Journal of Environmental Sciences - Volume 16, issue 4

Authors: ZHOU, Dong-mei | Alshawabkeh, Akram N. | DENG, Chang-fen | CANG, Long | SI, You-bin

Article Type: Research Article

Abstract: The electrokinetic removal of chromium and copper from contaminated soils by adding lactic acid in cathode chamber as an enhancing reagent was evaluated. Two sets of duplicate experiments with chromium contaminated kaolinite and with a silty soil sampled from a superfund site in California of USA and polluted by Cr and Cu, were carried out in a constant current mode. Changes of soil water content and soil pH before and after the electrokinetic experiments, and variations …of voltage drop and electroosmosis flow during the treatments were examined. The results indicated that Cr, spiked as Cr (VI) in the kaolinite, was accumulated mainly in the anode chamber, and some of Cr and metal hydroxides precipitated in the soil sections in contact with the cathode, which significantly increased electrical energy consumption. Treatment of the soil collected from the site showed accumulation of large amounts of Cr and Cu in the anode chamber while none was detected in the cathode one. The results suggested that the two metals either complexed with the injected lactic acid at the cathode or existed as negatively charged complex, and electromigrated toward the anode under a voltage gradient. Show more

Keywords: electrokinetic remediation, metal, soil, lactic acid

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 529-532, 2004

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

Article Type: Research Article

Abstract: The total carbon(C) and total nitrogen(N) content of suspended matter in a small undisturbed headwater drainage basin in the New Territories of Hong Kong has been monitored. Mean C and N contents were 12.85% and 0.99% respectively for 132 samples. Samples collected under stableflow conditions had mean C and N contents of 12.81% and 1.06% respectively. Stormflow samples had mean C and N values of 12.86% and 0.97% respectively, which were very similar to the levels …observed under stableflow conditions. The mean C:N ratios of 12.47 and 13.39 for stableflow and stormflow also reveal little difference according to hydrologic conditions. When all the data is considered little difference is observed in C and N according to the season. However, in winter there is a significant difference in C and N content between stable and stormflow samples. When C and N are plotted against water level the scattergraphs suggested that as stage increases the percentage of C and N in the suspended matter declines. Scattergraphs of C and N against suspended sediment concentration reveal a negative association. Comparison has been made between fresh leaf C, N and C/N ratio for trees and shrubs and the suspended matter. Fresh leaves do not appear to contribute significantly to suspended matter. The C/N ratio of suspended matter would also seem to exclude woody material and algae as sources of suspended matter. Show more

Keywords: carbon, nitrogen, suspended matter, Hong Kong

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 533-538, 2004

Authors: WU, Zu-liang | GAO, Xiang | LUO, Zhong-yang | NI, Ming-jiang | CEN, Ke-fa

Article Type: Research Article

Abstract: Non-thermal plasma technologies offer an innovative approach to decomposing various volatile organic compounds (VOCs). The decomposition of toluene from simulated flue gas was investigated using a pipe electrode with nozzles for the generation of free radicals. Corona characteristics and decomposition of toluene were investigated experimentally. In addition, the decomposition mechanism of toluene was explored in view of reaction rate. The experimental results showed that the humidity of additional gas has an important …effect on corona characteristics and modes and stable streamer corona can be generated through optimizing flow rate and humidity of additional gas. Applied voltage, concentration of toluene, humidity of toluene and resident time are some important factors affecting decomposition efficiency. Under optimizing conditions, the decomposition efficiency of toluene can reach 80%. These results can give a conclusion that the corona radical shower technology is feasible and effective on the removal of toluene in the flue gas. Show more

Keywords: decomposition, corona, radical, toluene

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 534-547, 2004

Authors: ZHENG, Wei | LIU, Wei-ping | WEN, Yue-zhong | Lee, Sang-jin

Article Type: Research Article

Abstract: The direct and sensitized photodegradations of imidacloprid, 1-(6-chloro-3-pyridinylmethyl)-N-nitro-2-imidazolidinimine. were investigated in aqueous solution and with and without various photo-sensitizers. Results of the study revealed that the intensity of lamp-house and irradiation wavelength had significant effects on the photolysis of imidacloprid. Complete degradation of 20 mg/L imidacloprid in aqueous phase was observed in 40 min under ultraviolet (UV) irradiation system, suggesting the ultraviolet ray played significant role in direct photolysis of imidacloprid. The …additions of various photo-sensitizers lead to improve the degradation efficiency of imidacloprid under the irradiation of black light fluorescent lamp. TiO_2 was the most efficient in the photo-catalytic degradation of imidacloprid among other photo-sensitizers in used this study. However, addition of acetone inhibited the photolysis of imidacloprid under the irradiation of UV, indicating the occurrence of competition between acetone and imidacloprid for photos. Mineralization of the imidacloprid was examined to clarify the final photochemical degradation products of the insecticide which were CO_2 , Cl^- and NO_3^- . Complete photo-oxidation of nitrogen to NO_3^- occurred very slowly via the intermediate formation of NH_4^+ and NO_2^- . Show more

Keywords: imidacloprid, photolysis, photo-sensitizers, photo-oxidation, mineralization

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 539-542, 2004

Authors: WANG, Ya-yi | PENG, Yong-zhen | Wang, Shu-ying | PAN, Mian-li

Article Type: Research Article

Abstract: Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated. Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD …carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrifying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration, it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations. Show more

Keywords: biological phosphorus removal, carbon source, nitrate, ORP, denitrifying phosphorus removal bacteria (DPB), anaerobic-anoxic processes

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 548-552, 2004

Authors: LIU, Jie-min | CHENG, Wei | WEN, Mei-juan | JIANG, Gui-bin

Article Type: Research Article

Abstract: A method was developed to determine the concentration of methyl tert-butyl ether (MTBE) in gasoline,diesel and heating oil by gas chromatography (GC) with mass spectrometry (GC-MS) or flame ionization detection (FID). The diluted gasoline was directly injected into the GC, and the complete separation of MTBE from co-eluting hydrocarbons was not required. GC/MS or GC/FID method can be used to analyze MTBE in different concentration range and have good consistency.

