In 2015, the United Nation has defined the Sustainable Development Goals (SDGs). The 6th goal of the SDGs defined “Sanitation for All”, which aims the provision of adequate access to sustainable water resource and sanitation up to 2030.
Indeed, “Sanitation for All” includes people living in remote areas suffering from lack of access to water, sanitation, and even food. For such communities, implementation of Resource-Oriented Sanitation (ROS) systems can be a sustainable and reliable solution toward the mentioned goals. Thus, the technical efficiency of these systems is an important factor for sustainable provision of their long-term benefits for the community.
Aims & Actions for Technical Efficiency
ROS systems generally have a routine mechanism: they separate urine and feces from the source, collection them and storage safely and separately, and treat them for further disposal or final utilization. For each of the mentioned steps, we currently have different technical options and approaches.
However, to provide an efficient and safe ROS system, aiming the final technical goals based on the requirements of the implementation area is essential. Recycling human excreta, especially human urine, for agronomic utilization like fertilizer is one of the most common technical goals for an implemented ROS system. In this case, the treatment process should be designed appropriately.
Biologically Treatment of Human Excreta through Nitrification Process
Considering the agronomic utilization of the treated ROS products, there are several approaches to treat urine and feces for being utilized as fertilizer or soil conditioner. One of these approaches is a treating by using nitrifying microorganisms.
Recent studies show that biologically treating human excreta using controlled nitrification procedure has a high efficiency in improving fertility and reducing the stabilization and retention time for treating source-separated urine .
As for the source separated feces, such methods are also useful in improving the bio-degradation process of feces by providing a more favorable condition for heterotrophic microorganisms . This method is even useful for stabilizing the C:N ratio of treated feces and removing fecal indicators from feces [2,3].
A recent study aimed for the field evaluation of the fertilizing potential of excreta treated through the nitrification process. In this study, it is shown that the combination of treated urine and feces could function as a combination of fertilizer and soil conditioner leading to a high productivity, indicated by the growth of bigger and sweeter white radishes high in water content .
Implementation of such an approach not only can provide sustainable sanitation services for all but also it might be very useful for areas with food shortages or agriculture-based communities.
The Road Ahead
On the way toward achieving SDG 6, along with providing innovative approaches in technical efficiency of the ROS systems, it is essential to define new standards for sanitation based on experiences in the field and advanced scientific and engineering knowledge. Thus, more demonstration projects including the pilot scaled, technically developed ROS are required to evaluate their technical efficiency in a specific community.
Before the implementation, the social and economic condition of the community should be carefully considered. Accordingly, designs of ROS systems should be more flexible to match the different needs and definitions of hygiene in different societies.
1. Hashemi, S., Han, M., & Kim, T. (2016). Optimization of fertilization characteristics of urine by addition of Nitrosomonas europaea bio‐seed. Journal of the Science of Food and Agriculture, 96(13), 4416-4422.
2. Hashemi, S., & Han, M. (2018). Optimizing source-separated feces degradation and fertility using nitrifying microorganisms. Journal of environmental management, 206, 540-546.
3. Hashemi, S., Han, M., & Namkung, E. (2018). Fate of Fecal Indicators in Resource-Oriented Sanitation Systems Using Nitrifying Bio-Treatment. International journal of environmental research and public health, 15(1), 164.
4. Hashemi, S., & Han, M. (2019). Field evaluation of the fertilizing potential of biologically treated sanitation products. Science of The Total Environment, 650, 1591-1598.