Frontiers of Environmental Science & Engineering

ISSN 2095-2201

ISSN 2095-221X(Online)

CN 10-1013/X

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Control concept and countermeasures for shallow lakes' eutrophication in China
JIN Xiangcan, LU Shaoyong, HU Xiaozhen, JIANG Xia, WU Fengchang
Front.Environ.Sci.Eng.. 2008, 2 (3): 257-266.  
https://doi.org/10.1007/s11783-008-0063-3

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Research on lake eutrophication in China began in the early 1970s, and many lakes in China are now known to be in meso-eutrophic status. Lake eutrophication has been showing a rapidly increasing trend since 2000. Investigations show that the main reasons for lake eutrophication include a fragile lake background environment, excessive nutrient loading into lakes, excessive human activities, ecological degeneration, weak environmental protection awareness, and lax lake management. Major mechanisms resulting from lake eutrophication include nutrient recycling imbalance, major changes in water chemistry (pH, oxygen, and carbon), lake ecosystem imbalance, and algal prevalence in lakes. Some concepts for controlling eutrophication should be persistently proposed, including lake catchment control, combination of pollutant source control with ecological restoration, protection of three important aspects (terrestrial ecology, lake coast zone, and submerged plant), and combination of lake management with regulation. Measures to control lake eutrophication should include pollution source control (i.e., optimize industrial structural adjustments in the lake catchment, reduce nitrogen and phosphorus emission amounts, and control endogenous pollution) and lake ecological restoration (i.e. establish a zone-lake buffer region and lakeside zone, protect regional vegetation, utilize hydrophytes in renovation technology); countermeasures for lake management should include implementing water quality management, identifying environmental and lake water goals, legislating and formulating laws and regulations to protect lakes, strengthening publicity and the education of people, increasing public awareness through participation in systems and mechanic innovations, establishing lake region management institutions, and ensuring implementation of governance and management measures.
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Critical flow-storm approach to total maximum daily load (TMDL) development: an analytical conceptual model
Zhang Harry, Yu Shaw
Front.Environ.Sci.Eng.. 2008, 2 (3): 267-273.  
https://doi.org/10.1007/s11783-008-0058-0

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One of the key challenges in the total maximum daily load (TMDL) development process is how to define the critical condition for a receiving waterbody. The main concern in using a continuous simulation approach is the absence of any guarantee that the most critical condition will be captured during the selected representative hydrologic period, given the scarcity of long-term continuous data. The objectives of this paper are to clearly address the critical condition in the TMDL development process and to compare continuous and event-based approaches in defining critical condition during TMDL development for a waterbody impacted by both point and nonpoint source pollution. A practical, event-based critical flow-storm (CFS) approach was developed to explicitly addresses the critical condition as a combination of a low stream flow and a storm event of a selected magnitude, both having certain frequencies of occurrence. This paper illustrated the CFS concept and provided its theoretical basis using a derived analytical conceptual model. The CFS approach clearly defined a critical condition, obtained reasonable results and could be considered as an alternative method in TMDL development.
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Rhizosphere effect of different aquatic plants on phosphorus depletion
WANG Zhenyu, WEN Shengfang, GAO Dongmei, LI Fengmin, XING Baoshan
Front.Environ.Sci.Eng.. 2008, 2 (3): 274-279.  
https://doi.org/10.1007/s11783-008-0048-2

