Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitr...Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitrogen management is important for solving these problems.Based on field trials in 2021 and 2022,this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height,stem diameter,crown width,yield,and water(WUE)and nitrogen use efficiency(NUE).The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity(θ_(f)),and four water levels,i.e.,adequate irrigation(W0,75%-85%θ_(f)),mild water deficit(W1,65%-75%θ_(f)),moderate water deficit(W2,55%-65%θ_(f)),and severe water deficit(W3,45%-55%θ_(f))were used,and three nitrogen application levels,i.e.,no nitrogen(N0,0 kg/hm^(2)),low nitrogen(N1,150 kg/hm^(2)),medium nitrogen(N2,300 kg/hm^(2)),and high nitrogen(N3,450 kg/hm^(2))were implied.The results showed that irrigation and nitrogen application significantly affected plant height,stem diameter,and crown width of wolfberry at different growth stages(P<0.01),and their maximum values were observed in W1N2,W0N2,and W1N3 treatments.Dry weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water treatment.Dry weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 treatment.However,under other water treatments,the values first increased and then decreased with increasing nitrogen application.Yield and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen treatment.Irrigation water use efficiency(IWUE,8.46 kg/(hm^(2)·mm)),WUE(6.83 kg/(hm^(2)·mm)),partial factor productivity of nitrogen(PFPN,2.56 kg/kg),and NUE(14.29 kg/kg)reached their highest values in W2N2,W1N2,W1N2,and W1N1 treatments.Results of principal component analysis(PCA)showed that yield,WUE,and NUE were better in W1N2 treatment,making it a suitable water and nitrogen management mode for the irrigation area of the Yellow River in the Gansu Province,China and similar planting areas.展开更多
Based on the regional water resources carrying capacity(WRCC)evaluation principles and evaluation index system in the National Technical Outline of Water Resources Carrying Capacity Monitoring and Early Warning(hereaf...Based on the regional water resources carrying capacity(WRCC)evaluation principles and evaluation index system in the National Technical Outline of Water Resources Carrying Capacity Monitoring and Early Warning(hereafter referred to as the Technical Outline),this paper elaborates on the collection and sorting of the basic data of water resources conditions,water resources development and utilization status,social and economic development in basins,analysis and examination of integrity,consistency,normativeness,and rationality of the basic data,and the necessity of WRCC evaluation.This paper also describes the technique of evaluating the WRCC in prefecture-level cities and city-level administrative divisions in the District of the Taihu Lake Basin,which is composed of the Taihu Lake Basin and the Southeastern River Basin.The evaluation process combines the binary index evaluation method and reduction index evaluation method.The former,recommended by the Technical Outline,uses the total water use and the amount of exploited groundwater as evaluation indices,showing stronger operability,while the latter is developed by simplifying and optimizing the comprehensive index system with greater systematicness and completeness.The mutual validation and adjustment of the results of the above-mentioned two evaluation methods indicate that the WRCC of the District of the Taihu Lake Basin is overloaded in general because some prefecture-level cities and city-level administrative divisions in the Taihu Lake Basin and the Southeastern River Basin are in a severely overloaded state.In order to explain this conclusion,this paper analyzes the causes of WRCC overloading from the aspects of basin water environment,water resources development and utilization,water resources regulation and control ability,water resources utilization efficiency,and water resources management.展开更多
This paper, based on the analysis and calculation of the groundwater resources in an arid region from 1980 to 2001, put forward the concept of ecological groundwater level threshold for either salinity control or the ...This paper, based on the analysis and calculation of the groundwater resources in an arid region from 1980 to 2001, put forward the concept of ecological groundwater level threshold for either salinity control or the determination of ecological warning. The surveys suggest that soil moisture and soil salinity are the most important environmental factors in determining the distribution and changes in vegetation. The groundwater level threshold of ecological warning can be determined by using a network of groundwater depth observation sites that monitor the environmental moisture gradient as reflected by plant physiological characteristics. According to long-term field observations within the Ejin oases, the groundwater level threshold for salinity control varied between 0.5 m and 1.5 m, and the ecological warning threshold varied between 3.5 m and 4.0 m. The quantity of groundwater re- sources （renewable water resources, ecological water resources, and exploitable water resources） in arid areas can be calculated from regional groundwater level information, without localized hydrogeological data. The concept of groundwater level threshold of ecological warning was established according to water development and water re- sources supply, and available groundwater resources were calculated. The concept not only enriches and broadens the content of groundwater studies, but also helps in predicting the prospects for water resources development.展开更多
This paper addresses the impact of climate change on the water cycle and resource changes in the Eastern Monsoon Region of China （EMRC）. It also represents a summary of the achievements made by the National Key Basi...This paper addresses the impact of climate change on the water cycle and resource changes in the Eastern Monsoon Region of China （EMRC）. It also represents a summary of the achievements made by the National Key Basic Research and Development Program （2010CB428400）, where the major research focuses are detection and attribution, extreme floods and droughts, and adaptation of water resources management. Preliminary conclusions can be summarized into four points： 1） Water cycling and water resource changes in the EMRC are rather complicated as the region is impacted by natural changes relating to the strong monsoon influence and also by climate change impacts caused by CO2 emissions due to anthropogenic forcing; 2） the rate of natural variability contributing to the influence on precipitation accounts for about 70%, and the rate from anthropogenic forcing accounts for 30% on average in the EMRC. However, with future scenarios of increasing CO2 emissions, the contribution rate from anthropogenic forcing will increase and water resources management will experience greater issues related to the climate change impact; 3） Extreme floods and droughts in the EMRC will be an increasing trend, based on IPCC-AR5 scenarios; 4） Along with rising temperatures of 1 ~C in North China, the agricultural water consumption will increase to about 4% of total water consumption. Therefore, climate change is making a significant impact and will be a risk to the EMRC, which covers almost all of the eight major river basins, such as the Yangtze River, Yellow River, Huaihe River, Haihe River, and Pearl River, and to the South-to-North Water Diversion Project （middle line）. To ensure water security, it is urgently necessary to take adaptive countermeasures and reduce the vulnerability of water resources and associated risks.展开更多
