[Show abstract][Hide abstract] ABSTRACT: China has been experiencing fast economic development in recent decades at the cost of serious environmental deterioration.
Wastewater discharge, especially municipal wastewater discharge, and non-point pollution sources are becoming the major water
pollution source and research focus. Great efforts have been made on water pollution control and a number of renovated technologies
and processes for municipal wastewater treatment and reclamation as well as non-point pollution control have been developed
and applied in China. This paper discusses the development and application of the appropriate technologies, including natural
treatment systems, anaerobic biological treatment, biofilm reactors and wastewater reclamation technologies, for water pollution
control in the country.
[Show abstract][Hide abstract] ABSTRACT: White rot fungi is capable of oxidizing many persistent organic pollutants including dyes. The application of the fungi has been limited for wastewater treatment under non-sterile conditions due to the contamination by bacteria and other micro-organisms. We developed a treatment approach by using immobilized white rot fungi Phanerochaete chrysosporium to degrade reactive dye K-2BP under non-sterile condition. Four different inert carriers were tested for immobilization of the white rot fungi with orthogonal experiments in comparison with suspension culture. The activity of manganese peroxidase (MnP) was used for the evaluation of oxidization performance in order to understand whether contamination of bacteria and other micro-organisms was suppressed. Under non-sterile conditions, the immobilized fungal cultures successfully restrained the growth of microzymes, coccies, and bacillus but suspension culture was highly contaminated with poor MnP activity. Under non-sterile conditions, higher MnP enzymatic activity (690U/L vs. 125U/L), higher decolorization efficiency (93.5% vs. 15%) and shorter reaction period (3 days vs. 6 days) were achieved in immobilized cultures in comparison with suspension culture. With the immobilized fungal cultures, no difference was observed under non-sterile and sterile conditions for the degradation of reactive dye K-2BP.
PROCESS BIOCHEMISTRY 09/2008; 43(9):937-944. · 2.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, together with two kinds of medium with different C/N ratios. Little lignin peroxidase (LiP) (< 2 U/L) was detected in free culture with nitrogen-limited medium (C/N ratio: 56/2.2, in mmol/L), while manganese peroxidase (MnP) maximum activity was 231 and 240 U/L in 50 and 100 ml medium culture, respectively. Immobilized culture with 50 ml nitrogen-limited medium gave the highest MnP and LiP production with the maximum values of 410 and 721 U/L separately on the day 5; however, flasks containing 100 ml nitrogen-limited medium only produced less MnP with a peak value of 290 U/L. Comparatively, carbon-limited medium (C/N ratio: 28/44, in mmol/L) was adopted in culture but produced little MnP and LiP. Medium type had the greatest impact on protease production. Large amount of protease was produced due to glucose limitation. Culture type and medium volume influence protease activity corporately by affecting oxygen supply. The results implied shallow immobilized culture was a possible way to gain high production of ligninolytic enzymes.
Journal of Environmental Sciences 02/2008; 20(1):94-100. · 1.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In order to explore ways for the application of white rot fungus in dye effluent treatment under non-sterile conditions, experiment
on decolorization of reactive brilliant red was carried out, employing nitrogen-limited and carbon-limited medium with C/N
ratio of 56/2.2 and 28/44 (in mmol/L), respectively. The results showed that the decolorization rate reached 92% while culturing
white rot fungus with nitrogen-limited medium; however, the decolorization process ended in carbon-limited medium (n(C)/n(N) = 28/44) because of bacterial contamination. In addition, pH rose up to 9.31 after 4 d of decolorization, which was caused
by bacterial contamination in the carbon-limited system. Therefore, it is concluded that nitrogen-limited medium can inhibit
bacterial growth to some extent while carbon-limited medium is more easily contaminated by bacteria. Nitrogen-limited medium
is more suitable in culture of white rot fungus for decolorization of reactive dye. Medium with the ability of inhibiting
yeast growth should be developed by adjusting other components of nitrogen-limited medium.
