Study on the Rational Water Reuse Ratios and Water Demand in Industry
| Autor: | Liang-Ching Chen, 陳亮清 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Water reuse is an effective way to promote industrial water use efficiency and is important in the modern industrial water management from economical and environmental point of view. However, works on industrial water reuse are unduly ignored. This study is focused firstly on the development of a calculating model of rational reuse ratio of industrial water use system by using minimum cost principle, and then an industrial water demand function is derived from concept of rational reuse ratio and economic theory. A typical industrial water use system of an individual factory consists of a gross water use system and three subsystems - including intake, reuse, and discharge water, and these subsystems’ cost functions. The rational reuse ratio is defined as a reuse ratio concerning the minimum total water use cost of these three subsystems. Establishment of reuse and discharge cost function is a key toward developing a calculating model of rational reuse ratio. In the study, discharge cost function, consisting of capital, power, and chemical costs, is established based on dada collected from local factories that meet EPA’s 1998 Discharge Regulations. This study especially provides a ranking scheme in a step function, through which a systematic and quantitative description of water reuse structure and reuse cost is presented for different water reuse streams. Economies of scale is considered for reuse and discharge facilities in the model. Furthermore, by using the water balance equations of the industrial water use system, the three subsystems are connected by reuse ratio, and the number of variable and dimensionality in the model are reduced. The calculating model of rational reuse ratio is proven to work well in a case study concerning an integrated circuit (IC) factory in northern Taiwan’s Hsinchu Science-based Industrial Park. Analysis results reveal that rational reuse ratio is not a fixed value and is affected by water price, water use structure, and reuse technology. Individual water demand and aggregate water demand of IC factories are further derived from rational reuse ratio model and economic theory. The aggregate water demand is approximated by an inverse-logistic function. The price elasticity function is also derived from the same inverse-logistic function. The finding is that price elasticity is not a fixed value and varies with water price. Based on data collected in 2000 from 25 IC factories in the Hsinchu Science-based Industrial Park, the price elasticity varies between -4.37 ~ -0.02 with water price. The industrial water demand is found to be price elastic when water price is between NT$34~80/m3, and the results is quite different from previous works about the inelasticity of the industrial water demand. By using the derived price elasticity function, the reuse value of IC industrial water is estimated at NT$55/m3 and is affected by current reuse technology and discharge regulation. Key Words: Water resources planning, Industrial water, Reuse, Rational reuse ratio, Water demand, Price elasticity. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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