Sanitary Landfill Leachate Treatment with Double Chamber Anaerobic Reactor in Series with Constructed Wetland

A treatment system composed of a double-chamber anaerobic (DCA) reactor in conjunction with a constructed wetland (CW) of horizontal sub-surface flow, for the treatment of leachates generated in the municipal sanitary landfill of a typical mid-sized city was investigated. The aim of this work was to assess the capability of the system to remove pollutants such as organic load, nutrients and solids. The system was evaluated at hydraulic retention times (HRT) of 7.97, 5.31 and 2.88 days. The highest removal efficiencies for the system were obtained at HRT of 7.97 days and were 89% and 91% for TCOD and BOD, respectively. In the case of NO3-, NO2-, NH4+ and Total Kjeldahl Nitrogen (TKN), their removal rates were estimated at 88%, 93%, 93% and 85%, respectively; whilst for TS, TVS and TTSS they were 88%, 86% and 90%, respectively, again at HRT of 7.97 d. Efficiencies of 78%, 83% and 77% were obtained respectively for TCOD, BOD and TKN in DCA reactor at HRT of 1.5 d. Typha domingensis was identified as a species capable of adapting to the physicochemical conditions of the leachate, exhibiting an average growth of 196 cm. In leachate there were found low concentrations of heavy metals, being aluminum the metal with the highest concentrations (between 3.31-10.09 mg/L). Results show that it is feasible to implement the DCA reactor in series with a constructed wetland for the treatment of sanitary landfill leachates. Therefore, this system can be replicated for the treatment of leachates with similar conditions.