Journal of Environmental Sciences - Volume 13, issue 2

Authors: Tian, Wen-dong | Wei, Xiao-lin | Li, Jun | Sheng, Hong-zhi

Article Type: Research Article

Abstract: The internal circulating fluidized bed (ICFB) system is characterized with fast combustion, low emission, uniformity of bed temperature and controllability of combustion process. It is a kind of novel clean combustion system, especially for the low-grade fuels, such as municipal solid waste(MSW). The experimental systems of ICFB with and without combustion were designed and set up in this paper. A series of experiments were carried out for further understanding combustion process and characteristics of several design …parameters for MSW. Based on the results, a design routine for the ICFB system was suggested for the calculation of energy balance, airflow rate, heat transfer rate, and geometry arrangement. A test system with ICFB combustor has been set up and the test results show that the design of the ICFB system is successful. Show more

Keywords: fluidized bed, ICFB, combustion, MSW

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 185-188, 2001

Authors: Deng, Yi-xiang | Chen, Ji-ning | Hu, Xue-tao

Article Type: Research Article

Abstract: MAGIC is one of the most widely used models for forecasting long-term acidification. The model's code, however, has been experiencing numerical instability, though this might not be widely known to the public users. The major instability comes from the analytical solution to two cubic equations for calculating SO_4²^-concentration and the exchangeable fraction of Al on the soils. The mathematical algorithm for calculating the concentration of SO_4²^- from a quadratic equation is also found instable. …This paper is aimed at improving the instability above through proved numericalalgorithms. Show more

Keywords: numerical instability, MAGIC model

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 189-191, 2001

Authors: You, Song-cai

Article Type: Research Article

Abstract: This paper presents the study on agriculture adaptation to climate change by adopting the assumed land use change strategy to resist the water shortage and to build the capacity to adapt the expected climate change in the northern China. The cost-benefit analysis result shows that assumed land use change from high water consuming rice cultivation to other crops is very effective. Over 7 billions m³ of water can be saved. Potential conflicts between different social interest …groups, different regions, demand and supply, and present and future interests have been analyzed for to form a policy to implement the adaptation strategy. Trade, usually taken as one of adaptation strategies, was suggested as a policy option for to support land use change, which not only meets the consumption demand, but also, in terms of resources, imports waterresources. Show more

Keywords: agriculture, adaptation, climate change, land use change

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 192-197, 2001

Authors: PU, Jiang-ping | PU, Pei-min | HU, Chun-hua | QIANG, Jun-ling | PU, Jue-xing | HUA, Ji-kang

Article Type: Research Article

Abstract: A new technology for harnessing the dye polluted water and dye collection was developed. It is based on the enhanced evaporation by using solar, wind, and air temperature energy and additional heat-electric energy. It consists of four parts: (1) evaporation carrier system (evaporation carrier and frame for evaporation carrier) for polluted water; (2) polluted water circulating system (pumping-spraying-collecting); (3) heating system; (4) workshop with polluted water reservoir-tanks and rainfall prevention roof. The …polluted water was (heated in case necessary) sprayed to the evaporation carrier system and the water was evaporated when it moved in the space and downward along the carrier mainly by using natural (solar, wind, and air temperature energy). In case, when there is no roof for the carrier system, thepolluted water can be stored in the reservoirs (storage volume for about 20 days). The first 10-25 mm rainfall also need to be stored in the reservoirs to meet the state standard for discharging wastewater. The dye may be collected at the surface in the reservoir-tanks and the crystallized salt may be collected at the bottom plate. The black-color wastewater released by the factory is no more discharged to the surface water system of Taihu Lake Basin. About 2 kg dye and 200 kg industrial salt may be collected from each tone of the polluted water. The non-pollution production of dye may be realized by using this technology with environmental, economical and social benefits. Show more

Keywords: dye polluted water harnessing, dye collection technology

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 198-200, 2001

Authors: Gu, Guo-bang | Huang, Guo-feng | Li, Xin-jun | Wan, Hong-fu | Li, Fang-bai