Keywords: methyl tert-butyl ether (MTBE), GC/MS, GC/FID

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 553-555, 2004

Authors: WAN, Jia-feng | FENG, Yu-jie | CAI, Wei-min | YANG, Shao-xia | SUN, Xiao-jun

Article Type: Research Article

Abstract: Four metal oxide catalysts composed of copper (Cu), stannum (Sn), copper-stannum (Cu-Sn) and copper-cerium (Cu-Ce) respectively were prepared by the co-impregnation method, and γ-alumina(γ-Al_2 O_3 ) is selected as support. A first-order kinetics model was established to study the catalytic wet air oxidation of phenol at different temperature when these catalysts were used. The model simulations are good agreement with present experimental data. Results showed that the reaction rate constants …can be significantly increased when catalysts were used, and the catalyst of 6% Cu-10% Ce/γ-Al_2 O_3 showed the best catalytic activity. This is consistent with the result of catalytic wet air oxidation of phenol and the COD removal can be arrived at 98.2% at temperature 210°C, oxygen partial pressure 3 MPa and reaction time 30 min. The activation energies of each reaction with different catalysts are nearly equal, which is found to be about 42 kJ/mol and the reaction in this study is proved to be kinetics control. Show more

Keywords: catalytic wet air oxidation, catalyst, phenol

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 556-558, 2004

Authors: LOU, Bao-feng | ZHU, Li-zhong | YANG, Kun

Article Type: Research Article

Abstract: Preliminary research was conducted about how to incorporate sorption/desorption of organic pollutants with suspended solids and sediments into single-chemical and one-dimensional water quality model of Jinghang Canal. Sedimentation-resuspension coefficient k_3 was deduced; characteristics of organic pollutants, concentrations and components of suspended solids/sediments and hydrological and hydraulic conditions were integrated into k_3 and further into river water quality model; impact of sorption/desorption of organic pollutants with suspended …solids and sediments on prediction function of the model was discussed. Results demonstrated that this impact is pronounced for organic pollutants with relatively large K_{oc} and K_{ow} , especially when they are also conservative and f_{oc} of river suspended solids/sediments is high, and that incorporation of sorption/desorption of organic pollutants into river water quality model can improve its prediction accuracy. Show more

Keywords: water quality model, sorption/desorption, sedimentation-resuspension coefficient

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 559-563, 2004

Authors: Hung, Nguyen Viet | Tateda, Masafumi | Ike, Michihiko | Fujita, Masanori | Tsunoi, Shinji | Tanaka, Minoru

Article Type: Research Article

Abstract: Nonylphenol (NP), nonylphenoxy acetic acid (NP1EC), nonylphenol monoethoxy acetic acid (NP2EC), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) are biodegradation end products (BEPs) of nonionic surfactant nonylphenolpolyethoxylates (NP nEO). In this research, sorption of these compounds onto model activated sludge was characterized. Sorption equilibrium experiments showed that NP, NP1EO and NP2EO reached equilibrium in about 12 h, while equilibrium of NP1EC and NP2EC were reached earlier, in about 4h. In sorption isotherm …experiments, obtained equilibrium data at 28°C fitted well to Freundlich sorption model for all investigated compounds. For NP1EC, in addition to Freundlich, equilibrium data also fitted well to Langmuir model. Linear sorption model was also tried, and equilibrium data of all NP, NP1EO, NP2EO and NP2EC except NP1EC fitted well to this model. Calculated Freundlich coefficient (K_F ) and linear sorption coefficient (K_D ) showed that sorption capacity of the investigated compounds were in order NP > NP2EO > NP1EO > NP1EC ≈ NP2EC. For NP,NP1EO and NP2EO, high values of calculated K_F and K_D indicated an easy uptake of these compounds from aqueous phase onto activated sludge. Whereas, NP1EC and NP2EC with Iow values of K_F and K_D absorbed weakly to activated sludge and tended to preferably remain in aqueous phase. Show more

Keywords: activated sludge, biodegradation end products, endocrine disruptor, nonylphenol polyethoxylates, sorption

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 564-569, 2004

Authors: HE, Ling-yan | HU, Min | WANG, Li | HUANG, Xiao-feng | ZHANG, Yuan-hang

Article Type: Research Article

Abstract: PM_{2.5} samples were collected by a three-stage cascade impactor at two kinds of Chinese restaurants to characterize fine organic particulate matter from Chinese cooking sources. Major individual organic compounds have been quantified by GC/MS, including series of alkanes, n-alkanoic acids, n-alkanals, alkan-2-ones and PAHs.Alkanes and ketones make up a significant fraction of particle-phase organic compounds, ranging from C_{11} to C_{26} , and C_9 to C_{19} …, respectively. In addition, other organic compound classes have been identified, such as alkanols,esters, furans, lactones, amides, and nitriles. The mass concentrations of fine particles, alkanes, n-alkanoic acids and PAHs in air emitted from the Uigur style cooking are hundreds times higher than ambient PM_{2.5} in Beijing. Show more

