N. Cicek et al., EFFECTIVENESS OF THE MEMBRANE BIOREACTOR IN THE BIODEGRADATION OF HIGH-MOLECULAR-WEIGHT COMPOUNDS, Water research, 32(5), 1998, pp. 1553-1563
This paper presents biological and physical performance data from a pi
lot-scale membrane bioreactor system fed with synthetic wastewater con
taining high molecular weight compounds. At steady stare, high effluen
t quality was obtained and maintained for about 350 days. The membrane
was effective in retaining heterotrophic microorganisms and MS-2 viru
ses, eliminating the need for effluent disinfection. The flux through
the membrane decreased rapidly with increasing total suspended solids
(TSS) concentrations between 2 and 15 g/L. The flux increased linearly
with the transmembrane pressure (TMP), before reaching a maximum. A l
inear relationship between the maximum flux and the cross flow velocit
y (CFV) for different TSS concentrations was observed. The ability of
the bioreacter culture to degrade high molecular weight compounds in t
he wastewater, and the mechanisms involved in this process were examin
ed in detail by performing respirometry experiments, Casein was used a
s the model compound and different initial substrate to biomass ratios
(S-o/X-o) were tested. In experiments with high S-o/X-o, several obse
rvations were made: (1) the oxidation of casein occurred in two distin
ct steps, (2) the yield coefficient is smaller than 0.15 mg VSS/mg COD
consumed, and (3) nitrification does not occur. Under low S-o/X-o con
ditions, using C-14-casein, the following observations were made: (1)
complete hydrolysis of casein occurs very fast (less than 100 h) and (
2) oxygen uptake and nitrogen measurements suggest nitrification takes
place. (C) 1998 Elsevier Science Ltd. All rights reserved.