The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture ...The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture the relationship between mining and other equilibrium elements.This study presents an innovative evaluation method to assess the water level recovery resulting from mining reduction based on the relationship between variation in exploitation and recharge.Firstly,the recharge variability of source and sink terms for both the base year and evaluation year is calculated and the coefficient of recharge variationβis introduced,which is then used to calculate the effective mining reduction and solve the water level recovery value caused by the effective mining reduction,and finally the water level recovery contribution by mining reduction is calculated by combining with the actual volume of mining reduction in the evaluation area.This research focuses on Baoding and Shijiazhuang Plain area,which share similar hydrogeological conditions but vary in groundwater exploitation and utilization.As the effect of groundwater level recovery with mining reduction was evaluated in these two areas as case study.In 2018,the results showed an effective water level recovery of 0.17 m and 0.13 m in the shallow groundwater of Shijiazhuang and Baoding Plain areas,respectively.The contributions of recovery from mining reduction were 76%and 57.98%for these two areas,respectively.It was notable that the water level recovery was most prominent in the foothill plain regions.From the evaluation results,it is evident that water level recovery depends not only on the intensity of groundwater mining reduction,but also on its effectiveness.The value of water level recovery alone cannot accurately indicate the intensity of mining reduction,as recharge variation significantly influences water level changes.Therefore,in practice,it is crucial to comprehensively assess the impact of mining reduction on water level recovery by combining the coefficient of recharge variation with the contribution of water level recovery from mining reduction.This integrated approach provide a more reasonable and scientifically supported basis,offering essential data support for groundwater management and conservation.To improve the accuracy and reliability of evaluation results,future work will focus on the standardizing and normalizing raw data processing.展开更多
Based on the water quality monitoring data of 5 large reservoirs in Ji’an City,Jiangxi Province from 2015-2021,the temporal and spatial variation characteristics and trends of water quality of the reservoirs were ana...Based on the water quality monitoring data of 5 large reservoirs in Ji’an City,Jiangxi Province from 2015-2021,the temporal and spatial variation characteristics and trends of water quality of the reservoirs were analyzed by single-factor evaluation method and seasonal Kendall test to evaluate the trophic status of the reservoirs and explore the influencing factors of characteristic pollutants.The results showed that:①the water quality of the reservoirs was good and could meet the water needs of various functions;②the water quality of the reservoirs had generally changed from bad to good in recent years,indicating that the implementation of“river chief system”has achieved certain results;③Kendall test analysis showed that,except for individual projects which showed an upward trend in water quality,other projects showed no obvious change trend or downward trend,indicating that the water quality of the reservoirs is indeed improving;④the causes of water pollution in reservoir area were further analyzed by exploring the natural and human factors of the characteristic pollutant total phosphorus.It is recommended to strengthen supervision in the later stage to control point and non-point source pollution.展开更多
The Group Ⅱ fresh groundwater bearing aquifers in the eastern plain of Tianjin underwent long term exploitation. This study shows that the area with greater water-level declining is associated with more rapid stratig...The Group Ⅱ fresh groundwater bearing aquifers in the eastern plain of Tianjin underwent long term exploitation. This study shows that the area with greater water-level declining is associated with more rapid stratigraphic compaction and consolidation. In the study area, the salty groundwater in the un-exploited overlying aquifers have the same dynamic characteristic of synchronization but different amplitude with the Group Ⅱ aquifers, showing that they have a close relationship. Cross-sectional study indicated that surface water, salty groundwater and underlying fresh groundwater belong to an integral water resources system. The compacted clay layers have the feature of semi-permeable membrane under alkaline condition. The infiltration of surface water is driven by the differences of osmotic pressure of salty water in each layer. When the water level difference between the Group Ⅱ aquifers and overlying salty aquifers is greater than osmotic water pressure difference, the salt water layer will desalinate downward and eventually, decreasing the water level of the upper aquifers, turning phreatic water amount supposed to evaporate to leakage recharge. Therefore, stopping mining groundwater in the Group Ⅱ aquifer will lead to other new environmental geology disaster.展开更多
Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types withi...Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types within the canopy are poorly quantified.In this study,the seasonality of leaf chlorophyll,nitrogen(N),and phosphorus(P)were quantified vertically along the canopy of four major tree species and two types of herbs in a temperate deciduous forest.The role of shade tolerance in shaping the seasonal variation and vertical differentiation was examined.During the entire season,chlorophyll content showed a distinct asymmetric unimodal pattern for all species,with greater chlorophyll levels in autumn than in spring,and the timing of peak chlorophyll per leaf area gradually decreased as shade tolerance increased.Chlorophyll a:b ratios gradually decreased with increasing shade tolerance.Leaf N and P contents sharply declined during leaf expansion,remained steady in the mature stage and decreased again during leaf senescence.Over the seasons,the lower canopy layer had significantly higher chlorophyll per leaf mass but not chlorophyll per leaf area than the upper canopy layer regardless of degree of shade tolerance.However,N and P per leaf area of intermediate shade-tolerant and fully shade-tolerant tree species were significantly higher in the upper canopy than in the lower.Seasonal variations in N:P ratios suggest changes in N or P limitation.These findings indicate that shade tolerance is a key feature shaping inter-specific differences in leaf chlorophyll,N,and P contents as well as their seasonality in temperate deciduous forests,which have significant implications for modeling leaf photosynthesis and ecosystem production.展开更多
