Abstract

Experiments carried out with young leachate in the highrate anaerobic bioreactors of UASB, FBABR and UFAF types showed that the immobilization of anaerobic biomass had taken place within a period of 70 - 90 days, forming rather dense sludge. During the period of 190 – 200 days, morphology of the granular sludge varied depending on a number of factors such as leachate content, toxicities, but could reach an activity higher than 5g COD/g VSS.day, allowing a volumetric organic loading as high as 30 - 32 g COD/l.day with an organic removal efficiency at 90 - 94 % for the UASB and FBABR reactors, at 96 % for the UFAF reactors. While the volumetric organic loading applied for the UASB and FBABR reactors are higher as compared to the UFAF reactor, the start-up process of the last appeared to be shorter considerably. Anaerobic biomass could be immobilized more rapidly, within 2 months, with an organic removal efficiency of > 75 % when a polyacrylamid based WAP and granular activted carbon Norit PK1,3 applied. Post treatment using FBR technique could reach an organic removal efficiency for the left organic compounds reached > 90 %. The total COD removal efficiency of the combined anaerobic - aerobic processes was 99% and even higher.