Optimizing Biogas Production from Cow Manure: A Comparative Study of Thermal Steam Explosion and Continuous Thermal Pretreatments

Abstract

The increasing environmental challenges of cow manure disposal, alongside the rising demand for renewable energy, underscore the need for efficient waste-to-energy conversion. Cow manure, rich in organic material, holds significant potential for biogas production. However, its anaerobic digestion efficiency is often hindered by the recalcitrant nature of lignocellulosic materials. This study directly compares the effectiveness of Thermal Steam Explosion Pretreatment (TSEP) and Continuous Thermal Pretreatment (CTP) in enhancing biogas yield from cow manure. A one-factor experimental design was employed, varying temperatures between 30 °C and 50 °C using Design Expert 7.0 software. Biogas volume was measured via the water displacement method, and gas composition was analyzed using gas chromatography. The results indicate that TSEP, particularly at an optimal temperature range of 47 °C to 49 °C, yielded higher biogas volumes and superior methane concentrations exceeding 57%, with minimal carbon dioxide content. Numerical optimization confirmed these findings, identifying highly desirable operational conditions with a strong desirability index. Overall, TSEP proves to be a highly effective pretreatment method, significantly improving both the quantity and quality of biogas from cow manure. These findings have important implications for biogas production, suggesting that TSEP could play a crucial role in advancing sustainable waste management and renewable energy generation.