Reductive dechlorination of 2-chlorophenol in a hydrogenotrophic, gas-permeable, silicone membrane bioreactor.
A gas-permeable silicone membrane bioreactor was used to cultivate the biofilm under hydrogenotrophic condition for reductive dechlorination of 2-chlorophenol (2-CP). The anaerobic sludge obtained from a swine wastewater treatment plant was immobilized by polyvinyl alcohol (PVA) so as to form a biofilm on the surface of the silicone tube. After acclimating for about 4 months, the bioreactor showed a high dechlorinating performance. Under the condition of continuous feeding with 2-CP at 25 mg/l and the hydraulic retention time of 15 h, the 2-CP removal efficiency reached 92.8% (2-CP decay rate: 0.67 g/m(2)d of surface area of silicone tube). H(2) was used as electron donor for dechlorinating 2-CP, and produced the dechlorinating intermediate, phenol. Both nitrate and sulfate played important roles in inhibiting 2-CP dechlorination through different biological mechanisms. Nitrate can be easily utilized as an electron acceptor by the biofilm, while sulfate cannot. Results of this study demonstrated that nitrate competed with 2-CP as the electron acceptor, while sulfate retarded the activity of hydrogen-dechlorinating bacteria and thus inhibited the 2-CP dechlorination.
Chang
Chao-Chien
CC
Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou Shan Rd., 106, Taipei, Taiwan, ROC. grasschang@seed.net.tw
Tseng
Szu-Kung
SK
Chang
Chih-Cheng
CC
Ho
Chun-Ming
CM
D018441:Biofilms; D019149:Bioreactors; D002733:Chlorophenols / Q000378:metabolism*; D007700:Kinetics; D008567:Membranes, Artificial; D009566:Nitrates / Q000378:metabolism; D010539:Permeability; D011142:Polyvinyl Alcohol / Q000378:metabolism; D012722:Sewage / Q000382:microbiology; D012828:Silicones / Q000737:chemistry; D013431:Sulfates / Q000378:metabolism; D018508:Water Purification / Q000379:methods*
D002733:Chlorophenols; D008567:Membranes, Artificial; D009566:Nitrates; D012722:Sewage; D012828:Silicones; D013431:Sulfates; D011142:Polyvinyl Alcohol; C030683:2-chlorophenol