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A series of pot experiments with Alternanthera philoxeroides, Typha latifolia, Sagittaria sagittifolia and Phragmites communis were conducted to assess the phosphorus depletion effect in the rhizosphere. The ratio of root to shoot, root morphology, phosphorus uptake efficiency and phosphorus utilization efficiency were analyzed. An obvious variation in phosphorus concentrations between the rhizosphere soil and non-rhizosphere soil was observed. The water-soluble P contents in the rhizosphere soil of A. philoxeroides, T. latifolia, S. sagittifolia and P. communis were reduced by 81%, 42%, 18% and 16%, respectively, compared with that in the non-rhizosphere soil. A. philoxeroides had the highest phosphorus uptake efficiency (1.32 mg/m), while T. latifolia achieved the effective phosphorus depletion by the strong rooting system and the high phosphorus uptake efficiency (0.52 mg/m). T. latifolia not only used phosphorus to produce biomass economically, but also adjusted carbon allocation to the roots to explore the soil for more available phosphorus. A. philoxeroides and T. latifolia were more effective in depleting phosphorus in the rhizosphere than S. sagittifolia and P. communis.
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Eutrophication status and control strategy of Taihu Lake
ZHANG Limin, XIA Minfang, ZHANG Lei, WANG Chun, LU Jilai
Front.Environ.Sci.Eng.. 2008, 2 (3): 280-290.  
https://doi.org/10.1007/s11783-008-0062-4

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The water quality and eutrophication status of Taihu Lake in recent years are presented and the pollution trends are analyzed. It is shown that because of unreasonable industrial structures, pollution discharge per GDP is high within the Taihu basin, and the pollution discharge from point and non-point sources exceed the basin’s environmental carrying capacity. Especially, excessive pollutants containing nitrogen and phosphorus are being discharged. Moreover, eutrophication may also result from internal pollution sources such as the release of nutrient elements from sediment. All these factors have resulted in the water quality deterioration of Taihu Lake. To solve this environmental problem, possible control strategies are summarized, including the control of internal pollution sources and inflow-river pollution, ecological restoration and reconstruction of the degraded lakeside zone ecosystem, clean water diversion, dredging, and manual algae removal.
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Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments
YU Chunyan, QUAN Xie, OU Xiaoxia, CHEN Shuo
Front.Environ.Sci.Eng.. 2008, 2 (3): 291-296.  
https://doi.org/10.1007/s11783-008-0049-1

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Four fractions (A, B, C, and D) of humic acids (HAs) were separated based on the polarity from weak to strong. UV-vis absorption and Fourier transform infrared spectroscopy (FTIR) analysis show that the fractions C and D possessed more aromatic C=C content. The influences of HAs and their fractions on the photolysis were investigated by the photodegradation of 2,4-D solutions under simulated solar light irradiation. The degradation rate of 2,4-D was found to decrease in the presence of bulk HAs or their fractions especially at high HAs concentration. The fractions of strong polarity C and D retarded the degradation rate more than the fractions of weak polarity A and B. This could be attributed to the different absorption intensity of the four HAs fractions in the order of D ≥ C > A > B, and the stronger ?-? electron donor-acceptor interactions between the strong polar fractions and 2,4-D.
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Allelopathic inhibition on red tide microalgae by five macroalgal extracts
AN Zhen, WANG Zhenyu, LI Fengmin, TIAN Zhijia, HU Hongying
Front.Environ.Sci.Eng.. 2008, 2 (3): 297-305.  
https://doi.org/10.1007/s11783-008-0055-3

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This study aims to identify effective antialgal allelochemicals from marine macroalgae that inhibit the growth of red tide microalgae. Practically, new algicidal agents were developed to control red tide. The growth inhibitory effects of 5 marine macroalgae Porphyra tenera, Laminaria japonica, Ulva pertusa, Enteromorpha clathrata, and Undaria pinnatifida on Skeletonema costatum were evaluated by adding crude seawater extracts of macroalgal dry tissue into the culture medium containing S. costatum. The half-effective concentrations at 120 h (EC50, 120 h) of the seawater extracts were 0.6, 0.9, 1.0, 1.0, and 4.7 g/L for the five macroalgae above, respectively. E. clathrata, L. japonica and U. pertusa showed strong allelopathic effect on the growth of S. costatum. There have been no previous reports with regard to the allelopathic effects of the former two macroalgae so far. The possible allelochemicals of 21 compounds of the E. clathrata were detected using Gas chromatography-mass spectrometry (GC-MS) analysis. Unsaturated fatty acids, acrylic acid (C3H4O2), and linolenic acid (C18H30O2) were the most likely allelochemicals in E. clathrata.
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Ecological assessment of lakeshore wetland rehabilitation on eastern route of South-to-North Water Transfer Project
ZHANG Jian, Lu Yifeng, JING Yuming, ZHANG Bo, ZHANG Chenglu, MENG Fei, ZHANG Huayong
Front.Environ.Sci.Eng.. 2008, 2 (3): 306-310.  
https://doi.org/10.1007/s11783-008-0057-1

