Journal of Environmental Sciences - Volume 17, issue 5

Authors: YANG, Shi-ying | CHEN, Ying-xu | LOU, Li-ping | WU, Xiao-na

Article Type: Research Article

Abstract: The effect of Cl^- on photocatalytic degradation (PCD) of pollutants is an important factor since it is ubiquitous in nature. In general, Cl^- showed an inhibition on photodegradation due to its scavenging HO^{&middot;} radicals. In this paper, experiments were carried out to examine the effects of Cl^- on the PCD of Methylene Blue (MB) and Orange II (Oll) in aqueous TiO_2 suspensions under UV light illumination. …It was found that low concentration of Cl^- (< 0.01 mol/L) showed little influence on both dyes, however, high concentration of Cl^- (> 0.10 mol/L) had a very different influence on the decolorization of dyes: a significant inhibition for MB but a great promotion for Oll. In the presence of 0.50 mol/L Cl^- , the rate decreased by 70% for MB while increased 7.5-fold for Oll. Furthermore, two bands in the ultraviolet region of Oll were rapidly broken down. The proposed mechanism was discussed in detail. Show more

Keywords: photocatalytic degradation, TiO_2, dye pollutants, chloride ion, mechanism

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 761-765, 2005

Authors: WEN, Yue-zhong | LIU, Wen-qi | FANG, Zhao-hua | LIU, Wei-ping

Article Type: Research Article

Abstract: Reactive Red 195, which is an azoic anionic dye characterized by the presence of five sulfonic groups and one azoic group, is efficiently removed using chitosan. The increasing chitosan dose had a dramatic positive impact on the achieved color removal, there was approximately a linear relationship between chitosan dose and color removal of dye before color removal reach maximum. Also, the increase of dye concentration led to the increase of chitosan dosage in order to get …the same color removal. 92 mg/L of chitosan dosage was sufficient to achieve complete remove of dye at initial concentration of dye at 200 mg/L. For the higher concentrations of dye, high dosages were necessary to reach complete color removal. On the other hand, the use of adsorption interferents (Fe^{2+} , Na^+ , HCO_3^- and others) can be interesting, addition of ions had effect on the color removal of Reactive Red 195. Comparing with blank, addition of chemical species approximately decreased the color removal except Na^+ and combination of Fe^{2+} + HCO_3^- . However, comparing with Fe^{2+} alone and HCO_3^- alone, combination of Fe^{2+} + HCO^-_3 increased the color removal. Show more

Keywords: chitosan, Reactive Red 195, dye, coagulation, color removal

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 766-769, 2005

Authors: GONG, Chun-ming | Inoue, Koichi | Inanaga, Shunji | Someya, Takashi

Article Type: Research Article

Abstract: Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157: H7 (E. Coli O157). We investigated pathogenic bacteria in compost collected from the compost facilities, and evaluated the survival of E. coli K12 and O157 in laboratory experiments. Out of 19 compost product samples, coliform bacteria and salmonella were detected in 7 and 3 samples respectively. The number of coliform bacteria was 1.8 × 10^2 …to 2.5 × 10^6 CFU/g dw and that of salmonella was 4.2 × 10^1 to 6.0 × 10^3 CFU/g dw. Moreover, coliform bacteria, fecal coliform, E. coli and salmonella were detected during composting at 54°C to 67°C. The results indicated that moisture content was a very important factor to the heat sensitivity of pathogenic bacteria in compost, E. coli in compost of high moisture content was more sensitive than that in compost of low moisture content, cells harvested in logarithmic phase was more sensitive than these in stationary phase, and E. coli K12 was more sensitive than E. coli O157. Based on the D values, the lethal time of E. coli K12 and O157 from 10^8 to 10^0 CFU/g dw were 16.3 and 28.8 min, respectively, at 60°C in compost with 40% moisture content. However, some E. coli cells survived in composting process at 54°C to 67°C. Water potential (low moisture content) and physiological aspects of bacteria (stationary phase) could explain only in part of the prolonged survival of E. coli in compost, and there should be some other factors that are conducive to bacterial survival in compost. Show more

