Effect of Nitrosomonas europaea Bio-Seed Addition on the Fate of Carbon and Nitrogen Compounds in Human Feces

Abstract

One of the most important roles of the resource-oriented sanitation (ROS) systems is handling source-separated human sanitary wastes so that they can be utilized for other purposes. Usually, these systems are constructed to use the source-separated feces as fertilizers or soil conditioners. However, there are some challenges with these systems, such as their high volume, low degradation rate, and lack of fertility management. To overcome these challenges and manage source-separated human feces more efficiently in ROS systems, utilizing nitrifying microorganisms is useful. Since the presence of both carbon and nitrogen compounds is essential for keeping these microorganisms active, and the feces contains plenty of carbon and nitrogen, higher growth rates of nitrifying microorganisms can be achieved for biodegrading the feces and modifying its fertility. In this study, the fate of carbon and nitrogen compounds in the presence of Nitrosomonas europaea bio-seeds was investigated. The results show that adding bio-seeds leads to better feces degradation. Moreover, the addition of bio-seeds can increase the fertilization capacity of feces for use as a fertilizer or soil conditioner, by reducing ammonia loss and providing a more variable nitrogen composition. This approach can be useful for handling source-separated human feces in ROS system practices.