Sustained Degradation of Trichloroethylene in a Suspended Growth Gas Treatment Reactor by an Actinomycetes Enrichment

Abstract

A laboratory-scale, suspended-growth, gas treatment bioreactor was used to study the sustained degradation of trichloroethylene (TCE)-contaminated gas by a phenolfed actinomycetes enrichment under aerobic conditions for 95 days at reactor TCE loadings of 27 and 72 mg L -1 d -1 with a 6-day solids retention time. The presence of TCE and phenol provided a selective pressure favoring the enrichment of actinomycetes over a TCE-degrading filamentous enrichment that was used to seed the reactor. The TCE transformation capacity of the actinomycetes enrichment in a batch test with phenol addition was 1.0 mg of TCE/mg of volatile suspended solids (VSS). This relatively high resistance to TCE metabolite toxicity resulted in sustained TCE degradation at a reactor transformation quantity (T q ) of 0.59 mg of TCE/mg of VSS wasted with a relatively high transformation yield (T y ) at 0.30 mg of TCE/ mg of phenol. Michaelis-Menten kinetic parameters for the actinomycetes enrichment were k TCE ) 0.15 d -1 and K S,TCE ) 0.14 mg/L for TCE and k P ) 10.2 d -1 and K S,P ) 0.34 mg/L for phenol. Phenol concentrations above 15 mg/L inhibited phenol degradation. Competitive inhibition between the growth substrate, phenol, and TCE was observed. The actinomycetes culture was capable of cis-DCE degradation.

Toluene biodegradation by Pseudomonas putida F1: targeting culture stability in long-term operation

“…Within these biological processes, bioscrubbers constitute a cost-effective bioreactor configuration, being more reliable in terms of construction and process control than conventional biofilters (Koutinas et al 2005). Bioscrubbers can be advantageous in processes operated at high pollutant loadings rates, where by-product accumulation is likely to occur, or during the degradation of chlorinated volatile organic contaminants, where medium acidification severely reduces process performance (Ensley and Kurisko 1994;Lee et al 2000).…”

Effect of Inhibitory Substances on <I>Microbiospora</I> Isolated from Soil under Cultivation of <I>Curcuma Longa</I> L.

“…The presence of trichloroethylene and phenol provided a selective pressure favouring the enrichment of actinomycetes over a TEC-degrading filamentous enrichment. Phenol concentration above15mg L −1 inhibited phenol degradation (Lee et al, 2000). Comparative inhibition between growth substrate, phenol and trichloroethylene was also observed by Lee et al (2000).…”

“…Phenol concentration above15mg L −1 inhibited phenol degradation (Lee et al, 2000). Comparative inhibition between growth substrate, phenol and trichloroethylene was also observed by Lee et al (2000).…”

“…Phenol concentration above 15 mg L −1 inhibited phenol degradation. Comparative inhibition between growth substrate, phenol and trichloroethylene was observed (Lee et al, 2000). Simultaneous degradation of P-nitrophenol and phenol by newly isolated Nocardiodes sp.…”

Removal of gaseous toluene using immobilized Candida tropicalis in a fluidized bed bioreactor

“…They can be advantageous in processes operated at high pollutant loading rates, where by-product accumulation is likely to occur, or during the degradation of chlorinated VOCs, where medium acidification severely reduces process performance (Lee et al 2000; Munoz et al 2007). Neal and Loehr (2000) demonstrated SGRs can achieve elimination capacities higher than biofilters for the treatment of toluene.…”