| Summary: | 碩士 === 國立中興大學 === 水土保持學系所 === 98 === According to the report of the Water Resources Agency (水利署), the demand of water resources in Taiwan is 20 billion m3/year and current supply only reaches 18 billion m3/year. The need of 2 billion m3/year is a big challenge for government. Moreover, owing to steep geographical features, river make 70% runoff into ocean and only 16% is stored. Consequently, water recycling and water reuse would be the primary development. The discharge of wastewater treatment plant and rainfall storage (中水) have great potential. The treated wastewater which meets the EPA requirements and the “clean” rainfall could meet certain water use. The purpose of this research was to evaluate the efficiency of water reuse in the highway service area. At present, there are totally fourteen zones of the highways in Taiwan. Among them, Ching-sheui service area was selected as the research site to study the existing runoff system, water supply, biological wastewater treatment plant, sewage/sewer disposal system and irrigation system. The method was to recycle water resources from rain water and to reuse the effluent of wastewater treated. Further treatments were completed to meet the requirements of reclamation water, then, the water can be used to flush toilets, irrigate plants, clean roads, fill courtyard pools, etc. Finally, this research was focused on the cost and benefit analysis of whole system in the area.
We setup 4 scenarios to analyze cost benefit ratio: (1) Discharge Water for Irrigation Only: we tried to utilize currently available facilities. In this case, 250 CMD water could be saved for irrigation. Current tap water is NT$ 11.15 per m3, the system reuse could reduce the water prices to NT$ 6.43 per m3 and the annual saving will be up to NT 0.5 million. (2) Discharge Water for Irrigation and Toilet Flush: for this purpose, we needed to increase reused water of 600 CMD and to build up the distribution system with the facilities of toilets cleaning. The results showed the binary water supply system will save up to NT$ 1.6 million annually with water price of NT$ 3.75 per m3. (3) Discharge Water for Both Irrigation and Toilet Flush to Meet Future Reclamation Standard: in order to raise the water quality to meet the standard in the future and to keep the same 600 CMD reused water. This case could save NT$ 1.2 million per year. (4) Further Storage of Rainfall 220 CMD: this case could save NT$ 0.1 million per year to make the system more reliable and flexible.
This study evaluated the feasibility of binary water supply system in Ching-sheui service area to promote and develop a practical nationwide project for water reclamation and to guide the direction of sustainable water use.
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