Date of Award
10-28-2024
Publication Type
Thesis
Degree Name
M.A.Sc.
Department
Civil and Environmental Engineering
Keywords
Co-digestion;Methane Yield;Organic Waste;Raw Sludge;Reactors;Wet Cake
Supervisor
Rajesh Seth
Supervisor
Niharendu Biswas
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Abstract
Many waste types from various industries require proper treatment send disposal especially if they are organic and generated daily. Anaerobic digestion can degrade this waste to form biogas, a main component of natural gas. Waste-to-energy would also enable practical and sustainable uses of these materials to help reduce the energy crisis and emissions that increase global warming. Using industrial waste such as wet distillers’ grains (wet cake) is a great method for improving the results of the digestion of raw sludge. Co-digestion is also conducted to try and boost biogas production, particularly the methane yield and to mix wastes that may have been deemed unfeasible by themselves. This was observed from the biomethane potential (BMP) test conducted, which utilised different mix ratios for co-digesting wet cake and raw sludge. The test was conducted under mesophilic conditions at a food-to-micro-organism ratio of 0.5. Results showed that mono-digestion of wet cake had the highest bio-methane potential at 256 ± 2.1 NmL CH4/gCODadded (382 ± 3.2 NmL CH4/gVSadded), while raw sludge had the lowest at 94 ± 2.3 NmL CH4/gCODadded (154 ± 3.7 NmL CH4/gVSadded). The co-digested mixes fell within the range of results for wet cake and raw sludge. Statistically, the mix ratios were not significantly different from the expected experimental yield based on the sum of the individual wastes to conclude there was no synergistic or antagonistic effect. Two (2) Reactors (R1: wet cake + raw sludge and R2 wet cake only) were also operated semi-continuously for a hydraulic retention time of 20 days. Reactor 1 demonstrated stable operations at an organic loading rate of 3.82 g VS/L.day with approximate VS and TCOD removals of 59% and 54%, respectively, for 40 days, after which instability occurred shown by high VFA concentrations. Reactor 2 sustained stable operations at a loading of 2.81 g VS/L.day for 24 days with VS and TCOD removal of 73% and 61%, respectively, but showed instability immediately after an increase in loading to 3.97 g VS/L.day with high VFA concentrations. Further assessment of the effects of co-digestion is required to determine optimal conditions
Recommended Citation
Williams, Rickel Hermay, "Biogas Recovery from Co-digestion of Wet Distillers' Grain and Raw Sludge in Batch and Semi-continuous Reactors" (2024). Electronic Theses and Dissertations. 9383.
https://scholar.uwindsor.ca/etd/9383