Date of Award
Master of Science (MS)
Civil, Environmental & Architectural Engineering
Karl G. Linden
R. S. Summers
The provision of sanitation services has been accelerated as part of the Sustainable Development Goals with increasing focus on the need for solutions within the fecal sludge management services supply chain. One common constraint in the sanitation value chain is malodor nuisance associated with fecal sludge. Finding cost-effective ways to minimize end user malodor nuisance from latrines is critical. Adsorption of malodor onto biochar was hypothesized as one possible technology intervention to malodor nuisance. Adsorption studies were conducted as part of a project funded by the Bill & Melinda Gates Foundation to control and mitigate malodors derived from human waste. Biochars derived from bamboo wood, pine wood, and human feces, and NORIT ROZ 3 activated carbon were used to evaluate adsorption of malodor. A reconstitution of fecal malodors was used, comprised of four compounds including carboxylic acids, sulfur and nitrogen containing compounds shown to be responsible for human fecal odor. Both batch and flow-through adsorption tests were performed. Odor was quantified using ascending concentration series method of dynamic threshold olfactometry by an odor panel, and a hydrogen sulfide (H2S) meter. Breakthrough capacities of the adsorbents for both odor reduction (odor units per g of adsorbent) and H2S reduction (mg/g of adsorbent) were determined for the equilibrium odor levels represented by the adsorption studies for batch and flow-through methods. Complete odor removal was never achieved; generally, 40-50% of odor could be removed by adsorption. Results showed that all biochars exhibited comparable adsorptive characteristics to each other and modified activated carbon. All experiments were performed at a high relative humidity, as would be typical in many latrine settings. Results indicated significant fouling by water vapor during continuous flow operation that generally decreased odor capacity of the chars by an order of magnitude. Specific compounds representing adsorption challenges were identified. Overall, the results provide baseline engineering data to apply and size biochar filters for adsorption as a malodor control method in various latrine settings.
Stetina, Kathleen, "Control of Fecal Malodor by Adsorption onto Biochar" (2017). Civil Engineering Graduate Theses & Dissertations. 86.