Journal of Environmental Sciences - Volume 18, issue 3

Authors: XIAO, Qin | ZHANG, Shi-cui | HU, Jia-hui | XU, Yu-yan

Article Type: Research Article

Keywords: motility, nonylphenol, rosy barb, sperm, ultrastructure

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 417-419, 2006

Authors: TIAN, Yu | ZHENG, Lei | SUN, De-zhi

Article Type: Research Article

Abstract: Extracellular polymeric substances (EPS) are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles …on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future. Show more

Keywords: activated sludge, environmental interest, extracellular polymeric substances (EPS)

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 420-427, 2006

Authors: GAO, Da-wen | WEN, Xiang-hua | QIAN, Yi

Article Type: Research Article

Abstract: Almost all the studies both domestic and international using white rot fungus for dye wastewater treatment are performed under sterile conditions. However, it is obviously unpractical that wastewater with dyes is treated under sterile conditions. A feasible study was made for using white rot fungus Phanerochaete chrysosporium to degrade reactive brilliant red K-2BP dye under non-sterile conditions. The results showed that there was no decolorizing effect under non-sterile condition if white rot fungus was incubated under …non-sterile condition, and the decolorization was always near to 0% during decolorizing test for 3 d; in the meantime, a lot of yeast funguses were found in liquid medium when white rot fungus was incubated under non-sterile conditions; however, if white rot fungus was incubated under sterile condition firstly, its decolorization was above 90% under non-sterile condition, which was similar to that of sterile condition. So we point out that the treating process for wastewater with dyes should be divided into two stages. The first stage is that white rot fungus should be incubated under sterile conditions, and the second stage is that reactive brilliant red K-2BP is decolorized under non-sterile conditions. The method not only save the operation cost which decolorizing reactive brilliant red K-2BP under sterile condition, but also provide the feasibility for using white rot fungus to degrade wastewater with dyes under non-sterile conditions. Show more

Keywords: white rot fungus, Phanerochaete chrysosporium, reactive brilliant red K-2BP, decolorization, non-sterile condition

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 428-432, 2006

Authors: XIA, Si-qing | LIU, Hong-bo

Article Type: Research Article

Abstract: Three parallel anaerobic-anoxic/anaerobic-aerobic (AN/AO) processes were developed to enrich denitrifying phosphorus removal bacteria (DPB) for low strength wastewater treatment. The main body of the parallel AN/AO process consists of an AN(anaerobic-anoxic) process and an AO (anaerobic-aerobic) process. In the AO process, the common phosphorus accumulating organisms (PAOs) was dominate, while in the AN process, DPB was dominate. The volume of anaerobic zone (V_{ana} ):anoxic zone (V_{ano} ): aerobic zone (V_{aer} …) for the parallel AN/AO process is 1:1:1 in contrast with a V_{ana} :V_{aer} and V_{ano} :V_{aer} of 1:2 and 1:4 for a traditional biological nutrient removal process (BNR). Process 3 excels in the 3 processes on the basis of COD, TN and TP removal. For 4 month operation, the effluent COD concentration of process 3 did not exceed 60 mg/L; the effluent TN concentration of process 3 was lower than 15 mg/L; and the effluent TP concentration of process 3 was lower than 1 mg/L. Show more

Keywords: parallel AN/AO process, denitrifying phosphorus removing bacteria (DPB), low strength wastewater, biological nutrient removal (BNR)

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 433-438, 2006

Authors: WANG, Zhi-wei | WU, Zhi-chao | GU, Guo-wei | YU, Guo-ping | MA, Lu-ming

Article Type: Research Article

Abstract: Simultaneous nitrification and denitrification (SND) effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids (MLSS) 19–20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor (MBR) and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2–0.3 mg/L. The main mechanisms …governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate (PFS) addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances (EPS) of mixed liquor. Show more

Keywords: membrane bioreactor (MBR), flat-sheet membrane, simultaneous nitrification and denitrifiction (SND), phosphor removal, wastewater treatment, oxygen transfer rate

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 439-445, 2006

Authors: ALAM, Md. Zahangir | MUYIBI, Suleyman A. | MANSOR, Mariatul F. | WAHID, Radziah

Article Type: Research Article

Abstract: The study was attempted to produce activated carbons from palm oil mill effluent (POME) sludge. The adsorption capacity of the activated carbons produced was evaluated in aqueous solution of phenol. Two types of activation were followed, namely, thermal activation at 300, 500 and 800°C, and physical activation at 150°C (boiling treatment). A control (raw POME sludge) was used to compare the adsorption capacity of the activated carbons produced. The results indicated that the activation temperature of …800°C showed maximum absorption capacity by the activated carbon (POME 800) in aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon of POME 800. It was observed that the adsorption capacity was higher at lower values of pH (2–3) and higher value of initial concentration of phenol (200–300 mg/L). The equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms. The adsorption of phenol onto the activated carbon POME 800 was studied in terms of pseudo- first and second order kinetics to predict the rate constant and equilibrium capacity with the effect of initial phenol concentrations. The rate of adsorption was found to be better correlation for the pseudo-second order kinetics compared to the first order kinetics. Show more

Keywords: activated carbon, adsorption, palm oil mill effluent (POME) sludge, phenol

