The waste biomass of Saccharomyces uvarum, used in fermentation industries to produce ethanol, were studied for their ability to absorb various heavy metal ions. Heavy metal ions studied in this research were Cd, Co, Cr, Cu, Ni and Pb. The order of the sorption capacity was Pb>Cu>Co=Cr=Cd>Ni. The living Saccharomyces uvarum exhibited higher metal-uptake capacity than the dead Saccharomyces uvarum. After we compare the uptake capacity of the Saccharomyces uvarum for individual metal ions with for a mixture of them, the following was observed: in the mixed heavy metal solution the uptake capacity was decreased than the one heavy metal solution. The selective uptake was observed when all the heavy metal ions were dissolved in a mixed solution. The adsorption isotherm modelling was decribed with the Langmuir and Freundlich model. The results were in good agreement with the Langmuir model.

A mathematical model for organic removal efficiency was investigated in a fluidized bed biofilm reactor by changing the feed flow rate, the residence time and the recycle flow rate. In batch experiment, organic removal could be assumed as first order and an intrinsic first order rate constant(kl) was found 6.4 x 10 exp (-6) ㎤/㎎ sec at influent COD range of 3040 - 6620 ㎎/L. In continuous experiment, at the condition of the influent COD, 3040 ㎎/L, the superficial upflow velocity, 0.47 ㎝/sec, the biofilm thickness 336 ㎛ and the biofilm dry density 0.091 g/mL, the calculated COD removal efficiency from the mathematical model gave 60 % which was very close to the observed value of 66 %. As the feed flow rate was increased, the COD removal efficiency was sharply decreased and at constant feed flow rate, the COD removal efficiency was decreased also as the residence time being decreased.

A number of experiments were conducted in order to investigate the organic removal efficiency and biomass characteristics according to the organic shock loading rate in a fluidized bed biofilm reactor. At the operation conditions of HRT, 8.44 hour, superficial upflow velocity, 0.9 ㎝/sec and temperature, 22±1 ℃, the removal efficiency of SCOD was founded to be 96.5, 92 and 90 % with the organic shock loading rate of 3.5, 10.8 and 33 kgCOD/㎥·day, respectively. Within the F/M ratio ranged 0.4 to 2.0 ㎏COD/㎏VSS·day, the SCOD removal efficiency was shown as 90% at F/M ratio of 2.0 ㎏COD/㎏VSS·day, but the TCOD removal efficiency was 72 % at F/M ratio of 1.8 kgCOD/kgVSS·day. The average biomass concentrations were 7800, 14950 and 27532 ㎎/l on the organic shock loading rate of 3.5, 10.8 and 33 ㎏COD/㎥·day, respectively. This result was agreed with the fact that more biomass could be produced at high concentration of substrate, but some biomass was detached at the onset of shock and easily acclimated at the shock condition.