Graduation Year

2015

Document Type

Thesis

Degree

M.S.E.V.

Degree Name

MS in Environmental Engr. (M.S.E.V.)

Department

Environmental Engineering

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Sarina J. Ergas, Ph.D.

Co-Major Professor

James R. Mihelcic, Ph.D.

Committee Member

Nancy Y. Romero-Daza, Ph.D.

Keywords

Urine-Diverting Dry Toilets, pathogen reduction, A. lumbricoides, sustainability, East Africa

Abstract

As Uganda works to transform itself into an industrialized, middle-income country in the coming decades, the country is faced with a number of problematic trends that could hinder this transition. High population growth and urbanization are quickly forcing small towns to deal with issues of limited space and the aesthetic conditions within sanitation systems, while declining soil fertility in surrounding rural areas calls into question the future nutritional security of the growing population. Ecological Sanitation (Eco-San) systems, which are designed to recover nutrients from human excreta, may help to address these trends.

Improved sanitation coverage in Uganda is currently estimated to be 34%, with most people using either improved or unimproved pit latrines. Eco-San systems, especially Urine-Diverting Dry Toilets (UDDTs, also referred to as composting toilets), have been promoted in the country, but uptake has been slow. Additionally, while UDDTs generally treat human feces to a greater degree than pit latrines and composting toilets (another type of Eco-San system), concerns have been raised as to the inactivation of environmentally persistent pathogens, such as Ascaris lumbricoides eggs. This research focused on two potential solutions to the issues of effective promotion and Ascaris inactivation, evaluating them in the context of Kalisizo, a small town in southern Uganda.

Demonstration facilities have been reported to effectively convince local stakeholders of the benefits and advantages of UDDTs, thereby increasing long-term uptake of the technology in the surrounding community. However, an unresolved question concerns whether these facilities should be installed in household or institutional settings. The initial effects of demonstration facilities constructed at local primary schools in Kalisizo were evaluated by assessing local knowledge and attitudes regarding UDDTs, both before installation and after several months of operation, through focus group discussions and key informant interviews. In general, this promotion strategy proved to be successful. After installation, students exhibited a marked increase in knowledge regarding these facilities and their benefits, and opinions were strongly positive. These changes were seen in users of the facilities as well as non-users, and students expressed clear acceptance of using the products of the toilets to fertilize crops. The introduction of an improved sanitation system at the schools also appears to have sparked other improvements related to sanitation and hygiene. In the future, it is likely that students will be compelling representatives for UDDTs within their households and communities.

Regarding the treatment of persistent pathogens, previous work has demonstrated that the elevation of free ammonia levels to levels that can inactivate Ascaris eggs can be achieved through the urea addition. In this research, use of stored urine as an ammonia source for treatment of fecal products from UDDTs in Uganda was investigated. Mixtures of stored urine, fecal products from UDDTs, and wood ash were prepared, and treatment conditions (pH, temperature, ammonia concentration) were compared to the results of previous Ascaris inactivation studies to determine whether this strategy would be a feasible and effective treatment alternative. Results indicated that a volumetric mixture containing two parts stored urine and one part fecal products could provide 4-log1¬0 inactivation of Ascaris eggs after five months of indoor storage or after three months of outdoor storage. This strategy could improve the safety of recovered products while maintaining their agricultural value. Social acceptance of the treatment system appears to be possible with proper education efforts, and a cost comparison showed that this system may be more economically favorable than typical double-vault UDDTs.

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