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Cycle 6 (2017 Deadline)
Promoting resource- oriented sanitation in peri-urban Ethiopia through the production of struvite from digested sludge filtrate
PI: Adey Desta, adey.desta@gmail.com, Addis Ababa University
U.S. Partner: Nancy Love, University of Michigan
Project dates: December 2017 - February 2022
Project Overview
Ethiopia has become one of the fastest growing economies in Africa, with an increasing rate of urbanization and demand for phosphate-based fertilizer to increase productivity in the agriculture sector. Phosphate rock, the starting material for phosphate fertilizer, is a finite resource, and Ethiopia is entirely dependent on importing different kinds of phosphate fertilizers and therefore is vulnerable to market fluctuations in fertilizer prices. The availability and affordability of imported fertilizers to most of the urban and peri-urban farmers is very low because of lack of government subsidies for urban/peri-urban farmers, unlike those provided for rural farmers. The urban/peri-urban farmers get fertilizers at a higher price from local vendors, and the product is difficult to get at any cost at times of shortage.
This scenario suggests the need to look for alternative sources of phosphate to achieve sustainable agriculture. Recovery of phosphorus from digested sludge water has long been a well-established technology in some of the developed countries. Different technologies are available to recover phosphorus from various wastewater streams. Some have been implemented at an industrial scale with maximum recovery efficiency. So far, Ethiopia has not adopted any phosphorus recovery technologies at any level.
This PEER project is aimed at demonstrating that digested wastewater can be used to reliably produce good quality, safe, and marketable struvite fertilizer using full-scale systems. The focus of the study will be on preferred approaches for recovery of phosphorus and nitrogen from digested wastewater with the minimum prevalence of various types of contaminants, such as micropollutants (drugs and metabolites) and biological contaminants (microorganisms and antibiotic resistance genes).
 | | Photo courtesy of Dr. Desta |
The information generated about the prevalence and persistence of the pollutants will be useful in further risk assessment studies to predict the risks associated with wastewater reuse. The lab facilities accessible through collaboration with the U.S. partner will be useful for the initial survey of these contaminants from the fertilizer product (struvite) and its raw material, and the information generated will leverage subsequent in-house monitoring studies.
The project will also demonstrate the impact of struvite on commonly grown vegetables, such as carrot and Ethiopian kale, as compared with synthetic fertilizer, which has further implications for addressing issues of food insecurity in the urban areas.
The research team plans to work in close collaboration with smallholder farmers of urban and peri-urban areas to understand problems of productivity, the perception of struvite by farmers, and impact of struvite application in the productivity of urban agriculture. Through this approach, the particular needs and challenges of women farmers will also be addressed.
Final Summary of Project Activities
In early 2022 as the project approached its closing date at the end of February, Dr. Desta and her team completed sampling from the pilot-scale FBR, extracted DNA samples from the FBR, and sent them to a sequencing facility. The results will be submitted to the U.S. National Center for Biotechnology Information for inclusion in their publicly accessible databases. Additionally, the researchers have partnered with an institute for HPLC analysis, and the samples were being validated for analysis at the time of the final report. The team also organized five focus-group discussions with fifteen voluntary farmers to discuss waste-derived fertilizer. They have also analyzed the struvite on selected vegetables in greenhouse scale.
Among the project’s outputs and potential impacts, the study included several activities focused on optimizing a struvite production method that is the first of its kind in Ethiopia. Assessment of pollutants (other than nitrogen and phosphorus) that might affect the production process is key task involved in harvesting the product in a safe and optimal way. Additionally, the metagenomic component of the project, although it remained in the primary result stage when the PEER project ended, is ultimately expected to reveal any potential risks in large-scale application of the product. This technology can be scaled up by relevant and interested stakeholders and is expected to cover a portion of the fertilizer demand in the urban and periurban agricultural settings.
On the capacity building and outreach side, the project supported three PhD candidates in pursuing their training in the biological, engineering, and social aspects of the research. Additionally, the team trained four MSC students (three women and one man) on the different objectives of the project throughout the project period. The PI Dr. Desta reports that she also contributed PEER findings to two Ethiopian governmental documents. The ten-year National Biotechnology Research and Development program document was finalized, reviewed, and validated pending implementation by the responsible institutions. The Environmental Biotechnology section was prepared based on research-based evidence, including from the PEER project. The concepts of recovery of nutrients from waste and wastewater as well as valorization of waste were strongly emphasized and action plans put forth for program implementation. Second, the recently started government genomic surveillance document also emphasized the need to pay attention to environmental health in order to address human health and stressed the importance of making wastewater surveillance one of the key focus areas for addressing public health emergencies such as SARS-CoV-2 and polio.
Dr. Desta and her team have also contacted key stakeholders to suggest ways of incorporating their findings and recommendations into policy and practice. They discussed with the Addis Ababa Water and Sewerage Authority the possibilities of establishing the FBR technology in the vicinities of some of their wastewater treatment plants. They also introduced and discussed with officials of the former Job Creation Commission (currently Ministry of Youth and Job Creation) possibilities of training youth on the available waste-to-fertilizer technologies. Regarding collaboration with farmers, the team learned the importance of working on the mindset of what waste and wastewater mean before demonstrating waste-derived products. The team also learned that talking about waste and wastewater is a taboo and using products derived from them is completely unimaginable in some parts of Ethiopia. Working to build acceptance and planning efforts to change community attitudes towards waste are essential.
The project has also had broader educational impacts beyond the benefits to the students who participated. Beginning in January 2022, the team initiated a curriculum review of the MSC and PhD programs in the Department of Microbial, Cellular, and Molecular Biology at Addis Ababa University. One of the streams, Applied Microbiology, focuses on nonclinical aspects of microorganisms and includes courses on soil microbiology, rhizobiology, food microbiology, plant pathogens, and industrial microbiology. Surprisingly, there are very few courses on wastewater microbiology, environmental microbiology, and nutrient recovery. Given the applied nature of the latter areas, the PI and her colleagues have improved the curriculum by adding extra courses on wastewater microbiology and nutrient recovery.
Although the PEER project has ended, Dr. Desta intends to continue collaborating with her U.S. partner Dr. Nancy Love on preparing manuscripts for publication. She is also seeking local funding to continue and expand her research.
Publications
Nayfach, S., Roux, S., Seshadri, R. et al. A genomic catalog of Earth’s microbiomes. Nat Biotechnol 39, 499–509 (2021) https://doi.org/10.1038/s41587-020-0718-6
Gebreab Teklebirhan Gessew, Adey Feleke Desta, Etsehiwot Adamu. High burden of multidrug resistant bacteria detected in Little Akaki River. Comparative Immunology, Microbiology and Infectious Diseases, vol. 80, 2022, 101723, ISSN 0147-9571. https://doi.org/10.1016/j.cimid.2021.101723
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