tailieunhanh - Water Pollution Control - A Guide to the Use of Water Quality_2

thủy lợi khu vực cảnh quan xung quanh công trình công cộng, khu dân cư, thương mại và công nghiệp. • thủy lợi của các sân golf. • Cảnh cảnh quan và các tính năng nước trang trí, chẳng hạn như đài phun nước, phản ánh hồ bơi và thác nước. • Phòng cháy chữa cháy. • Nhà vệ sinh và xả nước nơi để tiểu trong các tòa nhà thương mại và công nghiệp. | Irrigation of landscaped areas surrounding public residential commercial and industrial buildings. Irrigation of golf courses. Ornamental landscapes and decorative water features such as fountains reflecting pools and waterfalls. Fire protection. Toilet and urinal flushing in commercial and industrial buildings. The disadvantages of urban non-potable reuse are usually related to the high costs involved in the construction of dual water-distribution networks operational difficulties and the potential risk of cross-connection. Costs however should be balanced with the benefits of conserving potable water and eventually of postponing or eliminating the need for the development of additional sources of water supply. Potable urban reuse can be performed directly or indirectly. Indirect potable reuse involves allowing the reclaimed water or in many instances raw wastewater to be retained and diluted in surface or groundwaters before it is collected and treated for human consumption. In many developing countries unplanned indirect potable reuse is performed on a large scale when cities are supplied from sources receiving substantial volumes of wastewater. Often only conventional treatment coagulation-flocculation-clarification filtration and disinfection is provided and therefore significant long-term health effects may be expected from organic and inorganic trace contaminants which remain in the water supplied. Direct potable reuse takes place when the effluent from a wastewater reclamation plant is connected to a drinking-water distribution network. Treatment costs are very high because the water has to meet very stringent regulations which tend to be increasingly restrictive both in terms of the number of variables to be monitored as well as in terms of tolerable contaminant limits. Presently only the city of Windhoek Namibia is performing direct potable reuse during dry periods. The Goreangab Reclamation Plant constructed in 1968 is currently being enlarged to treat