Science in China Series B Chemistry 09/2007; 50(5):718-724. · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Microcystins (MCs) are a group of closely related toxic cyclic heptapeptides produced by common cyanobacteria, which cause
lots of accidents and threatens human health. In this paper, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA)
was established and used to detect microcystin-LR (MC-LR) in drinking and surface waters. The concentration of coating antigen
was 5 μ/mL, the dilution of monoclonal antibody MC10E7 was 1:3 000, the dilution of enzyme tracer (goat anti-mouse IgG-peroxidase)
was 1:3 000, the standard concentration of MC-LR ranged from 0.001 μg/L to 30 μg/L, and o-phenylenediamine was used as substrate. The assay showed high relativity with high performance liquid chromatography (HPLC)
with a correlation coefficient of more than 99%. The relative standard deviation was less than 10%, the detection limit was
achieved down to 0.01 μg/L and up to 5.1 μg/L. The quantitative detection range was from 0.03 μg/L to 3 μg/L, and the antibody
had high specificity for [4-arginine] microcystins. It performed well in spite of the influence of the real samples.
Frontiers of Environmental Science & Engineering in China 07/2007; 1(3):329-333. · 0.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Membrane separation was employed in a novel photocatalytic oxidation slurry reactor to conserve catalyst. This paper reports some critical operational conditions of this reactor. While fine-bubble aeration served to suspend the catalyst, introducing an intermittent coarse bubbling under the membrane during operation was vital to counteract TiO2 catalyst entrapment on membrane surface. Circulation flow in the reactor was also found to have certain effect on counteracting the dropping out of catalyst. A submerged membrane module with a pore size of 0.1μm successfully conserved the powdered catalysts within the reactor after 2 days’ preluding filtration. As for pollutant removal, membrane filtration and circulation flow had no effect, whereas increase in gas holdup had. Running the reactor to treat model pollutant dissolved in tap water revealed that calcium carbonate both deactivated the catalyst and contributed to membrane fouling, suggesting that water hardness and alkalinity deserves appropriate treatment to warrant a good performance of such a reactor.
Separation and Purification Technology 06/2007; 55(2):165-172. · 3.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Biomass control techniques are very important for biofilters treating volatile organic compounds (VOCs) to enhance their long-term operation performance. In this study, four paralleled biofilters were set up treating toluene gas. The chemical removal of excess biomass and its impact on biofilter operation were investigated. The experimental results of circulating wash showed that the optimal washing time for biomass removal was 2 - 3 hours by NaOH ranging from 0.2% to 0.8%. Among the four experimental concentrations, the NaOH solution of 0.4% was more effective to remove the biomass from the biofilter and biomass shearing was the main process of the biomass removal under this circumstance. According to the comparison results of three washing mode, circulating washing was found to be the most suitable mode for biomass removal. The monitoring results of the toluene removal performance demonstrated that the impacts of NaOH solutions with different concentrations had little difference and the toluene removal capacities could be recovered after 3 - 4 days.
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.] 03/2007; 28(2):300-3.
[Show abstract][Hide abstract] ABSTRACT: Sludge reduction in a conventional activated sludge (CAS) process combined with a recycled sludge reactor where Tubifex tubifex (one of Oligochaeta) was inoculated was investigated in this study. The results showed sludge production could be reduced through T. tubifex's predation on sludge in the recycled sludge reactor. The sludge reduction rate of T. tubifex (R) was from 0.18 to 0.81 mg-VSS mg-Tubifex(-1) d(-1). The sludge reduction capacity of the recycled sludge reactor E was from 650 to 1080 mg-VSS L(-1) d(-1). The optimum density of T. tubifex was 2500 mg L(-1) and the optimum sludge recycled ratio was 1. The existence of T. tubifex did not affect COD and NH(4)(+)-N removals in the process, but led to a slight decrease in TP removal. SVI almost did not change when the T. tubifex density was lower than 3300 mg L(-1). The LC50 values on T. tubifex of copper and ammonia were 2.5 and 880 mg L(-1), respectively, both of which were higher than those on Aeolosoma hemprichi.
