Inactivation of Ascaris in Double-Vault Urine-Diverting Composting Latrines in Panama: Methods and Environmental Health Engineering Field Applications

The United Nations Millennium Development Goals have prioritized improving access to sanitation, but unfortunately about a third of the global population is still without an improved sanitation source and one billion still practice open defecation. Lack of access to adequate and safe sanitation means the proliferation of dangerous pathogens in the environment, especially soil-transmitted helminths (STHs). In the Bocas del Toro Province of Panama (and similar locations in the world), composting latrines have been built in many of the indigenous communities in the area. They are a form of dry or ecological sanitation and are designed to produce an end product that can be used as a soil amendment for agricultural purposes. The issue is that many of these latrines are not working as designed and do not go through the composting process. Instead, they may act as incubators for harmful pathogens, such as Ascaris lumbricoides (roundworm). This research 1) provides an extensive literature review of the health situation of Panama, focusing on indigenous populations; soil-transmitted helminths and helminthiasis; Ascaris lumbricoides and its implications for wastewater reuse and land application of biosolids/sewage sludge; and inactivation of Ascaris in composting latrines; and 2) develops and proposes an experimental plan, with field-based methods, to assess the inactivation of Ascaris, by urea and solar heat (increased temperature), in composting latrines in Panama. Various experiments have been conducted in the laboratory using urea and increased temperature to inactive Ascaris; however few have been carried out in dry toilet technologies in the field. The contribution of this thesis is the field-based experimental design developed for inactivating Ascaris in composting latrines. The methods build upon previous research carried out both in the laboratory and in the field