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 446-452, 2006

Authors: LIU, Hai-long | WANG, Dong-sheng | SHI, Bao-you | WANG, Min | TANG, Hong-xiao

Article Type: Research Article

Abstract: Ozone plays an important role as a disinfectant and oxidant in potable water treatment practice and is increasingly being used as a pre-oxidant before coagulation. The purpose of this study is to obtain insight into the mechanisms that are operative in pre-ozonized coagulation. Effects ofpre-ozonation on organic matter removal during coagulation with IPF-PACl were investigated by using PDA (photometric disperse analysis), apparent molecular weight distribution and chemical fractionation. The dynamic formation of flocs …during coagulation process was detected. Changes of aquatic organic matter (AOM) structure resulted from the influence of pre-ozonation were evaluated. Results show that dosage of O_3 and characteristics of AOM are two of the major factors influencing the performance of O_3 on coagulation. No significant coagulation-aid effect of O_3 was observed for all experiments using either AlCl_3 or PACl. On the contrary, with the application of pre-ozonation, the coagulation efficiency of AlCl_3 was significantly deteriorated,reflected by the retardation of floc formation, and the removal decreases of turbidity, DOC, and UV_{254} . However, if PACl was used instead of AlCl_3 , the adverse effects of pre-ozonation were mitigated obviously, particularly when the O_3 dosage was less than 0.69 (mg O_3 /mg TOC). The difference between removals of UV_{254} and DOC indicated that pre-ozonation greatly changed the molecular structure of AOM, but its capability of mineralization was not remarkable. Only 5% or so DOC was removed by pre-ozonation at 0.6–0.8 mg/L alone. Fractionation results showed that the organic products of pre-ozonation exhibited lower molecular weight and more hydrophilicity, which impaired the removal of DOC in the following coagulation process. Show more

Keywords: natural organic matter (NOM), fractionation, pre-ozonation, PACl, coagulation

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 453-458, 2006

Authors: XING, Mei-yan | DENG, Can | Godefroid, Bukuru | , Jian | YANG,

Article Type: Research Article

Abstract: The advanced treatment using integrated Fenton's reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB (upflow anaerobic sludge bed) and a SBR (sequencing batch reactor) process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry (GC-MS), mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton's reaction was conducted at pH=3.0, …H_2 O_2 /COD_{Cr} =0.27, H_2 O_2 /Fe^{2+} =3:1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater. Show more

Keywords: pharmaceutical wastewater, GC-MS, recalcitrant compounds, Fenton's reaction, coagulation process, advanced wastewater treatment

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 459-463, 2006

Authors: JIN, Jian | ZHAO, Wei-rong | XU, Xin-hua | HAO, Zhi-wei | LIU, Yong | HE, Ping | ZHOU, Mi

Article Type: Research Article

Abstract: Steel manufacturing byproducts and commercial iron powders were tested in the treatment of Ni^{2+} -contaminated water. Ni^{2+} is a priority pollutant of some soils and groundwater. The use of zero-valent iron, which can reduce Ni^{2+} to its neural form appears to be an alternative approach for the remediation of Ni^{2+} -contaminated sites. Our experimental data show that the removal efficiencies of Ni^{2+} were 95.15% …and 94.68% at a metal to solution ratio of 20 g/L for commercial iron powders and the steel manufacturing byproducts in 60 min at room temperature, respectively. The removal efficiency reached 98.20% when the metal to solution ratio was 40 g/L for commercial iron powders. Furthermore, we found that the removal efficiency was also largely affected by other factors such as the pHs of the treated water, the length of time for the metal to be in contact with the Ni^{2+} -contaminated water, initial concentrations of metal solutions, particle sizes and the amount of iron powders. Surprisingly, the reaction temperature appeared to have little effect on the removal efficiency. Our study opens the way to further optimize the reaction conditions of in situ remediation of Ni^{2+} or other heavy metals on contaminated sites. Show more

Keywords: zero-valent iron, reduction, remediation, Ni^{2+}

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 464-467, 2006

Authors: XIAO, Xiang | LIAO, Ling | ZHANG, Xin-hua

Article Type: Research Article

Abstract: Constructed stormwater infiltration basins have been broad applied in urban areas in terms of stormwater disposal and compensation of reduced groundwater recharge. However, stormwater derived from sediments accumulating in infiltration beds may act as a source of dissolved contaminants for groundwater. Concentrations of DO, NO_3^- -N, NO_2^- -N, NH_4^+ -N and pO_4^{3-} -P were monitored at multiple depth with time. The results showed that the occurrence of denitrificarion …was restrained by sediments in term of no invertebrates. Under the conditions of invertebrates inoculated, the concentrations of DO, NO_3^- -N, NO_2^- -N, NH_4^+ -N and PO_4^{3-} -P varied respectively with time and the occurrence of nitrification and mobilizing nitrate in the sediment. It is concluded that there exist the invertebrate activities such as building tubes and galleries and excreting faecal pellet which may increase water dispersion and enhance accessibility of nutrient, and stimulate microbial process effected in the sediment. Besides, the natural death and rot of worms were also found to be important factors of the invertebrate activities. Show more

Keywords: infiltration basins, urban stormwater, polluted sediments, invertebrates, effects

