To reveal which parameters and assumptions from our analysis influenced the outcomes of cost and GHG emissions, we conducted a sensitivity analysis. Our uncertainty analysis for the Biogenic Refinery included 290 parameters for the mixed excreta and 319 parameters for the source-separated excreta. These results are separated into different categories along the sanitation chain (Figure ). In both scenarios, cost and GHG emissions were found to be highly sensitive to household size and toilet density, which in combination determined the number of users per toilet. Our range for number of users per toilet was generally 3 -35 (median of 4 people per household with a standard deviation of 1.8 and 3-5 households per toilet) and was based on survey results of an urban informal settlement. The impact of this estimate on deployment of the OP suggests aggregated household toilets may be the most cost effective or low-emissions practice. For example, this practice may include toilets from individual households connected to a central holding tank within a neighborhood or apartment building as well as deployment for public sanitation access (e.g., schools, parks, and informal settlements). For the mixed excreta scenario, sludge accumulation rate was found to influence both cost and GHG emissions; and energy excretion was found to be a key source of uncertainty GHG emissions, since it influences the amount of COD in excreta (thus amount of fugitive CH4 and N2O from COD). Other assumptions related to excretion were found to have a relatively higher influence on costs of the source-separated scenario since these will affect how much consumables are needed for resource recovery units (i.e., struvite precipitation and ion exchange). The impact of parameters related to excretion support the context specific findings, where calorie intake impacts emissions from the mixed treatment scenarios and protein intake impacts cost from the source-separated scenarios (as described in context-specific analysis). For assumptions relating to the frontend, the GHG emissions from the mixed excreta scenario were sensitive to emptying period of the pit latrine, while outcomes for the source-separated scenario were found to be sensitive to conveyance and resource recovery scenarios. The influence of these parameters on costs and emissions are further explored in Figure (described below). Significant parameters related to pretreatment and the OP included operator wages for both scenarios and dewatering energy for the treatment of mixed excreta. Our general range for wages was 14.55 -43.68 USD•d -1 . This value can vary greatly across contexts and should be considered in deployment. Overall, identifying which parameters are most influential to cost and emission uncertainty provides a basis for improving the relative sustainability of the OP.