Keywords: survival, pathogenic bacteria, compost, Escherichia coli, moisture

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 770-774, 2005

Authors: CHEN, Fei-zhou | XIE, Ping | TANG, Hui-juan | LIU, Hong

Article Type: Research Article

Abstract: Effects of Microcystis blooms on the crustacean plankton were studied using enclosure experiments during July–September, 2000. Eight enclosures were set in the hypereutrophic Donghu Lake. Different nutrient concentrations through additional nutrient and sediment in enclosures were expected to result in different abundance of Microcystis. From July to early August, the phytoplankton community was dominated by Chlorophyta, Cryptophyta, Bacillariophyta and Cyanophyta other than Microcystis aeruginosa. M. aeruginosa showed a rapid increase during early …August in all enclosures and predominated. Crustacean plankton was dominated by the herbivorous Moina micrura, Diaphanosoma brachyurum and Ceriodaphnia cornuta, and the predaceous Mesocyclops sp. and Thermocyclops taihokuensis. During the pre-bloom period, the dynamics of M. micrura population appeared to be mainly affected by the predaceous cyclopoids. With the development of Microcystis blooms, such interaction between M. micrura and cyclopoids seemed weakened, especially when the Microcystis biomass was high. But there was no apparent influence on the interaction between Leptodora kindti and its zooplanktonic prey. The density of two cyclopoids decreased with the enhancement of Microcystis. The density decline of M. micrura was caused by both predation and inhibition by Microcystis. The low food availability of other edible phytoplankton during the blooms led to low densities of both C. comuta and D. brachyurum by late August. lt appears that dense Microcystis blooms exert strong negative effects on the herbivorous cladocerans and the predaceous cyclopoids. Show more

Keywords: crustacean plankton, cladocerans, cyclopoids, food availability, Microcystis bloom

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 775-781, 2005

Authors: ZHANG, Wei-ming | CHEN, Jin-long | CHEN, Qun | HE, Min-yang-yang | PAN, Bing-cai | ZHANG, Quan-xing

Article Type: Research Article

Abstract: The adsorption behaviors of 1-naphthol, 1-naphthylamine and 1-naphthol/1-naphthylamine mixtures in water over two macroreticular adsorbents were investigated in single or binary batch systems at 293 K, 303 K and 313 K respectively. All the adsorption isotherms in the studied systems can be adequately fitted by Langmuir model. In the case of aminated macroreticular adsorbent NDA103, 1-naphthol is adsorbed to a larger extent than 1-naphthylamine; while, the opposite trend is found for nonpolar macroreticular …adsorbent NDA100. It is noteworthy that at higher temperature (303 K and 313 K), the total uptake amounts of 1-naphthol and 1-naphthylamine in all binary-component systems are obvious larger than the pure uptake amounts in single-component systems, which is presumably due to the cooperative effect primarily arisen from the hydrogen-bonding interaction between the loaded 1-naphthol and 1-naphthylamine molecules. The simultaneous adsorption systems were confirmed to be helpful to the selective adsorption towards 1-naphthol according to the larger selective index. Show more

Keywords: macroreticular adsorbent, adsorption, 1-naphthol, 1-naphthylamine, cooperative effect

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 782-785, 2005

Authors: OUYANG, Bin | FANG, Hao-jie | ZHU, Cheng-zhu | DONG, Wen-bo | HOU, Hui-qi

Article Type: Research Article

Abstract: The rate constants of reactions between the SO^{&middot;-}_4 radical and some common anions in atmospheric aqueous droplets e.g. Cl^- , NO_3^- , HSO_3^- and HCO_3^- were determined using the laser flash photolysis technique. Absorption spectra of SO^{&middot;-}_4 and the product radicals were also reported. The chloride ion was evaluated among all the anions to be the most efficient scavenger of …SO^{&middot;-}_4 . The results may supply useful information for a better understanding of the vigorous radical-initiated reactions in atmospheric aqueous droplets such as clouds, rains or fogs. Show more

Keywords: sulfate radical, common anions, atmospheric aqueous-phase chemistry, radical chemistry

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 786-788, 2005

Authors: ZHU, Ren-bin | SUN, Li-guang | ZHAO, San-ping | XIE, Zhou-qing | LIU, Xiao-dong | YIN, Xue-bin

