Use of solar energy in the composting of urban organic solid waste using solar collectors in high Andean conditions

Llave-Ciprian Y.J.; Callasi-Choquepuma S.; Vigo-Rivera J.E. · Revista Internacional de Contaminacion Ambiental (2025) · DOI: 10.20937/rica.55119

Resumen

Composting is a sustainable way to manage organic solid waste. This study evaluated the use of solar energy to increase the temperature in compost bins during the composting process of urban organic waste under high Andean conditions. Eight compost bins of 0.098 m3 each were installed: four with solar heating using flat HDPE collectors (Ø=¾”) and water as the heat transfer fluid, and four without solar heating. The experimental period was 45 days for the solar-heated bins and 60 days for the non-solar-heated bins. Each bin contained 52.5 kg of organic waste, 2.5 kg of sheep manure, and 100 mL of effective microorganisms. The pH, humidity, and temperature of the composting process were monitored, along with the ambient temperature, the temperature of the heat transfer fluid, and the greenhouse temperature using Arduino sensors. Organic matter, nitrogen, phosphorus, potassium, C/N ratio, and electrical conductivity of the produced compost were evaluated. The solar-heated compost bins reached compost maturity in 45 days, while the non-solar-heated bins did so in 60 days, with similar characteristics in terms of nitrogen, phosphorus, and potassium. The greenhouse covered with 180-micron agrofilm maintained the compost at an average temperature of 28.9 ºC during the 45 days, compared to an average ambient temperature of 5.2 ºC. The solar collectors provided heat to the system, reaching temperatures of up to 39.83 ºC and heat gains of 86.5 cal. These results demonstrate the feasibility of using solar energy for compost production in high Andean conditions.

Instituciones: Universidad Peruana Unión