sodium-acetate--anhydrous and 2-4-6-trichlorophenol

A test was conducted to examine the degradation effect and reductive dechlorination pathway of 2, 4, 6-trichlorophenol (2,4,6-TCP) in the presence of different electron donors, such as glucose, sodium lactate, sodium pyruvate and sodium acetate. The results showed that, compared with the effect of glucose, sodium lactate, sodium pyruvate and sodium acetate enhanced the dechlorination of 2, 4, 6-TCP effectively, among which sodium lactate could serve as a kind of hydrogen release compound, and the electrons required for reductive dechlorination were released in a sustained way. Substrate metabolism dehydrogenase activity was improved by the external electron donor; after reaction for 240 h, the activity of dehydrogenase was increased in the four electron donor systems, by 21.49%, 25.78%, 136.85% and 139.3%, respectively. The main reductive dechlorination products of 2,4,6-TCP included 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP) and phenol; when sodium acetate was used as the electron donor, 4-CP was the main degradation product, and the transformation ratio from 2,4,6-TCP to 4-CP was more than 22%.

Topics: Biodegradation, Environmental; Chlorophenols; Electron Transport; Electrons; Halogenation; Sodium Acetate; Waste Disposal, Fluid; Wastewater

In this study, the possibility to use acetate-fed aerobic granular sludge for the degradation of low chlorinated 4-mono-chlorophenol (4CP) and highly chlorinated 2,4,6-tri- chlorophenol (TCP) was investigated. A Granulated Sequencing Batch Reactor (GSBR) was used to carry out the experiments, with acetate as growth substrate. 4CP concentration in the influent ranged between 0 and 50 mg/l, while TCP concentration varied between 0 and 15 mg/l. Different operating conditions were applied in order to obtain the complete aerobic degradation of 4CP. For TCP degradation, anaerobic feeding and control of dissolved oxygen concentration in the bulk liquid were used to keep the granules core under anaerobic conditions due to diffusion limitations: the possibility to obtain TCP reductive dechlorination under aerated conditions was thus investigated. Differences in granules shape and size were observed with 4CP and TCP dosed in the influent, and the effects of such toxic compounds on acetate removal were evaluated.Aerobic granules grown on acetate as carbon source proved to be an interesting solution for the degradation of 4CP, showing good resistance to high 4CP concentrations in the influent even if unacclimated. The presence of TCP did not irreversibly inhibit biomass activity, and complete TCP degradation was achieved after acclimation.

Topics: Aerobiosis; Bioreactors; Chlorophenols; Sewage; Sodium Acetate; Time Factors; Water Pollutants, Chemical