Physical-chemical pre-treatment of sanitary landfill raw leachate by direct ascending filtration.

Several environmental problems in Brazil are caused by the accelerated urban and industrial growth and by the multiplicity of urban waste generated. Waste disposal in landfills is still common practice in Brazil. This work was conducted in sand filters and activated carbon column, proposing an alternative for the physical-chemical treatment of leachate as a pre-treatment to preserve the biological process. The results showed reductions of up to 74% for COD, 47% for BOD5, 93% for color, 90% for ammonia and an increase from 0.3 to 0.9 in the BOD5/COD ratio. Although the results obtained do not fall within the limits of the legislation, the results for ammonia concentration was reduced by 33.25% and 85.37% after filtration and activated carbon column treatment respectively. The use of activated carbon columns resulted in an excellent performance in the reduction of heavy metals in the leachate. The performance demonstrated a removal of 60-96%. Limitations were found in the length of the filtration races, as a limiting factor in the process. The results show the potential of using direct upward filtration with sand and activated carbon filters for the treatment of landfill leachate.