M. Fahmy et al., ANAEROBIC-AEROBIC FLUIDIZED-BED BIOTREATMENT OF SULFITE PULP BLEACHING EFFLUENTS .2. FATE OF INDIVIDUAL CHLOROPHENOLIC COMPOUNDS, Water research, 28(9), 1994, pp. 1997-2010
Four parallel biological fluidized bed reactor systems-one single aero
bic, one single anaerobic and two combined anaerobic-aerobic reactors-
were used to treat sulphite pulp chlorine bleaching wastewater. By tot
al mass balances it was proven that the individual compounds followed
were removed almost exclusively by biological degradation. The contrib
ution of removal by adsorption on biomass was less than 1% for all the
individual chlorophenolic compounds. In the three systems involving a
n aerobic step, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichloro
phenol were usually quantitatively removed. This was observed up to lo
adings of 1 mmol 2,4,6-trichlorophenol per m(3) and day. At lower load
ing rates, trichloroguaiacols were also removed quantitatively. Howeve
r, 4,5-dichloroguaiacol was only partly removed, whereas 3,5-dichloros
yringol was produced in the reactors from unidentified precursors. The
anaerobic-aerobic recycle reactor did remove individual chlorinated p
henolics at high loading rates better than the other reactor combinati
ons. In the aerobic systems removal rates of organic chlorine and carb
on correlated well with removal rates estimated from individual chloro
phenols measurements, despite its low contribution to the total values
(<<1%).