A robust multicriteria analysis for the post-treatment of digestate from low-tech digesters. Boosting the circular bioeconomy of small-scale farms in Colombia

Low-tech digesters are sustainable technologies to produce a clean fuel (biogas), which can be used for cooking and heating. Moreover, the degradation of organic waste in digester also produces liquid effluent (digestate), reused agriculture as biofertilizer. The direct application digestate soil may not either feasible due regulations or safe poor quality. study aims apply, first time, multicriteria analysis select most suitable solution post-treatment reuse from low-tech implemented small-scale farms. post-treatments considered are: degassing tank, sand filter, vermifilter, recirculation, facultative pond, combinations them. Ten criteria twenty-one sub-criteria including technical, environmental socio-economic aspects defined weighted by experts. employs triangular fuzzy numbers consider uncertainty increase robustness results, it is validated using three case studies Colombia. alternatives designed data collected in-situ on design operation quality digestates. Results confirm rankings show that vermifiltration best alternative digestates It fact high-quality biofertilizer, easy manage local materials. Other prominent filtration, recirculation tank coupled with vermifiltration.