Evaluation of the Efficiency of Reverse Osmosis in the Treatment of Sanitary Landfill Leachate in the Metropolitan Region of the Rio de Janeiro

The decomposition of the organic matter in municipal waste from landfills results in a highly polluted and toxic effluent, named sanitary landfill leachate. Due to the potential contamination for soil, groundwater and surface water bodies, the treatment of sanitary landfill leachate is essential to avoid environmental and public health damage. This study aims to evaluate the technical and environmental efficiency of reverse osmosis technology for the treatment of leachate in landfill from the Metropolitan Region of the Rio de Janeiro, Brazil. It was observed that the raw leachate from this landfill has highly polluting, and has chemical and physicochemical characteristics typical of mature landfills, with operation older than 5 years: pH = 7.85; ammonia nitrogen concentrations of 2,473.00 mg L-1; BOD 2,545.84 mg L-1 and COD 4,881.81 mg L-1, respectively. Except for only one sampling, with phenol parameter, reverse osmosis was technically and environmentally efficient in mitigating pollutants present in the raw sanitary landfill leachate with excellent removal rates: E-N(%) > 99 %; E-BOD(%) > 98%, and E-COD(%) > 99%. After reverse osmosis treatment, the treated leachate was respecting Brazilian legislation and could be released into the local stream. During reverse osmosis treatment of 120 m(3) day(-1) of leachate, prevented 107.84 kg year(-1) of N from being released into nature; 110.95 kg year(-1) of BOD, and 211.70 kg year(-1) of COD, avoiding eutrophication from nearby rivers that inevitably flow into Guanabara Bay. It becomes a promising technology to face the impacts that pressure the Planetary Boundaries in the Anthropocene.