Decentralized Solutions for Fecal Sludge Management
Summary
Recognizing the need for decentralized solutions for fecal sludge management in Dar es Salaam, international NGO BORDA Africa partnered with local entrepreneurs to safely transport fecal sludge to a newly constructed fecal sludge treatment plant. This plant treats and converts the sludge into biogas, thereby illustrating the potential for safe and sustainable small-scale fecal sludge management solutions.
The majority of Dar es Salaam's urban population, particularly in low-income and unplanned residential areas, is serviced by on-site sanitation, namely, pit latrines (Jenkins et al., 2014; Jenkins, Cummings & Cairncross, 2015; Kimwaga, 2020). Although official estimates indicate that approximately 90% of the population in high-density, unplanned areas are serviced by on-site pit latrines, field research shows that the actual percentage of this population reliant on pit latrines is closer to 97-99% (Jenkins, Cummings & Cairncross, 2015; Kimwaga, 2020). As such, the typical focus on wastewater in sanitation services is not particularly relevant to those serviced by on-site sanitation (e.g., pit latrines), thereby necessitating a shift in focus towards proper fecal sludge management (FSM) in such areas. Proper FSM can be instrumental in reducing the risk of water contamination and water-borne illnesses in many of Dar es Salaam's residential areas.
The use of under-regulated and inadequately managed pit latrines is associated with numerous potential public health risks: in particular, the possible contamination of drinking water, risk of flooding and overflow during the rainy season, and improper and unhygienic emptying practices (Berendes et al., 2017; Jenkins, Cummings & Cairncross, 2015). The need for appropriate FSM remains one of the primary concerns for proper water and sanitation services in low-income areas of Dar es Salaam and many other rapidly growing urban areas throughout the world (Berendes, Sumner & Brown, 2017).
Intervention
The Bremen Overseas Research and Development Association (BORDA Africa), an international NGO and civil society expert organization dedicated to the provision of essential services to those in need, began constructing a fecal sludge treatment plant (FTSP) in the Kigamboni district of Dar es Salaam in 2012 (BORDA Africa, n.d.).
BORDA Africa chose Kigamboni as the pilot project's focal area since the district presently has no communal sewage treatment plant for the proper disposal and treatment of wastewater generated in the area. Furthermore, households across the district primarily rely on on-site sanitation facilities (i.e., pit latrines) for waste disposal (BORDA Africa, n.d.). Such facilities require frequent emptying and adequate treatment and disposal of the fecal sludge and waste collected in the latrines (BORDA Africa, n.d.). As such, BORDA Africa decided to build an FSTP in Kigamboni and to pilot a partnership project with local entrepreneurs to empty local pit latrines and transport the sludge to the plant (BORDA Africa, n.d.). The overall project objective is to treat and re-use wastewater and fecal sludge to improve living conditions and mitigate potential public health risks for Kigamboni's residents. An additional project objective is to use this pilot project to gather research regarding the performance and financial viability of decentralized sludge treatment technologies. The ultimate project aim is to prove the utility of and promote a model that is financially viable for small-scale and local entrepreneurs in the sludge collection service sector, as well as compelling enough to attract potential investors (BORDA Africa, n.d.).
The Kigamboni FSTP was completed in 2013. The FSTP is built on private land and is operated by a local, privately-owned pit-emptying service provider, Sludge-Go, presently serving approximately 5,500 households (BORDA, 2019). BORDA Africa partnered with Sludge-Go, a local pit-emptying business that connects pits, tanks, and treatment centers across Dar es Salaam. Sludge-Go workers can service hard-to-reach, densely packed neighborhoods across the city by navigating narrow streets in small tractors. Workers collect and transport the sludge to the Kigamboni treatment plant; afterward, treated sludge is sold as fertilizer, and the treated water is used for irrigation at a local banana plantation (BORDA Africa, n.d.).
At the FSTP, wastewater from pit latrines is poured into the biogas digestor (BGD), which retains big particles and produces biogas (used for cooking or heating by a family living on the FSTP premises). Thereafter, wastewater travels to the anaerobic baffled reactor (ABR) for further treatment, which is connected to a French drain (surrounded by banana plants so that the treated effluent can serve directly as an irrigation source). The BGD is also connected to a sludge-drying bed, wherein stabilized sludge (from the bottom of the BGD) is drained and dried for subsequent use as fertilizer in the banana plantation (BORDA Africa, n.d.). The entire system is designed to require no electrical energy or chemicals, working solely via gravity flow (BORDA Africa, n.d.).
