The Waterless Portable Private Toilet: An Innovative Sanitation Solution in Disaster Zones

Fate of Fecal Indicators in Resource-Oriented Sanitation Systems Using Nitrifying Bio-Treatment

Hygienic fecal treatment in resource-oriented sanitation (ROS) systems is an important concern. Although the addition of nitrifying microorganisms is a sustainable fecal treatment method in ROS systems, it is essential to examine the cleanliness of this method. In this study, we investigated the fate of fecal indicators in source-separated fecal samples through tracking Escherichia coli and total coliforms. The effects of adding different amounts of Nitrosomonas europaea bio-seed, along with a constant amount of Nitrobacter winogradskyi bio-seed, were studied. In intact feces samples, the pathogen population underwent an initial increase, followed by a slight decrease, and eventually became constant. Although the addition of nitrifying microorganisms initially enhanced the pathogen growth rate, it caused the reduction process to become more efficient in the long-term. In addition to a constant concentration of 10,000 cells of N. winogradskyi per 1 g feces, a minimum amount of 3000 and 7000 cells of N. europaea per 1 g feces could completely remove E. coli and total coliforms, respectively, in less than 25 days. Increasing the amount of bio-seeds added can further reduce the time required for total pathogen removal.

Optimizing source-separated feces degradation and fertility using nitrifying microorganisms

Resource-oriented sanitation (ROS) systems play an important role in handling source-separated human sanitary wastes intended to be used for other purposes. Usually, the purpose of employing such systems is to render the source-separated human feces suitable as fertilizer or soil conditioner. However, the high volume, low degradation rate, and lack of fertility management pose challenges to such enterprises. Accordingly, treatment by applying controlled amounts of nitrifying microorganisms could be useful. The effect of adding different amounts of Nitrosomonas Europaea bio-seed, along with a certain amount of Nitrobacter Winogradskyi bio-seed, to source-separated human feces was investigated. The results show that adding 7000-8000 or more N. Europaea cells, along with 10,000 N. Winogradskyi cells, to 1 g feces, resulted in up to 90% degradation of the organic matter by enhancing the growth of heterotrophic microorganisms. Moreover, the nitrogen composition and pH of the degraded feces were optimized to meet the criteria for standard fertilizer. The results can be useful for managing source-separated feces in ROS systems in accordance with the specific aims of such systems, i.e., reducing feces volume by bio-degradation and increasing the fertility to meet the standard criteria for fertilizer.