2000 Vol. 25, No. 5
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2000, 25(5): 443-450.
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Abstract:
The need for predictions of groundwater flow and contaminant transport in the subsurface over large distances and long time periods has imposed extraordinary demands on the field of hydrogeology. Such a need arises in assessing the safety of a geologic nuclear waste repository and in evaluating groundwater contamination and remediation designs. One of the main difficulties in modeling groundwater flow and mass transport is the heterogeneity of the flow system, both in terms of its characterization through in situ measurements and its conceptualization and simulation. The paper reviews some important issues and challenges in modeling flow and transport in heterogeneous media, and discusses approaches to address certain aspects of the problem. Topics discussed include dynamic flow channeling, tracer breakthrough curves, multiple scales for flow in fractured rocks, different scales in measurement, modeling, prediction and heterogeneity, and system characterization and analysis for predictive modeling.
The need for predictions of groundwater flow and contaminant transport in the subsurface over large distances and long time periods has imposed extraordinary demands on the field of hydrogeology. Such a need arises in assessing the safety of a geologic nuclear waste repository and in evaluating groundwater contamination and remediation designs. One of the main difficulties in modeling groundwater flow and mass transport is the heterogeneity of the flow system, both in terms of its characterization through in situ measurements and its conceptualization and simulation. The paper reviews some important issues and challenges in modeling flow and transport in heterogeneous media, and discusses approaches to address certain aspects of the problem. Topics discussed include dynamic flow channeling, tracer breakthrough curves, multiple scales for flow in fractured rocks, different scales in measurement, modeling, prediction and heterogeneity, and system characterization and analysis for predictive modeling.
2000, 25(5): 451-455.
Abstract:
Modeling migration of uranium in groundwater is important for both groundwater protection and rehabilitation strategies of uranium mining sites due to the fact that uranium is both a radioactive element and an element with high chemical toxicity. Advection, dispersion, dilution, sorption and chemical interactions both in water and between water and solids have to be taken into account. This paper presents results which have been done in the context of the feasibility study for the in situ leaching mine Koenigstein near Dresden(Germany). Since reactive transport modeling is consuming a lot of CPU time all runs were performed 1 d but taken into account dilution by means of a simple mixing approach. PHREEQC version 2.2 proved to be a powerful tool for this kind of investigations. The database WATEQ4F which comes with PHREEQC containing 48 elements, more than 400 species and more than 300 minerals, was modified with respect to uranium and radium making it more consistent and reliable.
Modeling migration of uranium in groundwater is important for both groundwater protection and rehabilitation strategies of uranium mining sites due to the fact that uranium is both a radioactive element and an element with high chemical toxicity. Advection, dispersion, dilution, sorption and chemical interactions both in water and between water and solids have to be taken into account. This paper presents results which have been done in the context of the feasibility study for the in situ leaching mine Koenigstein near Dresden(Germany). Since reactive transport modeling is consuming a lot of CPU time all runs were performed 1 d but taken into account dilution by means of a simple mixing approach. PHREEQC version 2.2 proved to be a powerful tool for this kind of investigations. The database WATEQ4F which comes with PHREEQC containing 48 elements, more than 400 species and more than 300 minerals, was modified with respect to uranium and radium making it more consistent and reliable.
2000, 25(5): 456-461.
Abstract:
The coupled reaction transport modeling of uranium (Ⅵ) in shallow groundwater was created on the basis of the hydrogeological pattern for a huge uranium gangue site in southern China. The software Visual MODFLOW, the most up to date simulation of the three dimensional groundwater flow and pollutant migration, was used to simulate the migration of uranium (Ⅵ) in groundwater on different conditions. As shown in the simulated results, the uranium (Ⅵ) would seriously pollute the groundwater without remediation. On the other hand, the uranium (Ⅵ) that arises in the operation of the uranium gangue would be completely "digested" due to the self remediation of groundwater when the uranium gangue is being brought under control.
