Contract Mechanism of Water Environment Regulation for Small and Medium Sized Enterprises Based on Optimal Control Theory

The small and scattered enterprise pattern in the county economy has formed numerous sporadic pollution sources, hindering the centralized treatment of the water environment, increasing the cost and difficulty of treatment. How enterprises can make reasonable decisions on their water environment behavior based on the external environment and their own factors is of great significance for scientifically and effectively designing water environment regulation mechanisms. Based on optimal control theory, this study investigates the design of contractual mechanisms for water environmental regulation for small and medium-sized enterprises. The enterprise is regarded as an independent economic entity that can adopt optimal control strategies to maximize its own interests. Based on the participation of multiple subjects including the government, enterprises, and the public, an optimal control strategy model for enterprises under contractual water environmental regulation is constructed using optimal control theory, and a method for calculating the amount of unit pollutant penalties is derived. The water pollutant treatment cost data of a paper company is selected to conduct empirical numerical analysis on the model. The results show that the increase in the probability of government regulation and public participation, as well as the decrease in local government protection for enterprises, can achieve the same regulatory effect while reducing the number of administrative penalties per unit. Finally, the implementation process of contractual water environmental regulation for small and medium-sized enterprises is designed.

Integrated water risk early warning framework of the semi-arid transitional zone based on the water environmental carrying capacity (WECC)

Water risk early warning systems based on the water environmental carrying capacity(WECC)are powerful and effective tools to guarantee the sustainability of rivers.Existing work on the early warning of WECC has mainly concerned the comprehensive evaluation of the status quo and lacked a quantitative prejudgement and warning of future overload.In addition,existing quantitative methods for short-term early warning have rarely focused on the integrated change trends of the early warning indicators.Given the periodicity of the socioeconomic system,however,the water environmental system also follows a trend of cyclical fluctuations.Thus,it is meaningful to monitor and use this periodicity for the early warning of the WECC.In this study,we first adopted and improved the prosperity index method to develop an integrated water risk early warning framework.We also constructed a forecast model to qualitatively and quantitatively prejudge and warn about the development trends of the water environmental system.We selected the North Canal Basin(an essential connection among the Beijing-Tianjin-Hebei region)in China as a case study and predicted the WECC in 25 water environmental management units of the basin in 2018–2023.We found that the analysis of the prosperity index was helpful in predicting the WECC,to some extent.The result demonstrated that the early warning system provided reliable prediction(root mean square error of 0.0651 and mean absolute error of 0.1418),and the calculation results of the comprehensive early warning index(CEWI)conformed to the actual situation and related research in the river basin.From 2008 to 2023,the WECC of most water environmental management units in the basin had improved but with some spatial differences:the CEWI was generally poor in areas with many human disturbances,while it was relatively good in the upstream regions with higher forest and grass covers as well as in the downstream areas with larger water volume.Finally,through a sensitivity analysis of the indicators,we proposed specific management measures for the sustainability of the water environmental system in the North Canal Basin.Overall,the integrated water risk early warning framework could provide an appropriate method for the water environmental administration department to predict the WECC of the basin in the future.This framework could also assist in implementing corresponding management measures in advance,especially for the performance evaluation and the arrangement of key short-term tasks in the River Chief System in China.

Environmental and ecological water requirement of river system: a case study of Haihe-Luanhe river system

In order to reduce the environmental and ecological problems induced by water resources development and utilization, this paper proposes a concept of environmental and ecological water requirement. It is defined as the minimum water amount to be consumed by the natural water bodies to conserve its environmental and ecological functions. Based on the definition, the methods on calculating the amount of environmental and ecological water requirement are determined. In the case study on Haihe-Luanhe river system, the water requirement is divided into three parts, i.e., the basic in-stream flow, water requirement for sediment transfer and water consumption by evaporation of the lakes or everglades. The results of the calculation show that the environmental and ecological water requirement in the river system is about 124×108 m3, including 57×108 m3 for basic in-stream flow, 63×108 m3 for sediment transfer and 4×108 m3 for net evaporation loss of lakes. The total amount of environmental and ecological water requirement accounts for 54% of the amount of runoff (228×108 m3). However, it should be realized that the amount of environmental and ecological water requirement must be more than that we have calculated. According to this result, we consider that the rational utilization rate of the runoff in the river systems must not be more than 40%. Since the current utilization rate of the river system, which is over 80%, has been far beyond the limitation, the problems of environment and ecology are quite serious. It is imperative to control and adjust water development and utilization to eliminate the existing problems and to avoid the potential ecological or environmental crisis.

