Identifying R&D Policy Issues regarding the Ocean and Fisheries from the media

Abstract

Efficient water reuse through a water cycle was practiced in a university campus in Xi’an, China where less than 3000 m3/d of groundwater is the only freshwater source for 25000 population and 80 ha area with 60% green coverage. Under the constraints of limited source water and large water demand for potable and non-potable purposes, a water system was designed under the concepts of (1) integration of water supply, sewerage, water reclamation and reuse, and water landscaping in one framework, (2) introduction of a mimic natural water cycle for stepwise water use and maximized recycling, and (3) combination of engineering and natural processes for water quality control. After the groundwater was supplied for potable use, all collectable used-water was reclaimed. An environmental lake system with total storage capacity of 5000 m3 performed the functions of regulating basin for the reclaimed water and natural buffer zone in the water cycle. As a result of the system operation, groundwater supply was decreased to about 2000 m3/d, and with the recycling of all collectable used-water, 2000-2500 m3/d reclaimed water was produced so that the total water supply capacity became 4000-4500 m3/d for meeting the demand of various water uses. Discharge of excess water only occurred in rainy days through overflow from the lakes which, with frequent replenishment by receiving reclaimed water and pumping of the lake water for toilet constraints of limited source water and large water demand for potable and non-potable purposes, a water system was designed under the concepts of (1) integration of water supply, sewerage, water reclamation and reuse, and water landscaping in one framework, (2) introduction of a mimic natural water cycle for stepwise water use and maximized recycling, and (3) combination of engineering and natural processes for water quality control. After the groundwater was supplied for potable use, all collectable used-water was reclaimed. An environmental lake system with total storage capacity of 5000 m3 performed the functions of regulating basin for the reclaimed water and natural buffer zone in the water cycle. As a result of the system operation, groundwater supply was decreased to about 2000 m3/d, and with the recycling of all collectable used-water, 2000-2500 m3/d reclaimed water was produced so that the total water supply capacity became 4000-4500 m3/d for meeting the demand of various water uses. Discharge of excess water only occurred in rainy days through overflow from the lakes which, with frequent replenishment by receiving reclaimed water and pumping of the lake water for toilet