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To evaluate the ecological effects of lakeshore wetland rehabilitation on the eastern route of the South-to-North Water Transfer Project, species composition, coverage, height, and biomass of wetland communities at 22 sites of the study area on the shore of Nansi Lake in April and May 2007 were investigated. The wetlands under investigation were divided into platform fields, transition zones, and shallow water zones according to differences in elevations, water levels, and human activities. The species richness index, Shannon-Wiener index, Simpson index, and Pielou Evenness index were adopted to delineate and discuss the ecological effects of lakeshore wetland rehabilitation in 22 quadrates. Results showed that the species richness of the wetland areas after 2 years’ rehabilitation amounted to 47 of 24 families, higher than 25 of 20 families in areas without rehabilitation. The biodiversity index and abundance index of rehabilitated areas were also higher than those of platform fields and fish ponds where there was no rehabilitation. In addition, the Shannon-Wiener index, Simpson index, and community evenness index of platform fields in rehabilitated wetland areas were 1.619, 0.745, and 0.860, respectively, higher than those of the platform fields before rehabilitating. The results suggested that the constructed lakeshore wetland played an important role in protecting the diversity of species.
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Evaluation of ecosystem health for regional development in the southwestern Beijing, China
LIU Xuehua, ZHANG Shuang, XU Haoyang, SHAO Xiaoming
Front.Environ.Sci.Eng.. 2008, 2 (3): 311-317.  
https://doi.org/10.1007/s11783-008-0047-3

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Ecosystem health assessment is one of the most important issues in regional ecological quality and safety studies. It also has a great significance to ecological conservation and regional development. This study focused on assessing the health status of forest, agriculture and urban ecosystems in the southwestern Beijing, China, including the Fangshan and Fengtai Districts. Based on field surveys and data collection, an assessment index system containing the vigor, organization and resilience factors was developed to measure the ecosystem health. Each index was scored from 1 to 5, representing five levels that contribute to the whole ecosystem health. The analytic hierarchy process (AHP) method was used to measure the weights of each index and three factors, and thus an overall score for a certain ecosystem was calculated. The results show that the forest ecosystem in the Fangshan District had higher health value than the Fengtai District, while the urban ecosystem had a slightly lower value in the Fangshan District than the Fengtai District. Both districts show lower resilience values in forest and urban ecosystems. Maintaining the ecosystem health will definitely benefit the long-term development of two districts. This study suggested that an approach for assessing the regional ecosystem health could be further developed to address spatial and synergy relationships between ecosystems and the three health factors.
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Simulation analysis of environmental risk accident and management of high-sulfur gas field development in complex terrain
WANG Xiao, HAO Fanghua, ZHANG Xuan, SUN Wen, CHENG Hongguang
Front.Environ.Sci.Eng.. 2008, 2 (3): 318-325.  
https://doi.org/10.1007/s11783-008-0033-9

