A COMPARISON OF DIFFERENT SUPPORT MATERIALS IN ANAEROBIC FLUIDIZED-BED REACTORS FOR THE TREATMENT OF VINASSE

Three identical anaerobic fluidized bed reactors containing different biomass support media were fed a distillery wastewater at various hydr aulic retention times and COD loadings. The support media used were se piolite, pumice stone and sand; particle diameter was around 0.5 mm in all cases. Start-up of the reactors was achieved within 63 days using a regime that included stepped increases in influent COD concentratio n and substitution of methanol for part of the wastewater GOD. No sign ificant differences in performance between reactors were observed duri ng this period. Six different steady states at hydraulic retention tim es between 0.5 and 2.48 days were studied. Results obtained at these s teady states showed similar performances in all three reactors except at HRT of 0.5 days, when the reactors containing sepiolite and pumice stone achieved better COD removal efficiencies and higher methane yiel ds than the rand-containing reactor. It was concluded that sepiolite a nd pumice stone would be excellent solid supports in biological fluidi zed bed processes and have a lower energy consumption than the one dem anded when using a sand support.