Article Type: Research Article

Abstract: The gold ion modified TiO_2 was prepared by means of sol-gel whereas gold deposited TiO_2 was prepared by means of photo- reduction. The physical properties were influenced significantly by the presence of gold ion or gold. The enhanced photo-activity of gold modified TiO_2 was quantified in terms of methylene blue degradation. The presence of gold ion in TiO_2 lattices or gold on TiO_2 surface enhanced their photo-activity. The optimum molar content of gold ion doping and …gold deposition all was 0.5%. The first-order rates constants of gold modified TiO_2 was more than that of pure TiO_2, and decreased by increasing the content of gold ion and gold when their contents were more than 0.5%. Gold iondoped in TiO_2 lattices was more effective to enhance the photo-activity than gold on TiO_2 surface. Moreover, the relationship between physical properties, chemical properties and photo-activity has been discussed. Show more

Keywords: gold modification, titanium dioxide, photo-catalysis, methylene

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 201-204, 2001

Authors: Yang, Jian-xin | Nielsen, Per H.

Article Type: Research Article

Abstract: The methodological basis and procedures for determination of Chinese normalization references and weighting factors according to the EDIP-method is described. According to Chinese industrial development intensity and population density, China was divided into three regions and the normalization references for each region were calculated on the basis of an inventory of all of the region's environmental emissions in 1990. The normalization reference was determined as the total environmental impact potential for the area in question …in 1990(EP(j)_90) divided by the population. The weighting factor was determined as the normalization reference (ER(j)_90) divided by society's target contribution in the year 2000 based on Chinese political reduction plans, ER(j)_T2000.). This paper pressents and discuss results obtained for eight different environmental impact categories relevant for China:global warming,hazardous waste and slag and ashes. Show more

Keywords: life cycle, impact assessment factors, China

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 205-209, 2001

Authors: Fang, Zhan-qiang | Cheung, R. Y. H. | Wong, M. H.

Article Type: Research Article

Abstract: Molluscs are able to accumulate heavy metals and impose health hazard to consumers. The main objective of the present study is to investigate the heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta. Fourteen species of edible molluscs were purchased from six markets in Hong Kong and Guangdong Province. The fresh of these biota were tested for their cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), …chromium (Cr), antimony (Sb) and tin (Sn)concentrations (based on wet weight). The results indicated that amongst the 14 edible molluscs, only Cd, Pb, Ni, Cr, Sb and Sn concentrations in three species(Ruditapes philippinarum, Perna viridis and Hemifusus tuba) were within the local regulatory limits. Over 60% of bivalve species exceeded maximum permitted levels of Cd (2 µg/g) and Cr (1 µg/g), while over 40% of gastropod species exceeded the maximum levels of Sb (1 µg/g) and Cr(1 µg/g). Most of the samples collected from Hong Kong had significantly higher contents of Pb and Sb, but similar levels of Cd, Cu and Zn when compared with samples collected across the border (p<0.5; p<0.01; p<0.001 respectively). In general, the molluscs purchased in Guangdong markets had higher metal contents than those purchased from the Hong Kong markets. When compared with the Provisional Tolerable Weekly Intake or Maximum Acceptable Daily Load recommended by FAO/WHO Expert Committee on Food Additives, Cd levels of five species (Anadara ferruginea, Pinna pectinata, Chlamys nobilis, Babylonia lutosa and Hemifusus terntanus) and Cr levels of seven species (Anadara ferruginea, Paphia undulata, Pinna pectinata, Babylonia lutosa, Hemifusus terntanus, Cymbium melo and Cipangopaludina chinensis) were higher than both the human daily acceptable limits (for Cd and Cr respectively) and the local regulatory levels (for Cd and Cr respectively). Show more

Keywords: Heavy metals, edible molluscs, human health, Pearl River Delta

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 210-217, 2001

Authors: Khan, M. A.