Article Type: Research Article

Abstract: Methane flux from the omithogenic soils was preliminarily measured by closed chamber method on Xi-sha atoll, South China Sea during March 10 to April 11, 2003 for the first time. The CH_4 flux ranged from −226.7μg/(m^2 ·h) to 226.3μg/(m_2 ·h) at the observation sites on Dong Island. High atmospheric CH_4 consumption was observed from the ornithogenic soils on sunny days. CH_4 uptake rates showed …the highest value after the midday and they had a strong positive correlation with soil temperatures. Under the same weather conditions, the CH_4 fluxes were also observed from the intact and disturbed soils on Yongxing Island. Results showed that the intact soils with natural vegetation also showed high atmospheric CH_4 consumption and the average flux was −141.8μg/(m^2 ·h). However, disturbed soils via anthropogenic reclamation showed CH_4 emissions and the average flux was 441.7μg/(m_2 ·h). Therefore land use changes may have an important effect on the CH_4 fluxes from the tropical ornithogenic soils. In addition, different observation sites show a high spatial variation in CH_4 fluxes. The wetland in salt marsh showed the CH_4 emission on Dong Island, and the dry soil sites all showed high atmospheric CH_4 consumption, suggesting that CH_4 fluxes were predominantly controlled by soil water regime. The effects of soil chemical properties on CH_4 fluxes were also analyzed and discussed in this paper. Show more

Keywords: methane, flux, South China Sea, omithogenic soil, Xi-sha atoll

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 789-793, 2005

Authors: CUI, You-wei | PENG, Yong-zhen | GAN, Xiang-qing | YE, Liu | WANG, Ya-yi

Article Type: Research Article

Abstract: The principal aim of this paper is to develop an approach to realize stable biological nitrogen removal via nitrite under normal conditions. Validation of the new method was established on laboratory-scale experiments applying the sequencing batch reactor (SBR) activated sludge process to domestic wastewater with low C/N ratio. The addition of sodium chloride (NaCl) to influent was established to achieve nitrite build-up. The high nitrite accumulation, depending on the salinity in influent and the application …duration of salt, was obtained in SBRs treating saline wastewater. The maintenance results indicated that the real-time SBRs can maintain stable nitrite accumulation, but conversion from shorter nitrification-denitrification to full nitrification-denitrification was observed after some operation cycles in the other SBR with fixed-time control. The presented method is valuable to offer a solution to realize and to maintain nitrogen removal via nitrite under normal conditions. Show more

Keywords: nitrite accumulation, salt selective inhibition, real-time control of nitrification, biological nitrogen removal via nitrite, nitrite-oxidizers, ammonium-oxidizers

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 794-797, 2005

Authors: TIAN, Bing-hui | FAN, Bin | PENG, Xian-jia | LUAN, Zhao-kun

Article Type: Research Article

Abstract: In order to improve the flocculation efficiency of polydiallyldimethylammonium chloride (PDADMAC), high molecular weight PDADMAC should be prepared from high purity diallyldimethylammonium chloride (DADMAC) monomers. In this paper, a cleaner method with microwave irradiation and alkali solidification was proposed for preparing high pure DADMAC by selective heating under low temperature, and the prepared high purity DADMAC is characterized using FTIR and atomic absorption spectrometry. The new method provides a solution to the …key technical problem of PDADMAC synthesis. Comparing with the conventional methods, the results showed that the advantages of the novel synthesis include: (a) high purity DADMAC is improved from 57% to 71%; (b) reaction time of tertiary amine preparation is shortened from 6 h to 7 min; (c) water instead of acetone was used as reaction medium; (d) toxic by-products, wastewater and waste gas are eliminated. Flocculant made from the synthesized high purity DADMAC monomers was proved more efficient in flocculation tests. Show more

Keywords: diallyldimethylammonium chloride, microwave irradiation, flocculant, cleaner process

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 798-801, 2005

Authors: Akmal, Muhammad | WANG, Hai-zhen | WU, Jian-jun | XU, Jian-ming | XU, De-fu