The coupled reaction transport modeling of uranium (Ⅵ) in shallow groundwater was created on the basis of the hydrogeological pattern for a huge uranium gangue site in southern China. The software Visual MODFLOW, the most up to date simulation of the three dimensional groundwater flow and pollutant migration, was used to simulate the migration of uranium (Ⅵ) in groundwater on different conditions. As shown in the simulated results, the uranium (Ⅵ) would seriously pollute the groundwater without remediation. On the other hand, the uranium (Ⅵ) that arises in the operation of the uranium gangue would be completely "digested" due to the self remediation of groundwater when the uranium gangue is being brought under control.
2000, 25(5): 462-466.
Abstract:
In this paper, a coupling mathematical model of the moisture reactive petroleum pollutant migration is established on the bases of field investigation and indoor and outdoor tests in Shenyang Fushun irrigation area. In this model, the numerical method is first used to simulate the distribution pattern of the soluble oil (effective oil) and to analyze quantitatively the feasibilities of different restoration projects for the oil polluted soils. The research results show that the chemical reaction in the soil may lower the migration speed of the soluble oil far less than the penetration speed of the soil water. Therefore, the soluble oil is mainly distributed in the ploughed soil layer, making it difficult to pollute directly the groundwater by the penetration of the polluted water for irrigation. In addition, the controlling plans of the irrigation by the mixed clean and polluted water and of the change in the crop structures may greatly reduce the soluble oil concentration in the soil, but the complete elimination of the oil polluted soil must depend on the reasonable irrigation by the surface water or/and groundwater.
In this paper, a coupling mathematical model of the moisture reactive petroleum pollutant migration is established on the bases of field investigation and indoor and outdoor tests in Shenyang Fushun irrigation area. In this model, the numerical method is first used to simulate the distribution pattern of the soluble oil (effective oil) and to analyze quantitatively the feasibilities of different restoration projects for the oil polluted soils. The research results show that the chemical reaction in the soil may lower the migration speed of the soluble oil far less than the penetration speed of the soil water. Therefore, the soluble oil is mainly distributed in the ploughed soil layer, making it difficult to pollute directly the groundwater by the penetration of the polluted water for irrigation. In addition, the controlling plans of the irrigation by the mixed clean and polluted water and of the change in the crop structures may greatly reduce the soluble oil concentration in the soil, but the complete elimination of the oil polluted soil must depend on the reasonable irrigation by the surface water or/and groundwater.
2000, 25(5): 467-471.
Abstract:
The hydro geochemical research into the karst water of Niangziguan spring area indicates the gradual decrease both in the concentration of sulfate and in the mineralization degree, but the gradual increase in the ratios between Ca2+, Mg2+ and SO42- along the flow path. The hydro geochemical modeling shows that the widely dissolving of gypsum causes the high concentration of gypsum from recharge area to discharge area, and even at the shallow aquifer. In addition, the mixing with deep water and sidewise water from the runoff to the discharge area reduces the concentration of sulfate in the water. The extraordinarily high concentration of sulfate was initiated by the pollution by the seepage from the Carboniferous-Permian where the oxidation of sulfide produced much higher sulfate in the Middle Ordovician aquifer. The water from the Lower Ordovician aquifer would be much better.
The hydro geochemical research into the karst water of Niangziguan spring area indicates the gradual decrease both in the concentration of sulfate and in the mineralization degree, but the gradual increase in the ratios between Ca2+, Mg2+ and SO42- along the flow path. The hydro geochemical modeling shows that the widely dissolving of gypsum causes the high concentration of gypsum from recharge area to discharge area, and even at the shallow aquifer. In addition, the mixing with deep water and sidewise water from the runoff to the discharge area reduces the concentration of sulfate in the water. The extraordinarily high concentration of sulfate was initiated by the pollution by the seepage from the Carboniferous-Permian where the oxidation of sulfide produced much higher sulfate in the Middle Ordovician aquifer. The water from the Lower Ordovician aquifer would be much better.
2000, 25(5): 472-476.
