VINYL-CHLORIDE BIODEGRADATION WITH METHANOTROPHIC ATTACHED FILMS

Citation
Ym. Nelson et Wj. Jewell, VINYL-CHLORIDE BIODEGRADATION WITH METHANOTROPHIC ATTACHED FILMS, Journal of environmental engineering, 119(5), 1993, pp. 890-907
Citations number
38
Categorie Soggetti
Environmental Sciences","Engineering, Civil
ISSN journal
07339372
Volume
119
Issue
5
Year of publication
1993
Pages
890 - 907
Database
ISI
SICI code
0733-9372(1993)119:5<890:VBWMAF>2.0.ZU;2-1
Abstract
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.