Different forest stands in the Dongjiang Lake Reservoir area of Zixing were selected as the research objects to study the characteristics of runoff generation in different forest stands.The results showed that there w...Different forest stands in the Dongjiang Lake Reservoir area of Zixing were selected as the research objects to study the characteristics of runoff generation in different forest stands.The results showed that there was no significant difference in annual runoff among M3,M1,and M5,and no significant difference between each forest stand and the control.The order was M3(22.75 mm)>M1(21.77 mm)>M5(20.14 mm).Forest vegetation generates less runoff through vegetation restoration compared to the control,indicating that forest vegetation reconstruction and restoration are beneficial for soil and water conservation.展开更多
Population upsurge in Gwagwalada increased water demand in the area,thereby stressing water resources in the area.Aquifer properties in parts of Gwagwalada in North-Central Nigeria were therefore investigated using re...Population upsurge in Gwagwalada increased water demand in the area,thereby stressing water resources in the area.Aquifer properties in parts of Gwagwalada in North-Central Nigeria were therefore investigated using resistivity and hydrogeological approaches.Static water level measurements of hand dug wells were used to determine the groundwater flow direction for the area which coincides with the North East-South West joint direction.Constant rate pumping test was adopted for the research and 10 boreholes were pumped.The weathered/fractured basement range from 7.5 m to 56.7 m.The transmissivity values in the area ranged from 0.35 m^(2)/d to 3.63 m^(2)/d while the hydraulic conductivity range from 0.045 m/d to 0.18 m/d.The Vertical Electrical Soundings(VES)were carried out on the area.The geoelectric sections revealed four to five layers and the longitudinal conductance varied from 0.11Ω^(-1)to 0.37Ω^(-1).The results of the investigation characterized the groundwater potential in the study area into low and moderate while the aquifer protective capacity into weak and moderate zones.The efficacy of resistivity and pumping test data in quantifying aquifer properties has been established in this study.The findings of this study shed light on the properties of ground water and aquifer protective capacity in the area,hence assist in the effective future groundwater resources exploitation.展开更多
Taking the mountain flood disaster prevention and control project in Jiangxi province as the research object, the evaluation period is 2010-2015, and 29 evaluation indexes are selected from 7 aspects. In this paper, g...Taking the mountain flood disaster prevention and control project in Jiangxi province as the research object, the evaluation period is 2010-2015, and 29 evaluation indexes are selected from 7 aspects. In this paper, game theory is introduced to optimize the subjective and objective weights of the index, and the comprehensive weights are obtained by normalization. The results show that the eigenvalues of the grade variables of benefit evaluation decreased from 3.43 to 2.03, indicating that the project of mountain flood disaster prevention and control in Jiangxi province brings into play the benefits year by year, and the eigenvalues tend to decrease steadily after 2012, it is consistent with the changes of various engineering measures and non-engineering measures in the project.展开更多
Implementation of the Grain-for-Green project has led to rapid land cover changes and resulted in a significantly increased vegetation cover on the Loess Plateau of China during the past few decades. The main objectiv...Implementation of the Grain-for-Green project has led to rapid land cover changes and resulted in a significantly increased vegetation cover on the Loess Plateau of China during the past few decades. The main objective of this study was to examine the responses of soil water dynamics under four typical vegetation types against precipitation years. Soil water contents (SWCs) were measured in 0–4.0 m profiles on a hillslope under the four vegetation types of shrub, pasture, natural fallow and crop in a re-vegetated catchment area from April to October in normal (2010), dry (2011), wet (2014) and extremely wet (2013) years. The results indicated that precipitation and vegetation types jointly controlled the soil water temporal dynamics and profile characteristics in the study region. SWCs in 0–4.0 m profiles of the four vegetation types were ranked from high to low as crop>fallow>pasture>shrub and this pattern displayed a temporal stability over the four years. In the extremely wet year, SWC changes occurred in the 0–2.0 m layer under shrub and pasture while the changes further extended to the depth of 4.0-m deep layers under fallow and crop. In the other three years, SWCs changes mainly occurred in the 0–1.0 m layer and kept relatively stable in the layers deeper than 1.0 m for all the four vegetation types. The interannual variation in soil depth of SWCs was about 0–2.0 m for shrub and pasture, about 0–3.4 m for fallow and about 0–4.0 m for crop, respectively. The dried soil layers formed at the depths of 1.0, 0.6, 1.6 and 0.7 m under shrub, and 1.0, 1.0, 2.0 and 0.9 m under pasture, respectively in 2010, 2011, 2013 and 2014. The infiltrated rainwater mostly stayed in the 0–1.0 m layer and hardly supplied to soil depth >1.0 m in normal, dry and wet years. Even in the extremely wet year of 2013, rainwater recharge depth did not exceed 2.0 m under shrub and pasture. This implied that soil desiccation was difficult to remove in normal, dry and wet years, and soil desiccation could be removed in 1.0–2.0 m soil layers even in the extremely wet year under shrub and pasture. The results indicated that the natural fallow was the best vegetation type for achieving sustainable utilization of soil water and preventing soil desiccation.展开更多
