I have formulated and investigated a stoichiometric organic matter decomposition model in a chemostat culture that incorporates the dynamics of grazers. I performed complete local and global stability analyses of the system and determined the criteria for the uniform persistence and extinction of the species and chemicals. Moreover, I determined the optimal value of grazers that maximizes degradation of organic matter. Based on the parameters under the control of the ex- perimenter, I performed one- and two-parameter bifurcation analyses. Furthermore, I determined the switching time of bacterial growth rate from carbon dependent to nitrogen dependent and vice versa for different continuous cultures. I determined the sensitivity of the degradation rate with respect to the model parameters. I also discussed numerically how the dilution rate affects the decomposition percentage as well as decomposition speed. In collaboration with M. Lewis (math & biological sciences), T. Siddique (renewable resources), J. Foght (biological sciences), Hao Wang (math) and industrial partners, we have modified this model to a greenhouse gas (GHG) generation model for oil sands settling basins and end pit lakes. First, I fitted the model to naphtha hydrocarbons in tailings from Syncrude’s Mildred lake settling basin to determine optimal parameter values. Next, I extended it to a GHG generation model and then validated the model using measured methane data from Syncrude’s mature fine tailings (MFT). This model is cross validated using the hydrocarbons and methane data from Shell Albian’s MFT.