Abstract

The coffee industry significantly contributes to economic growth in rural communities within developing countries. However, coffee processing can lead to considerable water pollution. Therefore, exploring simpler and more sustainable treatment alternatives, such as constructed wetlands (CWs), is crucial. This study aims to evaluate the performance of a full-scale wastewater treatment plant (WWTP) with CWs for treating a co-mixture of rural domestic wastewater and coffee production wastewater in Mexico. For this, the WWTP consisting of a settler tank and four CWs in series was evaluated over the course of one year. The CWs units are planted with five different ornamental plant species. The results show no significant (p > 0.05) change in the influent characteristics when coffee production wastewater was added. A link was established between rainfall in the contributing area and removal efficiency in the settler tank located at the system's starting point. However, this behavior did not affect the CW's performance. The WWTP achieved annual mean removal efficiencies of 87 % for COD, 60 % for TN, 59 % for NH4+-N and NO3--N, 68 % for NO2--N, 76 % for TP, 74 % for PO43--P, and over 99 % for caffeine. Considering this performance, the WWTP effluent complies with the Official Mexican Standard provided permissible discharge values. Therefore, this study provides full-scale evidence of CWs potential for wastewater treatment in rural areas of developing countries. Furthermore, this type of WWTP offers a viable alternative for addressing the issue of untreated wastewater discharge in rural communities, particularly concerning when these communities developing productive activities like coffee processing.