Journal of Biotechnology 02/2007; 127(3):443-51. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Spatial distributions of ammonia oxidizing bacteria (AOB) and nitrobacteria in a renovated suspended carrier biofilm reactor (SCBR) were investigated by using fluorescence in situ hybridization (FISH) with 16S rRNA oligonucleotide probes in combination with confocal laser scanning microscopy (CLSM). Three bench-scale structurally identical SCBR reactors were operated under different ratios of COD to NH4(+) -N in influents, 5, 10 and 15, respectively. Each SCBR reactor was consisted of a 6 L of aeration basin and a 2L of clarifier, with the hydraulic retention time (HRT) of 1.0h. The monitoring results showed that the thickness of biofilm in the SCBR was about 80 to 120 micron. Both the total amount of AOB and nitrobacteria decreased with depth in biofilm, most of the nitrification bacteria communities lied in the upper layer of biofilm, about 20 to 30 micron. The proportion of AOB to all bacteria in biofilm decreased when the ratio of COD to NH4(+) -N increased.
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.] 12/2006; 27(11):2358-62.
[Show abstract][Hide abstract] ABSTRACT: The resistance analyses for recirculated membrane bioreactor by the resistance-in-series model and the modified gel-polarization model respectively were extended to the turbulent ultrafiltration system. The experiments are carried out by dye wastewater in a tubular membrane module, it is found that the permeate fluxes are predicted very well by these models for turbinate systems. And the resistance caused by the concentration polarization is studied; the gel layer resistance is the most important of all the resistances.
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.] 12/2006; 27(11):2344-9.
[Show abstract][Hide abstract] ABSTRACT: Three bio-methods for sludge reduction including aerobic digestion, anaerobic digestion and predation by T. tubifex were investigated. The sludge reduction rates in 24h by predation of T. tubifex, anaerobic digestion and aerobic digestion were 0.13 mg x (mg x d)(-1), 0.09 mg x (mg x d)(-1) and 0.03 mg x (mg x d)(-1) respectively, when sludge concentration was 2500 mg x L(-1). T. tubifex could destroy the cell membrane of the bacteria in a short time, which could increase the sludge reduction rate when anaerobic digestion was adopted after the predation of T. tubifex. Using the T. tubifex to reduce sludge for 12h combined with anaerobic digestion for 36h could reduce sludge by 30%, and the sludge reduction rate was 0.25 mg x (mg x d)(-1). If the initial sludge concentration increased, the time of predation by T. tubifex should be extended.
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.] 12/2006; 27(11):2339-43.
[Show abstract][Hide abstract] ABSTRACT: To achieve a stable performance during long-term operation of biofiltration process, the effect and control of excess biomass accumulation should be investigated in detail. In this study, a biofilter treating gaseous toluene was operated continuously under different operating conditions for more than 270 days. Decrease in toluene removal efficiency and increase in pressure drops of the filter bed were simultaneously observed during the operation period due to excess biomass accumulation. The distributions of toluene concentration and gas pressure suggested that more biomass would accumulate in the inlet section. By carbon balance analysis, the variation of the biomass concentration in the biofilter was calculated. The variation of the biofilter performance and the biomass concentration demonstrated that 10,000 g C m−3 might be a critical biomass concentration for the biofilter to maintain a stable operation. An evaluation equation based on biomass growth kinetics was successfully established and used to estimate the stable-run time of a biofilter under different VOCs loadings. Bed mixing was found to be able to remove approximately 4000 g VSS m−3 of excess biomass and could also recover the performance of the biofilter.
[Show abstract][Hide abstract] ABSTRACT: Growth of white rot fungus in liquid medium with different trace element and effect of these medium on suppressing the growth of yeast under non-sterile were investigated in agitated Erlenmeyer flasks. Results showed that the size and amount of mycelium pellets in liquid medium with trace element and Fe 3.5 mg/L was more than that with trace element but no iron and without any trace element under sterile condition; moreover, the size and amount of mycelium pellets increased with the rise of the concentration of trace element and iron. In addition, if applying the mode of incubating under sterile condition and degrading under non-sterile condition, the decolorization of reactive brilliant red K-2BP in liquid medium without any trace element and with trace element but no iron was similar to that of degrading under sterile condition; but the decolorization in liquid medium with trace element and Fe 3.5 mg/L was less than the results under sterile condition. Through observing under microscope, it was found that the amount of yeast in liquid medium with Fe 3.5 mg/L was more than the medium without any trace element and with trace element but no iron. Therefore, trace element, especially iron, plays a very important role in suppressing yeast in liquid medium; furthermore, iron also is necessary to the growth of whit rot fungus. So that, to control the concentration of iron in liquid medium could reduce the invasion of yeast under non-sterile condition as long as it does influence the growth of white rot fungus.
