Journal of Environmental Sciences - Volume 14, issue 2

Authors: Wang, Jing | Zhu, Li-zhong | Liu, Yong-jian

Article Type: Research Article

Abstract: Nine PAHs were surveyed in communication air of Hangzhou. The results indicated that the PAHs pollution is very serious and the total sum of 9 PAHs, on the average are 3.39- 13.82 µg/m3. The PAHs signatures for all streets are similar to each other. Multivariate statistical techniques were used to investigate source apportionment for PAHs. A factor analysis/multiple regression model was successfully applied to the study. The most important three PAHs sources in communication air are …diesel emission, gasoline engine emission, coal-burning accounting for 61. 1 ± 6.4%, 19.9 ± 8.3%, 10.8 ± 10.8% of total PAHs, respectively. The relationship for three source tracers and total PAHsis: [PAHs] =1.471(± 0.155)[Phen] + 2.538 (± 2.522)[1-Mepy] + 2.254 (± 0.943)[Chry] + 1.022 (± 1.767). Show more

Keywords: PAHs, air, source apportionment, city communication

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 145-150, 2002

Authors: Liu, Xin-hui | Wu, Chun-de | Han, Shuo-kui | Wang, Lian-sheng

Article Type: Research Article

Abstract: The logarithms of retention factors normalized to a hypothetical pure water eluent( log k_w ) were determined on a reversed-phase highperformance liquid chromatography(RP-HPLC) column (Li Chrosorb RP-18 column) for 20 new α-branched phenylsulfonyl acetates. The atomic charge method was applied to develop quantitative structure-retention relationships (QSRRs). Among the available geometric and electronic descriptors, surface area (S), ovality (O), and the charge of carboxyl group(Q_oc ) are significant. In the model, the contribution …of surface area (S) is the greatest. The molecular mechanism of retention was demonstrated through the model. With the correlation coefficient ( r^2_adj, adjusted for degrees of freedom) of 0. 964, the standard error of 0. 164 and the F-value of 170.39, the model has good predictive capacity. Show more

Keywords: phenylsulfonyl acetates, quantum chemical descriptor, quantitative structure-retention relationships (QSRRs), retention factor

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 151-155, 2002

Authors: Leung, Dennis Y.C. | Niewiadomski, Michal | Benoit, Robert

Article Type: Research Article

Abstract: This paper describes the set-up and application of a non-hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain of Hong Kong. Results of the simulations of one case are presented and compared with the results of radiosonde and aircraft measurements. The model is proved capable of predicting high-resolution,three-dimensional fields of wind and other meteorological parameters within the Hong Kong territory, using …reasonable computer time and memory resources. Show more

Keywords: mesoscale meteorological modelling, MC2 model, Hong Kong

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 156-164, 2002

Authors: Jones, Chilima | Huang, Chang-yong | Wu, Ci-fang

Article Type: Research Article

Abstract: Efforts to quantify management effects on decomposition rate of added substrates to the soil is important especially where such information is to be used for prediction in mathematical or simulation models. Using data from a short-term (60 days) greenhouse simulation study, a procedure for quantifying effects of management on SOM and substrate decomposition is presented. Using microbial growth rate u ( q ),microbial efficiency in substrate utilization e (q), specific decomposition rates for added plant residues …to two contrasting soils, red earth (Ferrasol) and black earth (Acrisol) were estimated. The treatments included straw addition + buried, (T1); straw addition + mineral N (T2); and straw addition + tillage, (T3). Sampling was done every 15 days. Straw decomposition rate was affected by external mineral N sources (Urea 46% N). Addition of an external N source significantly increased decomposition rates. The study could not, however, fully account for the effect of tillage on residues because of the limited effect of the tillage method due to the artificial barrier to mechanical interference supplied by the mesh bags. It is concluded that using few decomposer parameters, decomposition rates and consequently SOM trends in a soil system can be monitored and quantification of the influence of perturbations on decomposition rate of added substrates possible. Show more

Keywords: management factors, residue decomposition rate, maize, cotton, red soil, black soil

