Spencer Kirawa Lusi


Born on January 1, 1990 into a family of 13 siblings, I hold a BSc in Biosystems Engineering from The University of Nairobi and an MSc in
Nuclear Science from the same University. I work progressively towards positively impacting on the lives of Kenyans so as to live a life that brings good to humanity and honor to God. Having been born in Homabay county, the rest of my childhood was in the same locality. I was registered for pre-primary and primary Education in Masanga and Kalando primary schools in Rachuonyo sub county. I later joined Agoro Sare High School for Secondary Education and scored a B+ grade. This offered me an opportunity to join Kikuyu Campus of the University of Nairobi. I turned down the offer, repeated form four in Orero secondary school and scored an A- which then allowed me to pursue Biosystems Engineering degree under the government of Kenya scholarship. My university Education in the Department of Environmental and Biosystems Engineering saw me join students’ leadership as a chairperson of the Environmental and Biosystems Engineering Students Association (EBESA) in the Academic year 2015-2016. I graduated in the year 2016 and immediately became a research assistant in the same department of the University for six months. I later secured a scholarship to pursue a master’s degree in Nuclear Science in the year 2017 and will be graduating in September 2020. I am currently a Technical Trainer at Sikri Technical College for the Blind and Deaf in
Homabay County. Between 2016 and 2019 when I joined the government as a technical TVET trainer, I interned with the University of Nairobi,
Nairobi Innovation Week, the Ministry of Industry, Trade and Cooperatives and worked online. I am a husband and a father of two sons.

Project Summary

Comparative Evaluation of the Components of Biogas Digestate Slurries and Effects on Agricultural Soils

This study sought to characterize biogas digester slurries under varying  Feedstocks and provide information useful for assessing the potential impact of their usage as organic fertilizer on crop productivity and environment. The study was informed by the need to allow agricultural scientists determine how individual biogas feeds affect the composition of the final digestate. Digestates from human waste, livestock waste, and abattoir waste feedstock were sampled for the study. The pellets from the samples were then analyzed using Energy Dispersive X-ray Fluoroscopy (EDXRF) spectroscopy for elemental components. Human waste digestate had the highest concentration values for most elements. In human waste, essential elements were determined at 40600 ± 2000, 19000 ± 1140, 1300 ± 400, 200 ± 30, 900 ± 260 ppm for Ca, Fe, Mn, Zn and Cu respectively, as compared to Ca (26400 ± 1400), Fe (9500 ±
440), Mn (820 ± 190), Zn (180 ± 40), Cu (360 ± 70), in livestock waste. In abattoir waste, the mean content was 49500 ± 4100 for Ca, 15220 ± 1350 for Fe, 1090 ± 90 for Mn, 200 ± 50 for Zn and 140 ± 50 for Cu. Pb concentrations were highest in human waste at 20.81 ppm. The high amounts are associated with the micro industrial activities in Kibera. Therefore, human wastes digestates might be the best nutrient supplement but is the most probable threat to environment. For agronomists, crops need matching with digestates from which they would benefit the most, given unique crop requirements.