A project between the University of Sheffield and the Industrial University of Santander in Colombia has produced a new way of re-using agricultural waste so that rural farmers can produce their own heat and energy, making farming practices more sustainable and eco-friendly.
Dr Davide Poggio, Dr Kevin Hughes and PhD student Wenjun Peng from the Energy Institute and the Department of Mechanical Engineering have been working for the last two years on a Newton Fund project to design and evaluate an innovative integrated process for the production of energy and biofertilisers, in order to improve the sustainability and productivity of family farming in Colombia.
The collaborative project has been carried out together with Prof Liliana Castro, Prof Humberto Escalante, PhD Student Jaime Jaimes-Estévez and MSc student Alexander Muñoz, from the INTERFASE research group at the Industrial University of Santander.
Agriculture is a major part of the economy in Colombia, and many families, particularly in the Andean region this project focuses on, are active in animal husbandry, and dairy and sugarcane farming. The dairy industry improves food security and represents a source of employment and income to millions of rural families.
All of these activities produce significant amounts of waste residues, like manure, whey, bagasse (sugarcane pulp) and residual wood. Generally, the management of these wastes is poor, and impacts the efficiency of the processes and the environment around the farm. This new project has introduced a novel approach to the management of these bioresources, and turned waste into heat, gas and other materials which provide nutrients for soils. The results of the project will increase access to sustainable energy in the region, for both dairy industries and smallholders and family farmers.
To turn the agricultural wastes into energy, the project has developed an innovation based on existing anaerobic digestion and gasification technology. In this integration, wet wastes like manure and whey are converted into biogas and soil nutrients in anaerobic digester; while drier wastes such as residual wood and bagasse are converted into heat and biochar in a gasifier cookstove.
The project has investigated and demonstrated, in laboratory and pilot experiments, how the addition of biochar into anaerobic digesters improves the speed and stability of the biogas production. Biochar is a highly porous material which offers an excellent environment for the growth of microorganisms in biofilms, and accelerates waste conversion and biogas production. Additionally, biochars act like sponges, retaining the nutrients released from the conversion of biowastes and working as an improved soil conditioner and fertiliser when finally applied to the crops.
The collaboration between the two research groups has already led to a presentation at the 17th World Congress on Anaerobic Digestion (2022), and a publication showing the benefit of combining different biowaste streams to enhance the biogas production.
The next steps for the project is to expand the assessment to a variety of different biochars and identify what are the most important characteristics and mechanisms that enhance anaerobic digestion; and continue the monitoring and evaluation of the pilots in Colombia.
Working closely with the farming families the technology will support, this project combines engineering advances, knowledge exchanges between the two Institutes, and engagement with the beneficiaries to create new technology which will improve the daily lives of people who are closely affected by both energy security issues and the climate crisis.