Article Type: Research Article

Abstract: Heavy metal pollution has received increasing attention in recent years mainly because of the public awareness of environmental issues. In this study we have evaluated the effect of cadmium (Cd) on enzymes activity, substrate utilization pattern and diversity of microbial communities in soil spiked with 0, 20, 40, 60, 80, and 100 mg/kg Cd, during 60 d of incubation at 25°C. Enzyme activities determined at 0, 15, 30, 45, and 60 d after heavy metal application …(DAA) showed marked declines for various Cd treatments, and up to 60 DAA, 100 mg/kg Cd resulted in 50.1%, 47.4%, and 39.8% decreases in soil urease, acid phosphatase and dehydrogenase activities, respectively to control. At 60 DAA, substrate utilization pattern of soil microbial communities determined by inoculating Biolog ECO plates indicated that Cd addition had markedly inhibited the functional activity of soil microbial communities and multivariate analysis of sole carbon source utilization showed significantly different utilization patterns for 80 and 100 mg/kg Cd treatments. The structural diversity of soil microbial communities assessed by PCR-DGGE method at 60 DAA, illustrated that DGGE patterns in soil simplified with increasing Cd concentration, and clustering of DGGE profiles for various Cd treatments revealed that they had more than 50% difference with that of control. Show more

Keywords: enzyme activity, microbial community, soil, cadmium

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 802-807, 2005

Authors: LUO, Lin | LI, Wei-min | DENG, Yong-sen | WANG, Tao

Article Type: Research Article

Abstract: The standard three dimensional (3D) k-ε turbulence model was applied to simulate the flow field of a small scale combined oxidation ditch. The moving mesh approach was used to model the rotor of the ditch. Comparison of the computed and the measured data is acceptable. A vertical reverse flow zone in the ditch was found, and it played a very important role in the ditch flow behavior. The flow pattern in the ditch is discussed in …detail, and approaches are suggested to improve the hydrodynamic performance in the ditch. Show more

Keywords: oxidation ditch, 3D simulation, turbulence flow

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 808-812, 2005

Authors: DUO, Lian | GAO, Yu-bao | ZHAO, Shu-lan

Article Type: Research Article

Abstract: Seven kinds of heavy metal accumulation of rubbish compost in turfgrass by EDTA chelating were investigated. With EDTA application, heavy metal accumulation by two species of turfgrass was increased significantly. The enrichment coefficients of Lolium perenne L(L) and Festuca arundinacea L(F) to Cr reached 9.45 and 6.15 respectively. In the range of EDTA dosages given, heavy metal accumulation in turfgrass increased with increasing EDTA level. There were significant differences in remediation of different metals by …applying EDTA. L had high ability to accumulate Cr, Cd, Ni and Zn, showing better remediation to heavy metals of rubbish compost. In contrast, F showed high ability to accumulate Cr, Ni, Cu and Zn. Low EDTA level increased aboveground net primary production (ANP) of turfgrass, but EDTA would considerably inhibit it when EDTA was higher than 20 mmol/kg. The results demonstrated that the optimum dosage of EDTA for remediating heavy metals in rubbish compost by turfgrass was between 10 mmol/kg and 20 mmol/kg. Show more

Keywords: domestic rubbish compost, EDTA, turfgrass, heavy metal, accumulation

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 813-816, 2005

Authors: XU, Sheng-you | CHEN, Ying-xu | LIN, Qi | WU, Wei-xiang | XUE, Sheng-guo | SHEN, Chao-feng

Article Type: Research Article

Abstract: Phytoremediation has long been recognized as a cost-effective method for the removal of polycyclic aromatic hydrocarbons (PAHs) from soil. A study was conducted to investigate the uptake and accumulation of PAHs in root and shoot of Lolium perenne L. Pot experiments were conducted with series of concentrations of 3.31–378.37 mg/kg for phenanthrene and those of 4.22–365.38 mg/kg for pyrene in a greenhouse. The results showed that both ryegrass roots and shoots did take up PAHs from …spiked soils, and generally increased with increasing concentrations of PAH in soil. Bioconcentration factors (BCFs) of phenanthrene by shoots and roots were 0.24–4.25 and 0.17–2.12 for the same treatment. BCFs of pyrene by shoots were 0.20–1.5, except for 4.06 in 4.32 mg/kg treatment, much lower than BCFs of pyrene by roots (0.58–2.28). BCFs of phenanthrene and pyrene tended to decrease with increasing concentrations of phenanthrene and pyrene in soil. Direct uptake and accumulation of these compounds by Lolium perenne L. was very low compared with the other loss pathways, which meant that plant-promoted microbial biodegradation might be the main contribution to plant-enhanced removal of phenanthrene and pyrene in soil. However, the presence of Lolium perenne L. significantly enhanced the removal of phenanthrene and pyrene in spiked soil. At the end of 60 d experiment, the extractable concentrations of phenanthrene and pyrene were lower in planted soil than in non-planted soil, about 83.24%–91.98% of phenanthrene and 68.53%–84.10% of pyrene were removed from soils, respectively. The results indicated that the removal of PAHs in contaminated soils was a feasible approach by using Lolium perenne L. Show more

