis visar resultatet av denna studie att det finns potential för att producera VFA genom samjäsning av primarslam och matavfall utan pH kontroll.

In Europe, 45% of vegetables and fruit have been lost before consumption. The main reason for the loss is suboptimal food, which is perfect based on safety and security but imperfect according to appearance or packaging. In this project, I want to find out new possibilities in urban development by suggesting a participative food supply chain.  It aims to inspire a paradigm of urban development and shift people’s attitudes towards suboptimal food. The participative supply chain includes food production, distribution, and retail/consumption. By participating in the food supply, residents and visitors can understand how the food system works, grow their food and help with food processing. With interaction and collaboration workers, they can value more about the food they consume and even change their eating patterns.

Recognizing the importance of food waste as an environmental and social problem, this thesis aims to test nudging as a successful tool to promote a pro-environmental behaviour towards food waste reduction. The present research uses an experiment in a university canteen in Gotland, Sweden, with two interventions - posters with informational prompts and practical tips. Through quantitative analysis, we were able to conclude that nudging reduced overall food waste but with no statistical significance for the informational treatment. Furthermore, the informational prompts and the suggestions of shortcut solutions had similar positive impacts on food waste, with no significant difference. However, the study highlights some aspects that limit these results to a short-term perspective due to the experimental period of two months. On the other hand, the complementary qualitative data from interviews with customers revealed that nudges, especially practical suggestions, can be more useful as an awareness tool rather than a technique to actually change behaviours. Overall, the findings show that the two interventions reduced food waste with a continuous decreasing trend. Therefore, nudging can be a useful technique for canteens and restaurants to influence consumers’ behaviour towards food waste reduction.

Vanadin är en värdefull metall och kan lakas ur LD (Linz-Donawitz)-slagg med hjälp av vin. Ligander i vinet som lakar vanadin från LD-slagg studerades i denna rapport med mål att identifiera några av deras egenskaper såsom apparent molekylmassa och spektral information. Hyfenerad analys med hjälp av högupplösande vätskekromatografi-mikrovågsplasma med atomemissionspektrometer (HPLC-MP-AES) gjordes för att matcha vanadintoppen från vinet med ett apparent masspann från en gelfiltreringskolonn. Spektral analys visade att det fanns tre misstänkta vanadinligander i det analyserade vinet. Apparent molekylmassa hos liganderna var sannolikt inom spannet 24 Da – 570 Da. / Vanadium is a valuable metal and can be extracted from Linz-Donawitz (LD) converter slag using wine. Ligands in wine responsible for leaching vanadium from LD converter slag were studied in this report in an effort to identify some of their properties such as apparent molecular mass and spectral information. Hyphenated analysis using high performance liquid chromatography-microwave plasma atomic emission spectroscopy (HPLC-MP-AES) was performed to match a vanadium peak from the wine with an apparent mass span from a size exclusion chromatography (SEC) column. Spectral analysis of the vanadium peak revealed that there were three compounds suspected to be ligands to vanadium in the wine analyzed. Apparent molecular mass of the ligands wasfound to likely be between 24 Da - 570 Da.

<p>Sustainably meeting the food demands of a growing population based on finite resources while protecting the environment is one of the great challenges of humanity in the coming decades. This dissertation combines three essays that examine how future patterns of global food consumption will affect human health, and how the food system changes driven by the ongoing global nutrition transition will affect the environment. The production of food needed to meet a growing population combined with changes in food consumption patterns are placing unprecedented levels of stress on the planet’s scarce natural resources. In this context, while the existing literature has mainly focused on increasing production, the magnitude of loss and waste is too large to be ignored. The first essay contributes to the literature by examining the linkages between consumers’ food waste at the national level on the one hand, and global food security and environmental health on the other hand. Absent significant behavioral changes or successful policy interventions, food waste will nearly double by 2050. Emerging economies are likely to play a key role in driving this growth in global food waste. Further findings indicate that the global benefits of food waste mitigation are greatly enhanced in the context of a more open international trade regime. Yet even as food loss and waste has been undernutrition and overweight/obesity levels have also been increasing. Together, these trends form a triple challenge for food security, global sustainability and human health. In the second essay I examine the role of the excessive calorie availability as an historical driver of adult BMI. I find that, in part driven by excess in calorie availability, individuals in more recent cohorts are overweight or obese earlier and for larger proportions of their lifespan than those in earlier cohorts. This highlights the potential for unintended health consequences of agricultural and trade policies directed at increasing calorie supplies. In the third essay I introduce a novel framework that extends the UN-FAO’s methodology for assessing undernutrition to also assess the extent of overconsumption and obesity. This framework allows for examination of the dynamics of the double burden of malnutrition between 2015 and 2050. Specifically, this framework shows how shifting towards healthier and more sustainable food consumption levels and reducing food waste could synergistically address multiple health and environmental burdens. </p>

