Browsing by Subject "anaerobic digestion"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Biogas Production and Nutrient Recovery from Waste Streams
    (2013-07) Ye, Yulin
    Abstract Waste streams such as municipal wastewater and animal manure contain organic materials and nutrients that can be converted and recovered for bioenergy and renewable fertilizer production. In the first part of this thesis, the anaerobic co-digestion of dairy manure with kitchen waste and chicken fat was studied for the purpose of increasing biogas production. The methane yields of co-digestion substrates mixed at different ratios were determined by bio-methane potential tests. The highest methane yield, which was 114% higher than the baseline, was observed when dairy manure was mixed with kitchen waste and chicken fat at the ratio of 1:2:2 (volatile solids based). The mixed substrates were then fed to a lab-scale continuous stirred-tank reactor. The co-digestion was stable and biogas production was 1559�195 mL biogas/L·day at organic loading rate as high as 6.8g COD/L*day. In the second part, a new approach was proposed for phosphorus removal and recovery from wastewater. Nine strains were identified to have the capability of high phosphorus removal and storage comparable to Polyphosphate Accumulating Organisms (PAOs) in the Enhanced Biological Phosphorus Removal (EBPR) process. Batch experiment using synthetic wastewater showed that Mucor circinelloides can remove ~ 72-82% phosphorus when P to COD ratio was roughly 1:100. The phosphorus recovered from wastewater in the form of polyphosphate-containing fungal biomass could be used as fertilizer, providing a potential alternative to biological nutrient removal and a solution to sustainable agriculture.
  • Thumbnail Image
    Item
    Determination of Biomethane Generation Potential in the Domestic Municipal Waste Flow of Hanoi, Vietnam
    (2021-12) Nguyen, Allie; Tschirner, Ulrike
    The objective of this research project is to determine the anaerobic methane production capability of Hanoi’s domestic municipal waste flow given its chemical composition using biomethane potential tests. The research project sampled domestic waste matters from several households in Hai Ba Trung district, Hanoi. The chemical composition of the organic waste samples, including chemical oxygen demand (COD), total solids (TS), and volatile solids (VS), were examined, and the TS values were used to calculate the volume ratio between the organic waste and seeding sludge that has anaerobically digesting microorganisms. 10mL of waste and 290mL of sludge were combined for a 300 mL waste-sludge mixture. Four sludge mixtures were then placed in four reacting beakers at a temperature of 35oC for 21 days, two of which were mixed and the other two were not mixed. Two blank reactors with only the microorganisms were also placed in the same temperature condition. The results for the cumulative volume of methane generated were 294.3 mL per gram of VS for the mixed reactors and 177.8 mL per gram of VS for the unmixed reactors. Since the mixed reactors yield a much higher volume of CH4 generated than the unmixed reactors, it can be concluded that mixing of the substances in the beakers is important. Moreover, the maximum volume of generated methane for all the reactors was reached after day 3, which is a lot faster than the suggested experiment time for biomethane potential tests (21 days).