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Integrated water resources management for sustainable development of in western rural China
Management in water resources development of Jinghe watershed of western rural China is examined with Participatory Rural Appraisal method--a rare applied method in China and questionnaire survey of stakeholders.Combination of these two survey methods derives good results as it could avoid personal bias in identifying and ranking the issues on a concrete basis in following up households'survey.Statistic Package for Social Sciences(SPSS)was used for data analysis.Results indicate that since the early 1980s.issues of water scarcity,river pollution,soil erosion,insufficient participation of stakeholders in water resources use and management,as well as centrahzed water planning and management system have created difficulties for sustainable development of the watershed.The stakeholders and local governments are fully aware of the challenges and are committed to achieving a solution through integrated water resource management(IWRD).The concept and the application of IWRD for rural China are reviewed and analyzed,and a framework for implementation of IWRD in China is developed.It is conchided that the keys to successful implementation of the approach will depend on optimal arrangement of institutions,policy reforms,community involvement and capacity building in water sector,which need to fully integrate various management functions within the watershed....
2020-07-08 08:49:41浏览：49
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Modeling the fate of paddy field pesticide in surface water and environmental risk assessment
The risk of drinking water is greatly concerned because of the large amount of pesticide applied to paddy field and the contamination of drinking water sources due to the runoff. A mathematical model is developed, based on the mass balance, to predict the fate of paddy field pesticides from application, runoff and mixing in a river, taking account of the physical-chemical properties and processes of volatilization, degradation, adsorption and desorption. The model is applied to a river basin in Japan to estimate the contaminant level of several popularly used pesticides at the water intakes. The health risk in drinking water induced by each pesticide concerned is estimated and evaluated by comparing with the acceptable daily intake values (ADI) and with that induced by trihalomethanes. An index to evaluate the total risk of all pesticides appearing in water is proposed. The methods for risk management are also discussed....
2020-07-08 08:49:41浏览：76
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Combinatorial analysis on spatial information statistics for the karst water environment in Guiyang,
The karst groundwater system is extremely vulnerable and easily contaminated by human activities.To understand the spatial distribution of contaminants in the groundwater of karst urban areas and contributors to the contamination,this paper employs the spatial information statistics analysis theory and method to analyze the karst groundwater environment in Guiyang City,Based on the karst groundwater quality data detected in 61 detection points of the research area in the last three years,we made Kriging evaluation isoline map with some ions in the karst groundwater,such as SO42,Fe3+,Mn2+ and F,analyzed and evaluated the spatial distribution,extension and variation of four types of ions on the basis of this isoline map.The results of the analysis show that the anomaly areas of SO42-,Fe3+,Mn2+,F and other ions are mainly located in Baba'ao,Mawangmiao and Sanqiao in northwestern Guiyang City as well as in its downtown area by reasons of the original non-point source pollution and the contamination caused by human activities (industrial and domestic pollution)....
2020-07-08 08:49:41浏览：38
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Decomposition kinetics of dimethyl methylphospate(chemical agent simulant) by supercritical water ox
Supercritical water oxidation (SCWO) has been drawing much attention due to effectively destroy a large variety of high-risk wastes resulting from munitions demilitarization and complex industrial chemical. An important design consideration in the development of supercritical water oxidation is the information of decomposition rate. In this paper, the decomposition rate of dimethyl methylphosphonate(DMMP), which is similar to the nerve agent VX and GB(Sarin) in its structure, was investigated under SCWO conditions. The experiments were performed in an isothermal tubular reactor with a H2O2 as an oxidant. The reaction temperatures were ranged from 398 to 633 ℃ at a fixed pressure of 24 MPa. The conversion of DMMP was monitored by analyzing total organic carbon (TOC) on the liquid effluent samples. It is found that the oxidative decomposition of DMMP proceeded rapidly and a high TOC decomposition up to 99.99% was obtained within 11 s at 555℃. On the basis of data derived from experiments, a global kinetic equation for the decomposition of DMMP was developed. The model predictions agreed well with the experimental data....
