## 3 Results and Discussion  
### Agricultural Waste Generated in the Post-Harvest Facilities of the NEA: The Status Quo. In the field visits to the selected post-harvesting facilities (Section 2.1), it was observed that, in their collection and processing centers, they receive red coffee fruits (\"coffee cherries\") and cocoa seeds mainly from their associated farmers. According to the staff of the farmer's cooperatives, the associated farmers transport these products in small trucks from their farms to be processed in these communal centers (Figure 2a). In the case of cocoa, farmers collect the pods and extract the seeds in their farms manually and then deliver them to these communal centers to be fermented and dried. Accordingly, all the agricultural waste generated during the harvesting of cocoa (i.e., empty pods, pruned branches) remains on the farms. Unlike cocoa, the entire red coffee fruits are harvested and delivered to these centers, where they are processed according to the dry method, in which the moisture of these fruits must be reduced to about 10% by weight before threshing. The threshing (or hulling) machines, which are driven by electric or diesel motors, separate the coffee grain from the rest of the fruit (Figure 2b). The extracted husks include the outer skin, the pulp, and the parchment, with particle sizes in the range of 4 to 10 mm. The staff of the post-harvest facilities estimate that that 1 kg of husks are generated per kg of coffee beans produced. The coffee husks are the predominant agricultural waste observed in the four studied facilities (Figure 2c). Inside the collection and processing centers of FOCASH and PRIMAVERA, there are small, sheltered storage rooms in which the coffee husks generated during the threshing process are stored. When the amount of coffee husks generated is high, concrete structures (Figure 2d) are sometimes used to store the coffee husks, as in the case of APROCEL. Coffee husks, unlike other agricultural wastes, such as palm kernel cake or corn stems, are not used as feed for livestock, due to their low digestible protein content and low palatability [37]. In interviews with the presidents and workers of the farmers' cooperatives, it was mentioned that agricultural waste is currently stored until it can be transported back to the farms to be re-incorporated into the soil whenever trucks are available. The staff of the centers said that the incorporation of coffee husks into the soils is a way to prevent their accumulation in the centers. However, they indicated that no appreciable benefits are observed for the crops, such as increases in yield or reduced fertilizer input. Although coffee husks contain potassium and other minerals, their incorporation into the soils without adequate treatment (e.g., composting or vermicomposting) has negligible effects on the crop yields [38]. Therefore, the limited benefits that result from the incorporation of coffee husks in the soils and the high cost of transporting them back to the farms often dissuade this practice and lead to their accumulation in these processing centers, where storage capacity is often exceeded. In AGRODUP, the accumulation of coffee husks is a major environmental concern, since they are dumped into a nearby stream (Figure 2e), when the storage capacity is exceeded, threatening aquatic ecosystems downstream. Frequent rain in humid tropical areas causes the leaching of caffeine, free phenols, and tannins (polyphenols) from coffee husks, leading to groundwater pollution and soil acidification [39]. The high temperatures and moisture in such areas promote the decomposition of accumulated coffee husks, which is linked with the release of methane, a greenhouse gas whose global warming potential is 84-87 times that of CO2 when considering its impact over a 20 year timeframe and 28-36 times that of CO2 when considering its impact over a 100 year timeframe [40]. The decomposition of 1 kg of agricultural waste can release roughly 0.19 kg of methane [41].