Constructed or treatment wetlands (CWs) are a sustainable option to clean wastewater in the face of water pollution problems. Consequently, this study was aimed at reviewing and analyzing the use of CWs in Mexico. This involved types, sizes, and functionality in the removal of pollutants, as well as the main plant species that are used. Furthermore, 67 studies regarding CWs were found, which were classified according to the treatment area as microcosms, mesocosms, pilot scale, and full-scale at 18, 30, 25, and 27%, respectively. The most used types of CWs are those of subsurface flow (87%) versus free-water surface (13%), of which horizontal flow direction (58%) are the most common. Considering Full-Scale CWs, the pollutant removal reported for COD, BOD5, TN, and TP oscillated between 50–90%, 60–90%, 30–90%, and 30–70%, respectively. Among the vegetation that is more used for Mexican CWs, 78 different species were detected; Typha and Cyperus hydrophytes species and ornamental flowering plants as Zantedeschia aethiopica., Canna genus., Heliconia genus, Hedychium coronarium, and Anturium andreanum species (plants with commercial value) were the most used plants. It was concluded that although there is an important advance in the use of ecotechnology as it is an attractive answer for decentralized wastewater treatment in Mexico, results revealed the need to migrate towards the use of CWs in full-scale size, in order to address real pollution problems. Thus, the further implementation of CWs in rural and urban regions with similar tropical and subtropical characteristics as in Mexico is suggested by the authors.

Energy production in constructed wetlands is a little-known field, as is the operation of vertical partially saturated constructed wetlands (VPS-CWs) that promote both aerobic and anaerobic microbial interactions. By doing so, bacterial degradation is increased, becoming the main mechanism of pollutant removal in constructed wetlands (CWs). For the first time, the generation of bioelectricity, together with the production of ornamental plants in vertical partially saturated constructed wetlands during the treatment of domestic wastewater, was evaluated. Six VPS-CW systems functioned as bioelectricity generators, where the systems were filled with red volcanic gravel and activated carbon as anode and cathode. Three systems were planted with Zantedeschia aethiopica and three with Canna hybrids plants. The development was measured through mother plants and shoots produced every 60 days. The input and output of each VPS-CW was monitored using control parameters such as BOD5, phosphates (P-PO4), and total Kjeldahl nitrogen (TKN). Bioelectricity, power, voltage, and current measurements were performed every 15 days for a period of 7 months. It was found that the VPS-CWs used as biobatteries in combination with the use of domestic wastewater as a substrate improved the development of the two evaluated plant species and stimulated growth and germination of new shoots. No significant differences were found between the different treatments (p ≤ 0.05). Likewise, an average efficient removal of BOD5 (98%) for both systems without statistical differences was observed (p ≤ 0.05), but for TKN and P-PO4, significant differences (p ≤ 0.05) were found between systems planted with Z. aethiopica (TKN: 65%; P-PO4: 20%) and Canna hybrids (TKN: 69%; P-PO4: 27%). This method of water treatment and bioelectricity production with Canna hybrids was an efficient system that generated a great electric current (140 mA/m2), voltage (750 mV), and electric power (15 mW/m2), compared with those observed in systems with Z. aethiopica (60 mA/m2, 500 mV, 9 mA/m2).