Stable oxygen and hydrogen isotopic compositions(δ^(18)O and δD) of plant xylem water and its potential water sources can provide new information for studying water sources, competitive interactions and water use pa...Stable oxygen and hydrogen isotopic compositions(δ^(18)O and δD) of plant xylem water and its potential water sources can provide new information for studying water sources, competitive interactions and water use patterns of plants. The contributions of different water sources to three plants, Hedysarum scoparium(HS), Caragana Korshinskii(CK) and Artemisia ordosica(AO), were investigated in the artificial sand-fixed vegetation of Shapotou, the southeastern margin of the Tengger Desert of northwestern China, based on meteorological data and δ^(18)O and δD values of precipitation, groundwater, soil water and xylem water of HS, CK and AO. Our results indicated that soil water infiltration through precipitation was the main water source of the artificial sand-fixed vegetation. Obvious differences in soil water content and in δ^(18)O of soil water and xylem water were found among different seasons. No relationship was found between the δ^(18)O in plant xylem water and in soil water in January. The same water use patterns were found in CK, HS and AO in May, suggesting they have the same water sources. The different water sources of CK, HS and AO in August indicate that water competition occurred. In addition, the main water sources of CK, HS and AO in August mainly come from shallow soil water, while they use relatively deep soil water in May. This phenomenon is related to the differences of soil water content throughout soil profile, precipitation, transpiration and water competition under different growth periods. The water use patterns of CK, HS and AO respond to soil water content throughout the soil profile and their competition balance for water uptake during different growth season. The results indicate that these sandfixed plants have developed into a relatively stable stage and they are able to regulate their water use behavior as a response to the environmental conditions, which reinforces the effectiveness of plantation of native shrubs without irrigation in degraded areas.展开更多
Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalinatio...Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis （RO） system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of （1） a wind-driven pumping subsystem, （2） a pressure-driven RO membrane desalination subsystem, and （3） a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids （TDS） of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.展开更多
With the development of science and technology,the status of the water environment has received more and more attention.In this paper,we propose a deep learning model,named a Joint Auto-Encoder network,to solve the pr...With the development of science and technology,the status of the water environment has received more and more attention.In this paper,we propose a deep learning model,named a Joint Auto-Encoder network,to solve the problem of outlier detection in water supply data.The Joint Auto-Encoder network first expands the size of training data and extracts the useful features from the input data,and then reconstructs the input data effectively into an output.The outliers are detected based on the network’s reconstruction errors,with a larger reconstruction error indicating a higher rate to be an outlier.For water supply data,there are mainly two types of outliers:outliers with large values and those with values closed to zero.We set two separate thresholds,and,for the reconstruction errors to detect the two types of outliers respectively.The data samples with reconstruction errors exceeding the thresholds are voted to be outliers.The two thresholds can be calculated by the classification confusion matrix and the receiver operating characteristic(ROC)curve.We have also performed comparisons between the Joint Auto-Encoder and the vanilla Auto-Encoder in this paper on both the synthesis data set and the MNIST data set.As a result,our model has proved to outperform the vanilla Auto-Encoder and some other outlier detection approaches with the recall rate of 98.94 percent in water supply data.展开更多
Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, ...Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou(CZ) and Hengshui(HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.展开更多
In Sierra Leone, poor water quality is a major threat to public health and aquatic life. The main source of this problem appears to be poorly?regulated waste disposal. Even though water pollution laws exist, their enf...In Sierra Leone, poor water quality is a major threat to public health and aquatic life. The main source of this problem appears to be poorly?regulated waste disposal. Even though water pollution laws exist, their enforcement is challenged by many gaps and,?seemingly, they?focus on the quest to sustain natural resource exploitation. This work presents a case for?strengthening?such laws to promote public health, economic growth, and resource conservation. The article presents examples of problems that necessitated promulgation of water pollution laws in the US and the UK. Sierra Leone has been affected by similar problems such as public health, war efforts, and industrialization.展开更多
The concern in mitigating the negative impact generated by the discharge of nutrients in the receiving water body is a challenge for the sustainable development of Brazilian fish farms. Thus, the purpose of this study...The concern in mitigating the negative impact generated by the discharge of nutrients in the receiving water body is a challenge for the sustainable development of Brazilian fish farms. Thus, the purpose of this study was to evaluate the water quality and environmental impact caused by trout farming system effluent with focus on discharge of phosphorus. Sampling was performed on a weekly basis in triplicate from September to November 2010. Sample sites were distributed according to the water flow: upstream from trout farming system, water supply, effluent, artificial wetland, mixing zone and downstream (60 m from effluent). In the field, pH, conductivity, dissolved oxygen, water temperature and turbidity were measured. In laboratory, nitrogen and phosphorus series, chlorophyll a, total solids suspended and their organic and inorganic fractions were analyzed. For the good growth of trout in production system, the abiotic factors described in the water quality monitoring demonstrated acceptable values. Environmentally, after passing through the production system and artificial wetland, there was an increase in concentrations of total phosphorus, total nitrogen, orthophosphate, ammonium, chlorophyll a, total solids suspended and their organic and inorganic fractions (P < 0.05). These results are related with the quality of feed, feeding management and the inefficiency of the artificial wetland. Therefore, it is necessary to use best quality feed to meet the nutritional requirements of trout, maintaining an optimal feed conversion and reducing pollution generated by effluent.展开更多
In this study, Mucuna flagellipes seed extract was applied in the coagulation-flocculation of produced water （PW）. Process parameters such as pH, dosage, and settling time were investigated. Process kinetics was als...In this study, Mucuna flagellipes seed extract was applied in the coagulation-flocculation of produced water （PW）. Process parameters such as pH, dosage, and settling time were investigated. Process kinetics was also studied. Instrumental characterization of mucuna seed （MS）, mucuna seed coagulant （MSC）, and post effluent treatment settled sludge （PTSS） were carried out. The optimum decontamination efficiency of 95 % was obtained at 1 g/L MSC dosage, PW pH of 2, and rate constant of 0.0001 （L/g/s）. Characterization results indicated that MS, MSC, and PTSS were of network structure, primitive lat- tice, and thermally stable. It could be concluded that MSC would be potential biomass for the treatment of produced water under the experimental conditions.展开更多
