Separating WASTEWATER SYSTEMS is key in protecting source waters

Abstract

To help determine the future course of the source water management policies of Seoul, South Korea, this article qualitatively analyzes and compares the existing source water management systems of five large metropolitan areas: Seoul; Chicago, Illinois, and, New York City in the United States; and, Osaka and Tokyo in Japan. New York and Chicago have completely separated systems for source water and wastewater that do not allow wastewater, even treated effluent, to mix with source water. As a result, these cities enjoy source water of the highest quality on a sustainable basis. However, Tokyo and Osaka still struggle with low water quality, even though their wastewater handling capabilities are by no means inferior to those of the American cities. The Japanese cities' water quality problems appear to occur primarily because their systems allow treated effluents and discharges from agricultural and urban nonpoint sources to be mixed into their source water systems. Recently, through programs that build wastewater conveyance aqueducts along sections of the Yodo and Edo rivers, Osaka and Tokyo, respectively, have begun to adopt the concept of separating wastewater from source waters. The authors believe that if Osaka and Tokyo want to further improve their source water quality, they must follow the example of New York and Chicago and expand the concept of separation of systems farther upstream. Seoul has taken a similar approach by trying to separate its primary water and wastewater systems, and then proceed with expanding its waste systems and introducing advanced water treatment processes.