Abstract:
The Quaternary hydrogeological structure in Taian shows that the contamination in shallow groundwater is controlled by the Quaternary hydrogeological structure. When the lithology of vadose zone is the same as that of aquifer, the vadose zone is thicker, increasing the pollution prevention index, so that the contamination in the aquifer is smaller. However, on the similar conditions in surface environmental quality and in lithology and thickness of the vadose zone, the coarse sand aquifer is easier to contaminate than the silty clay aquifer.
The Quaternary hydrogeological structure in Taian shows that the contamination in shallow groundwater is controlled by the Quaternary hydrogeological structure. When the lithology of vadose zone is the same as that of aquifer, the vadose zone is thicker, increasing the pollution prevention index, so that the contamination in the aquifer is smaller. However, on the similar conditions in surface environmental quality and in lithology and thickness of the vadose zone, the coarse sand aquifer is easier to contaminate than the silty clay aquifer.
2000, 25(5): 477-481.
Abstract:
The groundwater quality in Xiezhou area of Yuncheng city has conspicuously deteriorated in recent years, directly affecting the water supply for the local people daily life and for the agricultural irrigation. The comparison of the hydrogeological condition with the water quality test results in the study area shows that the mass extraction of the groundwater in the mid upper section on fluvial filt plane has lowered the groundwater table and eased the hydraulic gradient. In this case, the extraction of the groundwater near the transitional zone of brackish water has resulted in the lower groundwater table than the niter poor water table, and further in the intrusion of the salt water and further deterioration of the groundwater quality. In order to prevent the further deterioration of groundwater quality and the expansion of the polluted groundwater, the amount of the extracted groundwater and the pumping sections should be controlled.
The groundwater quality in Xiezhou area of Yuncheng city has conspicuously deteriorated in recent years, directly affecting the water supply for the local people daily life and for the agricultural irrigation. The comparison of the hydrogeological condition with the water quality test results in the study area shows that the mass extraction of the groundwater in the mid upper section on fluvial filt plane has lowered the groundwater table and eased the hydraulic gradient. In this case, the extraction of the groundwater near the transitional zone of brackish water has resulted in the lower groundwater table than the niter poor water table, and further in the intrusion of the salt water and further deterioration of the groundwater quality. In order to prevent the further deterioration of groundwater quality and the expansion of the polluted groundwater, the amount of the extracted groundwater and the pumping sections should be controlled.
2000, 25(5): 482-486.
Abstract:
The evaluation and mapping of the groundwater vulnerability to contamination are of primary importance for hydrogeological studies. In this paper, the traditional methods are reviewed and a new DRAMIC model is presented by improving the DRASTIC model to make it suitable for the hydrogeological conditions of urban areas in China. The model DRAMIC can be used as a general index system for evaluating the vulnerability of groundwater to contamination in Chinese cities. In the final part of this paper, is introduced the method for the application of GIS to the mapping of the DRAMIC model.
The evaluation and mapping of the groundwater vulnerability to contamination are of primary importance for hydrogeological studies. In this paper, the traditional methods are reviewed and a new DRAMIC model is presented by improving the DRASTIC model to make it suitable for the hydrogeological conditions of urban areas in China. The model DRAMIC can be used as a general index system for evaluating the vulnerability of groundwater to contamination in Chinese cities. In the final part of this paper, is introduced the method for the application of GIS to the mapping of the DRAMIC model.
2000, 25(5): 487-491.
Abstract:
The upstream of the Hanjiang River is one of the major areas in waterenvironment program of the national tenth five-year plan. The Danjiangkou dam of strategic significance is a key protected water source. The present water source both in the main stream of the Hanjiang River and in the Danjiangkon dam has reached national gradeⅡ water-quality standard. However, this water source is being threatened by the seriously-polluted branch streams whose major pollutant COD may have exceeded the standard in the tenth five-year plan. The COD pollutants are mainly composed of daily life excreta 77.2%.Of the industrial pollu- tion sources, the pulp and papermaking industry is the largest pollution source whose COD excreta reaches 38. 29%. In this paper, is listed the pollution control scheme mainly based on the town wastewater treatment plants and composed of A, B and C types of engineer projects. The implementation of type A projects needs 275 000 000 yuan in investment, reducing the COD in the upstream of the Hangjiang River to 32 682.25 t in 2005, lower than the discharge level in the base yearof 1998 and within the range of the total discharges spec- ified by the Hubei provincial government. In this way, the water quality both in the main stream of the Han- jiang River and in the Danjiangkou dam is guaranteed to reach gradeⅡ national water-quality standard. Then the furtherimplementation of types B and C projects may guarantee the stable high water-quality standard and the conspicuous improvement of the water quality in the branch streams.