Since the system does not require any electrical or chemical inputs for fecal sludge treatment, it may be considered a cost-effective and sustainable FSM solution in low-income areas elsewhere (as the main associated expense is the one-off construction cost).
The project was funded entirely by BORDA Africa with support from the local municipal council (BORDA, 2019). The Kigamboni FSTP is currently active and continues to operate in partnership with Sludge-Go.
Challenges
Despite the promising results of BORDA Africa's pilot project in Kigamboni, it is unclear if such decentralized solutions for FSM can be effectively scaled-up to meet the sanitation service needs of the greater population. Critics highlight that such pilot projects typically lack sustainable business models that would make them viable city-wide solutions for FSM and improved sanitation services in low-income communities (Kimwaga, 2020).
Outcomes
BORDA Africa's FSM project in Kigamboni, Dar es Salaam, has resulted in safer sanitation services for thousands of people in the city's low-income neighborhoods. By partnering with a local entrepreneur (Sludge-Go) to ensure affordable and safe pit-emptying, the initiative minimizes risks: those associated with the improper emptying of latrines and with overflow during the rainy season. The pilot project thereby enhanced the safety of water and sanitation services for over 5,500 low-income Dar es Salaam residents. (BORDA, 2019).
References
Decentralized Solutions for Fecal Sludge Management
Summary
Recognizing the need for decentralized solutions for fecal sludge management in Dar es Salaam, international NGO BORDA Africa partnered with local entrepreneurs to safely transport fecal sludge to a newly constructed fecal sludge treatment plant. This plant treats and converts the sludge into biogas, thereby illustrating the potential for safe and sustainable small-scale fecal sludge management solutions.
The majority of Dar es Salaam's urban population, particularly in low-income and unplanned residential areas, is serviced by on-site sanitation, namely, pit latrines (Jenkins et al., 2014; Jenkins, Cummings & Cairncross, 2015; Kimwaga, 2020). Although official estimates indicate that approximately 90% of the population in high-density, unplanned areas are serviced by on-site pit latrines, field research shows that the actual percentage of this population reliant on pit latrines is closer to 97-99% (Jenkins, Cummings & Cairncross, 2015; Kimwaga, 2020). As such, the typical focus on wastewater in sanitation services is not particularly relevant to those serviced by on-site sanitation (e.g., pit latrines), thereby necessitating a shift in focus towards proper fecal sludge management (FSM) in such areas. Proper FSM can be instrumental in reducing the risk of water contamination and water-borne illnesses in many of Dar es Salaam's residential areas.
The use of under-regulated and inadequately managed pit latrines is associated with numerous potential public health risks: in particular, the possible contamination of drinking water, risk of flooding and overflow during the rainy season, and improper and unhygienic emptying practices (Berendes et al., 2017; Jenkins, Cummings & Cairncross, 2015). The need for appropriate FSM remains one of the primary concerns for proper water and sanitation services in low-income areas of Dar es Salaam and many other rapidly growing urban areas throughout the world (Berendes, Sumner & Brown, 2017).
Issue
Intervention
The Bremen Overseas Research and Development Association (BORDA Africa), an international NGO and civil society expert organization dedicated to the provision of essential services to those in need, began constructing a fecal sludge treatment plant (FTSP) in the Kigamboni district of Dar es Salaam in 2012 (BORDA Africa, n.d.).
BORDA Africa chose Kigamboni as the pilot project's focal area since the district presently has no communal sewage treatment plant for the proper disposal and treatment of wastewater generated in the area. Furthermore, households across the district primarily rely on on-site sanitation facilities (i.e., pit latrines) for waste disposal (BORDA Africa, n.d.). Such facilities require frequent emptying and adequate treatment and disposal of the fecal sludge and waste collected in the latrines (BORDA Africa, n.d.). As such, BORDA Africa decided to build an FSTP in Kigamboni and to pilot a partnership project with local entrepreneurs to empty local pit latrines and transport the sludge to the plant (BORDA Africa, n.d.). The overall project objective is to treat and re-use wastewater and fecal sludge to improve living conditions and mitigate potential public health risks for Kigamboni's residents. An additional project objective is to use this pilot project to gather research regarding the performance and financial viability of decentralized sludge treatment technologies. The ultimate project aim is to prove the utility of and promote a model that is financially viable for small-scale and local entrepreneurs in the sludge collection service sector, as well as compelling enough to attract potential investors (BORDA Africa, n.d.).
