ROLE OF OZONE AND RECIRCULATION IN THE STABILIZATION OF LANDFILLS ANDLEACHATES (REPRINTED FROM THE ROLE OF OZONE IN WASTE-WATER TREATMENT,1997)

This paper describes a long term experiment undertaken with six bench- scale landfill lysimeters to investigate whether ozone treatment can i ncrease the biodegradability of the leachates arising from the lysimet ers, and reduce the gradual build-up of difficult-to-treat 'hard' COD, typical of leachates of older landfills. Leachate from all six lysime ters was recirculated through pulverized domestic waste every two week s. Leachate from four of the lysimeters was ozonated at different dose s before recirculation; two lysimeters from the onset of the experimen t; and two after a stable methanogenic phase was established. The reci rculation of ozonated leachates did not prevent a fully developed meth anogenic phase from being established within the lysimeters. Ozone dos es of at least 0.06 mg O-3 per mg COD were found to increase the BOD5/ COD ratio, when applied to leachates from lysimeters in a post-methano genic phase.