LEACHATE TREATMENT BY HIGHRATE ANAEROBIC REACTORS OF UASB, FBABR AND UFAF COMBINED WITH FBR

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.