ABSTRACT
A bench scale system integrating a non-thermal plasma (NTP) unit with a biotricking filtration (BTF) unit for the treatment of gases containing hydrogen sulfide (H2S) was investigated. The additional use of the biotrickling filter to NTP reactor not only leads to the enhancement of hydrogen sulfide removal efficiency up from 83.4% to 90.1%, but also eliminates gas-phase intermediate products from NTP degradation of H2S to produce sulfate and H2O. The dynamic changes of microbial community in BTF influenced by ozone from NTP were assessed by PCR-DGGE. Results show that the microbial community was affected by ozone. After the integration, a part of microorganisms disappeared, and meanwhile some new microorganisms appeared. The microbial community structure in BTF changed from eight bands to nine bands; three bands which have the functions of desulfurization disappeared and four bands which have the functions of desulfurization appeared; five bands which have the functions of desulfurization and sulfate reduction were unchanged. The bacterial groups in the BTF unit of NTP-BTF system include Uncultured Thiobacillus sp., Acidithiobacillus thiooxidans strain dfI, Uncultured Thiobacillus sp., Uncultured Acidiphilium sp., Uncultured Xanthomonadaceae bacterium clone SBLE6C12, Uncultured 8-Proteobacterium and Paracraurococcus sp. 1PNM-27.
Subject(s)
Bioreactors , Hydrogen Sulfide/chemistry , Plasma Gases/chemistry , Bacteria/classification , Bacteria/metabolism , Biodegradation, Environmental , Filtration , Ozone/chemistry , Sulfates/chemistryABSTRACT
The performance of a bio-trickling filter (BTF) for treatment of phenol, a model pollutant, was presented. Influences of factors on phenol removal efficiency were studied. The BTF exhibited a high removal efficiency for phenol. The experimental results showed that the phenol efficiency reached 99.5% and kept 98% in the long-term run. The optimal residence time, pH value and spray density were 20.6 s, 7.0 and 1.67 m(3) x (m(2) x h)(-1), respectively. The microbial community structures in the bio-trickling filter for phenol removal were assessed by PCR-DGGE. Based on the 16S rDNA sequence data,results showed that the predominant bacteria for degradation of phenol were Polaromonas sp., Acinetobacter sp., Acidovorax sp., Veillonella parvula and Corynebacterium sp., GC-MS was used to detect component of BTF's outlet gases and pyruvic acid (CH3COCOOH) was found as one kind of intermediates of phenol degradation. Then one possible biodegradation pathway of phenol was inferred.
Subject(s)
Bacteria/metabolism , Filtration/methods , Phenols/chemistry , Bacteria/classification , Biodegradation, Environmental , Gases/chemistry , RNA, Ribosomal, 16S/geneticsABSTRACT
It can produce a large number of free radicals in O3/H2O2, system, ozone and free radical coupling oxidation can improve the styrene removal efficiency. Styrene oxidation by O3/H2O2 was investigated. Ozone dosage, residence time, H2o2 volume fraction, spray density and molar ratio of O3/C8H8 on styrene removal were evaluated. The experimental results showed that styrene removal efficiency achieved 85.7%. The optimal residence time, H2O2, volume fraction, spray density and O3/C8H8 molar ratio were 20. 6 s, 10% , 1.72 m3.(m2.h)-1 and 0.46, respectively. The gas-phase degradation intermediate products were benzaldehyde(C6H5CHO) and benzoic acid (C6H5 COOH) , which were identified by means of gas chromatography-mass spectrometry(GC-MS). The degradation mechanism of styrene is presented.
