Nanofiltration as post-treatment of MBR treating landfill leachate

Landfill leachate management has been a major environmental, economic, and social concern, and its treatment brings forth a challenge, especially regarding the high concentration of refractory organic matter, ammonia, and toxic compounds, which may vary considerably depending on the maturity, age, and biochemical reactions occurring in the landfill, besides the high variation on the volume generated. This study was aimed to investigate NF use as a post-treatment of landfill leachate that has been treated by membrane bioreactor (MBR). The experimental setup consisted of pilot plant comprised by an air stripping reactor, plus MBR and NF membranes. The pilot plant has a treatment capacity of 3 m(3)/d. The system has shown excellent leachate treatment performance, especially regarding the removal of chemical oxigen demand (80-96%), ammonia (85-95%), color (98-99.9%), and phosphorus (78-99.8%). The results have also shown the importance of NF to improve the effluent condition, and to produce treated effluents free of chemical substances and sludge. The membrane fouling was imputed to the adsorption of a humic substance on the membrane surface and the pore-blocking phenomena. By this route, treated landfill leachate may be reused at the landfill as water for dust arrestment, and also as earth work on construction sites.