Closing Coffee Production Loops With Waste To Ethanol In Matagalpa, Nicaragua

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Kristan Cockerill Ph.D., Associate Professor (Creator)
Appalachian State University (ASU )
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Abstract: Wet milling of coffee cherries is an effective process resulting in a high quality, high value product; however, it requires large volumes of fresh water and produces wastewater and pulp byproducts that pose environmental threats if unmitigated. A promising sucrose source is the fermentation sweet water (agua miel in Spanish) that showed an average Brix value of 12 from our sample area. These sugars can be directly fermented with conventional yeast strains, Saccharomyces cerevisiae and Zymomonas mobilis for conversion to ethyl alcohol. These sugars are the primary agent for eutrophication of adjacent water sources. Sweet water effluent samples from our study area in Nicaragua showed a pH of 4.64, ammonia nitrogen at > 10 mg/L, phosphates of 150 mg/L, dissolved oxygen of 0.01 mg/L and BOD > 200 ppm. Upon release into surface water sources, this concentrated effluent impacts aquatic life and creates ideal conditions for bacterial growth. Often, it leaches into the shallow groundwater sources, thus polluting drinking water for local communities. Health effects from consuming contaminated drinking water include skin irritation, stomach problems, nausea, and breathing problems. Surveys conducted in the study area showed a community with limited access to electricity and potable water whose greatest needs include health, education, and cooking fuels. The community was aware of negative environmental effects from wet-milling during the coffee harvest season. The objective of this study is to identify mitigation scenarios that utilize sweet water as a carbohydrate resource for conversion to bioethanol. Size of the byproduct resource base, economics of conversion, and technical and social feasibility for rural coffee producing communities are discussed. The study area for this research is an organic coffee farm (Finca Esperanza Verde, FEV) and surrounding communities in Matagalpa State in the central highlands of Nicaragua.

Additional Information

Ferrell, J. and K. Cockerill (2012). "Closing coffee production loops with waste to ethanol in Matagalpa, Nicaragua." Energy for Sustainable Development 16(1): 44-50. Publisher version of record available at:!
Language: English
Date: 2012
Coffee, Sweet water, Wet-milling, Ethanol, Biofuels, Nicaragua

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