Journal of Environmental Sciences - Volume 14, issue 4

Authors: Zhang, Shao-yuan | van Houten, Renze | Eikelboom, Dick H. | Jiang, Zhao-chun | Fan, Yao-bo | Wang, Ju-si

Article Type: Research Article

Abstract: Based on the microorganism kinetic model, the formula for computing hydraulic retention time in a membrane bioreactorsystem (MBR) is derived. With considering HRT as an evaluation index a combinational approach was used to discuss factors which have an effect on MBR. As a result, the influencing factors were listed in order from strength to weakness as: maximum specific removal rate K, saturation constant K_s, maintenance coefficient m, maximum specific growth rate µ_m and observed yield coefficient …Y_obs. Moreover, the formula was simplified, whose parameters were experimentally determined in petrochemical wastewater treatment. The simplified formula is ( = 1.1 (1/ - 1) (K_s + S) /KX_0, for petrochemical wastewater treatment K and K_s equaled 0.185 and154.2, respectively. Show more

Keywords: membrane bioreactor, wastewater treatment, hydraulic retention time, microbial kinetic model, kinetic constant, operation constant

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 501-507, 2002

Authors: Udo, Mfon T.

Article Type: Research Article

Abstract: Aspects of the trophic attributes of the mudskipper, Periophthalmus barbarus, occurring in the mangrove swamps of ImoRiver estuary, Nigeria, were investigated during a 12-month period(April, 1992-March, 1993). Feeding intensity increased with size;it was higher in the dry season (November-April) than in the wetseason (May-October); monthly changes in the indices of feeding intensity were significantly correlated. Major food objects comprised detritus and benthic algae; crustaceans, insects,macrophyte matter and sand grains were minor food …objects whilefish, molluscs, Chilopoda, nematodes and fungi were unconsciously devoured objects. Diet varied seasonally; algae and sesarmid crabs were generally more in the dry season than during the rains whereas FPOM and fish increased in the wet over dry season. The mudskipper display a high degree of euryphagy and can be considered as a generalist and an omnivore. The lower trophic status of P. barbarus qualifies it as a good aquaculture candidate. Food richness was higher in big-sized class (BSC) than small-sized class (SSC).Size-based and seasonal variations were not apparent in food richness. Diet breadth was higher in the BSC than the SSC; there was dry season increase in diet breadth. Show more

Keywords: Periophthalmus barbarus, indices of feeding intensity, diet composition, mangrove swamp, Imo River estuary, Nigeria

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 508-517, 2002

Authors: Liu, Shao

Article Type: Research Article

Abstract: The role of water pricing for managing water resources is widely recognized in many areas of the world because of the increasing scarcity of water resources, a high competition between water uses and environmental degradation. Based on the analysis of cost of water, this paper explores which types of cost should be reflected in the water pricing enhancing the sustainability of water resources. The principle of full cost pricing in which the cost should include supply …cost, opportunity cost and externalities is proposed as a means to achieve the sustainability of water resources. In a case study of Beijing, low water price is analyzed as one reason for unsustainable water consumption. Thus waterpricing justified is necessary and pressing. It is proposed to justify water price in phased manner and eventually towards full cost pricing. The assessment of impacts on water resources by raising water price shows water pricing could alleviate the conflict between water supply and demand. This paper concludes that water pricing can play an effective role in enhancing the sustainability of water resources in Beijing. Show more

Keywords: water resources, water price, cost, full cost pricing, sustainability, Beijing

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 518-523, 2002

Authors: Ye, Chang-ming | Wang, Xing-jun | Zheng, He-hui

Article Type: Research Article

Abstract: The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organicmatters addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS(sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid)mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soilalone samples were identified by GC/MS at the end of incubation.Addition of SDBS and HA to soil decreased acetochlor biodegradation, …but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone,soil-SDBS mixtures and soil-HA mixtures were 4.6d, 6.1d, 5.4d, and 5.3d, 4.9d, and 5.3d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor. Show more

Keywords: butachlor, acetochlor; , degradation products , biodegradation kinetics, soil