Water Environmental Impact Assessment and Analysis of Foshan Brewery Project

In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the environment. In order to evaluate and better solve the possible environmental impacts of beer treatment engineering projects, a brewery project in Foshan City is taken as an example to investigate the water pollution generation links of the engineering process including surface water and groundwater. According to the relevant technical methods and standards, water pollution factors are screened, and concentration and discharge are monitored. Through comprehensive analysis, predictive evaluation is obtained. It is confirmed that the project meets the requirements of national laws and regulations and environmental protection standards.

New Attempt for Building Rural Water Environment Management System Based on the Investigation and Analysis of Water Environment in Xianxia Town, Yudu County

Water environment is a part of ecological environment, and conservation of water environment has always been a focus of public attention in China, but water environment management in the vast countryside has been stuck in bottleneck. Based on the fi eld investigation in Xianxia Town, Yudu County, Ganzhou City, Jiangxi Province, this paper explored the current situation of local water environment and the management diffi culties, then introduced the holistic view to integrate the linkage of government, market and society, proposed the universality of the individual case, and the new attempt centering on urban-rural integrated water environment management system with public participation mechanism, management subjects' benefit balance and coordination system, marketing operation mechanism and economic incentive mechanism as the extension.

Analysis on Residents’ Satisfaction and Its Influencing Factors with Water Environment Management: Based on the Data from Xiaoqing River

Xiaoqing River is one of the key rivers in the Yellow River Basin, and its management satisfaction is the content that the government should consider when formulating policies. This paper concentrates on residents’ satisfaction of water environment management in Jinan section of Xiaoqing River, using questionnaires to find out the problems and effects of Xiaoqing River management. Based on the correlation analysis of the questionnaire data, the results show that five factors including the impact of water pollution, understanding of Xiaoqing River governance, willingness to participate in Xiaoqing River governance, policy publicity, and government regulation have a positive impact on the satisfaction of Xiaoqing River water environment governance. Finally, the paper puts forward some countermeasures and suggestions to increase residents’ satisfaction from five aspects, such as increasing publicity efforts, paying attention to the cultivation of public participation consciousness, etc.

A Scheme for a Sustainable Urban Water Environmental System During the Urbanization Process in China

Urbanization is a potential factor in economic development, which is a main route to social development. As the scale of urbanization expands, the quality of the urban water environment may deteriorate, which can have a negative impact on sustainable urbanization. Therefore, a comprehensive understanding of the functions of the urban water environment is landscape, culture, and economy. Furthermore, a the urban water environment, which is associated necessary, including its security, resources, ecology, deep analysis is required of the theoretical basis of with geographical location, landscape ecology, and a low-carbon economy. In this paper, we expound the main principles for constructing a system for the urban water environment （including sustainable development, ecological priority, and regional differ- ences）, and suggest the content of an urban water environmental system. Such a system contains a nat- ural water environment, an economic water environment, and a social water environment. The natural water environment is the base, an effective economic water environment is the focus, and a healthy social water environment is the essence of such a system. The construction of an urban water environment should rely on a comprehensive security system, complete scientific theory, and advanced technology.

Navigating Eutrophication in Aquatic Environments: Understanding Impacts and Unveiling Solutions for Effective Wastewater Management

Eutrophication is the term used to describe the presence of natural and artificial nutrients like phosphorus and nitrogen in aquatic ecosystems.The water quality in various bodies of water such as ponds,lakes,rivers,etc.is deteriorating as a result of an abundance of plant nutrients in these water sources.Over-enrichment of aquatic ecosystems with nutrients is a major hazard to the well-being of aquatic ecosystems worldwide.In addition,the circulations have lowered the requirements for home and agricultural consumption of water.The main origins of these plant nutrients within aquatic ecosystems stem from the discharges of industries engaged in activities like livestock farming,agriculture,fertilizer production,manufacturing of textiles,and clothing production.Therefore,a variety of methods and approaches have already been developed as safety measures to avoid the negative consequences of water tainted with those undesired minerals.Eutrophication presents many obstacles,but with the right public awareness campaign and global scientific efforts,its negative impacts may be lessened.This research seeks to pinpoint the primary origins of plant nutrients within the aquatic ecosystem and explore potential triggers for eutrophication.Additionally,it proposes innovative regulatory methods and offers suggestions for sustainable wastewater management practices.