Significant fractions of bromine-substituted disinfection byproducts (DBPs)—particularly trihalomethanes (THMs)— have been observed to form during treatment of water from the Missouri River. THM speciation was also ...Significant fractions of bromine-substituted disinfection byproducts (DBPs)—particularly trihalomethanes (THMs)— have been observed to form during treatment of water from the Missouri River. THM speciation was also noted to follow a seasonal pattern during a 2.5-year period, during which samples were collected multiple times per month. Although some treatment processes were effective at reducing the chloroform formation potential, no treatment used at this utility significantly reduced the formation of the three bromine-substituted THM species. Using chloramination rather than free chlorination for secondary disinfection, however, was effective at limiting increases in the concentration of all four regulated THM species in the distribution system.展开更多
基金funded by the National Natural Science Foundation of China(51969003)the Key Research and Development Project of Gansu Province(22YF7NA110)+4 种基金the Discipline Team Construction Project of Gansu Agricultural Universitythe Gansu Agricultural University Youth Mentor Support Fund Project(GAU-QDFC-2022-22)the Innovation Fund Project of Higher Education in Gansu Province(2022B-101)the Research Team Construction Project of College of Water Conservancy and Hydropower Engineering,Gansu Agricultural University(Gaucwky-01)the Gansu Water Science Experimental Research and Technology Extension Program(22GSLK023)。
文摘Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitrogen management is important for solving these problems.Based on field trials in 2021 and 2022,this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height,stem diameter,crown width,yield,and water(WUE)and nitrogen use efficiency(NUE).The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity(θ_(f)),and four water levels,i.e.,adequate irrigation(W0,75%-85%θ_(f)),mild water deficit(W1,65%-75%θ_(f)),moderate water deficit(W2,55%-65%θ_(f)),and severe water deficit(W3,45%-55%θ_(f))were used,and three nitrogen application levels,i.e.,no nitrogen(N0,0 kg/hm^(2)),low nitrogen(N1,150 kg/hm^(2)),medium nitrogen(N2,300 kg/hm^(2)),and high nitrogen(N3,450 kg/hm^(2))were implied.The results showed that irrigation and nitrogen application significantly affected plant height,stem diameter,and crown width of wolfberry at different growth stages(P<0.01),and their maximum values were observed in W1N2,W0N2,and W1N3 treatments.Dry weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water treatment.Dry weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 treatment.However,under other water treatments,the values first increased and then decreased with increasing nitrogen application.Yield and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen treatment.Irrigation water use efficiency(IWUE,8.46 kg/(hm^(2)·mm)),WUE(6.83 kg/(hm^(2)·mm)),partial factor productivity of nitrogen(PFPN,2.56 kg/kg),and NUE(14.29 kg/kg)reached their highest values in W2N2,W1N2,W1N2,and W1N1 treatments.Results of principal component analysis(PCA)showed that yield,WUE,and NUE were better in W1N2 treatment,making it a suitable water and nitrogen management mode for the irrigation area of the Yellow River in the Gansu Province,China and similar planting areas.
基金supported by the National Natural Science Foundation of China(Grant No.51379181)Phase Ⅲ Project(2018-2021)of the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Based on the regional water resources carrying capacity(WRCC)evaluation principles and evaluation index system in the National Technical Outline of Water Resources Carrying Capacity Monitoring and Early Warning(hereafter referred to as the Technical Outline),this paper elaborates on the collection and sorting of the basic data of water resources conditions,water resources development and utilization status,social and economic development in basins,analysis and examination of integrity,consistency,normativeness,and rationality of the basic data,and the necessity of WRCC evaluation.This paper also describes the technique of evaluating the WRCC in prefecture-level cities and city-level administrative divisions in the District of the Taihu Lake Basin,which is composed of the Taihu Lake Basin and the Southeastern River Basin.The evaluation process combines the binary index evaluation method and reduction index evaluation method.The former,recommended by the Technical Outline,uses the total water use and the amount of exploited groundwater as evaluation indices,showing stronger operability,while the latter is developed by simplifying and optimizing the comprehensive index system with greater systematicness and completeness.The mutual validation and adjustment of the results of the above-mentioned two evaluation methods indicate that the WRCC of the District of the Taihu Lake Basin is overloaded in general because some prefecture-level cities and city-level administrative divisions in the Taihu Lake Basin and the Southeastern River Basin are in a severely overloaded state.In order to explain this conclusion,this paper analyzes the causes of WRCC overloading from the aspects of basin water environment,water resources development and utilization,water resources regulation and control ability,water resources utilization efficiency,and water resources management.
基金funded by the National Natural Science Foundation of China(9102500230970492)+2 种基金the Fundamental Research Funds for the Central Universities(GK201101002)the Key Project of the Chinese Academy of Sciences(KZZDEW-04-05)the National Key Technology R & D Program(2012BAC08B05)
文摘This paper, based on the analysis and calculation of the groundwater resources in an arid region from 1980 to 2001, put forward the concept of ecological groundwater level threshold for either salinity control or the determination of ecological warning. The surveys suggest that soil moisture and soil salinity are the most important environmental factors in determining the distribution and changes in vegetation. The groundwater level threshold of ecological warning can be determined by using a network of groundwater depth observation sites that monitor the environmental moisture gradient as reflected by plant physiological characteristics. According to long-term field observations within the Ejin oases, the groundwater level threshold for salinity control varied between 0.5 m and 1.5 m, and the ecological warning threshold varied between 3.5 m and 4.0 m. The quantity of groundwater re- sources （renewable water resources, ecological water resources, and exploitable water resources） in arid areas can be calculated from regional groundwater level information, without localized hydrogeological data. The concept of groundwater level threshold of ecological warning was established according to water development and water re- sources supply, and available groundwater resources were calculated. The concept not only enriches and broadens the content of groundwater studies, but also helps in predicting the prospects for water resources development.
基金Acknowledgment This study was supported by the National Key Basic Research Development Program Project （2010CB428400） and the Natural Science Foundation of China （51279140）.
