Reuse Potential of the Secondary Effluent from a Wastewater Treatment Plant

In a recent United Nations report, Korea was classified as a water-scarce country based on the water stress index (WSI). However, the WSI is calculated using the uniform application of the amount of agricultural products, and this is difficult to apply in Korea, for which agricultural and livestock imports are high and self-sufficiency has not been achieved for agricultural products. This classification has been the subject of considerable controversy. Korea's WEI approaches 35% when the return rate for agricultural water is ignored, but falls below 30% when a return rate of 25% for agricultural water is taken into account. Therefore, in Korea, the ecological stress due to the water system is a more serious problem than the absolute lack of water, the need for national verification of the actual use of agricultural water and the regression rate is removed, and rather than the absolute amount of water shortage, climate change and water supply infrastructure are raised. It is also necessary to prepare an alternative for areas where the water supply is limited due to regional imbalances.