Operating mechanism and set pair analysis model of a sustainable water resources system

There is no altemative to the world＇s water resources, and their increasing scarcity is making it difficult to meet the world population＇s water needs. This paper presents a sustainable water resources system （SWRS） and analyzes the operating mechanism that makes it possible to evaluate the status of such a system. A SWRS can be described as a complex coupling system that integrates water resources, social, economic and ecological systems into a whole. The SWRS＇s operating mechanism is composed of dynamic, resistance and coordination components, and it interacts with and controls the system＇s evolution process. The study introduces a new approach, set pair analysis theory, to measure the state of a SWRS, and an evaluation index system is established using the subsystems and operating mechanism of a SWRS. The evaluation index system is separated into three levels （goal level, criteria level and index level） and divides the index standard into five grades. An evaluation model of the SWRS based on set pair analysis theory is constructed, and an example of SWRS evaluation in Shanghai is presented. The connection degrees of the index in the three levels are calculated, and the connection degree of the goal index is calculated to be 0.342, which classifies the city＇s SWRS condition as grade 2. The sustainable use of water resources in the region is determined to be at a relatively adequate level that meets the requirements of sustainable development.

Comprehensive Evaluation Model of Reservoir Operation Based on Improved Set Pair Analysis

A comprehensive evaluation model based on improved set pair analysis is established. Considering the complexity in decision-making process, the model combines the certainties and uncertainties in the schemes, i.e., identical degree, different degree and opposite degree. The relations among different schemes are studied, and the traditional way of solving uncertainty problem is improved. By using the gray correlation to determine the difference degree, the problem of less evaluation indexes and inapparent linear relationship is solved. The difference between the evaluation parameters is smaller in both the fuzzy comprehensive evaluation model and fuzzy matter-element method, and the dipartite degree of the evaluation result is unobvious. However, the difference between each integrated connection degree is distinct in the improved set pair analysis. Results show that the proposed method is feasible and it obtains better effects than the fuzzy comprehensive evaluation method and fuzzy matter-element method.

Study of Impact in Soil for Sewage Sludge Application

Land utilization is considered as a positive and effective method for sewage sludge disposal. This method takes use of a large number of rich nutrients for soil and crop. The application of sewage sludge in soil increases the concentration of heavy metals. Compared with 15-30 cm layer of soil, 0-15 cm layer increased significantly, especially for Cu, Zn and Ni. The concentration of Cd in soil is considered as the main limiting factor, which determines the years of land utilization. If the largest continuous application is 30 t/（hm2.a） to the soil, the largest application period will be 11.53 years. In this paper, set pair analysis model are used in safety evaluation of the soil. After one year application of sewage, the soil can be still safe. Finally, according to the process of the subject put forward some suggestions.