A method of analysis of macro water environmental systems

The phases of water environmental system (WES) and their emphatic intersections areanalysed in this paper. and from the view point of system analysis , an analytical process of WES is provided. Based on the balance network of WES, a goal programming model for regional water environmentalplanning and the main computational result for a coastal city are provided , thus proving its usefulness andeffectiveness.

Design and Realization of Baiyangdian Water Environment Information System Based on ArcGIS Engine

For the need to protect the eco-environment and to strengthen environmental management in Lake Baiyangdian, water environment information aimed to get the water quality information more convenient and more intuitionistic was of significance. Based on massive monitoring data of Lake Baiyangdian and the important advantage of spatial analysis functions of GIS （geographical information system）, a system of B-WEIS （Baiyangdian water environment information system） was designed in the work. Component GIS of ArcEngine 9.3 GIS, combined with GIS and component technology, was used to research and develop the proposed system. This system realized different functions of management, data query, statistic analysis and visualization query to the Lake Baiyangdian water monitoring results. It also integrated with professional water quality model to realize evaluation of water quality and calculation of environmental capacity function. The designed system contributed to expand the management on Lake Baiyangdian more professional and available.

Study on water environment restoration and urban water system healthy circulation

Studied on the law and interaction of hydrological cycle and social water circulation on the earth,it is pointed out that the water environment,water resources and water cycle are the unity of water movement.The roots of contemporary crisis are also analyzed.The strategy of water environment recovery and social water healthy cycle is proposed and applied in many cities,which has achieved good results.

Linking Numerical Water Quality Models in an Environmental Information System for Integrated Environmental Assessments

Decision makers involved in prevention of water contamination often lack the technical knowledge of water quality evaluation or the comprehension of complex software for environmental information management required to make effective decisions. Providing information about the environment is not an easy task due to its complex structure, relationships, and dynamic processes. Because environmental models play an important role in environmental decision support systems, the integration of models into user-friendly integrated information systems is a key factor in the support of such users. This paper presents an environmental information system which supports water protection of Coatzacoalcos River in Mexico, having as a main building block water quality assessments supported by mathematical modeling through the two-dimensional Saint Venant and Advection-Diffusion-Reaction equations to calculate the river hydrodynamics and the contaminant transport, respectively. The mathematical modeling solution yields appropriate results representing the river contaminant distribution when compared with field measurements. But the direct use of these models by decision makers is difficult at best, meaning they are not likely to be used in making practical decisions. The system described in this paper integrates these models, and several other tools, into a seamless, user-centered application, improving model usability, initial configuration, and results visualization.

The 3D simulation and optimized management model of groundwater systems based on eco-environmental water demand

Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.

Purification Effects of Aquatic Vegetations on Lake Wetland Water Environment and Analysis of the Influencing Factors in Hongze Lake

[Objective] To study the purification effect of plant community on wetland water environment in Hongze Lake, and to provide references to the ecological restoration of this area. [Methed] The typical lakeside zone of Hongze Lake Wetland National Nature Reserve was taken as the study area. Through the field survey based on environmental characteristics of aquatic areas and non-aquatic areas, combined with laboratory test, the content changes of nutrients （N and P）, COD （chemical oxygen demand） and SD （transparency） levels in the water body of lake wetland were measured; the purification effect of the lake wetland ecosystem in the growth process of aquatic vegetation was quantitatively analyzed, and possible influ- encing factors were discussed. [Result] Aquatic vegetation could remove the TN, TP, COD, Chla in wetland water environment and had obvious effects on the changes of SD content. Competition between aquatic plants can inhibit the growth of algae and relieve the eutrophication of water body. [Conclusion] This study provided theoretical basis for ecological restoration and enhancement of self-purification capability in the lakeside zone of Hongze Lake.

