Vermicomposting of municipal solid waste as a possible lever for the development of sustainable agriculture. A review

Continued population growth and urbanization as well as changing consumption patterns have led to an explosion in the amount of waste produced, especially in cities. To feed the world, we also need to increase agricultural production while limiting our impact on the environment. Part of the solution could be to recycle the organic fraction of municipal solid waste (OFMSW) as a resource for agriculture near cities with techniques such as vermicomposting, which uses earthworms to recycle organic waste into nutrient-rich vermicompost. The objective of this review was to examine (i) whether vermicomposting is appropriate for recycling OFMSW, (ii) the quality of the vermicompost produced, and (iii) the impact of this product on crops and soil parameters. We found that vermicomposting can be adapted for OFMSW recovery because the process is suitable for all the types of OFMSW (food, paper, and green waste). The vermicompost produced is both high in organic carbon (18.83-36.01%) and a potential fertilizer (1.16-2.58% N, 0.42-1.12% P, and 0.61-2.05% K). A comparison with compost from the same types of OFMSW suggested that vermicompost is slightly more suitable for crop production with significantly lower C/N and pH and higher N and P. Vermicompost was actually found to have a better effect on plant growth than compost, suggesting that classical chemical analyses are not always sufficient to characterize the potential of organic amendments/fertilizers. Indeed, the application of vermicompost in the field leads to an increase in carbon storage, water retention, enzymatic and microbiological activity, and soil fauna abundance and diversity. Finally, we found that reports on the use of vermicompost from OFMSW are scarce and most studies focused on the process itself. Overall, our review synthesizes data and the interest in this technique and proposes perspectives for future studies.