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 165-172, 2002

Authors: Liu, Wei-ping | Fang, Zhuo | Liu, Hui-jun | Yang, Wei-chun

Article Type: Research Article

Abstract: Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca^2+_-, Mg^2+_-. Al^3+_ - and Fe^3+_ - saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, K_f decreased in the order of metolachlor > acetolachlor > alachlor > propachlor on the same clay. FT-IR spectra …showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg^2+ < Ca^2+ < Al^3+ < Fe^3+ which coincided with the iucreasing aciditv of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions. Show more

Keywords: chloroacetanilide herbicides, adsorption, montmorillonite, humic acid, alachlor, acetochlor, metolachlor, propachlor

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 173-180, 2002

Authors: Zhang, Lin | Weng, Huan-xin | Gao, Cong-jie | Chen, Huan-lin

Article Type: Research Article

Abstract: Membrane separation, a new technology for removing VOCs including pervaporation, vapor permeation, membrane contactor, and membrane bioreactor was presented. Comparing with traditional techniques, these special techniques are an efficient and energy-saving technology. Vapor permeation can be applied to recovery of organic solvents from exhaust streams. Membrane contactor could be used for removing or recovering VOCs from air or wastewater. Pervaporation and vapor permeation are viable methods for removing VOCs from wastewater to …yield a VOC concentrate which could either be destroyed by conventional means, or be recycled for reuse. Show more

Keywords: volatile organic compounds (VOCs), membrane separation techniques, remove

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 181-187, 2002

Authors: Xia, Xing-hui | Xu, Jia-lin | Yun, Ying

Article Type: Research Article

Abstract: Experiments were carried out to study the effects of several anions on the photocatalytic degradation rates of sodium dodecylbenzene sulphonate (DBS) with TiO_2 as catalyst. The anions were added as Na_2 SO_4, NaNO_3, NaCl, NaHCO_3, NaH_2 PO_4 and Na_3 PO_4, and two levels of anion content, i.e. 12 mmol/L and 36 mmol/L in terms of Na^+ , were studied. The results revealed that: Cl^- , SO^2_4^- , NO^-_3 and HCO_3^-retarded the rates of DBS degradation to …different degrees; PO_4^3 - increased the DBS degradation rate at low concentration and decreased the rate at high concentration; H_2PO^-_4 accelerated the rate of DBS degradation. The mechanism of the effects of anions on DBS degradation was concluded as the following three aspects: anions compete for the radicals; anions are absorbed on the surface of catalyst and block the active site catalyst. Show more

Keywords: surfactant, anion, photocatalytic degradation, water environment

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 188-194, 2002

Authors: Quan, Xie | Liu, Zhen-yu | Xue, Da-ming | Zhao, Ya-zhi | Yang, Feng-lin

Article Type: Research Article

Abstract: A chemical sequential separation procedure for sediment bas been developed for the adsorptive investigation of hydrophobic organic compounds(HOCs) including four fractions: carbonate, hydrous metallic oxide(ferric oxide, manganese oxide and alumina), clay and organic matter. Adsorption isotherms of these hydrophobic solute probes, such as hexachloroethane, lindane and 1,2,4,5-tetrachlorobenzene were measured for model sorbents, model and natural sediment, and the latter of which was pretreated with the simplified sequential separation method. The linear and …Langmuir models are applied to correlate the experimental data of humic substance and other model sorbents respectively. Multi-component Adsorptive Model (MCAM) was used to simulate adsorption isotherms of model and natural sediment. The results reveal that( 1 ) the separation efficiencies of carbonate, organic matter, ferric oxide, manganese oxide and alumina are 98.1 % , 72.5% ,82.6%, 93.5% and 83.3%, respectively; (2) except for removing metallic oxide, the external structure of sediment is not changed greatly after separation; (3) the MCAM correlates the data of adsorption isotherm rather well with the maximal relative deviations of 9.76 % , 6.78 %and 9.53% for hexachloroethane, lindane and 1,2,4,5-tetrachlorobenaze in model sediment, respectively. The MCAM can clearly give expression to the different adsorptive mechanisms for HOCs in organic and inorganic matter, though the experimental data in each component are not very accurate due to the sequential separation efficiency. Show more

