| With the continuous development of modern chemical industry, a large number of toxic organic compounds which is difficult to degrade were discharged in the natural environment. For example, chlorophenols had brought great harm to the ecological environment. Therefore, the means of phenols degradation was a concerned problem. Anaerobic biodegradation was a kind of economically and effectively method. To discussed the degradation of 2,4,6-trichlorophenols by means of acclimation anaerobic sludge. It’s also contained high-throughput sequencing which combined with experiment results. Its actual applicated for further removed mechanism of chlorine and accelerated the reductive dechlorination method. The following results were obtained in this paper.The results showed that it used sodium lactate as electron donor. Anaerobic sludge would be acclimated in a closed container. It could be proved that the domestication process can enrich the anaerobic bacteria and the sludge had the characteristics of rapid reduction and removed chlorine. Besides, acclimated sludge had higher removal efficiency of ortho chlorine, and it showed obvious substrate specificity. It’s showed that the intermediate production of 2,4,6-trichlorophenols were 2,4-DCP、4-CP、phenol. Because of the output of less 2,4-DCP, there could be exist 2 metabolic pathways: The presence of 2,4,6-TCP inferred while removing two ortho chlorine passing. Meanwhile, in this way 2,4,6-TCP may occur simultaneously produce 2,4-DCP, and 2,4-DCP dechlorinates to generate 4-CP.Observing the scanning electron microscope, it was found that the increase of the spherical bacteria in the sludge during the acclimation. High through-put sequencing showed a large number of production of hydrogen producing bacteria during the acclimation. The production of hydrogen producing bacteria could improve the efficiency of anaerobic biological treatment system, indicated the existence of this bacteria which had important significance for the removal of chlorine. Although the production of hydrogen producing acetic acid bacteria didn’t have the function of removing chlorine, but it could be symbiotic with the symbiotic bacteria, and played the role of hydrogen releasing bacteria. In addition, a large number of desulfurization bacteria were found in the analysis of domestication and this bacteria had been considered to have the function of removing chlorine, which was great significance to understanding of the phenomenon about chlorine removal.The effect of electron acceptor on the anaerobic degradation of anaerobic sludge was investigated by shaking flask test. The results showed that sulfate could inhibit microbial degradation of chlorophenols, and the higher sulfate concentrations, inhibition of 2,4,6-TCP was more obvious. And inhibit concentration is 5m M. Nitrate inhibited microbial inhibition of 2,4,6-TCP obviously, the higher nitrate concentration, the higher the nitrate reduction activity was. When adding 1m M nitrate, the process of sludge significantly inhibited dechlorination of 2,4,6-TCP.Used Hungate technique to study various factors about acclimated sludge dechlorination effect. After experiment, the acclimated sludge’s ability of reductive dechlorination can be enhanced under the condition of existing electron donors. When sodium formate, sodium acetate, sodium lactate or glucose as an electron donor of acclimated anaerobic sludge, the degradation efficiency were: sodium lactate > sodium acetate > sodium formate≥glucose. When sodium lactate and glucose are equal in the number of the offered electron in theory, the degradation efficiency is approximately equal.The effect of Eh and p H on the removal of chlorine from activated sludge was investigated by shaking flask experiment, and the results showed that O2 could inhibit the process of removing chlorine. The range of Eh was-150~-220 m V. p H 7.5-8 in microbial enzyme activity was the highest and the best degradation effect during the whole process. |
PDF Full Text Request