文摘This paper addresses the impact of climate change on the water cycle and resource changes in the Eastern Monsoon Region of China （EMRC）. It also represents a summary of the achievements made by the National Key Basic Research and Development Program （2010CB428400）, where the major research focuses are detection and attribution, extreme floods and droughts, and adaptation of water resources management. Preliminary conclusions can be summarized into four points： 1） Water cycling and water resource changes in the EMRC are rather complicated as the region is impacted by natural changes relating to the strong monsoon influence and also by climate change impacts caused by CO2 emissions due to anthropogenic forcing; 2） the rate of natural variability contributing to the influence on precipitation accounts for about 70%, and the rate from anthropogenic forcing accounts for 30% on average in the EMRC. However, with future scenarios of increasing CO2 emissions, the contribution rate from anthropogenic forcing will increase and water resources management will experience greater issues related to the climate change impact; 3） Extreme floods and droughts in the EMRC will be an increasing trend, based on IPCC-AR5 scenarios; 4） Along with rising temperatures of 1 ~C in North China, the agricultural water consumption will increase to about 4% of total water consumption. Therefore, climate change is making a significant impact and will be a risk to the EMRC, which covers almost all of the eight major river basins, such as the Yangtze River, Yellow River, Huaihe River, Haihe River, and Pearl River, and to the South-to-North Water Diversion Project （middle line）. To ensure water security, it is urgently necessary to take adaptive countermeasures and reduce the vulnerability of water resources and associated risks.
基金supported by National Natural Science Foundation of China(41972262)Hebei Natural Science Foundation for Excellent Young Scholars(D2020504032).
文摘The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture the relationship between mining and other equilibrium elements.This study presents an innovative evaluation method to assess the water level recovery resulting from mining reduction based on the relationship between variation in exploitation and recharge.Firstly,the recharge variability of source and sink terms for both the base year and evaluation year is calculated and the coefficient of recharge variationβis introduced,which is then used to calculate the effective mining reduction and solve the water level recovery value caused by the effective mining reduction,and finally the water level recovery contribution by mining reduction is calculated by combining with the actual volume of mining reduction in the evaluation area.This research focuses on Baoding and Shijiazhuang Plain area,which share similar hydrogeological conditions but vary in groundwater exploitation and utilization.As the effect of groundwater level recovery with mining reduction was evaluated in these two areas as case study.In 2018,the results showed an effective water level recovery of 0.17 m and 0.13 m in the shallow groundwater of Shijiazhuang and Baoding Plain areas,respectively.The contributions of recovery from mining reduction were 76%and 57.98%for these two areas,respectively.It was notable that the water level recovery was most prominent in the foothill plain regions.From the evaluation results,it is evident that water level recovery depends not only on the intensity of groundwater mining reduction,but also on its effectiveness.The value of water level recovery alone cannot accurately indicate the intensity of mining reduction,as recharge variation significantly influences water level changes.Therefore,in practice,it is crucial to comprehensively assess the impact of mining reduction on water level recovery by combining the coefficient of recharge variation with the contribution of water level recovery from mining reduction.This integrated approach provide a more reasonable and scientifically supported basis,offering essential data support for groundwater management and conservation.To improve the accuracy and reliability of evaluation results,future work will focus on the standardizing and normalizing raw data processing.
基金Hydraulic Science and Technology Project of Water Resources Department of Jiangxi Province(202324YBKT14)Youth Science and Technology Innovation Fund of Jiangxi Hydrology Monitoring Center(SWJJKT202208).
文摘Based on the water quality monitoring data of 5 large reservoirs in Ji’an City,Jiangxi Province from 2015-2021,the temporal and spatial variation characteristics and trends of water quality of the reservoirs were analyzed by single-factor evaluation method and seasonal Kendall test to evaluate the trophic status of the reservoirs and explore the influencing factors of characteristic pollutants.The results showed that:①the water quality of the reservoirs was good and could meet the water needs of various functions;②the water quality of the reservoirs had generally changed from bad to good in recent years,indicating that the implementation of“river chief system”has achieved certain results;③Kendall test analysis showed that,except for individual projects which showed an upward trend in water quality,other projects showed no obvious change trend or downward trend,indicating that the water quality of the reservoirs is indeed improving;④the causes of water pollution in reservoir area were further analyzed by exploring the natural and human factors of the characteristic pollutant total phosphorus.It is recommended to strengthen supervision in the later stage to control point and non-point source pollution.
文摘The Group Ⅱ fresh groundwater bearing aquifers in the eastern plain of Tianjin underwent long term exploitation. This study shows that the area with greater water-level declining is associated with more rapid stratigraphic compaction and consolidation. In the study area, the salty groundwater in the un-exploited overlying aquifers have the same dynamic characteristic of synchronization but different amplitude with the Group Ⅱ aquifers, showing that they have a close relationship. Cross-sectional study indicated that surface water, salty groundwater and underlying fresh groundwater belong to an integral water resources system. The compacted clay layers have the feature of semi-permeable membrane under alkaline condition. The infiltration of surface water is driven by the differences of osmotic pressure of salty water in each layer. When the water level difference between the Group Ⅱ aquifers and overlying salty aquifers is greater than osmotic water pressure difference, the salt water layer will desalinate downward and eventually, decreasing the water level of the upper aquifers, turning phreatic water amount supposed to evaporate to leakage recharge. Therefore, stopping mining groundwater in the Group Ⅱ aquifer will lead to other new environmental geology disaster.
基金This work was supported by the National Natural Science Foundation of China(32171765).
文摘Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types within the canopy are poorly quantified.In this study,the seasonality of leaf chlorophyll,nitrogen(N),and phosphorus(P)were quantified vertically along the canopy of four major tree species and two types of herbs in a temperate deciduous forest.The role of shade tolerance in shaping the seasonal variation and vertical differentiation was examined.During the entire season,chlorophyll content showed a distinct asymmetric unimodal pattern for all species,with greater chlorophyll levels in autumn than in spring,and the timing of peak chlorophyll per leaf area gradually decreased as shade tolerance increased.Chlorophyll a:b ratios gradually decreased with increasing shade tolerance.Leaf N and P contents sharply declined during leaf expansion,remained steady in the mature stage and decreased again during leaf senescence.Over the seasons,the lower canopy layer had significantly higher chlorophyll per leaf mass but not chlorophyll per leaf area than the upper canopy layer regardless of degree of shade tolerance.However,N and P per leaf area of intermediate shade-tolerant and fully shade-tolerant tree species were significantly higher in the upper canopy than in the lower.Seasonal variations in N:P ratios suggest changes in N or P limitation.These findings indicate that shade tolerance is a key feature shaping inter-specific differences in leaf chlorophyll,N,and P contents as well as their seasonality in temperate deciduous forests,which have significant implications for modeling leaf photosynthesis and ecosystem production.