Keywords: hydrophobic organic compounds, sediment, adsorption, model

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 195-203, 2002

Authors: Li, Xiao-ming | Zeng, Guang-ming | Chen, Jian | Lun, Shi-yi

Article Type: Research Article

Abstract: The seed sludge originated from a methane fermentation reactor was enriched and acclimated with TA as sole carbon source under nitrate respiration mode first for 6 week, and then can be turned to methane fermentation conditions. After 6 weeks processing, the specific rate acclimation. After a total of 90 days for the enrichment and acclimation, the fermentative bacteria which originally existed in the seed sludge nearly disappeared, and instead of them, the TA reductive and cleaving …bacteria group was formed in the new consortia, which was confirmed by the MPN counts and roll tube counts. Compared with the control experiment, the acclimation period can be shortened by about 50%. Show more

Keywords: acclimation, anaerobic sludge, enrichment, nitrate, terephthalic acid (TA)

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 204-209, 2002

Authors: Tian, Gui-shan | Ma, Zhen-ji | Zhang, Xin-yi | Xu, Ting-xiang

Article Type: Research Article

Abstract: Analytical and numerical computed models are developed for reverse pulse cleaning system of candle ceramic filters. A standard turbulent model is demonstrated suitably to the designing computation of reverse pulse cleaning system from the experimental and onedimensional computational result. The computed results can be used to guide the designing of reverse pulse cleaning system, which is optimum Venturi geometry. From the computed results, the general conclusions and the designing methods are obtained.

Keywords: candle ceramic filters, reverse pulse cleaning, face velocity, numerical computed models, pressure difference

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 210-215, 2002

Authors: Xiong, Zhi-ting | Lu, Ping

Article Type: Research Article

Abstract: When EDTA was added alone in the Pb-contaminated sand, the plant biomass and the total Pb amount in plant decreased in both species, Brassica pekinensis and B. juncea var. multiceps, though the shoot Pb amount increased. In contrast, when (NH_4)_2 SO_4 was added alone in the Pb-contaminated sand, little effect was observed on the shoot Pb amount, though the root Pb amount was significantly increased in B. juncea var. multiceps. When amending EDTA and (NH_4)_2SO_4 in …combination, however, the shoot Pb amount in both species substantially increased, being, on an average, 2 times and 9 times higher than that in EDTA alone or (NH_4)_2 SO_4 alone amended treatment, respectively.The two amendments showed antagonism for plant growth, but synergism for Pb bioaccumulation. B. pekinensis showed its highest level of shoot and total Pb amount in the treatment amended with EDTA and (NH_4)_2 SO_4 only a half as much as in the other treatments. It is inferred that the mechanisms responsible for the joint-enhanced Pb accumulation might be concerned with the acidification of the growth medium, cation exchange reaction and relieving EDTA induced toxicity as results by amending ammonium sulfate. Show more

Keywords: lead bioaccumulation, Brassica ammonium sulfate, ammonium sulfate, EDTA

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 216-220, 2002

Authors: Udo, Mfon T.

Article Type: Research Article

Abstract: From April 1992 and March 1993, morphometric characteristics and reproductive maturation were studied in Periophthalmus barbarus from subsistence catches in the mangrove swamps of Imo estuary. Morphometrie equations for males and females at different stages of ovarian maturation are presented. Generally males were significantly heavier in weight than females, but the latter were heavier than the former of the same body length. Females with developing and mature ovaries were generally heavier than immature females …of the same length.Analyses of the gonadosomatie index and percentage of mature males and females indicate all year-round breeding such that: February-May was spawning, June-October postspawning and November to January recovery period. Fecundity varied between 900 and 23933 eggs per spawn and increased with fish size. Show more

Keywords: Nigeria, Imo estuary, mangrove swamps, reproductive maturation, morphometric relationships, periophthalmus barbarus