Keywords: phytoremediation, polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene, uptake and accumulation

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 817-822, 2005

Authors: LI, Li-jun | ZHANG, Feng | LIU, Xue-mei | GUO, Ya-ping | MA, En-bo

Article Type: Research Article

Abstract: The toxic effects of Cr(VI) on antioxidant enzymes of Oxya chinensis (Orthoptera: Acridoidae) were determined. Changes in the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GPx) were measured in O. chinensis insects injected with Cr(VI). Fifth-nymphs of O. chinensis insects were injected with Cr(VI) with different concentrations (0, 75, 150, 225, 300, 375, 450 mg/kg of body weight). The results showed that Cr(VI) led to the …change of SOD, CAT, and GPx activities at different concentrations, which revealed that: (1) The oxidative stress of SOD increased with the increase of Cr(VI) concentration. (2) With the increase of Cr(VI) concentrations, CAT activities for females increased at lower concentrations, but decreased at higher concentration range, which indicated that antioxidant system of O. chinensis was not influenced by the presence of Cr(VI). A very similar response to Cr(VI) effect for males indicated that Cr(VI) concentrations were not high enough to damage O. chinensis in terms of CAT. (3) The GPx activity for females increased in all treatments, which revealed that the damage power of Cr(VI) was increased with the increase of Cr(VI) concentrations in terms of GPx, but the effect was not so remarkable. There was not a consistent trend of GPx activities for males in all treatments of Cr(VI). Cr(VI)-induced changes in antioxidant enzymes were different for SOD, CAT and GPx, of which the tendency was that activities generally changed with increase of concentrations of Cr(VI) suggesting SOD, CAT, and GPx could serve as indices of oxidative stress to some extent. Show more

Keywords: Cr(VI), Oxya chinensis, oxidative stress, superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPx)

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 823-826, 2005

Authors: SU, Shi-jun | ZHU, Xiao-fan | LIU, Yong-jun | JIANG, Wen-ju | JIN, Yan

Article Type: Research Article

Abstract: MnO_2 in pyrolusite can react with SO_2 in flue gas and obtain by-product MnSO_4 ·H_2 O. A pilot scale jet bubbling reactor was applied in this work. Different factors affecting both SO_2 absorption efficiency and Mn^{2+} extraction rate have been investigated, these factors include temperature of inlet gas flue, ration of liquid/solid mass flow rate (L/S), pyrolusite grade, and SO_2 …concentration in the inlet flue gas. In the meantime, the procedure of purification of absorption liquid was also discussed. Experiment results indicated that the increase of temperature from 30 to 70 K caused the increase of SO_2 absorption efficiency from 81.4% to 91.2%. And when SO_2 concentration in the inlet flue gas increased from 500 to 3000 ppm, SO_2 absorption efficiency and Mn^{2+} extraction rate decreased from 98.1% to 82.2% and from 82.8% to 61.7%, respectively. The content of MnO_2 in pyrolusite had a neglectable effect on SO_2 absorption efficiency. Low L/S was good for both removal of SO_2 and Mn^{2+} extraction. The absorption liquid was filtrated and purified to remove Si, Mg, Ca, Fe, Al and heavy metals, last product MnSO_4 ·H_2 O was obtained which qualit could reach China GB1622-86, the industry grade standards. Show more

