Fate and Toxicity of Aircraft Deicing Fluid Additives Through Anaerobic Digestion

Abstract

Benzotriazole derivatives are widely used corrosion inhibitors and their fate during wastewater treatment processes is unknown. The purpose of this research was to study the toxic effects and fate of the two commercially significant benzotriazole isomers used in aircraft deicing fluids (4-, and 5-, methylbenzotriazole [MeBT]) during anaerobic digestion. Experiments were executed in microcosms using mesophilic anaerobic biomass co-digesting wastewater sludge and propylene glycol. Sorption of MeBT to digesting solids could be approximated with a Freundlich model, and no anaerobic breakdown of either MeBT isomer was detected. Digesters fed more than 300 mg/L MeBT responded with a significant decrease in methanogenic microbial activity and volatile solids production and a concomitant increase in accumulation of volatile fatty acids. Direct microscopic measurements using fluorescent phylogenetic probes applied to digesting biomass revealed that members of both Archaea and Bacteria domains were sensitive to MeBT. Granular activated carbon (GAC) (volatile solids: GAC ϭ 10%) reduced the apparent toxic effects of MeBT; GAC addition nearly restored the baseline activity of digesters fed MeBT (500 to 1000 mg/L). Water Environ. Res., 73, 72 (2001).

Biodegradation of three selected benzotriazoles in aquifer materials under aerobic and anaerobic conditions

“…Previous studies have shown that BTs in the environment are quite resistant to microbial degradation (Breedveld et al, 2003;Gruden et al, 2001;Weiss et al, 2006). BTs are reported to have low to moderate elimination rates (11-74%) in conventional wastewater treatment plants (Voutsa et al, 2006;Weiss et al, 2006).…”

Biodegradation of three selected benzotriazoles under aerobic and anaerobic conditions

“…BTs in the environment are quite resistant to microbial degradation (Gruden et al, 2001;Weiss et al, 2006). With the exception of a few reports on removal of BTs in conventional WWTPs, very little is known about their biodegradation potential and mechanisms under environmental conditions (Breedveld et al, 2003;Weiss et al, 2006).…”

Photolysis of benzotriazole and formation of its polymerised photoproducts in aqueous solutions under UV irradiation

“…Although BT is known to be quite resistant to microbial degradation, [17] it is highly photochemically sensitive. [18] UV photolysis has been applied as an advanced wastewater treatment technology to remove some trace organic contaminants in waste streams.…”