-
[show abstract]
[hide abstract]
ABSTRACT: A lab-scale internal circulation reactor (IC) fed by artificial brewery wastewater was operated with increasing volumetric loading rate under 35 degrees C continuously. The reactor performance and the relationship between microbial community structure and bioactivity in the anaerobic sludge were investigated during the operation. The COD removal efficiency was above 85%, furthermore, the maximum volumetric loading rate (VLR) and the maximum specific methanogenic activity (SMA) of the reactor could be up to 20 kg x (m3 x d)(-1) and 210 mL x (g x d)(-1) respectively. The results from the dehydrogenase and the bacteria DGGE experiments demonstrated that the dehydrogenase variation tendency was positively correlated to total light intensity of the whole bacteria DGGE bands for each sample. The total light intensity of the whole bacteria DGGE bands can use as a referential index for biomass liveweight in anaerobic system. Moreover, the coenzyme F420 content related to the relative abundance of Methanosaeta based on coenzyme F420 and archaebacteria DGGE analysis. As the volumetric loading rate increased, Methanomsaeta became significantly dominant, which was accompanied by the coenzyme F420 content increasing. The content could be up to 0.16 micromol x g(-1), meanwhile, the superiority of Methanosaeta became significantly obvious; UPGAMA analysis and Shannon index also confirmed the dynamic changes of microbial community structure during the operation.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 08/2012; 33(8):2715-22.
-
[show abstract]
[hide abstract]
ABSTRACT: Kinetics on degradation efficiency of medroxyprogesterone (MPA) by ozonation was investigated in this paper. And the operating parameters such as MPA initial concentration, ozone dosage, pH and radicals scavenger (HCO3-) were further discussed. Results showed that MPA could be degraded effectively by ozonation, with a first-order kinetics in continuous ozone aeration system and a second-order kinetics in semibatch ozone aeration system, when the initial concentrations of MPA were 3, 5, 10 mg x L(-1). The increases of pH and the addition of HCO3- would bring negative effects to the degradation of MPA. The degradation efficiency of MPA decreased from 89.8% to 54.8% with pH increase from 3.10 to 9.02, and the rate constant k decreased from 0.1463 L x (mg x min)(-1) to 0.049 5 L x (mg x min)(-1) and the degradation efficiency decreased 22.2 percentage points with the addition of HCO3-, in semibatch aeration system.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 04/2012; 33(4):1227-33.
-
[show abstract]
[hide abstract]
ABSTRACT: A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 09/2011; 32(9):2562-8.
-
[show abstract]
[hide abstract]
ABSTRACT: Pretreatment at different pHs was adopted in this study to enhance the substance solubilization and hydrogen production from kitchen wastes through anaerobic digestion. After a pretreatment set at pH = 13, solubilization of kitchen wastes improved substantially as the concentration of soluble carbohydrate, soluble protein, lipids and soluble chemical oxygen demand increased by 283.1%, 203.2%, 259.1% and 108.2%, respectively, as compared with those of the control. The maximum hydrogen production potential reached 105.38 mL/g VS after the pretreatment, which was 2.66 times that of the control. Furthermore, butyric acid and acetic acid were the major components in the total metabolites after fermentation, while propionic acid had a relatively low concentration. Finally, the concentration of exoprotein and exopolysaccharide within extracellular polymeric substances (EPS) kept increasing during the initial 14 and 9 hours, respectively, then decreased afterwards. However, the concentration of DNA increased throughout the whole stage. The total EPS might indirectly indicate the anaerobic digestion process. These findings may represent a feasible method for high-quality treatment of kitchen wastes.
Environmental Technology 01/2011; 32(1-2):119-25. · 1.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Degradation of algal toxin Microcystin-RR (MC-RR) by ozonation processes was investigated. The degradation rate of MC-RR reached 83.0% at ozone/MC-RR dosage of 6, and the degradation efficiency was decreased with increase of pH or NOM contents. Ozonation byproducts of MC-RR under different ozone dosages were detected by HPLC-MS to elucidate degradation mechanisms and pathways. The results showed that MC-RR degradation by attacking of ozone and hydrogen radicals mainly involved in substitution and cleavage of the Adda conjugated diene structure, cleavage of the peptide bond between Mdha and Ala. And Adda degradation pathway exerted a dominant position during the process.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 05/2010; 31(5):1239-45.
-
[show abstract]
[hide abstract]
ABSTRACT: In the present study, two Microsystins (MCs) of Microcystin-LR and Microcystin-RR were degraded with different dosages of ozone (O(3)). The possible degradation pathways were elucidated by analyzing their intermediates and end-products with liquid chromatography-mass spectrometry (LC-MS) method. The toxicity of the MCs ozonation products was also evaluated by assaying the protein phosphatase inhibition in vitro and acute toxicity in vivo. Results demonstrated that ozonation was a promising technology for removal and detoxification of the cyanotoxins. The MCs destruction was mainly involved in the attack of ozone on Adda side chain. First, the conjugated diene structure of Adda moiety was attacked by hydroxyl radical (OH()) to produce dihydroxylated products, then the hydroxylated 4-5 and/or 6-7 bond of Adda was cleaved into aldehyde or ketone peptide residues, and finally the residues were oxidized into the corresponding carboxylic acids. The fragmentation of the Mdha-Ala peptide bond of MCs also contributed positively to the oxidation process. Additionally, the attack on the benzene ring of Adda side chain was exclusively observed during MC-RR degradation. The toxicity evaluation of MCs ozonation products revealed that those end-products had no adverse effects in vivo and in vitro ozonation that could completely remove the MCs' toxicity.
Chemosphere 03/2010; 79(4):355-61. · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Degradation and byproducts of microcystin-LR (MC-LR) under different ozone dosages were investigated, and, the pathway and mechanism for the degradation of MC-LR were also elucidated according to the molecular weight of 8 degradation byproducts during ozonation process in this paper. The results showed that there were two pathways for the degradation of MC-LR by ozone. The first one is that the diene structure in Adda side chain was attacked and cleaved, which was named as Adda degradation pathway. The second one is that the pathway of Mdha and Ala degradation, which was that the peptide bond between Mdha and Ala was attacked and cleaved. Adda degradation pathway was dominant and mainly responsible for the degradation of MC-LR byozone. The removal of MC-LR by ozone could reach 92% when O3:MC is 6.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 11/2009; 30(11):3288-92.
-
[show abstract]
[hide abstract]
ABSTRACT: A process of highly stereoselective reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to ethyl (S)-4-chloro-3-hydroxybutanoate ((S)-CHBE) was established, using whole-cells of a fungus, Aureobasidium pullulans CGMCC1244. A high production yield was observed in a biphasic system composed of potassium phosphate buffer (0.1 M, pH 6.5) and dibutylphthalate. The influence of reaction parameters such as shaking speed, volumetric phase ratio, reaction temperature, biomass/substrate ratio and pH was tested. It was found that these parameters considerably influenced the molar conversion and the initial reaction rate, but had no significant effect on the optical purity of the product. Under the optimum conditions, the maximum concentration of (S)-CHBE in the organic layer, the molar conversion and the optical purity reached 56.8 g l−1, 94.5 and 97.7% enantiomeric excess (ee), respectively.
Process Biochemistry.