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Environmental risk of high sulfur gas field exploitation has become one of the hot spots of environmental management studies. Severe gas H2S blowout accidents in recent years have shown that poor understanding and estimates of the poisonous gas movement could lead to dangerous evacuation delays. It is important to evaluate the real concentration of H2S, especially in complex terrain. Traditional experiential models are not valid in the case of rough terrain, especially in low-lying areas where the gas accumulates. This study, using high sulfur content gas field of Sichuan “Pu Guang gas field” as study object and adopting objective diagnosis of wind field of land following coordinate three dimensions, applied Lagrangian Puff Model and breaking up technique of puffs to simulate the H2S diffusion condition of blowout accidents produced in the high sulfur content gas field of complex terrain area. The results showed that the H2S distribution did not occur mainly in low wind direction, and due to the obstruction of the mountain’s body, it accumulated in front of mountain on produced turn over, flowed around submitted jumping type distribution. The mountain waist near the hilltop and low hollow river valley site rapture points simulating contrast showed that the higher the rapture point, the better the diffusing condition of pollutant, the distribution of risk sensitive point decided piping rupture environmental risk size combining the H2S diffusion result and residential area dispersing in the study area, synthetic judge located in the high rapture point environmental risk was smaller than the low hollow point, thus it was suggested to carryout laying of lining build of equal high line of higher terrain. According to simulation results, the environmental risk management measures aimed at putting down adverse effects were worked out.
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Fenton oxidation of 2,4- and 2,6-dinitrotoluene and acetone inhibition
HE Yiliang, ZHAO Bin, HUGHES Joseph B., HAN Sung Soo
Front.Environ.Sci.Eng.. 2008, 2 (3): 326-332.  
https://doi.org/10.1007/s11783-008-0038-4

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The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4- and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4- and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography (HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde → 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol.
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Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast China
HUANG Jinliang, HONG Huasheng, ZHANG Luoping
Front.Environ.Sci.Eng.. 2008, 2 (3): 333-339.  
https://doi.org/10.1007/s11783-008-0035-7

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This paper presents the study carried out for controlling agricultural non-point source pollution (NSP) in a medium-sized watershed covering 1.47 × 104 km2 in Southeast China using quantitative analysis coupled with geographic information system (GIS), universal soil loss equation (USLE), soil conservation service-curve number (SCS-CN), nutrient loss equations, and annualized agricultural nonpoint source model (AnnAGNPS). Based on the quantitative results derived from GIS and environmental models, five control division units were generated for NSP control in Jiulong River watershed, namely, controlling unit for soil losses, controlling unit for livestock breeding and soil losses, controlling unit for excessive fertilizer use and livestock breeding, controlling unit for soil losses and fertilizer use, and controlling unit for excessive fertilizer use and soil losses. This study proved that integrating GIS with environmental models can be adopted to efficiently evaluate major sources and contributors of NSP, and identify the critical source areas of NSP, which enables adjusting measures to local conditions by further control division units developed through such study for control and management of water quality degradation induced by NSP in the Jiulong River watershed.
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Climate change and sandy land development in Qinghai Lake Watershed, China
SUN Yongliang, LI Xiaoyan, LIU Lianyou, XU Heye, ZHANG Dengshan
Front.Environ.Sci.Eng.. 2008, 2 (3): 340-348.  
https://doi.org/10.1007/s11783-008-0045-5

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The Qinghai Lake Watershed, containing the largest saline lake in northwest of China, has suffered from severe sandy land development in recent years. This paper analyzes its daily precipitation, temperature, and wind from 1958 to 2001, and the spatial and temporal distributions of sandy land through the interpretation of remote sensing images covering four years (1977, 1987, 2000, and 2004). Results showed that since the middle of the 1960s, the daily precipitation (P) of 0 < P≤ 5 mm decreased, while the P > 20 mm increased significantly (S < 0.05) in their annual total amounts and days. The maximum daily precipitation also increased significantly. Both the maximum dry spell and the total dry spell of more than ten days had a significant upward trend. Since the beginning of the 1960s, all the extremely high, extremely low and mean temperatures increased significantly (S < 0.01), at a rate of 0.1°C/10a, 0.2°C/10a, and 0.2°C/10a, respectively. The days with extremely high temperature had a significant upward trend, while the days with extremely low temperature had a significant downward trend. The Qinghai Lake was significantly shrinking (S < 0.01) and provided abundant sediments for Aeolian erosion. The NNW wind prevailed in the watershed, and the largest scale wind was from the west and concentrated on the dry months. As a result, the sandy land was mainly born on the east bank of Qinghai Lake. The total sandy land area in the watershed had grown from 587.4 km2, 660.7 km2, 697.6 km2 to 805.8 km2, accordingly, its area percentage growing from 2.0%, 2.2%, 2.4% to 2.7%, respectively.
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Circulating fluidized bed biological reactor for nutrients removal
CUI Yubo, LIU Hongbo, BAI Chunxue
Front.Environ.Sci.Eng.. 2008, 2 (3): 349-353.  
https://doi.org/10.1007/s11783-008-0051-7

