| The lower reaches of the Nakdong River, the longest river in Korea, is located on the water supply source for population of 10 million in Pusan Metropolitan City and Kyeongsang Namdo and a base of various industries. From the upper and the middle reaches of the river, the discharge of the wastewaters not adequately treated by existing secondary treatment plants have contaminated the river water and the estuary of the river through eutrophication; the existing plants consisted of the following liquid-stream unit processes: screening, grit removal, flow equalization, primary clarification, conventional activated sludge process (CASP) and disinfection (chlorination). This leads to a shortage of water resources as well as a coastal contamination. In order to solve these problems, this research proposed an advanced wastewater treatment systems such as Advanced Step Aeration (ASA) and Advanced Flocculation-Clarification-Stabilization plus Biofilm Filteration (AFB) system. To implement the advanced wastewater treatment processes, the existing secondary treatment processes may require modifications and the addition of adequate processes which can achieve the desired levels of nutrient removal such as nitrogen and phosphorus. The advanced treatment systems were divided into three functional zones; anaerobic, anoxic, and oxic (aerobic) conditions. We also laid out a scheme to increase the self-purification potential of the river through the reuse of the effluent from the FCS system plus reverse osomsis (RO) membrane with pretreatment unit, which is being used as part of a process to reclaim water from municipal secondary effluent containing salines. |
|
PDF