Keywords: Chinese cooking source, fine organic particles, GC/MS

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 570-575, 2004

Authors: ZHANG, Bang-jun | GUO, Chun-yan | Di, Guo-qing

Article Type: Research Article

Abstract: Noise contours are used to describe the extent of airport noise pollution and to plan land use around airports. The L_{WECPN} (weighted equivalent continuous perceive noise level) recommended by ICAO (International Civil Aviation Organization) is adopted as airport noise rating parameter in this paper. With the help of various mathematical models in the software Surfer, noise contours can be drawn automatically by the completed program in Visual C++ Code. Corrections for …thrust, velocity, atmospheric temperature, humidity and lateral ground attenuation are also considered in the new method, which can improve the efficiency of drawing contours. An example of its use for drawing noise contours of an airport in Zhejiang Province of China is proposed and the predictions and the measurements show agreements well. Show more

Keywords: airport, noise contours, weighted equivalent continuous perceive noise level (L_{WECPN}), Surfer

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 576-580, 2004

Authors: LUO, Hai-feng | QI, Hong-yan | ZHANG, Hong-xun

Article Type: Research Article

Abstract: By combining the cultivation methods with molecular fingerprinting techniques, the diversity surveys of soil bacterial community in 13 areas of China were carried out. The cultivable heterotrophic diversity was investigated by colony morphology on solid LB medium. Genetic diversity was measured as bands on denaturing gradient gel electrophoresis (DGGE) by the extraction and purification of the total soil DNA, and amplification of bacterial 16S rDNA fragments by polymerase chain reaction (PCR). The Shannon-Wiener indices of …diversity (H), richness (S) and evenness (E_H ) were employed to estimate the diversity of soil bacterial community. The results showed that there was an obvious diversification existed in soil from the different areas. However, the genetic diversity estimated by PCR-DGGE can provide more comprehensive information on bacterial community than the cultivation-based methods. Therefore, it is suggested to combine the traditional methods with genetic fingerprinting techniques to survey and estimate soil bacterial diversity. Show more

Keywords: bacterial community, colony morphology, DGGE, diversity

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 581-584, 2004

Authors: XU, Yi | SUN, Wei | WANG, Dong-sheng | TANG, Hong-xiao

Article Type: Research Article

Abstract: Water samples collected from early March 2001 to the end of April 2002 at the branch of Pearl River around the Guangzhou City were analyzed for its micro-polluted characteristics. The coagulation behavior of polyaluminum chlorides (PACls) was then examined focusing on the effect of primary water quality and speciation distribution. The results showed that PACls exhibit better coagulation efficiency than alum in accordance with the different speciation.The turbidity removal property of PACls is evidently better than …alum at Iow dosage. While in neutral zone (about 6.5–7.5), the turbidity removal of PACls decreases owing to the restabilization of particles at higher dosage. The organic matters in raw water exhibit marked influence on coagulation. In acidic zone, organic matters complex with polymer species and promote the formation of flocs. With an increase in pH, the complexation of organics with polymer species gradually decreases, and the removal of organics mainly depends on adsorption. The effect is evidently improved with the raise of B value. Show more

Keywords: PACl, micro-polluted river water, DOC, coagulation efficiency

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 585-588, 2004

Authors: XIA, Ying | MIN, Hang | LU, Zhen-mei | YE, Yang-fang

Article Type: Research Article

Abstract: Bacterium strain EVA17 was isolated from an oil-contaminated soil, and identified as Sphingononas sp.based on analysis of 16S rDNA sequence, cellular fatty acid composition and physiological-chemical tests. The salicylate hydroxylase and catechol 2, 3-dioxygenase (C23O) were detected in cell-free lysates, suggesting a pathway for phenanthrene catabolism via salicylate and catechol. Alignment showed that both of the C23O and GST genes of the strain EVA17 had high similarity with homologues of strains from genus …Sphingomonas. The phylogenetic analysis based on 16S rDNA and C23O gene sequence indicated that EVA17 should be classified into genus Sphingomonas, although the two phylogenetic trees were slightly different from each other. The results of coamplification and sequence determination indicated that GST gene should be located upstream of the C23O gene. Show more

Keywords: phenanthrene, 16S rDNA, glutathione S-transferase, catechol 2,3-dioxygenase, phylogenetic analysis

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 589-593, 2004

Authors: RU, Shu-hua | WANG, Ji-qing | SU, De-chun

Article Type: Research Article

Abstract: Two pot experiments were conducted under greenhouse conditions to investigate the characteristics of Cd uptake and accumulation by two Cd accumulator oilseed rape varieties and one Indian mustard grown on a loamy soil that had been artificially contaminated by different amounts of CdSO_4 (0, 20, 40, 60, 80, 100 mg/kg soil). The relationship between shoot Cd uptake of the two oilseed rape cultivars and the soil Cd concentrations could be simulated via quadratic equations. …The curve showed that maximum shoot Cd uptake of Indian mustard was 314.7 μg/pot at soil Cd concentration of 87.8 mg/kg, while maximum uptake of the variety Xikou Huazi was 543.3 μg/pot at soil Cd concentration of 69.1 mg/kg and that of the variety Zhongyou Za-1hao was 576.7 μg/pot at soil Cd concentration of 84.0 mg/kg, suggesting that shoot Cd uptake ability of the two Cd accumulator oilseed rapes was significantly higher than that of the Indian mustard. Xikou Huazi had higher phytoremediation potential for Cd contaminated soil. Shoot Cd accumulation ability of the two Cd accumulator oilseed rapes was correspond and Cd was easier translocated to the shoot than hyperaccumulator Indian mustard as comparation plant. Shoot Cd distribution pattern showed consistent and significant reduction from older leaves to younger ones of two oilseed rapes and Indian mustard. Cd uptake by oilseed rapes in growth prophase was higher than that of growth anaphase. Show more

Keywords: Cd accumulator oilseed rape, uptake, accumulate, characteristics

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 594-598, 2004

Authors: Lam, K.S. | Wang, T.J. | Wang, T. | Tang, J. | Kajii, Y. | Liu, C.M. | Shim, S.G.

