Physical Characterization of Coastal Macrowaste: A Comparison Between Cities in Central Western Africa (Libreville-Lome)

The sustainability of coastal environments is becoming a major issue in the face of constantly changing urban populations correlated with anthropogenic activities. As a result, in-depth knowledge is needed to assess the vulnerability of coastal areas in African cities faced with a profusion of solid waste. In Libreville and Lomé, the aim of the study was to carry out a systematic inventory of coastal macrowaste, and to break down and characterize the data collected at 12 sites and 6 sites, respectively. The methodological approach adopted combines documentary research, direct observations and characterization using the MODECOM tool (household waste characterization method) to reveal the widespread presence of macrowaste in the coastal areas of the two towns. With regard to the MODECOM method, the study is based specifically on the sorting of materials according to three granulometric fractions: >100 mm, between 20 and 100 mm, and <20 mm. In addition to the dimensions of the objects, the classification of solid waste according to its nature enabled thirteen (13) categories of macrowaste to be generated. The results show that the quantity of macrowaste inventoried in Libreville was 654.21 kg, while in Lomé the weight of waste collected was 510 kg. On the whole, the proliferation of solid waste is due to physical factors and human activities, especially economic activities and recreational activities, which increase the rate of production. In terms of sustainable material management, the results point to a prosperous future for the biodegradable, non-biodegradable and inert waste streams.