Landfill leachate biological pre-treatment stage successfully achieved

Leachate treatment
  • 85% COD reduction
  • Pre-treated leachate able to be carried through a final RO stage

early 2015 a new landfill cell in Mavrorachi landfill site went to operation, receiving waste from the Thessaloniki region (population of 1.300.000) and resulting in a daily production of 200 m3 leachate with a significant organic load and salinity. The leachate has been tested to be treated in the on-site wastewater treatment plant, being already in operation and receiving leachate from the two older landfill cells with much less organic load, resulting in an almost collapse of the biological activity due to the significant plant overloading. By applying the bioaugmentation process, the plant managed to cope with the increased organic load, by gradually reducing the incoming COD by more than 85%, although the leachate Electric Conductivity is typically more than 30 mS/cm. As a result, the leachate complies with the technical specifications of a downstream Reverse Osmosis stage, where the treated effluent is further carried through, so as a high quality final effluent is produced.