Comparative Nutrient Profiling of Kitchen Food Waste, Cow Dung, and Their Bio-slurries in Kilifi County, Kenya
Year: 2026
Type: article
Abstract: Kitchen food waste and cow dung are potential feedstocks for anaerobic digestion, but their comparative physicochemical characteristics and the nutrient properties of their resulting bio-slurries require direct evaluation. This study determined the physical and chemical properties of kitchen waste and cow dung feedstocks and assessed the effects of anaerobic digestion on the corresponding bio-slurries. The study was conducted at the Pwani University Integrated Biogas Research Unit in Kilifi County, Kenya, during the 2021/2022 and 2022/2023 growing seasons. Kitchen waste and cow dung were digested separately in a Flexi biogas system after each feedstock was mixed with water at a 1:1 ratio. Seventeen physical and chemical parameters were evaluated, including bulk density, dry matter, moisture content, pH, ammonium, nitrate, bicarbonate, electrical conductivity, and exchangeable macro- and micronutrients. Kitchen waste and cow dung feedstocks showed a very strong positive correlation (r = 0.999977) and no significant difference (t(16) = 1.0155, p = 0.325). Their bio-slurries were similarly strongly correlated (r = 0.999983), with no significant difference (t(16) = 1.0288, p = 0.319). Anaerobic digestion did not significantly alter kitchen waste or cow dung properties relative to their raw feedstocks. The findings indicate that both feedstocks produced bio-slurries with comparable physicochemical characteristics, supporting the potential use of kitchen waste as an alternative or complementary feedstock where cow dung is limited.
Authors: Allan Mwajoha, Elisha Otieno Gogo, Simon Muti
Institution: Pwani University
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7204228447