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 468-474, 2006

Authors: WANG, Jing-li | ZHANG, Yuan-hang | SHAO, Min | LIU, Xu-lin | ZENG, Li-min | CHENG, Cong-lan | XU, Xiao-feng

Article Type: Research Article

Abstract: The pollution of particulate matter less than 2.5μm (PM2.5) is a serious environmental problem in Beijing. The annual average concentration of PM2.5 in 2001 from seasonal monitor results was more than 6 times that of the U.S. national ambient air quality standards proposed by U.S. EPA. The major contributors to mass of PM2.5 were organics, crustal elements and sulfate. The chemical composition of PM2.5 varied largely with season, but was similar at different monitor stations in …the same season. The fine particles (PM2.5) cause atrnospheric visibility deterioration through light extinction. The mass concentrations of PM2.5 were anti-correlated to the visibility, the best fits between atmospheric visibility and the mass concentrations of PM2.5 were somehow different: power in spring, exponential in summer, logarithmic in autumn, power or exponential in winter. As in each season the meteorological parameters such as air temperature and relative humidity change from day to day, probably the reason of above correlations between PM2.5 and visibility obtained at different seasons come from the differences in chemical compositions of PM2.5. Show more

Keywords: PM2.5, atmospheric urban aerosol, air pollution, meteorological factor, visibility

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 475-481, 2006

Authors: WANG, Huan-hua | LI, Lian-qing | WU, Xin-min | PAN, Gen-xing

Article Type: Research Article

Abstract: Soil samples from 4 defined city zones of Nanjing were randomly collected at 0–5 cm and 5–20 cm intervals and size fractions of soil particles were separated from undisturbed bulk soils by low energy dispersion procedure. The total contents of Cu and Pb in the different particle size fractions of the urban soils were analyzed by HNO_3 -HF-HC1O_4 digestion and flame atomic absorption spectrophotometer determination. The total content of Cu and …Pb in soil particle size fractions varied with their size and with city zones as well. Both the content and variation with the size fractions of Pb was bigger than of Cu supporting our previous finding that there was Pb pollution to different degrees in the urban soils although the two elements were generally enriched in clay-sized fraction. Contaminated Pb tended to be preferentially enriched in the size fraction of 2000–250μm and clay-sized fraction. While the size fractions of the soils from newly developed and preserved area contained smaller amount of Cu and Pb, the partitioning of them in coarse and fine particle size fractions were insignificant compared to that from inner residence and commercial area. The very high Pb level over 150 mg/kg of the fine particle fractions from the soils of the inner city could be a cause of high blood Pb level reported of children from the city as acute exposure to Pb of fine particles of the urban soil might occur by soil ingestion and inhalation by young children. Thus, much attention should be paid to the partitioning of toxic metals in fine soil particles of the urban soils and countermeasures against high health risk of Pb exposure by soil ingestion and dust inhalation should be practiced against the health problem of blood Pb for young children from the cities. Show more

Keywords: urban soil, city zone, soil contamination, particle size fraction, heavy metals, lead, health risk

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 482-487, 2006

Authors: DONG, Yun-she | QI, Yu-chun | LIU, Ji-yuan | Domroes, Manfred | LIU, Li-xin | GENG, Yuan-bo | LIU, Xing-ren | YANG, Xiao-hong | LI, Ming-feng

Article Type: Research Article

Abstract: Using the static opaque chamber method, the soil respiration rates (SR) were measured through the continuous experiments in situ in semiarid Stipa grandis steppe in Xilin River Basin of Inner Mongolia, China from June 2001 to June 2003, in parallel, the difference between the SR and the ecosystem respiration rates (TER) were compared. The results indicated that the seasonal variations of the SR and TER were obvious with higher emissions in growing season and a relatively …low efflux level in non-growing season, furthermore, the negative effluxes were found in the observation site in winter; the annual CO_2 efflux of total ecosystem ranged from 160.5 gC/(m^2 ·a) to 162.8 gC/(m^2 ·a) and that of soil ranged from 118.7 gC(m^2 ·a) to 152.3 gC/(m^2 ·a). The annual SR accounted for about 74.0% to 93.5% of the annual TER but the results of Analysis of Variance (ANOVA) indicated that the difference between the annual average TER and SR did not reach the significance level of 0.05. The TER was under similar environmental controls as SR, in growing seasons of drought years, the variations of soil moisture at 0–10 cm and 10–20 cm depth could account for 79.1%–95.6% of the changes of the SR and TER, but in non-growing season, more than 75% of the variations of the SR and TER could be explained by the changes of the ground temperature of soil surface layers. Show more

Keywords: Inner Mongolia, semiarid grassland, Stipa grandis steppe, CO_2 fluxes, environmental factors

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 488-494, 2006

Authors: GUAN, Dong-sheng | Peart, M.R.

