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Landfill leachate contains valuable, recoverable organics, water, and nutrients. This project investigated leachate treatment and resource recovery from landfill leachates by innovative methods such as forward osmosis (FO), bioelectrochemical systems (BES), and advanced oxidation. In this study, a microbial fuel cell (MFC) removed 50-75% of the ammonia from a leachate through the electricity driven movement of ammonium to the cathode chamber followed by air stripping at high pH (> 9). During this process, the MFC system removed 53-64% of the COD, producing a net energy of 0.123 kWh m-3. Similarly, an integrated microbial desalination cell (MDC) in an FO system recovered 11-64% of the ammonia from a leachate; this was affected by current generation and hydraulic retention time in the desalination chamber. The MDC-FO system recovered 51.5% of the water from a raw leachate. This increased to 83.5% when the FO concentrate was desalinated in the MDC and then recirculated through the FO unit. In addition, the project investigated humic acid (HA) recovery from leachate during the synergistic incorporation of FO, HA recovery, and Fenton's oxidation to enhance leachate treatment and to reduce Fenton's reagent requirements. This led to the investigation of harmful disinfection byproducts (DBPs) formation during Fenton's oxidation of landfill leachate. The removal of leachate UV-quenching substances (humic, fulvic, and hydrophilic acids) using an MFC and a chemical oxidant (i.e., sodium percarbonate) with a focus on energy production and cost efficiency were also studied. BES treatment can reduce leachate organics concentrations; lower UV absorbance; recover ammonia; and, in combination with FO, recover water. Although BES is promising, significant work is needed before its use in landfill leachate becomes practical. FO application to leachate treatment must consider the choice of an appropriate draw solute, which should require minimal effort for regeneration. Resources like HA in leachate deserve more attention. Further efforts can focus on purification and application of the recovered products. The emerging issue of DBP formation in leachate treatment also requires attention due to the potential environmental and human health effects. The broader impact of this study is the societal benefit from more sustainable and cost-efficient leachate treatment. / Doctor of Philosophy / On average, each of us produces 3 – 4 pounds of solid waste every day. In the U.S., the yearly generation of solid waste is 250 million tons, while the global generation is 1.1 billion tons. The global management cost of solid waste is around 200 billion dollars. About half of U.S. municipal solid waste ends up in landfills, in China, this number is 80%. Among the different municipal solid waste (MSW) management approaches, landfilling is the most common because of its low cost and relatively low maintenance requirements. In a landfill, the combination of precipitation and solid waste degradation produce leachate, a complex wastewater. A ton of municipal solid waste can generate 0.05–0.2 tons of leachate in its lifetime during the process of landfilling. Leachate contains a vast array of pollutants, which can result in major environmental impact and adverse human health risk if not contained and treated appropriately. At present, leachate is mostly treated biologically, without any resource recovery. Among the myriad recoverable resources in landfill leachates, water and ammonia are the most abundant. We applied innovative approaches such as, bioelectrochemical systems, forward osmosis, advanced oxidation to recover resources and remove contaminants from leachate simultaneously. We also incorporated these novel technologies to help each other. For instance, we recovered humic fertilizer from leachate prior to advanced oxidation (i.e., Fenton’s oxidation) that helped the reduction of Fenton’s reagent requirements. The next step of our study could be the pilot scale application of the proposed techniques so that it can be applied in field. The broader impacts of this study include improvements in sustainability and cost efficiency of leachate treatment that can benefit the society.

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Biowaste Valorization (BV) includes practices that capture the value of biowaste through its conversion to high-value products. BV practices can influence the progress of various Sustainable Development Goals (SDGs) differently. BV can have several potential interactions with the SDGs (BV-SDGs interactions) that may take the form of either synergies or trade-offs. Therefore, the identification of BV-SDGs interactions is key to the successful achievement of SDGs. Sweden is a country at an advanced stage of BV implementation and can thus offer valuable insights. Through semi-structured interviews, relevant stakeholders evaluated the impact of BV on 15 selected SDGs targets in Sweden thus far. Both positive and negative effects were found, but synergies outnumbered the trade-offs with BV positively contributing to all 15 targets. However, this study also shows some potential trade-offs that require further investigation. The findings highlight the need for multidisciplinary collaboration to address BV-SDGs interactions comprehensively. The evidence provided in this study can inform the scientific community as well as other types of stakeholders towards better BV planning. The insights from the Swedish case can be valuable to Sweden and other countries in different stages in the transition to BV and a wider Circular Economy (CE). / Biowaste Valorization (BV) inkluderar metoder som fångar värdet av bioavfall genom dess omvandling till högvärdiga produkter. BV-praxis kan påverka utvecklingen av olika hållbara utvecklingsmål (SDG) på olika sätt. BV kan ha flera potentiella interaktioner med SDG (BV-SDG-interaktioner) som kan ta formen av antingen synergier eller avvägningar. Därför är identifieringen av BV-SDG-interaktioner nyckeln till ett framgångsrikt uppnående av SDG. Sverige är ett land i ett långt framskridet stadium av BV-implementering och kan därmed erbjuda värdefulla insikter. Genom semistrukturerade intervjuer utvärderade relevanta intressenter effekten av BV på 15 utvalda SDG-mål i Sverige hittills. Både positiva och negativa effekter hittades, men synergierna överträffade avvägningarna med BV som positivt bidrog till alla 15 målen. Men den här studien visar också på några potentiella avvägningar som kräver ytterligare utredning. Resultaten belyser behovet av tvärvetenskapligt samarbete för att ta itu med BV-SDG-interaktioner på ett heltäckande sätt. Bevisen som tillhandahålls i denna studie kan informera vetenskapssamhället såväl som andra typer av intressenter mot bättre BV-planering. Insikterna från det svenska fallet kan vara värdefulla för Sverige och andra länder i olika skeden av övergången till BV och en bredare cirkulär ekonomi (CE).