2020-07-08 08:49:41浏览：53
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Spatial Variation of P and N in Water and Sediments of Dianchi Lake, China
Dianchi Lake is one of the most eutrophic lakes in China. In order to understand this eutrophication and to help control the pollution, this research investigated the spatial distribution of Kjeldahl nitrogen (K-N) and total phosphorus(TP) through analysis of bottom water and sediment (3 depths) samples collected at 118 sites around Dianchi Lake. The concentrations of K-N and TP for the lake bottom water in the Caohai part of the lake were much higher than those in the Waihai part, generally decreasing from north to south. In the sediments, the K-N concentration was higher in the Caohai part and the middle of the Waihai part. On the other hand, TP in the sediments was greater in the southern and western parts. Both K-N and TP had similar spatial distributions for the sediment samples of three different depths.Vertically, the K-N and TP concentration in the sediments decreased with an increase in depth. This was evidence that eutrophication and pollution of Dianchi Lake was becoming gradually more severe. Exterior factors including uncontrolled input of domestic and industrial effluents as well as non-point pollution around the lake were the main reasons for serious eutrophication; therefore, controlling these was the first step in reducing eutrophication of Dianchi Lake....
2020-07-08 08:49:41浏览：48
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Removal of VOCs from Sudden Polluted Raw Water by Air Stripping
Volatile organic compounds (VOCs) are widely used in various industrial processes and generate water pollutions.VOCs removal from raw water is an important task for waterworks to guarantee drinking water security.The removal of VOCs such as chlorobenzene (CB) and ethylbenzene (EB) from raw water by air stripping was investigated under various conditions,including the variation of temperature (5-30℃),pH (3.5-10.5),and air/water ratio (10-60). The air stripping removal efficiency of VOCs decreased with VOCs concentration declining in water.And Henry's law constant was demonstrated as an indicator of the estimation of VOCs removal efficiency for air stripping. The effects of temperature and the ratio of air and water were found to play a great role in VOCs removal,but the effect of pH seemed to be negligible.This study demonstrates that air stripping provides a promising opportunity in removing VOCs in drinking water treatment,especially for the relatively high concentration of VOCs....
2020-07-08 08:49:41浏览：46
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Occurrence of Haloacetic Acids in Drinking Water in Certain Cities of China
Since haloacetic acids (HAAs), which are nonvolatile and of high carcinogenic risk, are common species of chlorinated disinfection by-products(DBPs) in drinking water, and little has been known in China, it is necessary to make a survey about the kinds and levels of HAAs in drinking water of the nation. Method HAAs were analyzed using gas chromatography with electron capture detector(GC/ECD) and relatively complex pretreatment process of sample was applied. Five main cities in different areas of China were chosen in the survey. Results Studies showed that the main species of HAAs in drinking water in China were DCAA and TCAA, ranging from 0.4 μg/L to 12.85 μg/L and from 0.56 μg/L to 10.98 μg/L, respectively. MBAA and DBAA were also detected in one city, ranging from 2.20 μg/L to 4.95 μg/L and 1.10 μg/L to 2.81 μg/L, respectively. Therefore, the contents of HAAs varied, usually no more than 25 μg/L. Based on the acquired data to date, it is known that the concentrations of HAAs in drinking water in China were surely under the limits of Sanitary Standard for Drinking Water Quality (China, 2001). Conclusion A wider survey of HAAs in drinking water should be conducted throughout the nation to get adequate data and information, the ultimate aim of which is to control HAAs pollution and keep the balance between microbiological safety insurance and chemical risk control, minimize the formation of DBPs and ensure the safety of water supply at the same time....
2020-07-08 08:49:41浏览：44
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A Water Movement Study in Lianzhou Bay, Guangxi Province,China
This study investigates the physical conditions (water depth, current speed, salinity, temperature) in Lianzhou Bay, a shallow coastal bay in southern China, during two expeditions in the dry and wet seasons of 2011. Based on these expedition data, basic hydrodynamic parameters like Brunt-V?is?l? Frequency, Richardson Number, Rossby radius, and Resonance Period are calcu-lated. The results show that Lianzhou Bay is characterized by comparatively small quantity of freshwater input and weak stratifica-tion. Strong tides, which are spatially uniform within the bay, cause turbulent mixing. Residence time of the water is shorter in winter due to a stronger coastal current in that season. Consideration of the water movement may help to reduce the harmful ecological impact of aquaculture waste water discharge....