Keywords: wet FGD, jet bubbling reactor, SO_2, pyrolusite, manganese sulfate

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 827-831, 2005

Authors: LIAO, Min | CHEN, Cheng-li | HUANG, Chang-yong

Article Type: Research Article

Abstract: The microbial biomass, basal respiration and substrate utilization pattern in copper mining wasteland of red soil area, southern China, were investigated. The results indicated that soil microflora were obviously different compared with that of the non-mine soil. Microbial biomass and basal respiration were negatively affected by the elevated heavy metal levels. Two important microbial ecophysiological parameters, namely, the ratio of microbial biomass C(C_{mic} )/organic C(C_{org} ) and metabolic quotient (qCO_2 …) were closely correlated to heavy metal stress. There was a significant decrease in the C_{mic} /C_{org} ratio and an increase in the metabolic quotient with increasing metal concentration. Multivariate analysis of Biolog data for sole carbon source utilization pattern demonstrated that heavy metal pollution had a significant impact on microbial community structure and functional diversity. All the results showed that soil microbiological parameters had great potential to become the early sensitive, effective and liable indicators of the stresses or perturbations in soils of mining ecosystems. Show more

Keywords: reclaimed mining wasteland, soil microorganism, soil microbial diversity

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 832-837, 2005

Authors: Tsai, Yih-Jin | Kuo, Ming-Ching T.

Article Type: Research Article

Abstract: Compounds in the atmosphere contaminate samples of groundwater. An inexpensive and simple method for collecting groundwater samples is developed to prevent contamination when the background concentration of contaminants is high. This new design of groundwater sampling device involves a glass sampling bottle with a Teflon-lined valve at each end. A cleaned and dried sampling bottle was connected to a low flow-rate peristaltic pump with Teflon tubing and was filled with water. No headspace volume was remained …in the sampling bottle. The sample bottle was then packed in a PVC bag to prevent the target component from infiltrating into the water sample through the valves. In this study, groundwater was sampled at six wells using both the conventional method and the improved method. The analysis of trichlorofluoromethane (CFC-11) concentrations at these six wells indicates that all the groundwater samples obtained by the conventional sampling method were contaminated by CFC-11 from the atmosphere. The improved sampling method greatly eliminated theproblems of contamination, preservation and quantitative analysis of natural water. Show more

Keywords: groundwater sampling, improved method, conventional method, tritium, trichlorofluoromethane (CFC-11)

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 838-841, 2005

Authors: FAN, Yao-bo | YANG, Wen-bo | LI, Gang | WU, Lin-lin | WEI, Yuan-song

Article Type: Research Article

Abstract: A water quality model for water reuse was made by mathematics induction. The relationship among the reuse rate of treated wastewater (R), pollutant concentration of reused water (C_s ), pollutant concentration of influent (C_0 ), removal efficiency of pollutant in wastewater (E), and the standard of reuse water were discussed in this study. According to the experiment result of a toilet wastewater treatment and reuse with membrane bioreactors, R would be set at less …than 40%, on which all the concerned parameters could meet with the reuse water standards. To raise R of reuse water in the toilet, an important way was to improve color removal of the wastewater. Show more

Keywords: water quality model, reuse rate, wastewater treatment, water reuse

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 842-845, 2005

Authors: YU, Gang | YU, Qi | ZENG, Ke-si | ZHAI, Xiao-dong

Article Type: Research Article

Abstract: An experimental system of De-NO with plasma-catalyst (Cu zeolite) was established to investigate the differences between DeNO with plasma-catalyst and De-NO only with plasma, to provide the instruction for selecting appropriate catalyst and operating condition. The characteristics of De-NO with plasma and De-NO with plasma-catalyst were investigated comparatively by experiments. The experimental results show that De-NO with plasma-catalyst has high NO removal rate; Cu zeolite is an effective catalyst which can promote …NO removal rate in plasma remarkably; De-NO with plasma-catalyst should be operated at low temperature and the temperature has opposite effects on the function of catalyst and plasma; water vapor and O_2 can increase the NO removal rate. Show more

Keywords: nitrogen monoxide (NO), synergistic removal, non-thermal plasma, catalyst, De-NO

