Ym. Nelson et Wj. Jewell, VINYL-CHLORIDE BIODEGRADATION WITH METHANOTROPHIC ATTACHED FILMS, Journal of environmental engineering, 119(5), 1993, pp. 890-907
Methanotrophic degradation of vinyl chloride (VC) is investigated usin
g a laboratory-scale methanotrophic attached-film expanded-bed (MAFEB)
bioreactor. This study provides a basis for applying a microbial come
tabolizing reaction to practical treatment of toxic chlorinated compou
nds. The MAFEB reactor was operated at 20-degrees-C with influent VC c
oncentrations ranging from 1,800 to 9,600 mug/L and bed hydraulic rete
ntion times ranging from 3.7 to 7.6 h. VC effluent concentrations duri
ng steady continuous operation ranged from 3 to 140 mug/L, with most v
alues less than 26 mug/L, resulting in removal efficiencies of 96.3% t
o 99.8%. The maximum continuous-flow VC degradation rate observed at 2
0-degrees-C was 2.5 mg VC per gram volatile solids (VS) per day [2.5 m
g VC/(g VS d)] or 30 mg VC per liter expanded bed per day 30 mg VC/L(e
b) d), under substrate-limited conditions. During semibatch runs at 35
-degrees-C, vinyl chloride degradation rates up to 60 mg VC/(g VS d) o
r 1 g/(L(eb) d) were observed. Degradation rates increased with temper
ature between 20-degrees-C and 35-degrees-C, approximately doubling ev
ery 10-degrees-C. Dissolved methane concentrations above 0.5 mg/L inhi
bited VC degradation, with no VC degradation observed with 8 mg/L diss
olved methane. The methane consumed during VC degradation was about 40
g CH4/g VC. Toxic effects were observed after prolonged exposure of t
he methanotrophic culture to high concentrations of VC.