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.] 09/2006; 27(8):1623-6.
[Show abstract][Hide abstract] ABSTRACT: Microcystins (MCs) are a group of closely related toxic cyclic heptapeptides produced by common cyanobacteria (blue-green algae), and microcystin-leucine-arginine (MC-LR) is among the most frequent and most toxic microcystin congeners. In this study, a free amino group was introduced to MC-LR at its seventh amino acid residue with 2-mercaptoethylamine, and the product aminoethyl-MC-LR was coupled to bovine serum albumin (BSA) and horseradish peroxidise (HRP) by glutaraldehyde to be complete antigen (MC-LR-BSA) and labelled hapten (MC-LR-HRP), respectively. Polyclonal antibodies against MC-LR were generated by immunization with MC-LR-BSA. A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was established to detect the MCs in waters, which showed a good cross-reactivity with MC-LR, MC-RR, MC-YR, MC-LF, MC-LW and nodularin, and have a detection limit for MC-LR 0.12 microg L(-1), the 50% inhibition concentration (IC50) for MC-LR was 0.63+/-0.06 microg L(-1) and the quantitative detection range was from 0.17 to 2.32 microg L(-1), the analysis result of water samples showed good recovery and reliability. So the comprehensive and reliable dc-ELISA will well potentially suit for sensitive analysis for total MCs in drinking as well as resource water samples.
[Show abstract][Hide abstract] ABSTRACT: In situ bioremediation is a safe and cost-effective technology for the cleanup of contaminated sites, but its remediation rate is usually very slow. This study attempted to accelerate the process of bioremediation by employing non-uniform electrokinetic transport processes to mix organic pollutants and degrading bacteria in soils under in situ conditions (namely, in situ bioelectrokinetic remediation) by use of an electrode matrix and a rotational operation mode. A bench-scale non-uniform electrokinetic system with periodic polarity-reversal was developed for this purpose, and tested by using a sandy loam spiked with phenol as a model organic pollutant. The results demonstrated that non-uniform electrokinetic processes could enhance the in situ biodegradation of phenol in the soil, the efficiency of which depended upon the operational mode of the electric field. Compared with the unidirectional operation and the bidirectional operation, the rotational operation could effectively stimulate the biodegradation of phenol in the soil if adopting appropriate time intervals of polarity-reversal and electrode matrixes. A reversal interval of 3.0 h and a square-shaped electrode matrix with four electrode couples appeared appropriate for the in situ biodegradation of phenol, at which a maximum phenol removal of 58% was achieved in 10d and the bioremediation rate was increased about five times as compared to that with no electric field applied. The results also showed that adopting a small polarity-reversal interval and an appropriate electrode array could produce a high and uniform removal of phenol from the soil. It is believed that in situ bioelectrokinetic remediation holds the potential for field application.
[Show abstract][Hide abstract] ABSTRACT: Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established to detect microcystin-LR in waters, with the concentration of the complete antigen was 5microg/mL, the dilution of the monoclonal antibody was 1:3,000, the dilution of the enzyme tracer (goat anti-rabbit IgG-peroxidase) was 1:3,000, the concentration range of microcystin-LR was between 0.001 approximately 30microg/L, and using o-phenylenediamine as substrate. The assay showed a high relativity of more than 99% with high performance liquid chromatography, a mean relative standard deviation less than 10% , a detection limitation under 0.01microg/L and quantitative detection range was 0.01 approximately 3microg/L, high specificity for [4-arginine] microcystin, and it could still perform well under the influence from the samples.
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.] 07/2006; 27(6):1166-70.