The Kigamboni FSTP was completed in 2013. The FSTP is built on private land and is operated by a local, privately-owned pit-emptying service provider, Sludge-Go, presently serving approximately 5,500 households (BORDA, 2019). BORDA Africa partnered with Sludge-Go, a local pit-emptying business that connects pits, tanks, and treatment centers across Dar es Salaam. Sludge-Go workers can service hard-to-reach, densely packed neighborhoods across the city by navigating narrow streets in small tractors. Workers collect and transport the sludge to the Kigamboni treatment plant; afterward, treated sludge is sold as fertilizer, and the treated water is used for irrigation at a local banana plantation (BORDA Africa, n.d.).
At the FSTP, wastewater from pit latrines is poured into the biogas digestor (BGD), which retains big particles and produces biogas (used for cooking or heating by a family living on the FSTP premises). Thereafter, wastewater travels to the anaerobic baffled reactor (ABR) for further treatment, which is connected to a French drain (surrounded by banana plants so that the treated effluent can serve directly as an irrigation source). The BGD is also connected to a sludge-drying bed, wherein stabilized sludge (from the bottom of the BGD) is drained and dried for subsequent use as fertilizer in the banana plantation (BORDA Africa, n.d.). The entire system is designed to require no electrical energy or chemicals, working solely via gravity flow (BORDA Africa, n.d.).
Since the system does not require any electrical or chemical inputs for fecal sludge treatment, it may be considered a cost-effective and sustainable FSM solution in low-income areas elsewhere (as the main associated expense is the one-off construction cost).
The project was funded entirely by BORDA Africa with support from the local municipal council (BORDA, 2019). The Kigamboni FSTP is currently active and continues to operate in partnership with Sludge-Go.
Challenges
Despite the promising results of BORDA Africa's pilot project in Kigamboni, it is unclear if such decentralized solutions for FSM can be effectively scaled-up to meet the sanitation service needs of the greater population. Critics highlight that such pilot projects typically lack sustainable business models that would make them viable city-wide solutions for FSM and improved sanitation services in low-income communities (Kimwaga, 2020).
Outcomes
BORDA Africa's FSM project in Kigamboni, Dar es Salaam, has resulted in safer sanitation services for thousands of people in the city's low-income neighborhoods. By partnering with a local entrepreneur (Sludge-Go) to ensure affordable and safe pit-emptying, the initiative minimizes risks: those associated with the improper emptying of latrines and with overflow during the rainy season. The pilot project thereby enhanced the safety of water and sanitation services for over 5,500 low-income Dar es Salaam residents. (BORDA, 2019).
Issues |
|---|
Water Pollution and Contamination |
Solutions |
|---|
Wastewater Management & Reuse |
References
Berendes, D. M., Sumner, T. A., & Brown, J. M. (2017). Safely managed sanitation for all means fecal sludge management for at least 1.8 billion people in low and middle income countries. Environmental Science & Technology, 51(5), 3074–-3083.
Berendes, D., Kirby, A., Clennon, J. A., Raj, S., Yakubu, H., Leon, J., ... & Ghale, B. (2017). The influence of household-and community-level sanitation and fecal sludge management on urban fecal contamination in households and drains and enteric infection in children. The American journal of tropical medicine and hygiene, 96(6), 1404–-1414.
BORDA Africa. (n.d.). Faecal Sludge Management (FSM) in Dar es Salaam, Tanzania. Retrieved November 28, 2020, from https://borda-africa.org/faecal-sludge-management-in-tanzania/
Bremen Overseas Research and Development Association (BORDA). (2019). Faecal Sludge Management (FSM): Inclusive Citywide Sanitation Services (Rep.). Retrieved November 28, 2020, from https://www.afwakm.com/wp-content/uploads/2019/06/2019-02-FSM-inclusive-citywide-sanitation-services.pdf
Jenkins, M. W., Cumming, O., & Cairncross, S. (2015). Pit latrine emptying behavior and demand for sanitation services in Dar Es Salaam, Tanzania. International journal of environmental research and public health, 12(3), 2588-2611.
Jenkins, M. W., Cumming, O., Scott, B., & Cairncross, S. (2014). Beyond ‘improved ’towards ‘safe and sustainable’ urban sanitation: assessing the design, management and functionality of sanitation in poor communities of Dar es Salaam, Tanzania. Journal of Water, Sanitation and Hygiene for Development, 4(1), 131-141.
Kimwaga, Richard (2020, November 13). EcoCiv Interview with Dr. Richard Kimwaga, Professor at the Water Resources Engineering Department at the University of Dar es Salaam.