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A new biological nitrogen removal process, which is named herein “The circulating fluidized bed bioreactor (CFBBR)”, was developed for simultaneous removal of nitrogen and organic matter. This process was composed of an anaerobic bed (Riser), aerobic bed (Downer) and connecting device. Influent and nitrified liquid from the aerobic bed enters the anaerobic bed from the bottom of the anaerobic bed, completing the removal of nitrogen and organic matter. The system performance under the conditions of different inflow loadings and nitrified liquid recirculation rates ranging from 200% to 600% was examined. From a technical and economic point of view, the optimum nitrified liquid recirculation rate was 400%. With a shortest total retention time of 2.5 h (0.8 h in the anaerobic bed and 1.5 h in the aerobic bed) and a nitrified liquid recirculation rate of 400% based on the influent flow rate, the average removal efficiencies of total nitrogen (TN) and soluble chemical oxygen demand (SCOD) were found to be 88% and 95%, respectively. The average effluent concentrations of TN and SCOD were 3.5 mg/L and 16 mg/L, respectively. The volatile suspended solid (VSS) concentration, nitrification rate and denitrification rate in the system were less than 1.0 g/L, 0.026–0.1 g NH4+-N/g VSSd, and 0.016–0.074 g NOx--N/g VSSd, respectively.
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Catalytic activity of cerium-doped Ru/AlO during ozonation of dimethyl phthalate
ZHOU Yunrui, ZHU Wanpeng, CHEN Xun
Front.Environ.Sci.Eng.. 2008, 2 (3): 354-357.  
https://doi.org/10.1007/s11783-008-0059-z

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In this paper, factors influencing the mineralization of dimethyl phthalate (DMP) during catalytic ozonation with a cerium-doped Ru/Al2O3 catalyst were studied. The catalytic contribution was calculated through the results of a comparison experiment. It showed that doping cerium significantly enhanced catalytic activity. The total organic carbon (TOC) removal over the doped catalyst at 100 min reached 75.1%, 61.3% using Ru/Al2O3 catalyst and only 14.0% using ozone alone. Catalytic activity reached the maximum when 0.2% of ruthenium and 1.0% of cerium were simultaneously loaded onto Al2O3 support. Results of experiments on oxidation by ozone alone, adsorption of the catalyst, Ce ion’s and heterogeneous catalytic ozonation confirmed that the contribution of heterogeneous catalytic ozonation was about 50%, which showed the obvious effect of Ru–Ce/Al2O3 on catalytic activity.
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Leaching characteristics of heavy metals during cement stabilization of fly ash from municipal solid waste incinerators
LIANG Shunwen, JIANG Jianguo, ZHANG Yan, XU Xin
Front.Environ.Sci.Eng.. 2008, 2 (3): 358-363.  
https://doi.org/10.1007/s11783-008-0060-6

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The leaching characteristics of heavy metals in products of cement stabilization of fly ash from a municipal solid waste incinerator were investigated in this paper. The stabilization of heavy metals such as Cd, Pb, Cu, and Zn in fly ash from such incinerators was examined through the national standard method in China based on the following factors: additive quantity of cement and Na2S, curing time, and pH of leaching liquor. The results showed that as more additives were used, less heavy metals were leached except for Pb, which is sensitive to pH of the leachate, and the worse effect was observed for Cd. The mass ratio of cement to fly ash = 10% is the most appropriate parameter according to the national standard method. When the hydration of cement was basically finished, stabilization of heavy metals did not vary after curing for 1 d. The mixtures of cement and fly ash had excellent adaptability to environmental pH. The pH of leachate was maintained at 7 when pH of leaching liquor varied from 3 to 11.
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Response of peroxidase and catalase to acid rain stress during seed germination of rice, wheat, and rape
WANG Lihong, HUANG Xiaohua, ZHOU Qing
Front.Environ.Sci.Eng.. 2008, 2 (3): 364-369.  
https://doi.org/10.1007/s11783-008-0053-5