The upstream of the Hanjiang River is one of the major areas in waterenvironment program of the national tenth five-year plan. The Danjiangkou dam of strategic significance is a key protected water source. The present water source both in the main stream of the Hanjiang River and in the Danjiangkon dam has reached national gradeⅡ water-quality standard. However, this water source is being threatened by the seriously-polluted branch streams whose major pollutant COD may have exceeded the standard in the tenth five-year plan. The COD pollutants are mainly composed of daily life excreta 77.2%.Of the industrial pollu- tion sources, the pulp and papermaking industry is the largest pollution source whose COD excreta reaches 38. 29%. In this paper, is listed the pollution control scheme mainly based on the town wastewater treatment plants and composed of A, B and C types of engineer projects. The implementation of type A projects needs 275 000 000 yuan in investment, reducing the COD in the upstream of the Hangjiang River to 32 682.25 t in 2005, lower than the discharge level in the base yearof 1998 and within the range of the total discharges spec- ified by the Hubei provincial government. In this way, the water quality both in the main stream of the Han- jiang River and in the Danjiangkou dam is guaranteed to reach gradeⅡ national water-quality standard. Then the furtherimplementation of types B and C projects may guarantee the stable high water-quality standard and the conspicuous improvement of the water quality in the branch streams.
2000, 25(5): 493-497.
Abstract:
This paper discusses the biodegradation of benzene in anaerobic microcosms. The incovula were from the suburban rice soil. The results indicate that benzene and toluene degradation occurred concomitantly with nitrate reduction in enrichment and transfer cultures. Toluene was degraded more readily than benzene, and benzene degradation was enhanced by the presence of toluene. This is an instance of benzene degradation on nitrate reducing conditions.
This paper discusses the biodegradation of benzene in anaerobic microcosms. The incovula were from the suburban rice soil. The results indicate that benzene and toluene degradation occurred concomitantly with nitrate reduction in enrichment and transfer cultures. Toluene was degraded more readily than benzene, and benzene degradation was enhanced by the presence of toluene. This is an instance of benzene degradation on nitrate reducing conditions.
2000, 25(5): 499-504.
Abstract:
In terms of the arid trend in the Northwest China, this paper deals with the system dynamic pattern of water transfer and salt accumulation in this closed inland basin and elucidates the basic cause for the corresponding imbalance between the supergene salt accumulation and water salt. In this context, the paper reveals the internal relations between the water salt distribution and the soil eco adaptability, presents the effect of the variation in the rhythm of water cycle on the spatial temporal distribution of the soil eco indices, and advances the great importance of the Great West Development by establishing the survival domains of various species and the soil eco indices in the Northwest China. In addition, this paper discusses the construction of the reservoir project and the selection of the irrigation techniques in this inland basin.
In terms of the arid trend in the Northwest China, this paper deals with the system dynamic pattern of water transfer and salt accumulation in this closed inland basin and elucidates the basic cause for the corresponding imbalance between the supergene salt accumulation and water salt. In this context, the paper reveals the internal relations between the water salt distribution and the soil eco adaptability, presents the effect of the variation in the rhythm of water cycle on the spatial temporal distribution of the soil eco indices, and advances the great importance of the Great West Development by establishing the survival domains of various species and the soil eco indices in the Northwest China. In addition, this paper discusses the construction of the reservoir project and the selection of the irrigation techniques in this inland basin.
2000, 25(5): 505-509.
