Biodegradability of some nitrogenous heterocyclic compounds and co-degradation with phenol by denitrifiers in anoxic sludge reactor

Abstract

Phenol and nitrogenous heterocyclic compounds (NHCs) are typical organic pollutants in coal gasification wastewater which are difficult to deal with. Unlike phenol, the stable molecular structure of NHCs make them nearly impossible to degrade under aerobic or anaerobic condition. In this paper, biodegradation of phenol and NHCs as carbon sources for denitrification was studied in a laboratory-scale anoxic reactor. Denitrifiers could degrade 490 mg/L phenol and 321.5 mg/L NO3(-)-N within 12 hours with removal efficiencies of 99.8% and 99.6%, respectively. The inhibition of pyridine on the microbes could be reduced by adding phenol into influent and the experimental results showed that pyridine could be degraded as the sole carbon source with the maximum organic loading rate of 4.38 mg/(g MLSS·h) (MLSS: mixed liquor suspended solids). When phenol was included as a growth substrate, the degradation performance of quinoline and pyrrole was improved due to co-degradation, and removal rate of NHCs increased according with increment of phenol in influent.

Aerobic Biodegradation of Quinoline Under Denitrifying Conditions in a Membrane-Aerated Biofilm Reactor

“…As nosZ is generally more sensitive to changes of environmental conditions compared to other denitrifying genes, nosZ has been reported to more severely inhibited by aromatic compounds (Gao et al, 2019;Li et al, 2021). The addition of phenol from P8 relieved the inhibitory effect of quinoline on norB and nosZ, likely due to the enhanced denitrifying activities by utilizing phenol as carbon source, since phenol was more easily degradable compared to quinoline (Wang et al, 2015b). Furthermore, the increasing phenol loading resulted in over one-third reduction in quinoline degradation rates from 12.9 g/(m 2 ⋅d) (Day 184) to 8.6 g/(m 2 ⋅d) (Day 210).…”

Development of an LC-MS method for determination of nitrogen-containing heterocycles using mixed-mode liquid chromatography

“…Many NCHs are mutagenic, carcinogenic, and thus, hazards to the environment and human health [19], e.g., pyridine is toxic for several bacterial species and a strong odor compound [20]. It can cause weakness, lung and liver damage, and gastrointestinal inflammation in humans by acute exposure [15].…”

“…To abate NCHs, different methods can be utilized [12,15,19]. Ozonation is one of the methods that is extensively used to eliminate NCHs, whether in wastewater [12] or process studies [26,27].…”