Analysis and Evaluation of Heavy Metal Environmental Quality of Irrigation Water in Vegetable Farmlands of Shandong Province

[Objective] The aim was to evaluate heavy metal environmental quality of irrigation water in vegetable farmlands of Shandong Province. [Method] Heavy metal contents including Hg,Cd,As,Cr (+6),Pb,Cu and Zn in irrigation water of main vegetable farmlands of Shandong Province were investigated by randomly sampling,and the environmental quality conditions of these heavy metals were evaluated by methods of single quality index and complex quality index. [Result] The results showed that the average contents of heavy metals in irrigation water of Shouguang,Laiyang,Jinxiang and Zhangqiu were all far lower than the limit values prescribed by 'Farmland Environmental Quality Evaluation Standards for Edible Agricultural Products' (HJ332-2006),and no heavy metal was found beyond the limit value in every sample. The single quality indices of the 7 elements in the studied 4 places were all lower than 0.5. The comprehensive quality index of the seven elements was 0.317 8 in Shouguang,0.320 4 in Laiyang,0.232 6 in Jinxiang,and 0.260 7 in Zhangqiu. The environmental quality of irrigation water in the studied four places were all set at the first class. [Conclusion] The environmental quality of irrigation water in the 4 places belonged to clean level and were fit for the plantation of no pollution vegetables.

Application of Grey Relational Analysis in Regional Water Environment Assessment——Taking Jin River Basin as An Example

According to the data from four water monitoring stations at Meihewan, Shimawan, Tanwan and Jinbin, the water environment at the downstream basin of Jin River was evaluated through grey reIational analysis in this study. The resuIts showed that the water environment was severeIy contaminated by phosphorus, am-monia nitrogen and permanganate.

Construction of Urban Overall Water Environment in Xi'an City

[Objective] The aim was to study on construction of overall water environment in Xi＇an. [Method] The study discussed necessity and basic principles of over-all restoration and construction of ＂Chang＇an Eight Water＂ from urban planning, and explored related methods from long term planning and concrete construction approaches. [Result] The study proposed that urban landscape substrates of ＂Chang＇ an Eight Water＂ should be restored based on overall planning about urban water environment, change of linear metabolism, and construction of drainage circulation system. Furthermore, self-circulation and purification of rainfall and sewage could be made use of there in view of present urban water environment. In addition, urban ＂metabolism＂ should be restored progressively to improve urban environment with consideration of water catchment, storage, and diversion. [Conclusion] We should take the initiative to catch the special opportunity to build Xi＇an into an international metropolis with overall planning, designing and implementation, which will be conducive to reconstruction of water system and pleasant surroundings, and to presentation of urban ecosystem and context in ＂Chang＇an Eight Water＂, providing many opportunities for urban development.

Countermeasures for Treatment in Water Environment of Nanfeihe River

According to current situation of the severe water pollution and bad water environment of Nanfeihe River catchment, the major environment problems were id- entified based on the investigation and analysis of the general situation of the catch- ment, the present situation of water quality and water volume composition, corre- sponding countermeasures were put forward to provide a reliable theoretical support for controlling pollution in water environment of Nanfeihe River.

Study on the Changes of China's Water Right System

Irrigation was developed in ancient China.The management of water resources has existed since ancient times when the embryonic form of water right system was established.From perspectives of environmental law,the water rights system in ancient China,especially the water rights system after Ming Dynasty,gave no explicit concept to water rights,but the participatory management of water users was included in implementation.Such management had the same connotation with the modern concept of water rights and thereby it has an instructional significance to perfect the water rights system of in modern China.

Industrial and Agricultural Effects on Water Environment and Its Optimization in Heavily Polluted Area in Taihu Lake Basin, China

The deteriorating water quality in the Taihu Lake Basin has attracted widespread attention for many years, and is correlated with a sharp increase in the quantity of pollutant discharge such as agricultural fertilizers and industrial wastewater. In this study, several factors were selected for evaluating and regionalizing the water environmental capacity by ArcG1S spatial analysis, including geomor- phologic characteristics, water quality goals, water body accessibility, water-dilution channels, and current water quality. Then, the spa- tial optimization of agriculture and industry was adjusted through overlay analysis, based on the balance between industrial space and water environmental capacity. The results show that the water environmental capacity gradually decreases from the west to the east, in contrast, the pollution caused by industrial and agricultural clustering is distributes along Taihu Lake, Gehu Lake and urban districts. The analysis of the agricultural space focuses on optimizing key protected areas of the Taihu Lake Basin, and the shores of Gehu Lake, optimally adjusting the second protected areas of the Taihu Lake Basin, and generally adjusting the urban areas of Changzhou and Wuxi cities. The analysis of industrial space focuses on optimizing the downtowns of Changzhou and Wuxi cities, optimally adjusting key protected areas and second protected areas of the Taihu Lake Basin, and generally adjusting the south and southwest of Gehu Lake. Lastly, some schemes of industrial and agricultural layouts and policies for the direction of industrial and agricultural development were proposed, reflecting a correlation between industry and agriculture and the water environment.