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 524-529, 2002

Authors: Ye, Dai-qi | Tian, Liu-qing | Liang, Hong

Article Type: Research Article

Abstract: NOx emission abatement catalysts V_2O_5 supported on various TiO_2 including anatase, rutile and mixture of both have been investigated with various physico-chemical measurements such as BET, NH_3-TPD, NARP, XRD and so on, and the effect of TiO_2 surface properties on the SCR activity of V_2O_5/TiO_2 catalysts was studied.It has been found that the TiO_2 surface properties had strong affect on the SCR activity of V_2O_5/TiO_2 catalysts. The stronger acidic property resulted the higher exposure of active …sites aswell as the higher SCR activity. Show more

Keywords: NOx, SCR, V2O5/TiO2 catalyst, surface acidity

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 530-535, 2002

Authors: Opara, K.N.

Article Type: Research Article

Abstract: The distribution, abundance and intensity of the annelid worm, Piscicola geometra(leeches) infecting Oreochromis niloticuscultured in a rainforest fish pond, South Eastern Nigeria wasstudied over a 12 months period. Three hundred fish were examined of which 48.3% were infected. Infection occurred throughout the year, with a peak in February. Female fish had a significantly higher intensity of infection(P<0.05) than males. There was a clear seasonal periodicity in the degree of infection and the distribution of …the parasite exhibited an aggregated or contagious model of dispersion. There was a significant positive correlation between the size of the fish and worm burden. Show more

Keywords: Piscicola geometra, pond, Oreochromis niloticus, population dynamics, parasites

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 536-540, 2002

Authors: Xia, Si-qing | Gao, Ting-yao | Zhou, Zeng-yan

Article Type: Research Article

Abstract: A practice wastewater treatment plant was operated usingintermittent aeration activated sludge process to enhancebiological nitrogen and phosphorus removal. When the influent concentrations of COD_Cr, BOD_5, TN, TP, NH_3-N, TKN, and SS varied in a range of 207.5-1640 mg/L, 61.8-637 mg/L, 28.5-75.6 mg/L, 4.38-20.2 mg/L, 13.6-31.9 mg/L, 28.5-75.6 mg/L, and 111-1208 mg/L, the effluent means were less than 50 mg/L, 20 mg/L, 5 mg/L, 1.0 mg/L,5 mg/L, 10 mg/L, and 20 mg/L, respectively. Based on a long …time of operating results, this process is very suitable for nutrient biological removal for treating the municipal wastewater those water characteristics are similar as that of the Songjiang Municipal Waste water Treatment plant( SJMWTP). Show more

Keywords: intermittent aeration process, high concentration activated sludge, nitrogen removal, phosphorus removal

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 541-546, 2002

Authors: Wang, Ren-zhong | Gao, Qiong | Tang, Hai-ping

Article Type: Research Article

Abstract: Plant life form diversity and its direct gradientanalysis on a larger scale climate change gradient were tested,based on the data from Northeast China transect platform. Theresults showed that the species numbers, life form richness andlife form diversity were relative higher at the eastern forests andthe ecotone between typical vegetation, while those on the meadowgrasslands and typical steppes were lower. Although plant lifeforms can reflect the climate variations, life form diversity is not consistent with the …major global gradient along the NECT. Show more

Keywords: northeast China transect, plant life form diversity, ecotone, gradient analysis

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 547-551, 2002

Authors: Yu, Ruilian | Hu, Gong-ren | Zhao, Yuan-hui

Article Type: Research Article

Abstract: Quantitative structure-activity relationships (QSARs) were developed for 43 aromatic compounds toxicity to Photobacterium phosphoreum and Daphnia magna based on four methods: octanol/water partition coefficient, linear solvation energy relationship, molecular connectivity index and group contribution. Through the evaluation of four QSAR methods, LSER was proved to be the best. And it applied to the widest range of chemicals with the greatest accuracy.