2020-07-08 08:49:41浏览：36
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Relationship between the Water Body Chlorophyll-a and Water Quality Factors of Wetlands Baiguishan R
[Objective]The aim was to explore the relationship between water body Chlorophyll-a and water quality factors of wetlands Baiguishan reservoir.[Method]Chlorophyll-a and water quality factors of water quality of Wetlands BaiGuishan Reservoir was studied, the analysis of the relationship on water quality of Wetlands Baiguishan Reservoir was made by use of trophic status indices and SPSS17.0 statistical analysis.[Result]Total phosphorus was an important factor of influence Chlorophyll-a in reservoir, water body had slight eutrophication phenomenon in reservoir of July to October in 2010.[Conclusion]Comprehensive management should be strengthened so as to improve the water quality of Baiguishan wetland....
2020-07-08 08:49:41浏览：54
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Mining-induced variation in water levels in unconsolidated aquifers and mechanisms of water preserva
Phreatic water resources are widely found in thick unconsolidated surface layers in western China, where water levels respond sensitively and quickly to large-scale underground mining in conjunction with shallow coal seams. Longwall face #32201 of the Bulianta Coal Mine, in the Shendong coalfield was selected as an industrial trail base, where field observations on ground-water levels were conducted when the working face was below a water-rich area. The space-time variation in the behavior of un-consolidated water levels in response to underground mining and its relation with of advance were observed through the field trials. The basic conditions for water preservation in mines are presented and the mechanisms of water preservation in mining analyzed, given the geological condition of two key strata and a severely weathered layer buried in the overburden. The field trails show that water preservation in mining shallow coal seams can be successful under suitable conditions, providing new technology for envi-ronmental protection in the desert coalfields of northwestern China....
2020-07-08 08:49:41浏览：26
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Comparison of the community structure of planktonic bacteria in ballast water from entry ships and l
In this study, the bacterial community structures in samples of ballast water collected from a ship from Singapore and of local sea water collected from Xiamen Port were compared using restriction fragment length polymorphism (RFLP) and 16S rDNA sequence analysis. Except for dominant α-Proteobacteria that are common to both systems, the bacterial community structures of the two systems were quite different. Most of the clones derived from the different systems were grouped into different phylogenetic clusters, and the sys-tems share only one common RFLP pattern. The ballast water, which is likely from clean offshore waters, contains sequences specific to α- and γ-Proteobacteria. Phylogenetic analysis revealed that the ballast water contained sequences belonging to attached bacteria and bacteria commonly found in the open sea, as well as many novel sequences. In addition, no known pathogenic bacteria were detected in the ballast water samples. Conversely, water samples from Xiamen Port were apparently affected by the near shore environments.Specifically, in addition to α- and γ-Proteobacteria, water from Xiamen Port contained β- and δ-Proteobacteria, Synechococcus, Bacter-oidetes and Actinobacteria, which are common in coastal environments. Additionally, four pathogenic bacterial sequences and one plas-mid sequence of a potential red tide forming alga were detected in the water from Xiamen Port, which suggests that the local sea water is polluted. The results of this study can be used as background information to assess the risk associated with the introduction of non-indig-enous species to local systems and to establish ballast water management systems....
