Adición de arcillas residuales industriales para estimular la producción de metano durante la co-digestión anaerobia de residuos porcinos y paja de arroz

Abstract

The evaluation of the addition of petrochemical residual clay (bentonite-base) during the anaerobic co-digestion of swine manure and agriculture solid waste, to enhance methane production. The experiments were carried out in 10 L continuously stirred tank reactor (CSTR), at 35 ºC. The clay addition was assayed at different organic loading rate of swine manure. The CSTR performance was monitored by daily biogas and methane production and also by physic-chemical parameter, ammonia nitrogen and volatile fatty acid. The addition of clay at lower dosage, enhanced the biogas production up to 40 %, and the methane content near to 15 % for all organic loading rate of swine manure assayed. It was elucidated by the adsorbent properties of clay showing a reduction of ammonia nitrogen within reactor after clay addition. This was corroborated by Freundlich coefficient (between 1.43 and 1.82) and the adsorption capacity (between 1,29 and 2,98). The others physic-chemical parameters during CSTR performance showed lower volatile fatty acids concentrations (< 1 g.L-1), the pH between 7.4 and 8.4, the alkalinity ratio below 0.3 and lower free ammoniac concentration (< 0.15 g.kg-1), indicating the co-digestion process stability and the feasibility to use clay residual bentonite-base to enhance methane production in anaerobic treatment of manure and agriculture waste.