Article Type: Research Article

Abstract: Surface ozone (O_3 ) was measured at Oki Island (Japan), Cheju Island (South Korea), Lanyu Island (Taiwan Province, China), Cape D' Aguilar (Hong Kong SAR) and Lin'an, Longfenshan, Waliguan (China mainland) during January 1994-December 1996 as a component of IGAC/APARE (International Global Atmospheric Chemistry/East Asia-North Pacific Regional Experiment). This paper gave a joint discussion on the observational results at these stations over the study region. Investigations showed that the average of …surface O_3 mixing ratios at the seven sites are 47.9 ± 15.8, 48.1 ± 17.9, 30.2 ± 16.4, 31.6 ± 17.5, 36.3 ± 17.5, 34.8 ± 11.5 and 48.2 ± 9.5 ppbv, respectively. Significant diurnal variations of surface O_3 have been observed at Oki, Cheju, D' Aguilar, Lin'an and Longfenshan. Their annual averaged diurnal differences range from 8 to 23 ppbv and differ in each season.Surface O_3 at Lanyu and Waliguan do not show strong diurnal variability. Seasonal cycles of surface O_3 showed difference at the temperate and the subtropical remote sites. Oki has a summer minimum-spring maximum, while Lanyu has a summer minimum-autumn maximum. The suburban sites at D' Aguilar and Lin' an report high-level O_3 in autumn and Iow level O_3 in summer. Surface O_3 remainshigh in autumn and Iow in winter at the rural site Longfenshan. For the global background station Waliguan, surface O_3 exhibits a broad spring-summer maximum and autumn-winter minimum. The backward air trajectories to these sites have shown different pathways of long-range transport of air pollution from East Asia Continent to North Pacific Ocean. Surface O_3 was found to be strongly and positively correlated with CO at Oki and Lanyu, especially in spring and autumn, reflecting the substantial photochemical buildup of O_3 on a regional scale. It is believed that the regional sources of pollution in East Asia have enhanced the average surface O_3 concentrations in the background atmosphere of North Pacific. Show more

Keywords: surface ozone, trajectory, transport, photochemistry

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 599-609, 2004

Authors: ZHANG, Feng | ZHANG, Xin-Shi

Article Type: Research Article

Abstract: Ecological construction and restoration for sustainable development are now a driving paradigm. It is increasingly recognized that ecological principles, especially landscape ecology theory, are not only necessary but also essential to maintain the long-term sustainability worldwide. Key landscape ecology principles – element,structure and process, dynamics, heterogeneity, hierarchies, connectivity, place and time were reviewed, and use Beijing area as a case study to illustrate how these principles might be applied to ecological construction …and restoration, to eventually achieve sustainability. An example to more effectively incorporate the ecological principles in sustainable planning in China was presented. Show more

Keywords: landscape ecology, ecological principles, ecological benefits, Beijing

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 610-615, 2004

Authors: WANG, WANG | YIN, Cheng-qing | SHAN, Bao-qing

Article Type: Research Article

Abstract: A case study on the transport process of agricultural diffuse P-pollutants was conducted in an experimental watershed locating in the north bank of Yuqiao Reservoir during 2001 and 2002. It was found that diversified artificial and natural buffer/detention landscape structures distributing along the ephemeral stream channel in this watershed played an important role of pollutants removal on downstream water quality, especially they have control effect on the diffuse P-pollutants transport process. Surface flow velocity was …reduced sharply after passing through these structures. During continuous runoff events, the removal rate of TSS, TP, TDP, DRP by the whole system were 66.7%, 60.7%, 48.4%, and 43.3%, respectively. During discontinuous runoff events, removal rate of pollutants by the whole system was higher due to there was no or little surface water and pollutants exported from the watershed, of which removal rate of pollutants all exceeded 99%. The statistical analysis results of runoff events (n = 8) indicated that dry pond was the steadiest structure for controlling diffuse P-pollutants export. Show more

Keywords: diffuse P-pollutants, buffer/detention structures, removal, transport process, water quality

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 616-620, 2004

Authors: WEI, Jian-jun | XU, Xin-hua | WANG, Da-hui

Article Type: Research Article

Abstract: Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the laboratory for treatment of o-chlorophenol. Most of the nanoscale particles are in the size range of 20–100 nm. BET specific surface area of the nanoscale Pd/Fe particles is 12.4 m^2 /g. In comparison, a commercially available Fe powder (< 100 mesh) has a specific surface area of just 0.49 …m^2 /g. Batch experiments demonstrated that the nanoscale Pd/Fe bimetallic particles can effectively dechlorinate o-chlorophenol. Dechlorination efficiency is affected by the mass fraction of Pd in the bimetal, nanoscale Pd/Fe mass concentration and mixing intensity. Show more