Article Type: Research Article

Abstract: Levels of Cu, Ni, Zn, Pb and Cr were measured in soils and trees in urban Guangzhou, China. Tree and soil samples were collected from the roadside, urban parks and a university campus. Mean concentrations of Cu, Ni, Zn, Pb and Cr in tree leaves were 28.3, 7.7, 142.1, 23.4, and 195.1 mg/kg respectively. In a comparison of heavy metal concentrations in tree leaves between roads and park locations, only Pb concentrations were significantly higher in the former. …Heavy metal concentrations were lower in the roots compared to leaves. It indicated that heavy metal pollution of trees is mainly from air pollution. For all top soil samples the mean concentrations of Cu, Ni, Zn, Pb and Cr were 24.3, 17.3, 121.5, 63.9 and 88.7 mg/kg, respectively. Heavy metal concentrations in roadside soils were higher and their coefficient of variation was higher than those in urban parks. Comparing heavy metal concentrations in trees and soil between urban Guangzhou and Hainan Island, China, Cu, Ni, Zn, Pb and Cr levels in soils and plants in urban Guangzhou were evidently affected by the human impact. However the heavy metal content in the soil compared to some international standards do not give cause for concern. Some observations on the implications of the data for environmental monitoring are made. Show more

Keywords: heavy metals, roadside, parks, plants, soil

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 495-502, 2006

Authors: YAO, Huai-ying | LIU, Yue-yan | XUE, Dong | HUANG, Chang-yong

Article Type: Research Article

Abstract: The phospholipid fatty acid (PLFA) composition was analyzed in two red soils experimentally contaminated with copper at different concentrations. The total amounts ofphospholipid fatty acids (PLFAs) in both red soils were significantly correlated with soil microbial biomass C and N, which decreased consistently with increasing levels of copper. The relative quantities of the PLFAs 17:0 (10 Me), i16:0, il5:0 and 16:1 w5c, decreased with increasing heavy metal concentration, while those of cy 17:0, which is an …indicator of gram-negative bacteria, increased. The Shannon index calculated from the PLFA data indicated that Cu addition in the red soils decreased the population diversity of soil microbial communities. Multivariate analysis of PLFA data demonstrated that high levels of Cu application had a significant impact on microbial community structure and there is a threshold metal concentration for PLFA composition. Comparatively higher toxic effect on microbial biomass and community structure were found in the red sandy soil than those in the red clayey soil. The differential effect of Cu addition on microbial communities in the two soils may be due to differences in soil texture and cation exchange capacity. Show more

Keywords: copper, phospholipid fatty acid, microbial biomass, red soil

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 503-509, 2006

Authors: LIAO, Min | XIE, Xiao-mei

Article Type: Research Article

Abstract: The degradative characteristics ofphenanthrene, microbial biomass carbon, plate counts of heterotrophic bacteria and most probable number (MPN) of phenanthrene degraders in non-rhizosphere or rhizosphere soils with uninoculating or inoculating phenanthrene degraders were measured. At the initial concentration of 20 mg phenanthrene/kg soil, the half-lives of phenanthrene in uninoculated non-rhizosphere soil, uninoculated rhizosphere soil, inoculated non-rhizosphere soil, and inoculated rhizosphere soil were measured to be 81.5, 47.8, 15.1 and 6.4 d, respectively, and …corresponding kinetic data fitted first-order kinetics. The highest degradation rate of phenanthrene was observed in inoculated rhizosphere soil. The degradative characteristics of phenanthrene were closely related to the effects of vegetation on soil microbial process. Vegetation could enhance the magnitude ofrhizosphere microbial communities, microbial biomass content, and heterotrophic bacterial community, but barely influence those community components responsible for phenanthrene degradation. Results suggested that combination of vegetation and inoculation with degrading microorganisms of target organic contaminants was a better pathway to enhance degradation of the organic contaminants in soil. Show more

Keywords: phenanthrene, bioremediation, degradation

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 510-513, 2006

Authors: ZHU, Cheng-jun | CHENG, Shu-pei | ZHANG, Xu-xiang | LANG, You-zhe | SUN, Shi-lei | GU, Ji-dong | ZHAO, Da-yong | PAN, Wen-yang | YU, Hong-xia

Article Type: Research Article

Abstract: The purified terephthalic acid (PTA) petrochemical wastewater molecular toxicity detected by use of Mouse Genome 430A 2.0 GeneChip was conducted in this research. The toxic dose to male mice was 0.03 g/(kg·d) of PTA in the wastewater. The mice liver total RNA was isolated as the temple for synthesis of cDNA and then the cDNA as the temple for synthesis of cRNA. Hybridizing the cRNA with the target genes on the gene chip, there were 232 …genes expression levels up-regulated and 74 genes down-regulated discovered obviously. The foremost 40 genes for both the highest and the lowest expression levels involved endogenetic steroid and hormone metabolism, immune system, the leukocyte activity and inflammation, detoxification in liver, reproduction and growth hormone, regulation immune factors of anti-tumor and anti-infection and cancer to the mice sampled. The data suggest the PTA wastewater contained over 5 aromatics and their toxicities integrated were much higher than the pure chemical PTA. And the pure chemical PTA toxicities data cannot be used to evaluate the toxicity of the PTA wastewater instead. Show more

Keywords: gene chip, PTA wastewater, male mice, molecular toxicity, predication of security

