Innovative low-cost approaches to biogas purification in developing economies

Abstract

The increasing environmental degradation and dependency on fossil fuels have accelerated the global push toward renewable energy. Sustainable Development Goal 7 underscores the critical role of clean, affordable energy in fostering social and industrial development. In developing regions, where organic waste is abundant, biogas—rich in methane—offers a viable renewable energy source. However, raw biogas contains impurities like carbon dioxide and hydrogen sulfide, reducing usability and requiring purification. Conventional purification technologies are often expensive, technologically intensive, and unsuitable for decentralized or small-scale applications in low-resource settings. This review evaluates low-cost, locally sourced materials for biogas purification suited to household and community-level systems. Several affordable materials show promising purification potential: clay removes up to 90 % of contaminants, iron-rich soils up to 93.8 %, steel wool about 95 %, and compost-based media around 80 %.

To further enhance these materials, the study suggests approaches such as drying biomass ash to reduce moisture content, modifying the surface chemistry of activated carbon to improve gas adsorption, combining multiple materials for synergistic effects, and reusing adsorbents to lower costs and environmental impact. Evidence from reviewed literature and pilot projects indicates that these low-cost materials can substantially reduce purification costs and operational burdens. Moreover, some have been successfully implemented in community-level biogas programs, improving energy access in underserved regions. These efforts align directly with the objectives of SDG 7, contributing to cleaner energy transitions and increased energy equity in low-income communities.