ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Kinetic parameters of inactivation of Trichuris suis and bioenergy production from the thermal-anaerobic stabilization process of pig manure

Maricruz Murillo-Espinosa, Noemí Nava-Valente, Nayeli Gutiérrez-Casiano, Joaquín Estrada-García, and Juan Manuel Méndez-Contreras

Tecnológico Nacional de México, Instituto Tecnológico de Orizaba, Orizaba, Mexico

E-mail: juan.mc@orizaba.tecnm.mx

Received: 6 June 2025  Accepted: 24 October 2025

Abstract:

The inadequate management of pig manure (PM) is recognized as an environmental and public health issue due to its high organic matter content and the presence of pathogens, including helminth eggs. Moreover, the energy potential of these wastes remains underutilized due to degradation challenges. This study aimed to evaluate the effects of thermal pretreatment on the inactivation of Trichuris suis, the solubilization of organic matter, and biogas production during the anaerobic digestion of PM. Pig manure, collected from backyard systems, was characterized and subjected to thermal pretreatment at 70, 80 and 90 °C for 60, 90 and 120 min, followed by anaerobic digestion in an ovoid-reactor with a methanogenic inoculum. The anaerobic digestion of untreated PM was also evaluated as a control. The inactivation kinetics of Trichuris suis in PM were described using the modified Hom model; the rate constant (k) increased from 2.55 × 10^− 7 to 2.38 × 10^− 6 with rising time and temperature, while the thermal coefficient (n) decreased from 3.72 to 3.25 after 120 min, indicating reduced efficiency over prolonged exposure. The modified Gompertz model was applied to adjust the cumulative production of biogas and methane, revealing a maximum production rate of 27.5 L day⁻¹ and a potential yield of up to 855.7 L in semicontinuous operation with treated PM. This approach to pathogen and helminth egg inactivation, combined with energy recovery, can support hundreds of small-scale pig producers in reducing the environmental impact of their waste, mitigating health risks, and benefiting from enhanced energy efficiency.

Keywords: Sludge anaerobic digestion; Mathematical prediction; Biogas production; Energy conversion; Helminth egg inactivation

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04477-8

Chemical Papers 80 (2) 1641–1651 (2026)