[2, 4, 6-Trichlorophenol Mineralization Promoted by Anaerobic Reductive Dechlorination of Acclimated Sludge and Extracellular Respiration Dechlorination Pathway].

In anaerobic conditions, the acclimation of activated sludge was studied with sodium lactate as the electron donor and 2,4,6-trichlorophenol as the electron acceptor. Metabolic characteristics of dechlorination were the focus of this study. The result showed highly efficient dechlorination on 2, 4, 6-trichlorophenol that the conversion rate reached to 100% in 9 - 24 h when initial concentrations of sodium lactate and 2,4, 6-trichlorophenol were 20 mmol x L(-1) and 40 - 80 µmol x L(-1), respectively. The intermediate product 2,4-dichlorophenol was found in low concentration (< 4.22 µmol x L(-1)). And 4-chlorophenol and phenol were the main products. Ortho chlorophenol (2, 4, 6-trichlorophenol, 2, 4-dichlorophenol) can be converted rapidly by acclimated sludge, while the further conversion of 4-chlorophenol and phenol was limited. The residues of anaerobic metabolism were degraded by aerobic sludge, among which 4-chlorophenol (initial concentration of 33 mol x L(-1)) removal rate was up to 100% under aerobic conditions. The acclimated bacteria can rapidly transfer Fe(III) and humus (AQDS) into reductive Fe(II) and AQH2DS which indicated that the dissimilatory iron reducing bacteria was enriched in the acclimated sludge. The electron mediator [Fe(III) and AQDS] significantly accelerated the dechlorination rate. The acclimated sludge could perform extracellular respiration dechlorination with electron mediators.

[Analysis of dynamic characteristics for fermentative hydrogen-producing bacteria community and hydrogen producing capability in CSTR].

The start into the types of fermentation was carried out by pH adjustment from 4.2 to 6.0 in CSTR system. The process of transforming of hydrogen production and dynamic community of bacteria were studied. The results showed that with the organic load maintained at (33 +/- 1) kg/(m3 x d), there was no change in 10 d for the type of fermentation, the amount of hydrogen does not reduce in 8 d. After 15 d, the system was transformed from the ethanol-based type into butyric acid type and water alkalinity was from 250 mg/L to 2450 mg/L. The use of fluorescence in situ hybridization (FISH) system was in response to the 3 groups of micro-organisms. It was found that in the process of transforming, Clostridium cluster XI increases and Clostridium cluster I and II decreases. Enterobacteriaceae always existed with no change. The microbial growth must be considered with hydrogen production capability. The average hydrogen production rate reached to 23.6 mol/(kg x d) with Clostridium cluster I and II dominated in fermentation reactor.

[Competitive adsorption between bromine and bromate on activated carbon and impact on bromate formation].

Regularity of adsorption removal for bromine and bromate in water has been tested by three different activated carbon. It is demonstrated that in single adsorbent solution adsorption removal rates for bromine and bromate is 69% and 88%, respectively. As for double adsorbent solution, the removal rate of bromine decreased to 10% and of bromate is higher than 60%. The competitive adsorption between NOM and bormate is due to surface area and pore size distribution etc. The pore size distribution for AC-400 favors NOM adsorption process but hinders bromate adsorption. In low concentration solution(c(e) < 72 mg x L(-1)) NOM is absorbed with high rate, while in the solution with the concentration between 72 mg x L(-1) and 211 mg x L(-1), AC-150 is effective in removing NOM. Furthermore, ammonia concentration and pH level has impact on bromate removal rate in water. The optimal conditions for bromate removal are determined by ammonia concentration less than 200 microg/L and low pH in water.

[Effects of terminal products on hydrogen production by ethanol hydrogen-producing microflora].

The effects of terminal products on hydrogen production were conducted in continuously stirred tank reactor (CSTR) by the acclimated ethanol hydrogen-producing bacteria. Glucose was added as carbon source and different ambient pH was carried out by buffer solution. High ethanol production was simultaneously achieved with high hydrogen production. The addition of 40 mol/L ethanol or acetic acid can result in the reduction of hydrogen production, the former was 34% and the latter was 84.3%. The ethanol fermentation formation for mixed microflora was attributed to the natural selection.

[Community of activated sludge based on different targeted sequence of 16S rDNA by denaturing gradient gel electrophoresis].

In order to realize effect of different sets of universal primers on the analysis of microbial community of activated sludge based on targeted sequence of 16S rDNA and employ effectively denaturing gradient gel electrophoresis (DGGE), activated sludge were obtained from the continuous stirred tank reactor (CSTR), 16S rDNA fragments were amplified with there primer sets (341f/534r, 968f/1401r and 341f/926r), and the diversity and dynamics of microbial communities were investigated by DGGE. The results indicated that community diversity and dynamics was obviously different based different sets of universal primers by DGGE. Separated patterns of the targeted sequence of primer 341f/534r and 968f/1401r were better than of 341f/926r. The similarity of communities between S2 and S3 was high in the DGGE profiles with primer 341f/534r and 341f/926r, the similarity of communities between S1 and S2 was high in the DGGE profiles with primer 968f/1 401r, it demonstrated that the similarity and dynamics of communities was different each other based different sets of universal primers. In the DGGE profiles, bands and diversity from primer 341f/534r were most, bands and diversity from primer 341f/926r were least. Thereby, while activated sludge was analyzed by DGGE, primers 341f/534r and 968f/1401r were more effective than 341f/926r.