Biodegradation of 2,4,6-trichlorophenol in a packed-bed biofilm reactor equipped with an internal net draft tube riser for aeration and liquid circulation

• Published in: Journal of hazardous materials Vol. 161; no. 2; pp. 1140 - 1149
• Main Authors: Jesús, A. Gómez-De, Romano-Baez, F.J., Leyva-Amezcua, L., Juárez-Ramírez, C., Ruiz-Ordaz, N., Galíndez-Mayer, J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30-01-2009; Elsevier
• Subjects: Adsorption; Airlift reactor; Applied sciences; Biodegradation, Environmental; Biofilms; Biological and medical sciences; Bioreactors; Biotechnology; Burkholderia; Burkholderia - metabolism; Chemical engineering; Chlorides - chemistry; Chlorophenols - chemistry; Cometabolism; Equipment Design; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Hydrodynamics of contact apparatus; Hydrogen-Ion Concentration; Ions; Methods. Procedures. Technologies; Others; Oxygen - chemistry; Packed-bed reactor; Phenol - chemistry; Pollution; Porosity; Reactors; Stenotrophomonas; Stenotrophomonas - metabolism; Trichlorophenol; Various methods and equipments; Airlift reactor; Packed-bed reactor; Trichlorophenol; Stenotrophomonas; Cometabolism; Dehalogenation; Mixing time; Overflow; Biological purification; Aeration; Mass transfer coefficient; Chemical oxygen demand; Mineralization; Chlorides; Lead; Riser; Microbial community; Biodegradation; Gas holdup; Packed bed; Pollutant behavior; Pesticides; Fixed bed reactor; Hydrodynamics; Aerobe; Fungicide; Mass transfer; Bioreactor; Water quality; Draft tube; Biofilm; Phenols; Oxygenation
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2008.04.077

For the aerobic biodegradation of the fungicide and defoliant 2,4,6-trichlorophenol (2,4,6-TCP), a bench-scale packed-bed bioreactor equipped with a net draft tube riser for liquid circulation and oxygenation (PB-ALR) was constructed. To obtain a high packed-bed volume relative to the whole bioreactor volume, a high
A
D/
A
R ratio was used. Reactor's downcomer was packed with a porous support of volcanic stone fragments. PB-ALR hydrodynamics and oxygen mass transfer behavior was evaluated and compared to the observed behavior of the unpacked reactor operating as an internal airlift reactor (ALR). Overall gas holdup values
ɛ
G, and zonal oxygen mass transfer coefficients determined at various airflow rates in the PB-ALR, were higher than those obtained with the ALR. When comparing mixing time values obtained in both cases, a slight increment in mixing time was observed when reactor was operated as a PB-ALR.
By using a mixed microbial community, the biofilm reactor was used to evaluate the aerobic biodegradation of 2,4,6-TCP. Three bacterial strains identified as
Burkholderia sp.,
Burkholderia kururiensis and
Stenotrophomonas sp. constituted the microbial consortium able to cometabolically degrade the 2,4,6-TCP, using phenol as primary substrate. This consortium removed 100% of phenol and near 99% of 2,4,6-TCP. Mineralization and dehalogenation of 2,4,6-TCP was evidenced by high COD removal efficiencies (≈95%), and by the stoichiometric release of chloride ions from the halogenated compound (≈80%). Finally, it was observed that the microbial consortium was also capable to metabolize 2,4,6-TCP without phenol as primary substrate, with high removal efficiencies (near 100% for 2,4,6-TCP, 92% for COD and 88% for chloride ions).