Nutrient Recovery for Use
in Agriculture: Economic Assessment
of Decentralized Compost Business
Model in Nairobi
Solomie Gebrezgabher, Avinandan Taron,
and Sena Amewu
Abstract
Large cities in developing countries are facing
the challenge of rapid urban population
growth, which results in increasing waste
generation. In Nairobi, the solid waste situation is characterized by low coverage of
collection, pollution from uncontrolled dumping, inefficient public services, unregulated
and uncoordinated private sector operators
and lack of key solid waste management
infrastructure. About 3,121 tons of municipal
solid waste (MSW) is generated daily, of
which about 850 tons are collected and the
remaining is burnt or dumped in unauthorized
sites or landfilled in the Dandora dumpsite
causing health and environmental problems.
The recovery of nutrients from the organic
content of MSW for reuse in agriculture has
the potential to address the dual challenge of
waste management and soil nutrient depletion.
This study assessed the economic and environmental impact of decentralized composting
business model in Nairobi based on a comparison with the baseline scenario using an
indicator expressed in tons CO 2 equivalent.
The cost–benefit analysis was based on data
collected from existing compost plants in
Kenya. To assess the sensitivity of the results
to variation in input variables, a simulation
model was developed using the Monte Carlo
method. The decentralized composting business model resulted in a net GHG emission
saving of 1.21 tons CO 2 -eq/ton of compost,
being both financially and economically feasible with more than 70% chance of economic
success. Assessing the economic and environmental impact is an important tool for decision
making and to ensure that the business model
results in desired benefits to society.
Keywords
Nutrient recovery Á Nexus Á Decentralized
compost Á Costs and benefits Á Monte Carlo
simulation
1 Introduction
The increasing quantity of urban waste in urban
agglomerations of developing nations coupled
with the inadequate sanitation services is a
growing concern to the deteriorating urban
environment (Oyoo et al. 2011). Solid waste
management (SWM) is a major public health and
environmental concern in urban areas of many
developing countries. Nairobi’s solid waste
S. Gebrezgabher (&) Á S. Amewu
International Water Management Institute,
PMB CT 112, Cantonments, Accra, Ghana
e-mail: s.gebrezgabher@cgiar.org
A. Taron
International Water Management Institute,
P.O. Box 2075, Colombo, Sri Lanka
© Springer Nature Switzerland AG 2021
S. Hülsmann and M. Jampani (eds.), A Nexus Approach for Sustainable Development,
https://doi.org/10.1007/978-3-030-57530-4_3
25
in Agriculture: Economic Assessment
of Decentralized Compost Business
Model in Nairobi
Solomie Gebrezgabher, Avinandan Taron,
and Sena Amewu
Abstract
Large cities in developing countries are facing
the challenge of rapid urban population
growth, which results in increasing waste
generation. In Nairobi, the solid waste situation is characterized by low coverage of
collection, pollution from uncontrolled dumping, inefficient public services, unregulated
and uncoordinated private sector operators
and lack of key solid waste management
infrastructure. About 3,121 tons of municipal
solid waste (MSW) is generated daily, of
which about 850 tons are collected and the
remaining is burnt or dumped in unauthorized
sites or landfilled in the Dandora dumpsite
causing health and environmental problems.
The recovery of nutrients from the organic
content of MSW for reuse in agriculture has
the potential to address the dual challenge of
waste management and soil nutrient depletion.
This study assessed the economic and environmental impact of decentralized composting
business model in Nairobi based on a comparison with the baseline scenario using an
indicator expressed in tons CO 2 equivalent.
The cost–benefit analysis was based on data
collected from existing compost plants in
Kenya. To assess the sensitivity of the results
to variation in input variables, a simulation
model was developed using the Monte Carlo
method. The decentralized composting business model resulted in a net GHG emission
saving of 1.21 tons CO 2 -eq/ton of compost,
being both financially and economically feasible with more than 70% chance of economic
success. Assessing the economic and environmental impact is an important tool for decision
making and to ensure that the business model
results in desired benefits to society.
Keywords
Nutrient recovery Á Nexus Á Decentralized
compost Á Costs and benefits Á Monte Carlo
simulation
1 Introduction
The increasing quantity of urban waste in urban
agglomerations of developing nations coupled
with the inadequate sanitation services is a
growing concern to the deteriorating urban
environment (Oyoo et al. 2011). Solid waste
management (SWM) is a major public health and
environmental concern in urban areas of many
developing countries. Nairobi’s solid waste
S. Gebrezgabher (&) Á S. Amewu
International Water Management Institute,
PMB CT 112, Cantonments, Accra, Ghana
e-mail: s.gebrezgabher@cgiar.org
A. Taron
International Water Management Institute,
P.O. Box 2075, Colombo, Sri Lanka
© Springer Nature Switzerland AG 2021
S. Hülsmann and M. Jampani (eds.), A Nexus Approach for Sustainable Development,
https://doi.org/10.1007/978-3-030-57530-4_3
25