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 846-848, 2005

Authors: XU, Xin-hua | ZHOU, Hong-yi | ZHOU, Mi | WANG, Da-hui

Article Type: Research Article

Abstract: Over Pd/Fe bimetallic catalyst, o-nitrochlorobenzene (o-NCB), at a concentration of 20 mg/L in aqueous solutions, is rapidly converted to o-chloroaniline (o-CAN) first, and then quickly dechlorinated to aniline (AN) and Cl^- , without other intermediate reaction products. The aminated and dechlorinated reactions are believed to take place on the surface site of the Pd/Fe. The o-NCB removal efficiency and the next dechlorination rate increase with an increase of bulk loading of palladium and catalysts …addition due to the increase of both the surface loading of palladium and the total surface area. These results indicate that reduction, amination and dechlorination of o-NCB by palladium-catalyzed Fe^0 particles, can be designed for remediation of contaminated groundwater. Show more

Keywords: palladium-catalyzed Fe^0, amination, dechlornation, o-NCB

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 849-852, 2005

Authors: ZHAO, Wen-yu | WANG, Qi-shan | WU, Li-bo | ZHANG, Bin | WANG, Xiao-qin

Article Type: Research Article

Abstract: Yellow River water transfer for Tianjin is important in solving the water shortage in Tianjin, which facilitate economic development and social progress for many years. Fresh water drawn from Yellow River (i. e., Yin-Huang water) becomes saltier and saltier when being stored in the Bei-Da-Gang reservoir. We qualitatively analyze the water salinization mechanism based on mass transfer theory. The main factors are salinity transfer of saline soil, evaporation concentrating, and the agitation of wind. A simulative …experimental pond and an evaporation pond were built beside the Bei-Da-Gang reservoir to quantitatively investigate the water salinization based on water and solute balance in the simulative pond. 80% of increased [Cl^- ] is due to the salinity transfer of the saline soil and the other 20% is due to evaporation concentrating, so the former is the most important factor. We found that the salinization of Yin-Huang water can be described with a zero-dimension linear model. Show more

Keywords: Yin-Huang-Ji-Jin Project, water salinization, simulative experiment, saline soil, evaporation concentrating, mass transfer, mathematical model

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 853-856, 2005

Authors: ZHANG, Ke-cun | QU, Jian-jun | ZU, Rui-ping | FANG, Hai-yan

Article Type: Research Article

Abstract: The purpose of this present study is to investigate the frequency and variation of sandstorm in Minqin Oasis. Using daily observational data of sandstorm and other meteorologic data from 1954 to 2000, we have illuminated the relationship between sandstorm, meteorological parameters and human activities. The results of the analysis show that the highest frequency of sandstorms occurrence and their duration mainly focus on March, April and May, especially in April. Most of sandstorms occur from midday …to nightfall, but relative few appear from midnight to forenoon, which apparently correlates to the daily variations of atmospheric thermal stability within atmospheric boundary layer. Monthly mean and annual mean duration of sandstorms coincide well with the frequencies of sandstorm occurrence. Show more

Keywords: Minqin Oasis, sandstorm, environmental characteristics

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 857-860, 2005

Authors: ZHOU, De-min | RADKE, John | TIAN, Yong-qian | XU, Jian-chun | MU, Lan

Article Type: Research Article

Abstract: A research method was presented for spatially quantifying and allocating the potential activity of a fine particle matter emission (PM_{2.5} ), which originated from residential wood burning (RWB) in this study. Demographic, hypsographic, climatic and topographic data were compiled and processed within a geographic information system (GIS), and as independent variables put into a linear regression model for describing spatial distribution of the potential activity of residential wood burning as primary …heating source. In order to improve the estimation, the classifications of urban, suburban and rural were redefined to meet the specifications of this application. Also, several definitions of forest accessibility were tested for estimation. The results suggested that the potential activity of RWB was mostly determined by elevation of a location, forest accessibility, urban/non-urban position, climatic conditions and several demographic variables. The linear regression model could explain approximately 86% of the variation of surveyed potential activity of RWB. The analysis results were validated by employing survey data collected mainly from a WebGIS based phone interview over the study area in central California. Based on lots free public GIS data, the model provided an easy and ideal tool for geographic researchers, environmental planners and administrators to understand where and how much PM_{2.5} emission from RWB was contributed to air quality. With this knowledge they could identify regions of concern, and better plan mitigation strategies to improve air quality. Furthermore, it allows for future adjustment on some parameters as the spatial analysis method is implemented in the different regions or various eco-social models. Show more

