| dc.description.abstract | Global warming, climate change and water pollution have become pressing environmental
concerns worldwide. By 2050, the world’s population is expected to grow from 7.8 billion in 2020
to 9.9 billion people, generating more waste. The improper disposal of the organic waste has
profound impact on the water quality in Nairobi’s River since they end up in open drains and
waterways leading to elevated levels of nutrient such as phosphorus, which promotes and degrade
aquatic ecosystems. This waste also results in increased greenhouse gases (GHGs) emissions into
the atmosphere. Currently, in Kenya, the organic waste management, including faecal matter (FM),
pig manure (PM), and chicken manure (CM), poses a significant challenge in the context of water
pollution, global warming and climate change. Hence, this problem pertains to the need for an
efficient way and cost-effective technology to manage waste that ultimately reduces the global
warming potential (GWP). This research aimed to assess the global warming potential of the black
soldier fly’s bioconversion of faecal matter (FM), pig manure (PM) and chicken manure (CM). It
adopted Black soldier fly larvae (BSFL, Hermetia illucens) technology, which is environmentally
friendly as it mitigates the amount of greenhouse gases released in the atmosphere because of its
quick bioconversion rate, good sustainability, and low cost-effectiveness. The set-up was in a
greenhouse tunnel at the Department of Soil, Water and Environmental Engineering, Jomo
Kenyatta University of Agriculture and Technology (JKUAT). The study used the MQ4 and
MQ135 sensors to measure in real time the concentration of methane (CH4), carbon dioxide (CO2),
Nitrous oxide (N2O), and ammonia (NH3) emitted during the bioconversion process. A comparison
of the concentration of gas emissions from the bioconversion of the three substrates was studied.
Finally, the Life Cycle Assessment (LCA) of BSFL during bioconversion of the FM, PM and CM
was undertaken. The data was analyzed using R Studio 4.3.3 software for graphical visualization
of GHGs concentrations and OpenLCA software for the LCA of the gases. The total GWP values
were: as follows: 0.194 kg CO2-eq (CM), 0.072 kg CO2-eq (FM), 0.005 kg CO2-eq (PM), 0.011
kg CO2-eq (BSFCM), 0.006 kg CO2-eq (BSFFM) and 0.001kg CO2-eq (BSFPM). CM had the
highest GWP, FM had a notable GWP while PM recorded the lowest GWP. BSFL bioconversion
process can be used to manage organic waste from the environment while at the same time
mitigating the GHGs emissions. The study suggests that large-scale adoption of BSFL as a climate
smart waste management solution can be promoted by developing supporting policies and
regulatory frameworks. Additionally, various governments should provide incentives to enhance
awareness campaigns and training programs to educate waste producers, farmers and industries to
effectively contribute to the advancement of the circular economy. | en_US |