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 514-518, 2006

Authors: ZHAO, Bing | LIU, Zheng-tao | XU, Zhang-fa

Article Type: Research Article

Abstract: Both pentachlorophenol and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) had been studied widely because of their probable anti-estrogenic activity. Sodium pentachlorophenol (PCP-Na), as a industrial product used in many fields, usually contains a trace of TCDD. The aim of this study was to assess the anti-estrogenic effect of PCP-Na in juvenile goldfish (Carassius auratus) hepatocyte cultures using vitellogenin (VTG) as the biomarker. The ID_{50} of PCP-Na was investigated and then a series of concentrations …(0.001–0.5μg/ml) of PCP-Na were evaluated to estimate the anti-estrogenic activity. Results showed that PCP-Na was cytotoxic for hepatocytes even at very low concentration <1.21μg/ml, and it could not induce VTG at any concentrations tested. Since it failed to stimulate VTG production, the possibility of its anti-estrogenic effect was tested, and a well-known anti-estrogenic compound-tamoxifen was used as positive control. PCP-Na caused a reduction in VTG synthesis in juvenile goldfish (Carassius auratus) hepatocytes at concentrations >0.1μg/ml when co-exposure with 1μg/ml 17β-estradiol (E2), making its anti-estrogenic activity approximately as potent as tamoxifen. Our results indicate that PCP-Na can act as negative modulators of estrogenic function in juvenile goldfish (Carassius auratus) hepatocytes. Show more

Keywords: PCP-Na, vitellogenin, juvenile goldfish, hepatocytes, anti-estrogenic activity

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 519-524, 2006

Authors: LI, Ping | LIU, De-li | NAHIMANA, Liberat | CHEN, Shu-li | YANG, Xi | ZHAO, Li

Article Type: Research Article

Abstract: Three new bacteria HS-03, HS-043 and HS-047 isolated from different ecosystems were found capable of aerobic denitrification. The potential application of these strains in wastewater treatment under aerobic conditions was investigated. These three bacteria all presented high nitrogen removal from wastewater that more than 98% of 10 mmol/L nitrate could be removed in 12–24 h by adding cheap external carbon source and low concentration of iron as well as molybdate. The mechanism at molecular level was …analyzed. The success of this aerobic denitrification applied to wastewater treatment may serve as an alternative to enhance the practical nitrogen removal from wastewater. Main biochemical and physiological features of these strains were characterized. The16S rDNA sequences were compared with the published data in GenBank by using BLAST. The results of phenotype and genotype proved that strain HS-03 and HS-047 belonged to Pseudomonas stutzeri and Pseudomonas pseudoalcaligenes respectively. Strain HS-043 was identified as Delftia acidovorans of which denitrifying activity has not previously been explored. Show more

Keywords: high nitrogen removal, aerobic denitrification, wastewater treatment, identification

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 525-529, 2006

Authors: ZHENG, Jun-fang | LIU, Gui-rong | LIU, Shu-lin

Article Type: Research Article

Abstract: Previous research reveals that the genome structures of rhizobial type strains and reference strains can reflect their phylogenetic relationships. In order to further explore the potential application of genome structure as a phylogenetic marker in rhizobial natural taxonomy, this study analyzed the genome structures of 29 unclassified nodule bacteria isolated from the root nodules of leguminous trees, Robinia sp., Dalbergia spp., and A lbizia spp. and 7 rhizobial reference strains by I-CeuI cleavage, then clustered these …bacteria phylogenetically based on their genome structures and compared these clusters with those based on numerical taxonomy and 16S rDNA PCR-RFLP. Eleven phylogenetic clusters were obtained. The clusters were in large part consistent with those based on numerical taxonomy and 16S rDNA PCR-RFLP. Also there are inconsistent clusters based on the above three methods. But results are completely consistent with 16S rRNA clusters. This suggested that the genome structure clustering method can be used to fastly identify root nodule isolates and detect their phylogenetic relationships. The credibility and repeatability of the results, together with the simplicity and possibility to analyze a large number of strains in a short time of the method, indicates the broad potential application of genome structure as phylogenetic marker to categorize rhizobial isolates and should in the future facilitate biodiversity studies. Show more

Keywords: rhizobia, genome structure, phylogenetic analysis, pulsed field gel electrophoresis, I-CeuI

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 530-536, 2006

Authors: WU, Gen-fu | WU, Xue-chang | XUAN, Xiao-dong | ZHOU, Xue-ping

Article Type: Research Article

Abstract: There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named "nitrogen fixing bacterial growth potential" (NFBGP) test, which is based on pre-culturing ofautochthonous (target) microorganisms was described. The method was applied to evaluate …phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential (AGP) test and the bacterial regrowth potential (BRP) test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment. Show more

Keywords: environment monitoring, nitrogen fixing bacterium, limiting nutrient, phosphorus, growth potential

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 537-542, 2006

Authors: WANG, You | TANG, Xue-xi | YANG, Zhen | YU, Zhi-ming

Article Type: Research Article

Abstract: We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as Alteromonas espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and …to find the possibly effective mechanism. Results showed that: (1) The blades of L. japonica exhibited symptoms of lesion, bleaching and deterioration when infected by the bacterium, and their growth and photosynthesis were dramatically suppressed. At the same time, the reactive oxygen species (ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The contents of malonaldehyde (MDA) and free fatty acid in the microsomol membrane greatly elevated, but the phospholipid content decreased. Result suggested an obvious peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activities demonstrated that superoxide dismutase (SOD) and catalase (CAT) increased greatly when infected by the bacterium, but glutathione peroxidase (Gpx) and ascorbate peroxidase (APX) did not exhibit active responses to the bacterium throughout the experiment. (3) The histomorphological observations gave a distinctive evidence of the severity of the lesions as well as the relative abundance in the bacterial population on the blades after infection. The bacterium firstly invaded into the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L. japonica. Show more