基金Supported by Hunan Province Science and Technology Plan Project(2019SK2336,2019sfq21,2021SFQ19)Hunan Forestry Science and Technology Plan Project(OT-S-KTA5,2024YBC15).
文摘Different forest stands in the Dongjiang Lake Reservoir area of Zixing were selected as the research objects to study the characteristics of runoff generation in different forest stands.The results showed that there was no significant difference in annual runoff among M3,M1,and M5,and no significant difference between each forest stand and the control.The order was M3(22.75 mm)>M1(21.77 mm)>M5(20.14 mm).Forest vegetation generates less runoff through vegetation restoration compared to the control,indicating that forest vegetation reconstruction and restoration are beneficial for soil and water conservation.
基金Authors wish to acknowledge the African Water Resources Mobility Network(A WaRMN)for supporting this research through the Intra-African Academic Mobility Programme No.2019-1973/004-001,which was funded by the European Union.
文摘Population upsurge in Gwagwalada increased water demand in the area,thereby stressing water resources in the area.Aquifer properties in parts of Gwagwalada in North-Central Nigeria were therefore investigated using resistivity and hydrogeological approaches.Static water level measurements of hand dug wells were used to determine the groundwater flow direction for the area which coincides with the North East-South West joint direction.Constant rate pumping test was adopted for the research and 10 boreholes were pumped.The weathered/fractured basement range from 7.5 m to 56.7 m.The transmissivity values in the area ranged from 0.35 m^(2)/d to 3.63 m^(2)/d while the hydraulic conductivity range from 0.045 m/d to 0.18 m/d.The Vertical Electrical Soundings(VES)were carried out on the area.The geoelectric sections revealed four to five layers and the longitudinal conductance varied from 0.11Ω^(-1)to 0.37Ω^(-1).The results of the investigation characterized the groundwater potential in the study area into low and moderate while the aquifer protective capacity into weak and moderate zones.The efficacy of resistivity and pumping test data in quantifying aquifer properties has been established in this study.The findings of this study shed light on the properties of ground water and aquifer protective capacity in the area,hence assist in the effective future groundwater resources exploitation.
文摘Taking the mountain flood disaster prevention and control project in Jiangxi province as the research object, the evaluation period is 2010-2015, and 29 evaluation indexes are selected from 7 aspects. In this paper, game theory is introduced to optimize the subjective and objective weights of the index, and the comprehensive weights are obtained by normalization. The results show that the eigenvalues of the grade variables of benefit evaluation decreased from 3.43 to 2.03, indicating that the project of mountain flood disaster prevention and control in Jiangxi province brings into play the benefits year by year, and the eigenvalues tend to decrease steadily after 2012, it is consistent with the changes of various engineering measures and non-engineering measures in the project.
基金financially supported by the National Natural Science Foundation of China(51179180,41390463)
文摘Implementation of the Grain-for-Green project has led to rapid land cover changes and resulted in a significantly increased vegetation cover on the Loess Plateau of China during the past few decades. The main objective of this study was to examine the responses of soil water dynamics under four typical vegetation types against precipitation years. Soil water contents (SWCs) were measured in 0–4.0 m profiles on a hillslope under the four vegetation types of shrub, pasture, natural fallow and crop in a re-vegetated catchment area from April to October in normal (2010), dry (2011), wet (2014) and extremely wet (2013) years. The results indicated that precipitation and vegetation types jointly controlled the soil water temporal dynamics and profile characteristics in the study region. SWCs in 0–4.0 m profiles of the four vegetation types were ranked from high to low as crop>fallow>pasture>shrub and this pattern displayed a temporal stability over the four years. In the extremely wet year, SWC changes occurred in the 0–2.0 m layer under shrub and pasture while the changes further extended to the depth of 4.0-m deep layers under fallow and crop. In the other three years, SWCs changes mainly occurred in the 0–1.0 m layer and kept relatively stable in the layers deeper than 1.0 m for all the four vegetation types. The interannual variation in soil depth of SWCs was about 0–2.0 m for shrub and pasture, about 0–3.4 m for fallow and about 0–4.0 m for crop, respectively. The dried soil layers formed at the depths of 1.0, 0.6, 1.6 and 0.7 m under shrub, and 1.0, 1.0, 2.0 and 0.9 m under pasture, respectively in 2010, 2011, 2013 and 2014. The infiltrated rainwater mostly stayed in the 0–1.0 m layer and hardly supplied to soil depth >1.0 m in normal, dry and wet years. Even in the extremely wet year of 2013, rainwater recharge depth did not exceed 2.0 m under shrub and pasture. This implied that soil desiccation was difficult to remove in normal, dry and wet years, and soil desiccation could be removed in 1.0–2.0 m soil layers even in the extremely wet year under shrub and pasture. The results indicated that the natural fallow was the best vegetation type for achieving sustainable utilization of soil water and preventing soil desiccation.
