title: Bioaugmenting bioreactors for the continuous removal of 3-chloroaniline by a slow release approach.
abstract: The survival and activity of microbial degradative inoculants in bioreactors is critical to obtain successful biodegradation of non- or slowly degradable pollutants. Achieving this in industrial wastewater reactors is technically challenging. We evaluated a strategy to obtain complete and stable bioaugmentation of activated sludge, which is used to treat a 3-chloroaniline (3-CA) contaminated wastewater in a lab-scale semi-continuous activated sludge system. A 3-CA metabolizing bacterium, Comamonas testosteroni strain I2, was mixed with molten agar and encapsulated in 4 mm diameter open-ended silicone tubes of 3 cm long. The tubes containing the immobilized bacteria represented about 1% of the volume of the mixed liquor. The bioaugmentation activity of a reactor containing the immobilized cells was compared with a reactor with suspended I2gfp cells. From day 25-30 after inoculation, the reactor with only suspended cells failed to completely degrade 3-CA because of a decrease in metabolic activity. In the reactors with immobilized cells, however, 3-CA continued to be removed. A mass balance indicated that ca. 10% of the degradation activity was due to the immobilized cells. Slow release of the growing embedded cells from the agar into the activated sludge medium, resulting in a higher number of active 3-CA-degrading I2 cells, was responsible for ca. 90% of the degradation. Our results demonstrate that this simple immobilization procedure was effective to maintain a 3-CA-degrading population within the activated sludge community.
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Leen
authors.initials: L
authors.lastname: De Gelder
authors.forename: Hanne
authors.initials: H
authors.lastname: Lievens
authors.forename: Steven D
authors.initials: SD
authors.lastname: Siciliano
authors.forename: Eva M
authors.initials: EM
authors.lastname: Top
authors.forename: Willy
authors.initials: W
authors.lastname: Verstraete
mesh_terms: D000814:Aniline Compounds / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D020604:Comamonas testosteroni / Q000502:physiology*; D007220:Industrial Waste; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000814:Aniline Compounds; D007220:Industrial Waste; C031392:3-chloroaniline