Analysis of the Composition and Physicochemical Characteristics of Household Solid Waste in the Northern Municipalities of Conakry (Guinea)

Municipal solid waste (MSW) management represents a major environmental and public health challenge for rapidly growing urban and peri-urban areas in sub-Saharan Africa. In Greater Conakry, rapid urbanization, population growth, and changing consumption patterns have led to a significant increase in waste generation, while collection, treatment, and recovery systems remain insufficiently developed.

The present study aims to analyze the composition and physicochemical properties of municipal solid waste in five northern municipalities of Conakry (Coyah, Dubréka, Sanoyah, Kagbelen and Kountia), taking into account seasonal variability between the dry and rainy seasons. The study is based on a standardized characterization methodology combining manual gravimetric sorting and laboratory physicochemical analyses, in accordance with international standards (ASTM, AFNOR, UNEP). A stratified sampling plan was implemented in several neighborhoods per municipality, with two campaigns corresponding to the main climatic seasons.

The results show a structural predominance of the biodegradable organic fraction, representing on average 46–50% of total waste in the dry season and 50–55% in the rainy season. Plastics constitute the second largest fraction (15–22%), followed by paper and cardboard (5–10%), metals (3–6%), glass (2–5%), and textiles/wood (4–7%). Moisture content varies markedly between seasons, with higher values observed during the rainy season.

Physicochemical parameters indicate a strong potential for biological valorization of MSW. The slightly acidic to neutral pH (6.2–7.1), high organic matter content (48–56%), and C/N ratios mostly between 20 and 25 place the waste within a favorable range for composting and anaerobic digestion. The lower heating value, estimated between 6 and 9 MJ/kg, remains moderate and is strongly influenced by moisture content, which limits the attractiveness of thermal treatment options without prior drying or pre-treatment.

Overall, this study highlights that household solid waste in the northern municipalities of Conakry exhibits a highly biodegradable profile, offering significant opportunities for the development of composting and material recovery pathways. The results provide a useful scientific basis to guide local integrated solid waste management policies, with the aim of reducing landfill disposal, improving resource recovery, and enhancing environmental sustainability.