Vertical flow wetlands as the core for the sustainable treatment of coffee wastewater in small communities in Colombia: preliminary results of the treatment of coffee wastewater in rural areas by vertical flow wetlands.

Coffee is one of the most important agricultural products in Colombia. To date, small-scale Colombian coffee growers have developed this activity with a simple infrastructure and random use of water that generates harmful by-products to the water resource mainly in the stage of separation of the mucilage. The coffee mucilage wastewater (CMW) is composed of high organic loads and its impact on water sources is due to its high load of nutrients such as nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) values of over 25,000 mg/L. However, there is no consensus on what treatment can be used, especially whether it is accessible to coffee producers. Thus , the aim of this study consisted of assessing the performance of the combination of a carbon filter (CF) as pretreatment and vertical flow wetland (VFW) as a Natural-based Solution (NbS). The results show a reduction of more than 85% of COD, 96% of total solids, and UV254 close to 94%. It was remarkable that both treatments are appropriate for waters with a high concentration of solids. Finally, it can be concluded that CF + VFW is a feasible technology to treat the coffee wastewater from small communities of coffee producers.