Keywords: Laminaria japonica, alginic acid decomposing bacterial, infection, growth, mechanism

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 543-551, 2006

Authors: JIANG, Xiao-dong | WANG, Gui-zhong | LI, Shao-jing

Article Type: Research Article

Abstract: Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The potential effects of two organochlorine pesticides, hexchloriobinzene (HCH) and dichlorodiphenyltrichloroethane (DDT), on the recruitment of Acartia pacifica nauplii from benthic resting eggs in the seabed of Xiamen Bay were experimentally investigated. The abundance of A. pacifica nauplii hatched from the sediment significantly decreased with the increase of pesticide …concentration. Trimmed Spearman-Karber analysis gave sediment 96-h LC_{50} values were 84.81 ng/g for HCH, and 157.94 ng/g for DDT. The median AI (AI_{50} ) was −0.77, which suggested that the combined effect of HCH and DDT showed a weak effect than individual effects. There was a positive relationship between mortality and exposure time in DDT treatment, while the relationship was not significant in HCH treatment. The results suggest that organochlorine pesticides can reduce recruitment of A. pacifica nauplii from benthic resting eggs to planktonic population. Show more

Keywords: organochlorine pesticide, resting egg, recruitment, A cartia pacifica

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 552-556, 2006

Authors: LIU, Shou-xin | SUN, Cheng-lin

Article Type: Research Article

Abstract: Preparation ofphotocatalytic regenerationable activated carbon (AC) is the key step for the practical application of in situ regeneration of exhausted AC. A novel photocatalytic regenerationable AC was prepared by sol-gel TiO_2 in this work. The adsorption and regeneration performance of TiO_2 /AC were evaluated using phenol as model compound. Scanning electron microscope (SEM) and nitrogen (77 K) adsorption isotherm were used to determine the surface area, pore structure and the …distribution of TiO_2 . The results showed that with the increase of TiO_2 loading, adsorption capacity of TiO_2 /AC decreased and the regeneration efficiency increased. The photocatalytic regenerationable AC with suitable TiO_2 loading (2 wt%) exhibited suitable adsorption capacity and regeneration efficiency. TiO_2 located mainly in the entrance of macro-pore of carbon. The prepared TiO_2 /AC exhibited similar surface structure and pore structure with material carbon. Show more

Keywords: photocatalytic regenerationable, activated carbon, titanium dioxide

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 557-561, 2006

Authors: WANG, Yu-ping | WANG, Lian-jun | PENG, Pan-ying

Article Type: Research Article

Abstract: TiO_2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO_2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO_2 particles can be effectively suppressed by added polyethylene glycol (PEG) as a surface modifier. The average particle diameter of TiO_2 , specific surface area and absorbability of catalyst can be modified. Based on characteristics of the …TiO_2 photocatalyst with XRD, specific surface area, adsorption valves of methylene blue and the amount of TiO_2 supported on the activated carbon, the photocatalytic degradation of L-acid was studied. The effect of the factors, such as pH of the solution, the initial concentration of L-acid on the photocatalytic degradation of L-acid, were studied also. It was found that when the pH of the solution is 1.95, the amount ofphotocatalyst is 0.5 g, the concentration of the L-acid solution is 1.34 × 10^{-3} mol/L and the illumination time is 7 h, the photocatalytic degradation efficiency of L-acid can reach 89.88%. The catalyst was reused 6 times and its degradation efficiency hardly changed. Show more

Keywords: L-acid, activated carbon, supported TiO_2, photodegradation

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 562-566, 2006

Authors: ZHOU, Chun-qiong | DENG, Xian-he | PAN, Zhao-qun

Article Type: Research Article

Abstract: Absorption and catalytic oxidation of nitric oxide can be achieved by using cobalt(III) ethylenediamine (Co(en)_3^{3+} ). When simultaneous absorbing SO_2 and NO, the precipitation of CoO_2 (SO_3 )_3 will be yielded and the NO removal will be decreased. A new catalyst system using Co(eh)_3^{3+} coupled with urea has been developed to simultaneous remove NO and SO_2 in the flue gas. NO is …absorbed and catalytically oxidized to nitrite and nitrate by Co(en)_3^{3+} . The dissolved oxygen in scrubbing solution from the feed stream acts as oxidant. Urea restrains the precipitation of CoO_2 (SO_3 )_3 by oxidizing SO_3^{2-} to SO_4^{2-} as CoSO_4 is more soluble in water. The experimental results proved that nearly all SO_3^{2-} can be oxidized to SO_4^{2-} and the high NO and SO_2 removal could be obtained with the new system. The NO removal is influenced by gas flow rate, the concentration of Co(en)_3^{3+} and urea in the absorption solution, the temperature of the scrubbing solution and the content of oxygen in the flue gas. The low gas flow rate is favorable to increase the NO removal. The experiments proved that the NO removal could be maintained at more than 95% by the system of 0.02 mol/L Co(eh)_3^{3+} and 1% urea at 50°C with 10% O_2 in the flue gas. Show more

Keywords: simultaneous removing SO_2 and NO, Co(en)_3^{3+}, urea, SO_3^{2-} oxidation