Keywords: nanoscale particles, Pd/Fe, dechlorination, o-chlorophenol

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 621-623, 2004

Authors: CAI, Chun-guang | ZHU, Nan-wen | LIU, Jun-shen | WANG, Zhen-peng | CAI, Wei-min

Article Type: Research Article

Abstract: Aerobic heterotrophic granular sludge was cultivated in a sequencing batch shaking reactor (SBSR) in which a synthetic wastewater containing glucose as carbon source was fed. The characteristics of the aerobic granules were investigated. Compared with the conventional activated sludge flocs, the aerobic granules exhibit excellent physical characteristics in terms of settleability, size, shape, biomass density, and physical strength.Scanning electron micrographs revealed that in mature granules little filamentous bacteria could be found, rodshaped …and coccoid bacteria were the dominant microorganisms. Show more

Keywords: aerobic granulation, sequential batch reactor, granule characteristics

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 624-626, 2004

Authors: QIN, Yan-wen | PAN, Gang | ZHANG, Ming-ming | LI, Xian-liang

Article Type: Research Article

Abstract: The adsorption and desorption processes of Zn(II) on γ-MnOOH as a function of particle concentrations (C_p ) were studied. An obvious C_p effect was observed in this adsorption system. The degree of adsorption hysteresis increased greatly with the increasing of C_p , indicating that the extent of the real metastable-equilibrium states deviating from the ideal equilibrium state was enhanced with the increasing of C_p . The C_p …-reversibility relationship confirmed the metastable-equilibrium adsorption (MEA) inequality (Pan, 1998a), which was the core formulation of the MEA theory. Because the MEA inequality was based on the basic hypothesis of MEA theory that adsorption density Γ is not a state variable, the C_p -reversibility relationship gave indirect evidence to the basic hypothesis of MEA theory. Show more

Keywords: zinc, γ-MnOOH, adsorption reversibility

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 627-630, 2004

Authors: Satyanarayan, Shanta | Bejankiwar, Rajesh S. | Chaudhari, P.R. | Kotangale, J.P. | Satyanarayan, Ahana

Article Type: Research Article

Abstract: The effects of pesticides on blood characteristics and histological changes in erythrocytes of the fish species Cyprinus carpio and Puntius ticto were studied. The fishes were exposed to sub lethal concentrations of different chlorinated pesticides namely aldrin, dieldrin, DDT, BHC and chlordane for 10, 20 and 30 d in continuous flow-through test. The LC_{50} values were calculated based on acute toxicity tests and the sublethal doses were arrived at for chronic bioassay studies. Results …showed an increase in haemoglobin content of both Cyprinus carpio and Puntius ticto in case of aldrin and dieldrin. Haemoglobin content reduced from an initial 13 g/100 ml to 8.07 and 10.15 g/100 ml in case of Cyprinus at the end of ten days exposure to aldrin and dieldrin respectively, and gradually increased to 8.7 g/100 ml and 10.15 g/100 ml after 20 d of exposure. The haemoglobin content after 30 d exposure to aldrin and dieldrin was 10.15 g/100 ml and 11.6 g/100 ml respectively. In case of Puntius ticto, the haemoglobin content in control fishes recorded was 12.8 g/100 ml while in case of fish exposed to aldrin, the haemoglobin content reduced initially on ten days exposure to 10.15 g/100 ml and increased to 11.6 g/100 ml and 13.0 g/100 ml during twenty days and thirty days exposure respectively. This trend was also observed with dieldrin in both the fishes studied. Red blood cells were also counted in case of all the pesticides and exposure periods with respect to Cyprinus carpio and Puntius ticto. Irrespective of the species and pesticide, the RBC counts uniformly showed decreasing trend with the increase in exposure period, while packed cell volume, PCV(%) showed increasing trend with respect to increase in exposure period in case of aldrin and dieldrin in both the fishes. But DDT, BHC and chlordane showed decreasing trend in PCV(%) values with increasing periods of exposure. Show more

Keywords: histology, aldrin, dieldrin, DDT, BHC, chlordane

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 631-634, 2004

Authors: SUN, Lu-shi | Abanades, S. | Lu, J.D. | Flamant, G. | Gauthier, D.

Article Type: Research Article

Abstract: Incineration experiments with MSW, which had been impregnated with heavy metals, were presented toobtain information on the volatilization behavior of the elements cadmium (Cd), lead (Pb), and zinc (Zn) underdifferent conditions. Experiments were carried out in a bubbling fluid bed system connected to a customizedinductively coupled plasma optical emission spectroscopy (ICP-OES) for analyzing metals in the flue gas. The resultsindicated that the combustion temperature, the gas atmosphere, and the chlorine content in …the flue gas could affectthe volatilization behavior of heavy metals. In the fluidized bed combustion, a large surface area was provided by thebed sand particles, and they may act as absorbents for the gaseous ash-forming compound. Comparer with themetals Cd and Pb, the vaporization of Zn was Iow. The formation of stable compounds such as ZnO˙Al_2 O_3 couldgreatly decrease the metals volatilization. The presence of chlorine would enhance the volatilization of heavy metalsby increasing the formation of metal chlorides. However, when the oxygen content was high, the chlorinatingreaction was kinetically hindered, which heavy metals release would be delayed. Show more

Keywords: municipal solid waste, incineration, heavy metal emission, fluidized bed

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 635-639, 2004

Authors: WU, Hai-suo | ZHANG, Ai-qiang | WANG, Lian-sheng

Article Type: Research Article

Abstract: Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(II), zinc(II), and chromimum(II), from aqueous solution in the concentration range of 10-100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH ⩽ 5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. …The adsorption rate of immobilized pretreated activated sludge (PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40°C. Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS. Show more

