Every day, large quantities of coffee are consumed across Lebanon, generating a waste stream that is often treated simply as something to be discarded. But spent coffee grounds contain more than organic waste. They also contain recoverable oils that can potentially be transformed into renewable energy.
A project funded by the Arab Fund through the Environmental and Sustainable Development Unit (ESDU) at the American University of Beirut (AUB) and implemented by the School of Engineering at the Holy Spirit University of Kaslik (USEK) explored this potential by developing and validating a process for producing biodiesel from spent coffee grounds. Over eight months, the project brought together laboratory research, student training, and applied experimentation to investigate how a common waste material could become a locally produced source of renewable energy.
Turning an Everyday Waste into a Resource
The project responds to two challenges facing Lebanon: the growing quantities of organic waste generated through coffee consumption and the need to develop locally produced renewable energy sources.
Rather than viewing spent coffee grounds only as a waste management problem, the research explored their potential as a feedstock for biodiesel production. Coffee grounds were collected from university facilities and partner coffee shops, then dried, characterized, and processed to extract their oil.
The research team tested two extraction methods, including Randall extraction and ultrasonic-assisted extraction using newly acquired laboratory equipment. Different sources of coffee grounds, solvent types, and solvent-to-solid ratios were also tested to identify the conditions that could maximize oil recovery while keeping the process feasible.
From Laboratory Research to Biodiesel
The extracted oil was found to have physicochemical properties suitable for biodiesel production. However, its relatively high free fatty acid content meant that the oil required a two-step conversion process to produce biodiesel efficiently and achieve the desired fuel quality.
Following optimization, biodiesel was successfully produced at laboratory scale. Its density was also measured and found to comply with applicable ASTM standards, confirming the technical feasibility of producing biodiesel from spent coffee grounds under Lebanese conditions.
The results demonstrate the potential of an abundant organic waste stream to contribute to renewable energy production while reducing the environmental burden associated with its disposal.
Building Knowledge Alongside Technology
The project also created opportunities for research and learning. A final-year engineering student participated directly in the project, contributing to literature reviews, laboratory experiments, data analysis, and reporting related to the optimization of biodiesel production.
This hands-on experience provided practical training in renewable energy technologies, laboratory experimentation, process optimization, and sustainable waste valorization. At the same time, the project strengthened research capacity within USEK’s School of Engineering.
The project also invested in laboratory infrastructure. An ultrasonic homogenizer and associated materials were procured and commissioned, expanding the laboratory’s capacity to undertake research on renewable fuels. These resources will continue to support future work on biofuels, waste valorization, and circular economy applications beyond the project’s implementation period.
Putting the Circular Economy into Practice
At its core, the project demonstrates the principles of a circular economy: finding ways to keep materials in use and create new value from resources that would otherwise be discarded.
Spent coffee grounds are only one example. The technical knowledge and research capacity developed through the project can support future investigations into other organic waste streams, including olive pomace and food-processing residues. Future work could also explore pilot-scale biodiesel production and partnerships with municipalities and private-sector stakeholders to assess possibilities for larger-scale implementation.
The project also contributed to wider discussions around sustainable waste management and renewable energy. Its findings were shared through a seminar at USEK and presented internationally at the International Conference on Circular Economy and Waste Minimization Strategies in Paris, creating opportunities for knowledge exchange with academic and industrial stakeholders.
From Waste to Possibility
The project shows how local research can help reimagine the materials that surround us. A cup of coffee may seem far removed from renewable energy, but the grounds left behind contain resources that can be recovered and put to use.
By demonstrating the technical feasibility of producing biodiesel from coffee waste collected in Lebanon, the project establishes a foundation for further research and potential scale-up. More broadly, it highlights the role universities can play in developing practical solutions that connect waste management, renewable energy, research, and innovation.
For Lebanon, where environmental pressures and energy challenges intersect, finding value in locally available resources can be an important part of building more sustainable systems. Sometimes, the first step is simply to look at what we throw away differently.