Abstract:
The palaeoclimatic and palaeo environmental information in Hubei region 19.0 to 6.9 thousand years ago is obtained from the analyses of the sedimentary, carbon and oxygen isotope features of the stalagmite numbered as HS-2 in the Heshangdong cave, Qingjiang, Hubei and with the uranium series dating method. The following four climate changes can be concluded (with the average resolution 17 a, and the local resolution 7 a) : (1) In 19.1~16.6 ka, the smaller values of both δ(13C) and δ(18O) suggest a cooler and wetter climate. (2) In 16.6~11.1 ka, the greater values of both δ(13C) and δ(18O) suggest a dry and warm climate. (3) In 11.1~10.3 ka, the sudden return of the cold climate in the dry and hot period may have corresponded to the Younger Dryas event. (4) In 10.3~6.9 ka, the change from the warm and rainy climate to the cold climate reflects the alternate changes from humid, cold, dry hot, up to the warm weather, showing some climate change patterns in the order of 100 or 1 000 years.
The palaeoclimatic and palaeo environmental information in Hubei region 19.0 to 6.9 thousand years ago is obtained from the analyses of the sedimentary, carbon and oxygen isotope features of the stalagmite numbered as HS-2 in the Heshangdong cave, Qingjiang, Hubei and with the uranium series dating method. The following four climate changes can be concluded (with the average resolution 17 a, and the local resolution 7 a) : (1) In 19.1~16.6 ka, the smaller values of both δ(13C) and δ(18O) suggest a cooler and wetter climate. (2) In 16.6~11.1 ka, the greater values of both δ(13C) and δ(18O) suggest a dry and warm climate. (3) In 11.1~10.3 ka, the sudden return of the cold climate in the dry and hot period may have corresponded to the Younger Dryas event. (4) In 10.3~6.9 ka, the change from the warm and rainy climate to the cold climate reflects the alternate changes from humid, cold, dry hot, up to the warm weather, showing some climate change patterns in the order of 100 or 1 000 years.
2000, 25(5): 510-513.
Abstract:
The more and more severe arid trend in the climate of the northern China has produced a great effect on the local ecological environment. On the basis of the present research into the arid climate, this paper touches upon the role of the groundwater system in the earth's surface system, the regulating effect of the groundwater system in the earth's surface system, and the significance of the research into the arid trend of the northern China. Then this paper analyzes the effect of the groundwater system degradation on the climate arid in the northern China, indicating that such an effect has already produced some environmental effects that can not be neglected. For example, the excessive extraction of the local groundwater has resulted in the degradation of the regional groundwater system, in the change in the transformation patterns of the surface water, heat and CO 2, in the imbalance between the water and heat, and finally in the arid of the local climate. Therefore, the evolution pattern of the groundwater system should be studied in order to reveal the effect of time space change on the formation and development of the climate arid, to evaluate and forecast the environmental effects related to the future groundwater exploitation and to present the regulating model of groundwater exploitation free of climate arid, providing a scientific basis for the sustained development in the climate arid area in the northern China.
The more and more severe arid trend in the climate of the northern China has produced a great effect on the local ecological environment. On the basis of the present research into the arid climate, this paper touches upon the role of the groundwater system in the earth's surface system, the regulating effect of the groundwater system in the earth's surface system, and the significance of the research into the arid trend of the northern China. Then this paper analyzes the effect of the groundwater system degradation on the climate arid in the northern China, indicating that such an effect has already produced some environmental effects that can not be neglected. For example, the excessive extraction of the local groundwater has resulted in the degradation of the regional groundwater system, in the change in the transformation patterns of the surface water, heat and CO 2, in the imbalance between the water and heat, and finally in the arid of the local climate. Therefore, the evolution pattern of the groundwater system should be studied in order to reveal the effect of time space change on the formation and development of the climate arid, to evaluate and forecast the environmental effects related to the future groundwater exploitation and to present the regulating model of groundwater exploitation free of climate arid, providing a scientific basis for the sustained development in the climate arid area in the northern China.
2000, 25(5): 514-517.