Keywords: biosorption, alginate beads, immobilization, heavy metal, activated sludge, wastewater treatment

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 640-645, 2004

Authors: HAO, Fang-bua | ZHANG, Xue-song | YANG, Zhi-feng

Article Type: Research Article

Abstract: The applicability of a non-point source pollution model – SWAT (soil and water assessment tools) in a large river basin with high sediment runoff modulus (770 t/km^2 in the Yellow River) was examined. The basic database,which includes DEM, soil and landuse map, weather data, and land management data, was established for the study area using GIS. A two-stage "Brute Force" optimization method was used to calibrate the parameters with the observed monthly flow and …sediment data from 1992 to 1997. In the process of calibration automated digital filter technique was used to separate direct runoff and base flow. The direct runoff was firstly calibrated, and the base flow, then the total runoff was matched. The sediment yield was calibrated to match well. Keeping input parameters set during the calibration process unchanged, the model was validated with 1998-1999's observed monthly flow and sediment. The evaluation coefficients for simulated and observed flow and sediment showed that SWAT was successfully applied in the study area: relative error was within 20%, coefficient of determination and Nash-Suttcliffe simulation efficiency were all equal to or above 0.70 during calibration and validation period. Show more

Keywords: Yellow River, SWAT, sediment, flow, non-point source pollution

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 646-650, 2004

Authors: WANG, Guan-ping | SHI, Han-chang | SHEN, Zhi-song

Article Type: Research Article

Abstract: Osmotic distillation (OD) was found to be a coupled process in membrane absorption (MA) for the treatment of high strength ammonia wastewater. As a result, ammonia could not be concentrated in absorption solution (AS) as expected. The inhibition of the coupled OD in MA process was investigated as well as various factors affecting the inhibition. The results indicated that the coupled OD can be effectively inhibited by heating concentrated solution and cooling dilute solution. It was …also found that experimental minimum inhibition temperature difference (MITD) between concentrated and dilute solutions was different when using polyvinylidene fluoride (PVDF) and polypropylene (PP) membranes respectively, which could be ascribed to material properties, such as OD and membrane distillation (MD) coefficients of the membranes. Experimental MITDs were found to be higher than theoretical MITDs which were calculated using a simplified method. Show more

Keywords: membrane absorption, osmotic distillation, high strength ammonia wastewater

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 651-655, 2004

Authors: CHEN, Ying-xu | YIN, Jun | FANG, Shi

Article Type: Research Article

Abstract: The nuisance impact of air pollutant emissions from wastewater pumping stations is a major issue of concern to China. Hydrogen sulfide and ammonia are commonly the primary odor and are important targets for removal. An alternative control technology, biofiltration, was studied. The aim of this study is to investigate the potential of unit systems packed with compost in terms of ammonia and hydrogen sulfide emissions treatment, and to establish optimal operating conditions for a full-scale conceptual …design. The laboratory scale biofilter packed with compost was continuously supplied with hydrogen sulfide and ammonia gas mixtures. A volumetric load of less than 150 gH_2 S/(m^3 ˙ d) and 230 gNH_3 /(m^3 ˙ d) was applied for about fifteen weeks. Hydrogen sulfide and ammonia elimination occurred in the biofilter simultaneously. The removal efficiency, removal capacity and removal kinetics in the biofilter were studied. The hydrogen sulfide removal efficiency reached was very high above 99%, and ammonia removal efficiency was about 80%. Hydrogen sulfide was oxidized into sulphate. The ammonia oxidation products were nitrite and nitrate. Ammonia in the biofilter was mainly removed by adsorption onto the carrier material and by absorption into the water fraction of the carrier material. High percentages of hydrogen sulfide or ammonia were oxidized in the first section of the column. Through kinetics analysis, the presence of amrronia did not hinder the hydrogen sulfide removal. According to the relationship between pressure drop and gas velocity for the biofilter and Reynolds number, non-Darcy flow can be assumed to represent the flow in the medium. Show more

Keywords: biological removal, hydrogen sulfide, ammonia mixture

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 656-661, 2004

Authors: ZHOU, Qi-xing | SYLVESTER, Runyuzi | YU, Ji-yu | ZHANG, Qian-ru

Article Type: Research Article

Abstract: Accidental collapse resulted from unstable factors is an important technological problem to be solved in sanitary landfill. Microbiological degradation of organic matters in landfilled solid waste are an important unstable factor. A landfill reactor was thus manufactured and installed to examine quantitative and population dynamics of microorganisms during degradation of landfilled solid waste. It was showed that unstable landfill can be reflected and indicated by microbiological features such as rapidly decreased growth …amount of microorganisms, no detection of fungi and actinomyces, and changing the dominant population into methanogenic bacteria and Acinotobacter. Show more

Keywords: municipal solid waste, sanitary landfill, unstable factor, microbiological indication

