Evaluation of a Compost-Digester for the Treatment of Organic Waste Generated in Family Farming

Quipuzco Ushñahua L.; Gómez Calle M.A.; Juscamaita Oncebay M.F.; Mayta Bernuy J.C.; Torres Tipula S.S.E. · Green Energy and Technology (2026) · DOI: 10.1007/978-3-032-22411-8_14

Resumen

Smallholder farming systems generate large amounts of organic residues whose mismanagement contributes to greenhouse gas emissions and soil and water pollution. This study evaluates the performance of an innovative integrated technology, the Compost-Digester, designed for decentralized treatment and valorization of organic waste. The system combines aerobic composting and anaerobic digestion in a single modular, low-cost unit fabricated from recycled materials. Three replicated units were operated over four months under mesophilic conditions (~24 °C) using kitchen waste and cattle manure as feedstock. The composting process increased biodigester temperature by ~5 °C, enhancing thermal stability. The biogas contained 53% CH4 and 33% CO2, with a methane yield of 0.032 Nm3 CH4 kgVS−1, which was lower than reference values due to high solids, salinity, and substrate limitations. The compost met maturity indicators (OM = 40.4%, C/N = 12.55, pH = 8.14, and low pathogens) but exceeded the electrical conductivity threshold established by the Peruvian standard NTP 201.207:2020 (21.9 dS m−1 vs. ≤ 5 dS m−1), raising concerns about salinity-related phytotoxicity. The liquid digestate (biol) presented a nutrient imbalance, with high potassium (1414 mg/L) and sodium (1003 mg/L) but relatively low nitrogen and phosphorus, requiring dilution prior to agricultural use. Compared to conventional systems, the Compost-Digester demonstrated advantages in thermal synergy, compactness, and material efficiency, but also revealed technical limitations that must be addressed. Overall, the system shows potential as a low-cost, decentralized option for circular waste management in rural contexts, provided that process optimization strategies are implemented to improve methane productivity and reduce salinity risks. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.

Instituciones: Universidad Nacional Agraria La Molina