基金supported by the National Science Foundation China (Grants No. 41771028 and 41571025)the Key Laboratory of Agricultural Water Resources, the Chinese Academy of Sciences (Grants No. KFKT201606)the Shaanxi province natural science foundation research project (Grants No. 2016JM4006)
文摘Stable oxygen and hydrogen isotopic compositions(δ^(18)O and δD) of plant xylem water and its potential water sources can provide new information for studying water sources, competitive interactions and water use patterns of plants. The contributions of different water sources to three plants, Hedysarum scoparium(HS), Caragana Korshinskii(CK) and Artemisia ordosica(AO), were investigated in the artificial sand-fixed vegetation of Shapotou, the southeastern margin of the Tengger Desert of northwestern China, based on meteorological data and δ^(18)O and δD values of precipitation, groundwater, soil water and xylem water of HS, CK and AO. Our results indicated that soil water infiltration through precipitation was the main water source of the artificial sand-fixed vegetation. Obvious differences in soil water content and in δ^(18)O of soil water and xylem water were found among different seasons. No relationship was found between the δ^(18)O in plant xylem water and in soil water in January. The same water use patterns were found in CK, HS and AO in May, suggesting they have the same water sources. The different water sources of CK, HS and AO in August indicate that water competition occurred. In addition, the main water sources of CK, HS and AO in August mainly come from shallow soil water, while they use relatively deep soil water in May. This phenomenon is related to the differences of soil water content throughout soil profile, precipitation, transpiration and water competition under different growth periods. The water use patterns of CK, HS and AO respond to soil water content throughout the soil profile and their competition balance for water uptake during different growth season. The results indicate that these sandfixed plants have developed into a relatively stable stage and they are able to regulate their water use behavior as a response to the environmental conditions, which reinforces the effectiveness of plantation of native shrubs without irrigation in degraded areas.
基金supported in part by the U.S.Department of the Interior Bureau of Reclamation(USBR)through a research grant(04-FG-81-1062)
文摘Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis （RO） system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of （1） a wind-driven pumping subsystem, （2） a pressure-driven RO membrane desalination subsystem, and （3） a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids （TDS） of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.
基金The work described in this paper was supported by the National Natural Science Foundation of China(NSFC)under Grant No.U1501253 and Grant No.U1713217.
文摘With the development of science and technology,the status of the water environment has received more and more attention.In this paper,we propose a deep learning model,named a Joint Auto-Encoder network,to solve the problem of outlier detection in water supply data.The Joint Auto-Encoder network first expands the size of training data and extracts the useful features from the input data,and then reconstructs the input data effectively into an output.The outliers are detected based on the network’s reconstruction errors,with a larger reconstruction error indicating a higher rate to be an outlier.For water supply data,there are mainly two types of outliers:outliers with large values and those with values closed to zero.We set two separate thresholds,and,for the reconstruction errors to detect the two types of outliers respectively.The data samples with reconstruction errors exceeding the thresholds are voted to be outliers.The two thresholds can be calculated by the classification confusion matrix and the receiver operating characteristic(ROC)curve.We have also performed comparisons between the Joint Auto-Encoder and the vanilla Auto-Encoder in this paper on both the synthesis data set and the MNIST data set.As a result,our model has proved to outperform the vanilla Auto-Encoder and some other outlier detection approaches with the recall rate of 98.94 percent in water supply data.
基金financially supported by the 100-Talent Project of Chinese Academy of Sciencesthe Key Program of the National Natural Science Foundation of China (No.41471028)
文摘Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou(CZ) and Hengshui(HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.
文摘In Sierra Leone, poor water quality is a major threat to public health and aquatic life. The main source of this problem appears to be poorly?regulated waste disposal. Even though water pollution laws exist, their enforcement is challenged by many gaps and,?seemingly, they?focus on the quest to sustain natural resource exploitation. This work presents a case for?strengthening?such laws to promote public health, economic growth, and resource conservation. The article presents examples of problems that necessitated promulgation of water pollution laws in the US and the UK. Sierra Leone has been affected by similar problems such as public health, war efforts, and industrialization.
基金financial support(Process 2010/07658-3)Marcos Guilherme Rigolino from Experimental Station of Salmon in memoriam.
文摘The concern in mitigating the negative impact generated by the discharge of nutrients in the receiving water body is a challenge for the sustainable development of Brazilian fish farms. Thus, the purpose of this study was to evaluate the water quality and environmental impact caused by trout farming system effluent with focus on discharge of phosphorus. Sampling was performed on a weekly basis in triplicate from September to November 2010. Sample sites were distributed according to the water flow: upstream from trout farming system, water supply, effluent, artificial wetland, mixing zone and downstream (60 m from effluent). In the field, pH, conductivity, dissolved oxygen, water temperature and turbidity were measured. In laboratory, nitrogen and phosphorus series, chlorophyll a, total solids suspended and their organic and inorganic fractions were analyzed. For the good growth of trout in production system, the abiotic factors described in the water quality monitoring demonstrated acceptable values. Environmentally, after passing through the production system and artificial wetland, there was an increase in concentrations of total phosphorus, total nitrogen, orthophosphate, ammonium, chlorophyll a, total solids suspended and their organic and inorganic fractions (P < 0.05). These results are related with the quality of feed, feeding management and the inefficiency of the artificial wetland. Therefore, it is necessary to use best quality feed to meet the nutritional requirements of trout, maintaining an optimal feed conversion and reducing pollution generated by effluent.
文摘In this study, Mucuna flagellipes seed extract was applied in the coagulation-flocculation of produced water （PW）. Process parameters such as pH, dosage, and settling time were investigated. Process kinetics was also studied. Instrumental characterization of mucuna seed （MS）, mucuna seed coagulant （MSC）, and post effluent treatment settled sludge （PTSS） were carried out. The optimum decontamination efficiency of 95 % was obtained at 1 g/L MSC dosage, PW pH of 2, and rate constant of 0.0001 （L/g/s）. Characterization results indicated that MS, MSC, and PTSS were of network structure, primitive lat- tice, and thermally stable. It could be concluded that MSC would be potential biomass for the treatment of produced water under the experimental conditions.
文摘Significant fractions of bromine-substituted disinfection byproducts (DBPs)—particularly trihalomethanes (THMs)— have been observed to form during treatment of water from the Missouri River. THM speciation was also noted to follow a seasonal pattern during a 2.5-year period, during which samples were collected multiple times per month. Although some treatment processes were effective at reducing the chloroform formation potential, no treatment used at this utility significantly reduced the formation of the three bromine-substituted THM species. Using chloramination rather than free chlorination for secondary disinfection, however, was effective at limiting increases in the concentration of all four regulated THM species in the distribution system.