Abstract:
Deep geological disposal of high level radioactive waste (HLW) is introduced briefly in this paper. It is very important to research into the coupled calculation of the dose field temperature field hydro potential field stress field associated with HLW disposal. The equations, which are used to calculate the dose rate and THM coupled process are provided and the solutions to these equations are discussed. Finally, several aspects in this area are suggested for further research.
Deep geological disposal of high level radioactive waste (HLW) is introduced briefly in this paper. It is very important to research into the coupled calculation of the dose field temperature field hydro potential field stress field associated with HLW disposal. The equations, which are used to calculate the dose rate and THM coupled process are provided and the solutions to these equations are discussed. Finally, several aspects in this area are suggested for further research.
2000, 25(5): 518-521.
Abstract:
The leakage of waste liquid and the groundwater pollution from the leachate of solid waste in geological disposal of waste material are basic hydrogeological problems indispensable to the site selection. The authors analyze several basic problems in the groundwater pollution, and propose some solution and countermeasures to the site selection and designing of the waste material disposal.
The leakage of waste liquid and the groundwater pollution from the leachate of solid waste in geological disposal of waste material are basic hydrogeological problems indispensable to the site selection. The authors analyze several basic problems in the groundwater pollution, and propose some solution and countermeasures to the site selection and designing of the waste material disposal.
2000, 25(5): 522-525.
Abstract:
The research shows that the white crystal that arises from the anaerobic oxic treatment of acetone and butanol's wastewater in North China Medicine Factory is determined to be MgNH4PO4 which blocks up the pipelines and reduces the production. Several kinds of approaches are presented in terms of theoretical analysis and techniques not only to overcome the disadvantages of blocking up pipelines by MgNH 4PO 4, but also to make efficient use of these waste materials.
The research shows that the white crystal that arises from the anaerobic oxic treatment of acetone and butanol's wastewater in North China Medicine Factory is determined to be MgNH4PO4 which blocks up the pipelines and reduces the production. Several kinds of approaches are presented in terms of theoretical analysis and techniques not only to overcome the disadvantages of blocking up pipelines by MgNH 4PO 4, but also to make efficient use of these waste materials.
2000, 25(5): 526-528.
Abstract:
This paper presents the manufacture of the porous materials from the fly ash at the Qingshan Power Station, Wuhan. Two of our sintered samples have their porosities of 45.8% and 61%, respectively. This kind of materials may serve as the muffling and heat insulating material used for the highway and urban or rural constructions. The manufacturing of this kind of materials can consume a large amount of fly ash to protect our environment.
This paper presents the manufacture of the porous materials from the fly ash at the Qingshan Power Station, Wuhan. Two of our sintered samples have their porosities of 45.8% and 61%, respectively. This kind of materials may serve as the muffling and heat insulating material used for the highway and urban or rural constructions. The manufacturing of this kind of materials can consume a large amount of fly ash to protect our environment.
2000, 25(5): 529-531.
Abstract:
The mononuclear aromatics in mining drainage were determined in line with the China national standard methods and American EPA methods. During the determination, QA/QC experiments were completed and samples were quantitatively measured by external standard. This paper compares the injection methods by HP 7694E Headspace Sampler and HP 7695 Purge & Trap Concentrator. Using HP 7694E Headspace Sampler, the mononuclear aromatics recovered ranged from 108.58% to 116.38% and the limits of the method detection were in the range between 5.00 and 10.00 μg/L. Using HP 7695 Purge & Trap Concentrator, the mononuclear aromatics recovered ranged from 94.87% to 105.63% and the limits of the method detection were in the range 0.25-0.50 μg/L.
The mononuclear aromatics in mining drainage were determined in line with the China national standard methods and American EPA methods. During the determination, QA/QC experiments were completed and samples were quantitatively measured by external standard. This paper compares the injection methods by HP 7694E Headspace Sampler and HP 7695 Purge & Trap Concentrator. Using HP 7694E Headspace Sampler, the mononuclear aromatics recovered ranged from 108.58% to 116.38% and the limits of the method detection were in the range between 5.00 and 10.00 μg/L. Using HP 7695 Purge & Trap Concentrator, the mononuclear aromatics recovered ranged from 94.87% to 105.63% and the limits of the method detection were in the range 0.25-0.50 μg/L.