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 221-226, 2002

Authors: Feng, Zong-wei | Miao, Hong | Zhang, Fu-zhu | Huang, Yi-zong

Article Type: Research Article

Abstract: South China has become the third largest region associated with acid deposition following Europe and North America, the area subject to damage by acid deposition increased from 1.75 million km² in 1985 to 2.8 million km² in 1993. Acid deposition has caused serious damage to ecosystem. Combined pollution of acid rain and SO_2 showed the obvious multiple effects on crops. Vegetable was more sensitive to acid deposition than foodstuff crops. Annual economic loss of crops due …to acid deposition damage in eleven provinces of south China was 4.26 billion RMB Yuan. Acid deposition caused serious damage to forest. Annual economic loss of wood volume was about 1.8 billion RMB Yuan management, specifying acid-controlling region, controlling and abating the total emission amount of SO_2; (2) selecting practical energy technologies of clean coal, for example, cleansing and selecting coal, sulfur-fixed-type industrial briqutting, abating sulfur from waste gas and so on; (3) developing other energy sources to replace coal, including water electricity, atomic energy and the new energy such as solar energy,wind energy and so on; (4) in acid deposition region of south China, selecting acid-resistant tvpe of crop and tree to decrease agricultural losses, planting more green fertilizer crops, using organic fertilizers and liming, in order to improve buffer capacities of soil. Show more

Keywords: acid rain, agriculture, forestry, economic loss, rehabilitation strategies

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 227-233, 2002

Authors: Liu, Jing-ling | Yang, Zhi-feng

Article Type: Research Article

Abstract: The purpose of this paper is to present a brief concept of the ecological and environmental water demand of lake. The present situation and affecting factors of lake ecological system in the Haihe-Luanhe Basin of North China was analyzed. The calculating method of the ecological and environmental water demand of the lake basis on the water body and the calculating method of the ecological and environmental water demand of the lake basis on the aquatic ecosystem, …wetland and vegetation were compared and discussed. As the examples of Baiyangdian Lake and Beidagang Lake in Haihe-Luanhe river basin, the ecological and environmental water demand of the two lakes was calculated to be 27 × 10^8m³ . It is 6.75 times to the water demand according to the calculating method of the ecological and environmental water demand of the lake basis on the water body. The research result indicated: ( 1 ) The calculating methods of the ecological and environmental water demand of the lake basis on the aquatic ecosystem should be better than only basis on the water body of lake. (2) The data, such as area of the vegetation kind around and in the lake, the vegetation coefficient, the evaporating amount of the vegetation and the vegetation water demand itself around and in the lake are lack and urgent need. Some suggestions for controlling and regulating the water resource of the lake in North China were proposed. Show more

Keywords: eco-environment, water demand, lake, the Haihe-Luanhe Basin

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 234-238, 2002

Authors: Chen, Jia-jun | Wang, Hong-qi | Zhang, Zheng

Article Type: Research Article

Abstract: Based on the theory of fluid dynamics in porous media, a numerical model of gas flow in unsaturated zone is developed with the consideration of gas density change due to variation of air pressure. This model is characterized of its wider range of availability. The accuracy of this numerical model is analyzed through comparison with modeling results by previous model with presumption of little pressure variation and the validity of this numerical model is shown. Thus …it provides basis for the designing and management of landfill gas control system or soil vapor ex.action system in soil pollution control. Show more

Keywords: numerical model, compressible gas, landfill gas, migration, soil vapor extraction, pollution control

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 239-244, 2002

Authors: Liu, Jun-xin | van Groenestijn, J. W. | Doddema, H. J. | Wang, Bao-zhen

Article Type: Research Article

Abstract: The oxidation ditch has been used for many years all over the world as an economic and efficient wastewater treatment technology. It can remove COD, nitrogen and a part of phosphorus efficiently. In the experiment described, a pilot scale Pasveer oxidation ditch system has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that influent total phosphorus(TP) was removed for 35% -50%. After this, two anaerobic tanks with total volume of …11 m³ were added to the system to release phosphorus. As a result, the TP removal efficiency increased by about 20%. At an anaerobic HRT of about 6 hours, a TP removal efficiency of 71 % was achieved. Show more

Keywords: wastewater treatment , oxidation ditch, phosphorus removal

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 245-249, 2002

Authors: Zheng, Ping | Hu, Bao-lan

Article Type: Research Article

Abstract: Two start-up strategies of upflow anaerobic sludge blanket (UASB) reactor for treatment of pharmaceutical wastewater were investigated. The results showed that both of them were workable. Compared with the strategy that started up the reactor directly using chloromycetin wastewater, the strategy that started up the reactor first using mixed wastewater and then using chloromycetin wastewater could save time by 23%. When the latter strategy was adopted the development of sludge activity fluctuated more largely and its …final activity was lower, but the sludge grew faster in the course of start-up. Show more