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 662-665, 2004

Authors: XU, Zhen-zhu | ZHOU, Guang-sheng | LI, Hui

Article Type: Research Article

Abstract: Controlled experiment of Leymus chinensis seedlings grown in the environmental growth chambers at 3 soilmoisture levels and 3 temperature levels was conducted in order to improve the understanding how leafphotosynthetic parameters will respond to climatic change. The results indicated that soil drought and hightemperature decreased the photochemical efficiency of photosystem (F_v /F_m ), the overall photochemical quantumyield of PSIl (yield), the coefficient of photochemical fluorescence quenching (q_p ), but …increased the coefficient ofnon-photochemical fluorescence quenching (q_N ). Severe soil drought would decrease F_v /F_m and yield by 3.12% and 37.04% under 26°C condition, respectively, and 6.60% and 73.33% under 32°C condition, respectively, suggesting that higher temperature may enhance the negative effects of soil drought. All the soil drought treatments resulted in the decline in leaf nitrogen content. There was no significant effect of temperature on leaf nitrogen level, but higher temperature significantly reduced the root nitrogen content and the ratio of root nitrogen to leaf nitrogen, indicating the different strategies of adaptation to soil drought and temperature. It was also implied that higher temperature would enhance the effect of soil drought on leaf photosynthetic capacity, decrease the adaptability of Leymus chinensis to drought. Show more

Keywords: chlorophyll fluorescence, nitrogen level, Leymus chinensis, soil moisture, soil temperature

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 666-669, 2004

Authors: YANG, Zhong-yi | CHEN, Fu-hua | YUAN, Jian-gang | ZHENG, Zheng-wei | WONG, Ming-hung

Article Type: Research Article

Abstract: Responses of Sesbania rostrata and S. cannabina to Pb, Zn, Cu and Cd toxicities were assessed by a seed-suspending seedbed (SSS) approach. The results showed that the SSS approach was suitable for testing the tolerance of a plant to the stress of toxic metals. The endpoints include seed germination success, straightened radicle and hypocotyl of the seedlings from the seeds. The measurements could be done easily and accurately. It was found that the elongation of radicle …was the most sensitive indicator to the stress of heavy metals among the endpoints. When exposure to Iower or medium concentrations of Pb, Zn, and Cd, the development of the lateral roots were favorable. Species of S. rostrata was more tolerant than S. cannabina to the heavy metals, especially to Zn and Cd. The ED_{50} of Pb, Zn, Cu and Cd were 32.90, 5.32, 4.40 and 12.00 μg/ml for S. rostrata,respectively, and.they were 30.11, 2.87, 4.05 and 4.94 μg/ml respectively for S. cannabina. Show more

Keywords: Sesbania rostrata, Sesbania cannabina, heavy metal tolerance, testing method, root elongation, Pb/Zn tailings

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 670-673, 2004

Authors: ZHAO, Yi | FU, Yan-chun | MA, Shuang-chen | HUANG, Jian-jun

Article Type: Research Article

Abstract: The highly active absorbent with oxidization based on fly ash, lime and additive was prepared. Experiments of simultaneous desulfurization and denitrification were carried out using fixture bed and duct injection.The influencial factors for the absorptive capacity of the absorbent were studied. The absorptive capacities of 120.7 mg for SO_2 and 43.7 mg for NOx were achieved at a Ca/(S + N) molar ratio 1.2, respectively, corresponding removal efficiencies of 87% and 76%, while spent …absorbent appeared in the form of dry powder. The optimal temperature and humidity of flue gas treated with this process were shown to be approximately 50°C, and 5% respectively. The mechanism of removal for SO_2 and NOx was investigated. In comparison with traditional dry FGD, this process appears to have lower cost, less complicated configuration and simpler disposal of used absorbent. The valuable references can be provided for industrial application by this process. The foreground of application will be vast in China and in the world. Show more

Keywords: simultaneous desulfurization and denitrification, duct injection, absorptive capacity

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 674-677, 2004

Authors: LI, Lian-fang | LI, Guo-xue | YANG, Ren-bin | GUO, Zheng-yuan | LIAO, Xiao-yong

Article Type: Research Article

Abstract: Laboratory experiments about the dissipation, adsorption and translocation in four paddy topsoils were conducted in this paper. From the results it can be concluded as follows: the dissipation rate of clomazone differed greatly in different paddy soil derived from different parent materials. The half-lives for clomazone degradation in paddy soils ranged from 5.7 to 22.0 d. The order of clomazone dissipation rate was reddish yellow paddy soil > alluvial sandy paddy soil > yellow clayey paddy …soil > purple sandy paddy soil. Clomazone sorption quantity was significantly correlated with organic carbon (R^2 = 0.62) and clay content (R^2 = 0.67) in the tested paddy soils.Positive correlation was found between apparent K_d value and cation exchange content (CEC). The consequences for the adsorption of different soils were purple sandy paddy soil > yellow clayey paddy soil > reddish yellow paddy soil > alluvial sandy paddy soil. Under the simulated rainfall of 200 mm through four different unsaturated soil lysimeters over 24 h, clomazone was readily to be leached into lower surface soil and there was about 2.6%–4.2%of applied clomazone leached out of 20 cm cultivated soil layer. Translocation experiments showed that the order of clomazone leaching ability was: alluvial sandy paddy soil > reddish yellow paddy soil > yellow clayey paddy soil > purple sandy paddy soil. Simple regression results manifested that factors like CEC, organic carbon, clay, and adsorption rate constant had been negatively correlated with the percentage of clomazone loss from soil lysimeters. Show more

Keywords: clomazone, dissipation, adsorption, translocation, paddy topsoils

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 678-682, 2004

Authors: ZHAI, Yun-bo | WEI, Xian-xun | ZENG, Guang-ming

Article Type: Research Article

Abstract: According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters including the total yield, adsorption of methylene blue, adsorption of iodine, BET surface area, micro-pore volume are 35%–49%, 16.5–38 mg/g, 285–362 mg/g, 185–359 m^2 /g, and 0.112–0.224 m^3 /g, respectively. According to the experimental data, the multi-linear regression method was adopted to …fit the relations between the characteristic parameters and influential factors. At final, through optimization method, the optimal adsorbent is obtained when using 62 min as hold time and 1105 K as pyrolysis temperature. Under the conditions, the adsorbent was produced and compared the characteristic parameters with model forecast value, the coherence is satisfied. Show more