Article Type: Research Article

Abstract: In arid zone of Rajasthan, India, nearly 21900 hm² area along Bandi River has been affected by industrial effluent discharge into the river bed. Analysis of groundwater samples collected from these sites revealed that area at the vicinity of the river is most affected. The effluent water in the river is the main source of contamination of ground water. Concentration of sodium and chloride has been higher with proportional increase in TDS and EC value in …the area within zone A (river water), zone B(0-100m), zone C (101-250m), zone D (251-500m) and zone E (501-1000m). There is decreasing trend in ion concentration from zone A to zone E and F, reflecting reduced effect of effluents. The pollution of water resources has resulted in the degradation of other natural resources such as land, soil and vegetation. Nearly 4463 hm² (20.38%) area has been very severely affected. EC value at places exceeds 20 dS/m. Soil and land have become hard, compact and saline. Cropping intensity has declined. In the area (3633 hm²)affected severely, the EC value of water varies from 10-20 dS/m.Irrigation with such water has created problem of salinity, sodicity in soils. Herbal biomass declined considerably. Double cropping has almost stopped. Almost 8494 hm² area is affected moderately. EC of ground water varies form 5 to 10 dS/m. Fragile surface crust, declining trend of phosphorous and potassium in the soil, poor density of natural vegetation are significant manifestations. Apart from this, 5305 hm² area is slightly affected. Show more

Keywords: pollution, water resources, industrialization, arid zone, India

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 218-223, 2001

Authors: Sheng, Xue-bin | Sun, Jian-zhong | Liu, Yun-xia | Feng, Jiang-bin

Article Type: Research Article

Abstract: The Bashang region is a typical vulnerable eco-environmental zone. Our analysis of paleodunes, paleosol profiles, and lake changes taking place during last ten thousands years indicated that:(1) 10-6.9 ka B.P. was a post-glacial temperature-increasing stage, in which lakes had their high water level; (2) 6.9-3.0 ka B. P. was a large warm stage, during which four paleosol layers were developed and climate fluctuation has assumed 4-5 small cold-humid and cold-dry alternations. Since 5.4 ka B.P, the …lakes tended to gradually shrink; and by 2.1 ka B.P., water level has fallen by 2.7 m; (3) since 3.0 ka B. P. a general trend of the region was to change into a dry, warm-dry and cold-dry environment. Show more

Keywords: Bashang region, environmental change

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 224-227, 2001

Authors: Liu, Dong-hua | Jang, Wu-sheng | Hou, Wen-qiang

Article Type: Research Article

Abstract: The effects of different concentrations of copper sulfate on root and shoot growth of maize(Zea mays L.) and the uptake and accumulation of Cu²^+ by its roots and shoots were investigated in the present study. The concentrations of opper sulfate (CuSO_4·5H_2O) used were in the range of 10^-^5-10^-³mol/L. Root growth decreased progressively with increasing concentration of Cu²^+ in solution. The seedlings exposed to 10^-³ mol/L Cu²^+ exhibited substantial growth reduction, yielding only 68% of …the root length of the control. The shoot growth of the seedlings grown at 10^-^5-10^-^4 mol/L Cu²^+ were more or less than the same as the control seedlings. The leaves treated with 10^-³ mol/L Cu²^+ were obviously inhibited in shoot growth. The fresh and dry weights both in roots and shots decreased progressively with increasing Cu²^+ concentration.This fits well with the above mentioned effects of copper sulfate on root growth. Zea mays has considerable ability to remove Cu from solutions and accumulate it. The Cu content in roots of Z. Mays increased with increasing solution concentration of Cu²^+. The amount of Cu in roots of plants treated with 10^-³, 10^-^4 and 10^-^5 mol/L Cu²^+ were 10, 8 and 1.5 fold, respectively, greater than that of roots of control plant. However, the plants transported and concentrated only a small amount of Cu in their shoots. Show more

Keywords: Zea mays L., uptake, accumulation, Cu²^+

Citation: Journal of Environmental Sciences, vol. 13, no. 2, pp. 228-232, 2001