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 567-571, 2006

Authors: ZHANG, An-ping | LUO, Fan | CHEN, Sheng-wen | LIU, Wei-ping

Article Type: Research Article

Abstract: Cyclodextrins (CDs), with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD (RAMEB) and hydroxypropyl β-CD (HP-β-CD), were tested. It was found that RAMEB could …inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35°C. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP-β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25°C, pH 9.0. Show more

Keywords: cyclodextrin, malathion, hydrolysis, urea

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 572-576, 2006

Authors: YAN, Jian-hua | TAN, Zhong-xin | JIANG, Xue-guang | CHI, Yong | CEN, Ke-fa

Article Type: Research Article

Abstract: Dyestuff residue, a type of hazardous waste, is incinerated in the tubular furnace, and thermodynamic equilibrium model is used to calculate and analyze the chlorine behavior. The HCl emission and its effects on the behaviors of heavy metals are studied. Meanwhile, the effects of three dechlorine reagents are predicted at a high temperature. Results show that HCl emission is dependent on incineration temperature. The HCl evaporated mainly derives from the organic chlorine. Under the working condition …of 500–900°C, the main products of Hg, Pb, Cu, Ni, Zn, and Mn in reaction with HCl are HgCl_2 (g), PbCl_4 (g), PbCl_2 (g), (CuCl)_3 (g), NiCl_2 (s), NiCl_2 (g), ZnCl_2 (s), ZnCl_2 (g), Zn(g), MnCl_2 (s), and MnCl_2 (g), respectively. Among the three dechlorine reagents, CaCO_3 is optimal to remove chlorine at high temperature, little of HCl is released below 800°C, whereas Fe_3 O_4 is unstable at high temperature. Show more

Keywords: hazardous waste, thermodynamic equilibrium model, HCl, heavy metals, dechlorine reagents

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 577-582, 2006

Authors: ZHANG, Hua | HE, Pin-jing | SHAO, Li-ming | FENG, Jun-hui | CAO, Qun-ke

Article Type: Research Article

Abstract: Increasing attention has been paid to air pollution control (APC) residues in China recently due to the rising proportion of waste incineration and the hazardous characteristics of the residues, among which heavy metal leaching toxicity plays an important role. Leaching behavior and potential risk of Pb and Zn in the APC residues from a Shanghai municipal solid waste (MSW) incinerator was studied, based on the leaching tests under different conditions and theoretical calculation using a geochemical …thermodynamic equilibrium model MINTEQA2. Results showed that, extractant species and liquid to solid (L/S) ratio predominantly controlled the leaching toxicity of Pb and Zn, while ionic strength, vibration method and leaching time had less effect on the metals release. Leachate/final pH determined the metal leaching behavior, which changed the speciation of heavy metals in the extraction system. The equilibrium aqueous speciation, precipitation-dissolution of Pb and Zn was investigated according to the model computation, which was well in agreement with the experimental results. Show more

Keywords: leaching behavior, air pollution control residues, MINTEQA2, incineration plant, heavy metals

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 583-586, 2006

Authors: LI, Yu-ying | ZHENG, Xi-lai | LI, Bing

Article Type: Research Article

Abstract: There were six high diesel oil degrading bacteria strains isolated from the oil contaminated soil that collected from Linzi City. The strain Y1 was able to produce biosurfactant rhamnolipid when cultivated on diesel oil as carbon source. The critical micelle concentrations (CMC) of rhamnolipid in water and in the soil were measured respectively according to the correlation between the surface tension of the medium and the added rhamnolipid concentration. The results showed that the CMC of …rhamnolipid in water was 65 mg/L, and was 185 mg/L in soil. The tests on diesel oil biodegradation were conducted with the addition of different concentrations of rharnnolipid in water and in soil respectively. When 0.01% rhamnolipid was added to water, the diesel oil degradation was enhanced. On the contrary, when the same concentration of rhamnolipid was added to the soil, the degradation of diesel oil was inhibited. The results suggested that the rhamnolipid could enhance the diesel oil biodegradation, indicating that the concentration of rhamnolipid was higher than the corresponding CMC in the medium. Kinetics parameters for the diesel oil biodegradation parameters such as biodegradation constant (λ), coefficient of correlation (r) and half life (t_{1/2} ) in both tests were numerically analyzed in this paper, indicating that the moderate concentration of rhamnolipid in the medium could not only enhance the extent of diesel oil biodegradation but also shorten the time for oil remediation. Show more

Keywords: biosurfactant, diesel oil, remediation, bacteria

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 587-590, 2006

Authors: XUE, Lian-qing | HAO, Zhen-chun

Article Type: Research Article

Abstract: The sediment distributed and insolated under lake was collected for experiments. The nutrient layer distribution conditions of sampled sediment and its physical and chemical characteristics were analyzed to simulate and assess the influence degree to lake water quality. Based on the dynamic water exchanging experiments the nutrient release process in sediment and influence mechanism to substance exchanging on water-sediment interface was studied, and the correlation between the changing content of total phosphors and total …nitrogen in sediment and covered water were analyzed for setting up a simulation model. At the same time the influence degree is explained in detail. The experimental results indicated that even if clean water without nutrient contents was used for water exchangement so as to decrease pollution or prevent eutrophication, however owing to the vertical nutrient distribution in lake sediment, it will lead to the increasing release amount greatly especially when the organic nutrient contained in sediment turns into inorganic status because of isolation. Besides the release process of total phosphate (TP) and total nitrogen (TN) were modeled and each nutrient's exchanging equation at interface caused by covered water nutrient concentration changing was set up. According to the simulating prediction, TP and TN content of cover water will also sustain a steady higher level in a long period. The nutrient release amount of sediment is not only affected by the covered water concentration but also connects with accumulative time. The experiments provide the fundamental theoretical and practical basis for taking ecological restoration project. And research is helpful to prevent or restore lake eutrophication. Show more

