Current understanding and perspectives on anaerobic digestion in developing countries: Colombia case study

Anaerobic digestion (AD) technology has become increasingly important due to its contribution to sustainability and a circular bioeconomy. While AD technologies are widespread in developing countries, developed countries have mainly driven research. The aim of this research is to analyze the biogas sector development from the point of view of a developing country like Colombia. AD research ranges from laboratory mesophilic AD to psychrophilic full-scale digesters, which are intergrated with household farms as a thermal energy source for cooking, nutrient recycling for agriculture, and waste management. Research on agricultural waste substrates, inocula, and co-digestion has dominated the Colombian publications, while full-scale digesters performance research is incipient. A survey of installed digesters collected information about 996 systems and found that 79% were psychrophilic low-cost tubular digesters. Regulations for biogas were reviewed, and it was found that they are not adequate for low-cost digesters and are inherited from developed countries, ignoring the national context. Five case studies are presented on the characterization of AD technology experiences, analyzing barriers and opportunities for the technology. National networks that include farmers, NGOs, and academia are driven slowly by Colombia's widespread AD technology, mainly on small-to medium-scale farms.