Keywords: adsorbent, sewage sludge, pyrolysis temperature, hold time, Doehlert's matrix

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 683-686, 2004

Authors: YANG, Xi | ZHAN, Man-jun | KONG, Ling-ren | WANG, Lian-sheng

Article Type: Research Article

Abstract: The qualitative and quantitative analyses of reactive oxygen species are essential to determine their steady-state concentration and related reaction mechanisms in environmental aquatic systems. In this study, salicylic acid was employed as an innovative molecular probe of hydroxyl radical (OH) generated in aqueous nitrate and nitrite solutions through photochemical reactions. Kinetic studies showed that the steady-state concentrations of OH in aqueous NO_3^- (10 mmol/L, pH = 5) and NO_2^- (10 …mmol/L, pH = 5) solutions under ultraviolet irradiation were at a same magnitude, 10^{-15} mol/L. Apparent quantum yields of OH at 313 nm were measured as 0.011 and 0.07 for NO_3^- and NO_2^- respectively, all comparable to the results of previous studies. Show more

Keywords: photochemistry, hydroxyl radical, salicylic acid, nitrate, nitrite

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 687-689, 2004

Authors: ZHANG, Ke-qiang | CHEN, Xiu-wei | JI, Min | NING, An-rong | FAN, Huan | ZHOU, Ke

Article Type: Research Article

Abstract: A composite microbial system, including a strain of Candida tropicalis (W3), a strain of Lactobacillus plantarm (WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade corn straw.The final pH was acid owing to the inoculation of acidogenic bacteria, and under this condition the composite fungi system could produce complex enzyme to destroy the compact structure of corn straw. The experimental results showed that the biomass of composite fungi could reach up …to maximum when the pH value was 4.5. Through the bio-degradation by combining acidogenic bacteria with the composite fungi system, the cellulose, hemi-cellulose and lignin degradation rates of corn straw powder were 26.36%, 43.30% and 26.96%, respectively. And the gross crude protein content increased 60.41%. This study provided the evidence for the feasibility of developing a composite microbial system with high capability of degrading straw lignocelluloses in order to make reasonable use of straw resource and protect rural eco-environment. Show more

Keywords: lignocellulose, bio-degradation, acidogenic bacteria, composite fungi system

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 690-693, 2004

Authors: ZHANG, Ming-ming | PAN, Gang | YAN, Hai | CHEN, Hao

Article Type: Research Article

Abstract: A simple and Iow-cost method to obtain cyanobacterial toxin microcystin-LR (MC-LR) was developed. A new strain of Microcystis aeruginosa, named DC-1, producing microcystin-LR but not microcystin-RR, was separated from the field blooming algae samples of Dianchi Lake, in southwest of China. Following three times' freeze and thaw treatment, the cultivated DC-1 cells were extracted with 40% methanol in water. The extract was centrifuged and the supernatant applied to a Hydrophilic-Lipophilic Balance (HLB) SPE cartridge. …Eluted impurities with a certain gradient from 30% to 50% methanol in water, MC-LR was finally eluted from the HLB cartridge with 60% methanol in water, and samples containing 3.85% to 14.8% of MC-LR were obtained. These MC-LR samples may be used in adsorption and biodegradation experiments instead of using expensive standard reagents. Show more

Keywords: purification, extraction, microcystins, HLB cartridge

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 694-696, 2004

Authors: MAO, Zhan-po | YIN, Cheng-qing | SHAN, Bao-qing

Article Type: Research Article

Abstract: The spatial and temporal variability of nutrients and suspended solids were investigated for two years in a 1.8 km agricultural headwater stream, located by Chaohu Lake, southeastern China. The stream form was greatly modified by human activities into channelized, pond and estuary shapes. The stream could be divided into 4channelized reaches (1.3 km), a pond reach (0.15 km) and 3 estuary reaches (0.36 km). It was found that nutrients and TSS concentrations in the stream showed …temporal variability, and higher concentrations occurred in months with high precipitation and intensive agricultural activities. And, retention of total nitrogen (TN), nitrate (NO^-_3 -N),ammonium (NH^+_4 -N) and total suspended solids (TSS) predominantly occurred in the pond reach and estuary reaches with larger width and Iow current velocity. Pollutants retained in these reaches accounted for more than 50%of those retained in whole stream. The retention mostly happened in the rain-runoff events and it was 7 to 27 times than that in base flow. The results showed that the channelized reach was the most important source for pollutants release under either runoff or base flow, and its release accounted for more than 90% of whole stream release.There was a high spatial variability of nutrients retention in different channelized reaches. The channelized reach directly discharging into the pond did always retain nutrients and TSS under base flow and runoff conditions, whereas the other channelized reaches performed differently in different hydrological conditions. The high spatial and temporal variability of nutrients and TSS in the stream indicated that anthropogenic disturbance of the agricultural headwater stream, such as channelization and excavation, would be expected to decrease the capacity of nutrients retention in the stream. Show more

Keywords: retention, release, nutrients, variability, stream forms

Citation: Journal of Environmental Sciences, vol. 16, no. 4, pp. 697-704, 2004