Efficiency assessment of constructed wetlands for fuel contaminated water treatment

Constructed wetlands are novel systems distinguished by their economy, easy maintenance and operation, also characterized by their complex mechanism to remove a wide range of pollutants. Four artificial wetlands, two planted with Typha latofolia and two unplanted, were filled with wastewater obtained from the mixture of residual fuel from the service stations maintenance storage systems and clean water, at a 3% v(fuel)/v(clean water) ratio, a planted wetland and an unplanted one were biostimulated with fertilizer at a 100:10:1 ratio, and all wetlands were studied for 72 days, analyzing total petroleum hydrocarbons in the organic range of gasoline and diesel, pH, oxide reduction potential, phosphate and nitrate. The obtained results showed that facultative conditions prevailed in the wetlands when reporting data on the reduction oxide potential -100 to 300 mV, favoring the denitrification process and removal of total petroleum hydrocarbons with an efficiency greater than 84%. In conclusion, the phytotoxic effect was evidenced in the planted wetlands when the macrophages showed deterioration on the last sampling day; on the other hand, all wetlands showed good performance for total hydrocarbons removal, being the biostimulated and planted with Typha latifolia wetland the one that obtained the highest removal percentage, showing the potential of these systems for hydrocarbon-contaminated wastewater treatment.