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Seed germination of plants with various acid-resistance display different responses to acid rain. To understand the reason why such differences occur, the effects of simulated acid rain (pH 2.5–5.0) on the activities of peroxidase (POD) and catalase (CAT) during seed germination of rice (O. sativa), wheat (T. aestivum), and rape (B. chinensis var. oleifera) were investigated. Results indicated that the maximum change in activities of CAT and POD by acid rain treatment with different acidity and time in relation to the referent treatment without acid rain, was in the order: rice (28.8%, 31.7%) < wheat (34.7%, 48.3%) < rape (79.3%, 50.0%). The pH level for which the treatment with acid rain did not cause significant difference (p < 0.05) was in the order: rice (3.5) > wheat (4.0) > rape (5.0). Moreover, the change in activity of POD was higher than that of CAT, which showed that POD was more sensitive to acid rain stress than CAT. The difference in the ability of POD and CAT in removing free radicals was one reason why the germination indexes of these three species behaved differently.
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Comprehensive evaluation of heavy metal contamination of sediment in Lake Dianchi by using modified AHP method and Cs dating
ZHANG Yan, GAO Xiang, ZHONG Zhenyu, PENG Buzhuo, DENG Xihai
Front.Environ.Sci.Eng.. 2008, 2 (3): 370-379.  
https://doi.org/10.1007/s11783-008-0054-4

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Through the use of general sampling and measurement by 137 Cs dating, problems regarding the absence of monitoring data can easily be resolved. Further, weighted values need to be determined while Environment Quality Comprehensive Index (EQCI) is commonly used as applied in environmental quality comprehensive evaluation. In order to overcome the subjectivity in determining weights, the modified Analytical Hierarchy Process (AHP) method was designed. The modified AHP method involved the following key procedures: First, the parameters yi1 and yi2 were calculated based on the monitoring data; second, the factors were put in order according to the symbol and value of yi1 and yi2; third, the continuous odd integers, which represented the importance of factors, were given to factors according to their seating order; and, fourth, the factor weights were determined from the pair-wise comparison matrix calculated by the ratio of the given odd integers. Therefore, the weights were completely based on the monitoring data. In the present study, the comprehensive quality of sediments in five sections of Lake Dianchi were evaluated and the results indicated that the current contamination of sediments in each lake section is much more serious than at any other time in history.
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Improvement of detection method of and in reclaimed water
ZHANG Tong, XIE Xing, HU Hongying, SONG Yudong, WU Qianyuan, ZONG Zusheng
Front.Environ.Sci.Eng.. 2008, 2 (3): 380-384.  
https://doi.org/10.1007/s11783-008-0052-6

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Cryptosporidium and Giardia are two typical species of pathogenic protozoans that seriously endanger water quality. Previous works indicated that detection of Cryptosporidium and Giardia with modified United States Environmental Protection Agency (USEPA) method-1623 using a membrane filtration-elution for sample concentration attained better recovery and lower cost compared to the USEPA method-1623. Several improvements of membrane filtration-elution step as well as immunomagnetic separation (IMS) steps were investigated and an optimized method for detection of Cryptosporidium and Giardia in wastewater reclamation system was recommended in this paper. The experimental results show that an overnight soak of the membrane after scraping and vortex agitation before elution could enhance and stabilize the recovery. Increasing turbidity to 4 NTU by adding kaolin clay before filtration could effectively improve the recovery of low-turbidity water. Washing the concentrate after centrifugation and twice acid dissociation both reduced the impact of water quality to protozoan recovery. Protozoans in different water samples were determined by this optimized method, and the recovery of Cryptosporidium and Giardia were above 70% and 80% respectively, much higher than the acceptance of method-1623.
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18 articles