The use of vermifilters for wastewater treatment in rural areas of Latin America and Africa offers an efficient and cost-effective alternative to conventional systems. However, there is a need to identify alternative materials for substrates to support earthworm development in many rural areas. This study aims to evaluate the impact of using Brachiaria sp. as a substrate colonized by earthworms on the efficacy of vermifiltration in treating raw sewage. To achieve this, a bench-scale experiment was conducted using 15 vermifilters filled with different substrates, each supplemented with 10 earthworms of the Eisenia andrei species. The substrates studied included: (1) soil; (2) soil + grit; (3) soil + Brachiaria; (4) soil + milled Brachiaria; and (5) grit + milled Brachiaria. The number of earthworms increased significantly in the Brachiaria substrate, indicating its favorable effects on the earthworm population. Therefore, Brachiaria emerges as a promising substrate for raw sewage treatment in vermifilters, offering benefits for the environment, economy, and society.