2000, 25(5): 532-535.
Abstract:
A method has been developed for the determination of trace lead in the environmental samples by slurry sampling with graphite furnace atomic absorption spectrometry (GFAAS). The effects of particle size, slurry concentration, modifiers and slurry stability agents on the accurate determination are dealt with in this paper. The research shows that the particle size < 38 μm, the magnetic agitation with 0.2 g/L Triton-100 as stability agent, and the 3 g/L (NH4)2HPO4 as a modifier are of practical use. The detection limit is 0.10ng/g, and the precision (RSD, n=10) is 3.31%. The analytical results of the standard reference samples are consistent with the certified values.
A method has been developed for the determination of trace lead in the environmental samples by slurry sampling with graphite furnace atomic absorption spectrometry (GFAAS). The effects of particle size, slurry concentration, modifiers and slurry stability agents on the accurate determination are dealt with in this paper. The research shows that the particle size < 38 μm, the magnetic agitation with 0.2 g/L Triton-100 as stability agent, and the 3 g/L (NH4)2HPO4 as a modifier are of practical use. The detection limit is 0.10ng/g, and the precision (RSD, n=10) is 3.31%. The analytical results of the standard reference samples are consistent with the certified values.
2000, 25(5): 536-541.
Abstract:
In this paper, are introduced the principle of the semiconductor heterogeneous photocatalysis oxidation technology, its application to the degradation of the pollutants and environmental protection, and some new types of reaction instruments. Then the paper suggests the method for the improvement of the photocatalytic activity of the photocatalytic agents. The paper also discusses the factors affecting both the reaction rate of the photocatalysis oxidation, and the increase in the reaction rate. In addition, this paper presents some recommendations on the future research orientation and emphases in the photocatalysis oxidation technology.
In this paper, are introduced the principle of the semiconductor heterogeneous photocatalysis oxidation technology, its application to the degradation of the pollutants and environmental protection, and some new types of reaction instruments. Then the paper suggests the method for the improvement of the photocatalytic activity of the photocatalytic agents. The paper also discusses the factors affecting both the reaction rate of the photocatalysis oxidation, and the increase in the reaction rate. In addition, this paper presents some recommendations on the future research orientation and emphases in the photocatalysis oxidation technology.
2000, 25(5): 542-546.
Abstract:
The analysis of the Tertiary sedimentary environments in the eastern Pearl River Mouth basin shows that the sea level fluctuations controlled by the tectonic movements not only affected the syndepositional features, but also determined the patterns of palaeo groundwater flow. The environmental evolution marked by the alternation of continental and marine facies may give rise to the change between the infiltration potential and the compaction potential. In consequence, both potentials affect the changes in the Tertiary palaeo groundwater flow patterns.
The analysis of the Tertiary sedimentary environments in the eastern Pearl River Mouth basin shows that the sea level fluctuations controlled by the tectonic movements not only affected the syndepositional features, but also determined the patterns of palaeo groundwater flow. The environmental evolution marked by the alternation of continental and marine facies may give rise to the change between the infiltration potential and the compaction potential. In consequence, both potentials affect the changes in the Tertiary palaeo groundwater flow patterns.
2000, 25(5): 547-552.
Abstract:
The highway noise pollution is a hot issue nowadays. The Yichang Huangshi highway is taken as an example to monitor, assess, analyze and predict the noise pollution in different profiles of the whole highway. In addition, the highway noise pollution principles are characterized, and the prevention measures of the noise pollution are proposed, serving as the scientific basis for the environmental management of the highways.
The highway noise pollution is a hot issue nowadays. The Yichang Huangshi highway is taken as an example to monitor, assess, analyze and predict the noise pollution in different profiles of the whole highway. In addition, the highway noise pollution principles are characterized, and the prevention measures of the noise pollution are proposed, serving as the scientific basis for the environmental management of the highways.