Keywords: phosphate and nitrogen release, water-sediment interface experiments, simulation model

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 591-595, 2006

Authors: LIU, Yong | GUO, Huai-cheng | WANG, Li-jing | DAI, Yong-li | ZHANG, Xiu-min | LI, Zi-hai | HE, Bin

Article Type: Research Article

Abstract: Lake eutrophication caused by excess phosphorus (P) loading from point sources (PS) and nonpoint sources (NPS) is a persistent and serious ecological problem in China. A phosphorus budget, based on material flow analysis (MFA) and system dynamic (SD), is proposed and applied for the agriculture-dominated Qionghai Lake watershed located in southwestern China. The MFA-SD approach will not only cover the transporting process of P in the lake-watershed ecosystems, but also can deal with the changes of …P budget due to the dynamics of watershed. P inflows include the fertilizer for agricultural croplands, soil losses, domestic sewage discharges, and the atmospheric disposition such as precipitation and dust sinking. Outflows are consisted of hydrologic export, water resources development, fishery and aquatic plants harvesting. The internal P recycling processes are also considered in this paper. From 1988 to 2015, the total P inflows for Lake Qionghai are in a rapid increase from 35.65 to 78.73 t/a, which results in the rising of P concentration in the lake. Among the total P load 2015, agricultural loss and domestic sewage account for 70.60% and 17.27% respectively, directly related to the rapid social-economic development and the swift urbanization. Future management programs designed to reduce P inputs must be put into practices in the coming years to ensure the ecosystem health in the watershed. Show more

Keywords: phosphorus budget, lake-watershed ecosystems, material flow analysis, system dynamic

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 596-603, 2006

Authors: WANG, Jun | TANG, Xue-xi

Article Type: Research Article

Abstract: A mass transport model was developed to predict the transport rate of ions within biofilms, which was experimentally verified using the fluxes of NH_4^+ and Ca^{2+} through the heterotrophic biofilms with the thickness varying from 230 to 1430μm under the effect of external field in the range of −20 V/m to 60 V/m. It is found that the result predicted by the model is in agreement with the experimentally obtained one, with …the error less than 5 percent for the thin biofilms. The error increases with the increase of the biofilm thickness. The transport rate of ions caused by electric migration is affected by the charges, field strength, and biofilm thickness and so on. Show more

Keywords: biofilms, external field, mass transport

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 604-609, 2006

Authors: QIN, Yan-wen | MENG, Wei | ZHENG, Bing-hui | SU, Yi-bin

Article Type: Research Article

Abstract: Three sediment cores were collected in November 2003 from Dagu estuary to Qikou estuary. The main polluted heavy metals in the sediment of tidal zones for the Bohai Bay have been found by analyzing the relationship among the contents of heavy metals, the contents of geochemical elements (Fe, Al and Mn) and the size of grain. The dominating contaminative elements in tidal sediments of Bohai Bay are Pb, Zn and Cd. Their contents are higher than …the corresponding upper limit of environmental background values and they have very faint correlation with the corresponding contents of geochemical elements and the size of grain, indicating the anthropogenic enrichment. Especially, the preliminary study on the pollution sources and the history of heavy metals in the Dagu estuary has been done using the dated results. The contamination by Zn and Cd also started in the middle 1950s, while the contamination by Pb appeared in the early 1940s. The pollution by Zn and Cd mainly originate from sewage discharge, while the pollution by Pb has many sources, like atmosphere deposition and industrial discharge. Show more

Keywords: Bohai Bay, tidal zone, the dated sediment core, heavy metal, pollution

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 610-615, 2006

Authors: GAO, Qun | LIU, Ying-tao | MAO, Han-ying

Article Type: Research Article

Abstract: In Wuhan urban agglomeration (WUA), the population growth and concentration, the industrial development and urban sprawl have been affecting the environment fundamentally. Comparing with Yangtze delta metropolitan region, the level of urbanization and industrialization of WUA has lagged behind for about 10 years; but the problems in environmental protection and rehabilitation are commonly serious. In the future, WUA should avoid unnecessary mistakes and seek a win-win strategy for economy and environment in …its large-scale development stage. Based on the analysis of the changing of main environmental pollutants and the coupled curves in past decades, the paper discussed the important links among the urban environmental pollutions, industry growth and urban sprawl in WUA. It is concluded that the integration of economic and environmental policies in urban development is more required and significant at the large urban agglomeration region. Four proactive and long-term strategies need to be adopted to provide prior guidance and better protection for the development of WUA. Show more

Keywords: environmental problem, urban development, Wuhan urban agglomeration, strategies

Citation: Journal of Environmental Sciences, vol. 18, no. 3, pp. 616-623, 2006