Thermophilic composting of human excreta, cattle manure, and organic waste with biochar can be a sustainable solution for sanitation and fertilizer needs in developing countries. The study showed that adding biochar to compost helped maintain nutrient levels and reduced organic matter and nitrogen losses. The composting process reached high temperatures, ensuring pathogen-free final products. Biochar also improved compost quality by decreasing extractable nitrate levels. Overall, this ecological sanitation approach can provide safe and affordable fertilizer while managing waste effectively.