Worldwide, around 17% of food waste produced in high income countries is constituted of dairy products. In Sweden, Dairy Company A has been dealing with food waste production throughout all their sites. Although it already practices actions such regarding food waste minimization such as biogas generation and animal food, reduction and prevention practices are still an area of opportunity. The aim of this study is to explore alternatives for food waste prevention in Company A CSE dairy supply chain and generate recommendations that help the company achieve a more sustainable supply chain.  This study furthermore proposes a 5-step research methodology to identify food waste causes and drivers, including data gathering mainly through interviews and analysis based on proposed frameworks in relevant literature. It was found that activities related to systematic root cause identification and information storage and sharing play a key role in improving existing practices that aim to reduce and minimize food waste production from a supply planning perspective.  The research identified and recommended not only to raise awareness, which is key to reducing food waste, but to put into a broader context how decisions taken by any planner could be influencing the sustainability of the supply chain. This could be done through the adoption of process-driven mechanisms to share relevant information as well as food waste root cause identification. / Över hela världen utgörs cirka 17 % av matavfallet som produceras i höginkomstländer av mejeriprodukter. I Sverige har Mejeriföretag A sysslat med produktion av matavfall på alla sina anläggningar. Även om det redan tillämpar åtgärder som när det gäller minimering av matsvinn, såsom generering av biogas och djurfoder, är metoder för reduktion och förebyggande fortfarande ett område med möjligheter. Syftet med denna studie är att utforska alternativ för att förebygga matsvinn i Company A CSE-mejeriförsörjningskedjan och generera rekommendationer som hjälper företaget att uppnå en mer hållbar försörjningskedja.  Denna studie föreslår dessutom en 5-stegs forskningsmetodik för att identifiera orsaker och drivkrafter för matsvinn, inklusive datainsamling främst genom intervjuer och analyser baserade på föreslagna ramverk i relevant litteratur. Det visade sig att aktiviteter relaterade till systematisk rotorsaksidentifiering och informationslagring och -delning spelar en nyckelroll för att förbättra befintliga metoder som syftar till att minska och minimera produktionen av matavfall ur ett utbudsplaneringsperspektiv.  Forskningen identifierade och rekommenderade inte bara att öka medvetenheten, vilket är nyckeln till att minska matsvinnet, utan för att sätta in i ett bredare sammanhang hur beslut som fattas av alla planerare kan påverka leveranskedjans hållbarhet. Detta skulle kunna göras genom antagandet av processdrivna mekanismer för att dela relevant information samt identifiering av rotorsak för matavfall.

Every year 1.6 billion tons of food is thrown away corresponding to one third of all the food that is roduced. It accounts for 8 % of the global greenhouse gas emission, meaning that it has a huge negative impact on the environment. In Sweden, households account for the largest amount of food waste. Therefore, this study focuses on reducing food waste on a household level in Swedish households. There is a growing interest in HCI for how design can be used for reducing food waste by changing unsustainable behaviour. In this work a working mobile prototype, FoodEd, was designed, implemented and studied. FoodEd contains information of how to handle and store different food items in an optimal way. The aim was to raise awareness of good food handling practices and edibility beyond expiry dates in order to prevent unnecessary food waste in households. In this study, FoodEd was used by 10 participants during a week’s time. Two qualitative interviews were held with each participant during the study. The findings of the study indicate that an informative design can be effective in providing relevant information for its users leading to more sustainable food waste behaviours. / Varje år kastas 1,6 miljarder ton mat, motsvarande en tredjedel av all mat som produceras. Det står för 8% av det globala utsläppet av växthusgaser, vilket innebär att det har en enorm negativ påverkan på miljön. I Sverige står hushållen för den största mängden matavfall. Därför fokuserar denna studie på att minska matavfall på hushållsnivå i svenska hushåll. Det finns ett växande intresse för HCI och för hur design kan användas för att minska matsvinn genom att förändra ohållbart beteende. I detta arbete designades, implementerades och studerades en fungerande mobilprototyp, FoodEd. FoodEd innehåller information om hur man hanterar och lagrar olika livsmedel på ett optimalt sätt. Målet var att öka medvetenheten om goda mathanterings praktiker och olika livsmedels ätbarhet utöver utgångsdatum för att förhindra onödigt matsvinn i hushållen. I denna studie användes FoodEd av 10 deltagare under en veckas tid. Två kvalitativa intervjuer genomfördes med varje deltagare under studien. Resultaten av studien indikerar på att en informativ design kan vara effektiv när det gäller att tillhandahålla relevant information till dess användare vilket leder till ett mer hållbart matsvinn beteende.