Research On Cleaner Production Evaluation Index System And Grade Comprehensive Evaluation Methodologies Of Wastewater Treatment Plants In Cities And Towns

Cleaner production in wastewater treatment may contribute to improve the management level of wastewater treatment plants. Furthermore, through using energy conservation and consumption reduction in the production process, cleaner production may reduce operating costs of production and hereby improve production efficiency. Thus, wastewater treatment plants may provide better services for environments of cities and towns and urbanization-constructing. For the cleaner production of wastewater treatment plants in cities and towns, according to the concept of grade comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns and inherent requirements, this dissertation systemically and deeply investigates meanings and standards of cleaner production and every key processes of grade comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns, including construction of the evaluation index system, determination method of the evaluation index weights, choice of evaluation grades and classification criteria, choices of grade benchmarks and grade membership functions of the evaluation indexes, models and methods of grade comprehensive evaluation of cleaner production, and identification and determination of sensitive evaluation indexes and sensitive evaluation index values.The main contents and research results of this dissertation are summarized as follows:(1) According to wastewater treatment characteristics and international practices in developed countries, based on the systematic analysis and scientific selection, this dissertation establishes the grade comprehensive evaluation index system of cleaner production of wastewater treatment plants in cities and towns, which is a hierarchy with three levels and three grades, where there are six evaluation indexes in the first level,24 evaluation indexes in the second level and 13 evaluation indexes in the third level.(2) According to the technics, equipment and management of wastewater treatment industries and standards and requirements of cleaner production, this dissertation divides the comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns into three grades, where the grade e1 represents the advanced level of the international cleaner production, the grade e2 represents the advanced level of the domestic cleaner production, the grade e3 represents the common (or ordinary) level of the domestic cleaner production. Using the historical data of wastewater treatment plants and real benefits and levels of comprehensive evaluation indexes of cleaner production of wastewater treatment plants in cities and towns, combining the opinions of experts related fields with the developed pairwise-ordered-comparison determination method of evaluation index weights, this dissertation specifically determines the weights of all grade comprehensive evaluation indexes of cleaner production.(3) Utilizing fuzzy mathematics, this dissertation constructs grade membership functions of qualitative and quantitative indexes for grade comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns. By using multiattribute decision making (or multiple index comprehensive evaluation) and optimization methods, according to the concept of grade comprehensive evaluation of cleaner production, this dissertation establishes a fuzzy multiple index model of grade comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns. Through analysis and comparison, this dissertation points out that the maximum membership principle is inapplicable to determining grades of cleaner production of wastewater treatment plants in cities and towns. Hereby, through introducing the concept of grade eigenvalues and analysing its applicability, the grade eigenvalues are expressed as two-tuple semantics. Based on the idea of two-tuple semantics, this dissertation stipulates ranking (or comparison) relations of grade comprehensive evaluation two-tuple semantics of cleaner production of wastewater treatment plants in cities and towns and hereby establishes a grade comprehensive evaluation two-tuple semantic method of cleaner production of wastewater treatment plants in cities and towns.(4) In order to verify the applicability of the developed grade comprehensive evaluation model and two-tuple semantic method of cleaner production of wastewater treatment plants in cities and towns, this dissertation chooses three representative wastewater treatment plants for case study. According to the stipulated comparison relations of two-tuple semantics, the wastewater treatment plants A1, A2 and A3 are finally evaluated to the grade e2 (i.e, the advanced level of the domestic cleaner production). However, the extent of cleaner production of these three wastewater treatment plants are not completely identical. Their order is A2> A3> A1, which is consistent with the real situations of the three wastewater treatment plants. These research results show that the develped grade comprehensive evaluation model and two-tuple semantic method of cleaner production of wastewater treatment plants in cities and towns are of applicability.(5) For the developed grade comprehensive evaluation two-tuple semantic method of cleaner production of wastewater treatment plants in cities and towns, according to the concepts of sensitive (or instable) evaluation index values and sensitive evaluation indexes, combining with the hierarchy characteristic of the grade comprehensive evaluation index system of cleaner production of wastewater treatment plants in cities and town, this dissertation proposes an analysis method of the sensitive evaluation indexes and sensitive evaluation index values for grade comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns, specifically inculding the identification, judgement and determination methods of sensitive evaluation index values and sensitive evaluation indexes, which provide theoretical basis and references for effectively controling or improving cleaner production of wastewater treatment plants in cities and towns.In a sum, it is seen from the aforementioned research results that the developed fuzzy multiple index model and two-tuple semantic method of grade comprehensive evaluation of cleaner production of wastewater treatment plants in cities and towns are validated. This dissertation reaches some useful and valuable conclusions, which provide a new evaluation and management method for cleaner production of environmental protection and treatment enterprises in the process of new-type urbanization in China. They also are of use for reference to study of theory and application of other similar fields or industries.