Keywords: start-up, toxic wastewater, UASB

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 250-254, 2002

Authors: Xu, Fu-liu | Tao, Shu | Dawson, Richard W. | Lu, Xiao-yan

Article Type: Research Article

Abstract: This paper provides some introductory information on the history, development, and characteristics of various lake ecosystem models.The modeling of lake ecological processes began to gain importance in the early 1960s. There are a number of models available today, with varying levels of complexity to cope with the variety of environmental problems found in lake environments, e.g. eutrophication, acidification,oxygen depletion, wetland management, heavy metal and pesticide pollution, as well as hydrodynamic problems. In particular, …this paper focuses on lake eutrophication and wetland models, as well as addressing strategies appropriate for the design and development of reliable lake ecological models. Show more

Keywords: lake ecosystem, eutrophication model, wetland model, pollution model

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 255-263, 2002

Authors: Xi, Bei-dou | Liu, Hong-liang | Zeng, Guang-ming | Huang, Guo-he | Bai, Qing-zhong

Article Type: Research Article

Abstract: The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.

Keywords: effective complex microorganisms(ECM), temperature, oxygen consumption, organic matter, C/N ratio

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 264-268, 2002

Authors: Ye, Chang-ming | Lei, Zhi-fang

Article Type: Research Article

Abstract: The behavior of herbicide acetochlor adsorption-desorption to soil in the presence of humic acid (HA), anionic surfactant sodium dodecylbenzene sulfonate (SDBS), cationic surfactant hexadecyltrimethyl-ammonium bromide (HDAB) and NH_4NO_3 as a chemical fertilizer was studied. Observed acetochlor adsorption isotherm were well described using Freundlich isotherm equation, from which the desorption isotherm equation has been deduced. The deduced equation can more directly describe acetochlor desorption process. The results showed that the enhance of acetochlor …adsorption capacity by solid HA was greater than by soluble HA. The presence of NH_4 NO_3 can slightly enhance acetochlor adsorption to soil by comparison with that measured in NH_4NO_3-free solution. In soil-water system, surfactant-acetochlor interaction is very complex, and the surfactant adsorptions as well as acetochlor adsorption need to be considered. When acetochlor-soil suspensions contained lower concentration SDBS or HDAB (40 mg/L), K_f for acetochlor adsorption was decreased in comparison to that measured in SDBSor HDAB-free solution. When acetochlor-soil suspensions contained higher concentration SDBS or HDAB (corresponding 1400 mg/L or 200 mg/L), K_f for acetochlor adsorption was increased in comparison to that measured in SDBS- or HDAB-free solution. Show more

Keywords: adsorption-desorption, acetochlor, humid acid, surfactants, ammonium nitrate, soil

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 269-276, 2002

Authors: Xiao, Chun-wang | Jia, Fu-ping | Zhou, Guang-sheng | Jiang, Yan-ling

Article Type: Research Article

Abstract: Response patters were investigated for seedlings of Hedysarum mongolicum, a dominant shrub in Maowusu sandland, to the simulated precipitation change by artificially controlling water supply at four levels. Plant growth characters, in terms of branch number and length, leaf number and area, and biomass, increased while water supply increased. However, the effect of water supply on leaf photosynthetic rate was not significant. Root/shoot biomass ratio significantly decreased with the increase of water supply, which …was considered adaptive distribution of biomass investments in the different water supply. Water supply obviously affected branching patter. Branch section number,branch number and length of the same section enhanced as water supply increased. Branch number and length were clearly positive correlation with total and aboveground biomass in four water supply treatments. Branch character fully showed plant growth. Show more

Keywords: branching patter , Hedysarum mongolicum, semi-arid area, Maowusu sandland, simulated precipitation

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 277-283, 2002

Authors: Liu, Shu-qin | Liu, Jun-hua | Yu, Li

Article Type: Research Article

Abstract: Environmental benefits of underground coal gasification are evaluated. The results showed that through underground coal gasification,gangue discharge is eliminated, sulfur emission is reduced, and the amount of ash, mercury, and tar discharge are decreased. Moreover, effect of underground gasification on underground water is analyzed and CO_2 disposal method is put forward.

Keywords: environmental benefits, coal, underground coal gasification

Citation: Journal of Environmental Sciences, vol. 14, no. 2, pp. 284-288, 2002