Keywords: residential wood burning (RWB), PM_{2.5}, demographical characteristies, Geographic information system (GIS), stepwise linear regression

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 861-865, 2005

Authors: CAI, Yue-wei | CHEN, Xiao-yong

Article Type: Research Article

Abstract: Our previous studies indicated that genotypes at locus Sod-1 of Poa annua changed clinally along a gradient of gaseous organic pollution. In the present study, we aimed to know whether there were differential responses of activities of different superoxide dismutase (SOD) genotypes to short-term treatment of ambient gaseous organic pollution. Significant bias from Hardy-Weinberg equibrium was observed on locus Sod-1, and no genotype Sod-1-BB was found. Significantly increased activities were observed in most treatments …for genotype Sod-1-AA and in one treatment for genotype Sob-1-AB. However, no significant difference in SOD activities was found between the two genotypes. It was interpreted that fitness difference between the two genotypes was small and treatment duration was too short or extent of ambient organic pollution was too low to lead to differential responses. Other environmental factor effects on activities of superoxide dismutases can also explain the results. Show more

Keywords: superoxide dismutase, genotype, activity, gaseous organic pollution, Poa annua

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 866-868, 2005

Authors: Mohammed, Abdul K. | McKenzie, Katrina T.

Article Type: Research Article

Abstract: Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are: Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such …as NO_3^- and SO^{2-}_4 . Chemical oxygen demand (COD) measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions required long degradation time. Show more

Keywords: titanium dioxide, photocatalysis, photocatalytic degradation, azo dyes

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 869-872, 2005

Authors: CHEN, Yuan-cai | LAN, Hui-xia | ZHAN, Huai-yu | FU, Shi-yu

Article Type: Research Article

Abstract: The successful application of co-immobilized aerobic-anaerobic biomaes under limited aeration in wastewater treatment systems would eliminate the problems associated with the intermediates mono-chlorophenol (MCP) and di-chlorophenol (DCP) accumulations. With low initial pentachlorophenol (PCP) concentration, all PCP could be completely removed under oxygen-limited strict anaerobic conditions, and the removal efficiencies with different initial haedspace oxygen percentage (IHOP) were not obviously different from each other. While at high initial PCP concentration, under strictly anaerobic …conditions PCP and their intermediates were clearly higher than that under other conditions, and produced obvious accumulation, the highest PCP reduction was achieved by the system receiving 30 IHOP, oxygen-limited system also exhibited lower residual TOC concentration and lower concentration of metabolic intermediates MCP and DCP. These results suggested that under strictly anaerobic condition the reductive dechlorination of low chlorinated compounde became rate limiting in the reductive dechlorination pathway, less chlorinated compounds be more amenable to aerobic degradation, and the aerobes of outer layers could function under limited oxygen. The co-immobilized aerobic-anaerobic biomass for methanogeneeis under limited-aeration for chlorophenol degradation might be an attractive and efficient altemative for the sequential anaerobic/aerobic system to achieve mineralization of a broad range of recalcitrance highly chlorinated organics and low final TOC concentrations. Show more

Keywords: PCP, oxygen-limited, immobilized cellr

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 873-875, 2005

Authors: ZHANG, Xu-xiang | WAN, Yu-qiu | CHENG, Shu-pei | SUN, Shi-lei | ZHU, Cheng-jun | LI, Wei-xin | ZHANG, Xiao-chun | WANG, Gui-lin | LU, Jian-hua | LUO, Xiang | GU, Ji-dong

Article Type: Research Article

Abstract: The biodegradation and toxicity of the purified terephthalic acid (PTA) processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process (CASP). Sludge loading rate (SLR) for Fhhh to COD of the wastewater was 1.09 d^{-1} and to PTA in the wastewater was 0.29 d^{-1} . The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC_{50} (median lethal …concentration) to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were 5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper. Show more

Keywords: fusant strain, purified terephthalic acid, wastewater, biodegradation, toxicity, software

Citation: Journal of Environmental Sciences, vol. 17, no. 5, pp. 876-880, 2005