Characterization of food wastes from the hotel industry as a potential feedstock for energy production

Abstract

Food waste contribute to 38% of total Municipal Solid Wastes (MSW) in Kenya and end up in landfills. Due to high competition in the available space, most cities, including Nairobi, do not have enough space for landfills. Therefore, there is a need for efficient ways to manage the generated waste. Developed countries have embraced Waste-to-Energy technologies, minimizing waste generation and converting generated waste into energy and other resources. Waste characterization is a key element in the energy generation process not only to identify important parameters but also to guide biomass source segmentation. In this study, food wastes were collected from 21 hotels within Nairobi City County, in different mixed ratios and subdivided into five samples for investigation and analysis. The average feedstock characteristics were observed to be moisture content (6.0%, p < .001, R² = 90.70 %), total solid (93.7%, p < .001, R² = 99.97 %), volatile solid (84.3%, p < .001, R² = 99.80 %), ash content (4.2%, p = .005, R²= 48.54 %), fixed carbon (5.4%, p < .001, R² = 88.61%), nitrogen (3.6%, p = .04, R² = 36.81 %), carbon to nitrogen ratio C/N (4.0), crude protein (22.4%, p = .004, R² = 49.36 % ), crude lipids (12.1%, p < .001, R² = 89.06 %), total organic carbon (44%, p < . 001, R² = 94.70%), potassium (0.6%), sodium (1.2%), calcium (0.2%), and phosphorus (0.4%). The potassium, sodium, calcium and phosphorus p and R² values all calculated together were p < .001 and R²= 72.35%. The results showed a significant difference in the means of the samples with the majority of the parameters registering a strong positive correlation of above 50%. The analysis revealed that the feedstock under investigation contained well-balanced parameters for briquette, biogas, syngas and biochar production. Therefore, the findings of this research provide vital knowledge in integrating energy production from food wastes thereby improving the efficiency of food waste utilization.