For the production of coffee in the so-called “wet processing” large amounts of water are used, mainly as transport medium. After processing the water is discharged as wastewater, and contains large amounts of (fermented) organic matter from the coffee cherries. In Central America there are many coffee processing plants, ranging in sizes from a one-family operation to large industrial plants. Wastewater treatment is not yet in place in most of the “beneficios” (coffee processing plants) and when a system has been installed this often constitutes of inadequate pond systems. As a result, the beneficios are a heavy burden on local fresh water resources, not only because of their water consumption but also because of pollution. Effective treatment of the so-called “aguas mieles” is urgently needed to improve the environmental situation. In addition, for the owners of the beneficio wastewater treatment is increasingly important to be able to obtain certifications, and to comply with local legislation.
There is a system of support to farmers in the form of technical assistants that help them optimise the way their plantation and/or beneficio is managed, but the TAs are usually not well informed on the possibilities of wastewater treatment. The project “cleaner coffee processing”, coordinated by Solidaridad, targeted this knowledge gap. LeAF, BZ Innovatiemanagement and Micro Water Facility made an inventory of options for treatment of aguas mieles, and gathered the existing information on technologies and practices for treatment of aguas mieles in Central America. Field visits were conducted in Nicaragua and Honduras. The information was present in the form of a guide for agronomists (in Spanish) that facilitates a better understanding of coffee wastewater treatment and a better selection of treatment options. In the guide a distinction was made between solutions for small, medium and large beneficios, as the treatment strategy is heavily influenced by the amounts of wastewater and the available space and funds. A diagnostics form was developed and included in the guide to assist the TAs with the selection of the most appropriate treatment option for a specific beneficio. In addition to the technical basis of treatment systems information was included on organisational and financial side of the implementation process.