Keywords: aromatic compounds, Photobacterium phosphoreum, Daphnia magna, QSAR models

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 552-557, 2002

Authors: Guo, Yu-qing | Warwick, R.M. | Zhang, Zhi-nan | Mu, Fang-hong

Article Type: Other

Abstract: A hierarchical diversity index--taxonomic distinctness index +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes. The result showed that the Bohai Bay and other coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of the benthos in these locations. And most offshore sampling sites …in the middle of the Bohai Sea were clear and unpolluted. Show more

Keywords: taxonomic distinctness index +, freeliving marine nematodes, Bohai Sea

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 558-562, 2002

Authors: Luo, Yi | Tackx, Mickey | Li, Fa-yun | Mao, Da-qing | Zhou, Qi-xing

Article Type: Research Article

Abstract: Two dominant species of Willow (Salix triandra) and Reed(Phragmites australis) along the Schelde estuary (in Belgium) were selected in this research. The pigments of higher plant was used as biomarkers, the decomposition process of the two species were studied after they fall into the Schelde estuary. After statistical analysis (Spearman rank order correlation, p<0.05), the results has shown the decomposition dynamics pattern of the pigments, and the willow showed different pattern in comparing with the reed, …eg. Chlorophyll-a decomposition dynamics for willow is: y_1 = 12196x² -175895x + 1E + 06 + k, R2 = 0.5706 while for reed is: y_2 = -37878x²+ 229782x + 734282 + k, R² = 0.9065. The precise time of the leaf litter spent in the water was also calculated as were less than 24 days, 24-37 days, longer than 37 days (willow) and less than 24 days, longer than 24 days (reed), the leaf litter fate of the two dominant species in the Schelde estuary was also compared. Show more

Keywords: leaf litter ecological fate, Salix triandra, Phragmites australis, Schelde estuary

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 563-567, 2002

Authors: Li, Guo-qing | Zheng, Yuan-run

Article Type: Research Article

Abstract: The characteristics of precipitation, temperature andtheir combination determine the special ecological environmentpattern of Ordos Plateau. Analyzing its evolutionary trendattributes to understanding the succession process of theecological environment of Ordos Plateau and has crucialinstructional significance on the ecological restoration researchbeing conducted in this region. Four time scales, arranging fromten days, one month, one season (growing season contrasting tonon-growing season) to one year were adopted to analyze the climatedata which included nearly 30 years …and were collected by eightweather stations on Ordos Plateau. The results indicated that the mean annual temperature and the mean monthly temperature ofFebruary, September and December, had increased significantlyduring the late 30 years. The annual precipitation did not showsignificant changes but its distribution pattern had changedobviously. The ratio of precipitation of major growing season(May-October) to annual precipitation had increased distinctively,and five counties' precipitation reached statistically significantlevel. And the ratio of precipitation of latter growing season(September) to one year decreased significantly while the ratio ofnon-growing season(November-next April) to one year changedinsignificantly. The results showed that maybe the interaction ofincreased mean temperature and insignificant change ofprecipitation in non-growing season was one of the reasons why thedesertification of the region was deteriorating in recent years. Using some factors closely relating to vegetation succession suchas mean annual temperature, mean annual precipitation, distributivepattern of precipitation, mean temperature of the coldest month,mean temperature of the warmest month, precipitation of the warmestmonth, mean temperature of growing season, precipitation of growingseason, potential evapotranspiration(PET) and radiative drynessindex(RDI), to synthetically analyze the climate characteristics ofOrdos Plateau. The regionalized Ordos Plateau to three syntheticalclimate types were recognized as follows: Type I, semi-humid andlow evaporation (including Jungar Banner, Dongsheng City and EjinHoro Banner), Type II, semi-arid, semi-humid and moderateevaporation (including Uxin Banner and Dalad Banner), Type III,arid and high evaporation (including Hanggin Banner, Otog Bannerand Otog Qian Banner). Show more

Keywords: climate change, climatic synthetical regionalization, restoration ecology, Ordos Plateau

Citation: Journal of Environmental Sciences, vol. 14, no. 4, pp. 568-576, 2002