2020-07-08 08:49:41浏览：27
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Characteristics of Underground Water Flow at Different Water Levels in Tianshengan Karst Area, Yunna
Three tracing tests from the same injection point executed at low, medium, and high water levels in the karst aquifer near Tianshengan village, Lunan Stone Forest, Yunnan Province, China, have revealed the basic properties of underground water flow. They showed the general directions of water flows; tracer concentrations were observed at six successive points allowing for the calculation of apparent dominant flow velocities at these sections towards the Dalongtan karst spring. For the high water level, the discharge between single sections was between two and 10 times greater than that at low water level. For the medium water level, the flow velocity at different sections was between 1.4 and 3.7 times faster than that at low water level; and for high water level, it was between 1.3 and 2.7 times faster than that at medium water level. The fastest water flow appeared at the first section (23 cm/s at medium water level); and the slowest (0.6 cm/s at low water level) appeared where water flow must cross the Tianshengan fault (north-south direction), and later, a layer of 20-30 m thickness of quartz sandstone and shale clay-stones. It was also possible to calculate the recovery of the tracer for point 4, Dakenyan, where discharge was measured. At the medium water level, 50% of the injected tracer was detected a half-day after its first appearance and at low water level after more than 3 days. The previously published research illustrates the transport velocities of possible contaminants and their solubilities in water at different hydrological conditions....
2020-07-08 08:49:41浏览：29
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Exploration of Water Resource and Multiple Model for Water Resource Development in Karst Areas with
According to the theory of preferred plane, preferred planes (faults) always control the distribution of bedrock fissure water and hold abundant groundwater. Thus, the exploration of fissure or karst water can be converted into searching for the watery preferred plane (WPP). In the paper, the characteristic of watery preferred planes is analyzed and a series of superior indices has been set up. It is introduced that WPPs are determined by the methods of geological analysis, superior index and complex geophysical analysis. Meanwhile, new multiple model for water resource development in the water-scarce areas of karst mountainous regions are advanced....
2020-07-08 08:49:41浏览：54
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Water Wave Scattering by an Elastic Thin Vertical Plate Submerged in Finite Depth Water
The problem of water wave scattering by a thin vertical elastic plate submerged in uniform finite depth water is investigated here. The boundary condition on the elastic plate is derived from the Bernoulli-Euler equation of motion satisfied by the plate. Using the Green’s function technique, from this boundary condition, the normal velocity of the plate is expressed in terms of the difference between the velocity potentials (unknown) across the plate. The two ends of the plate are either clamped or free. The reflection and transmission coefficients are obtained in terms of the integrals’ involving combinations of the unknown velocity potential on the two sides of the plate, which satisfy three simultaneous integral equations and are solved numerically. These coefficients are computed numerically for various values of different parameters and depicted graphically against the wave number in a number of figures....
2020-07-08 08:49:41浏览：39
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Water-Assisted Injection Molding System Based on Water Hydraulic Proportional Control Technique
Water-assisted injection molding(WAIM), an innovative process to mold plastic parts with hollow sections, is characterized with intermittent, periodic process and large pressure and flow rate variation. Energy savings and injection pressure control can not be attained based on conventional valve control system. Moreover, the injection water can not be supplied directly by water hydraulic proportional control system. Poor efficiency and control performance are presented by current trial systems, which pressurize injection water by compressed air. In this paper, a novel water hydraulic system is developed applying an accumulator for energy saving. And a new differential pressure control method is proposed by using pressure cylinder and water hydraulic proportional pressure relief valve for back pressure control. Aiming at design of linear controller for injection water pressure regulation, a linear load model is approximately built through computational fluid dynamics(CFD) simulation on two-phase flow cavity filling process with variable temperature and viscosity, and a linear model of pressure control system is built with the load model and linearization of water hydraulic components. According to the simulation, model based feedback is brought forward to compensate the pressure decrease during accumulator discharge and eliminate the derivative element of the system. Meanwhile, the steady-state error can be reduced and the capacity of resisting disturbance can be enhanced, by closed-loop control of load pressure with integral compensation. Through the developed experimental system in the State Key Lab of Fluid Power Transmission and Control, Zhejiang University, China, the static characteristic of the water hydraulic proportional relief valve was tested and output pressure control of the system in Acrylonitrile Butadiene Styrene(ABS) parts molding experiments was also studied. The experiment results show that the dead band and hysteresis of the water hydraulic proportional pressure relief valve are large, but the control precision and linearity can be improved with feed-forward compensation. With the experimental results of injection water pressure control, the applicability of this WAIM system and the effect of its linear controller are verified. The novel proposed process of WAIM pressure control and study on characteristics of control system contribute to the application of water hydraulic proportional control and WAIM technology....
2020-07-08 08:49:41浏览：40
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