| Title |
Operational Variables and Performance of Hydrodynamic Separator Treating Rainfall Runoff from Bridge |
| Authors |
김연석 ( Yeon Seok Kim ) ; 우강화 ( Jiang Hua Yu ) ; 김영철 ( Young Chul Kim ) |
| Keywords |
First flush; Hydrodynamic separator; Natural free energy; Separation efficiency; Stormwater |
| Abstract |
A hydrodynamic separator using natural free energy provided by bridge was operated for the treatment of stormwater runoff. The separator was automatically controlled by using electronic valve which is connected with pressure meter. Normally the separator was opened during dry days, but it was closed after the capture of first flush. The results indicated that the average pressure and the flow rate were directly affected by the rainfall intensity. The pressure was more than 3 meters as the rainfall intensity was above 5 mm/hr. The percent volume of underflow decreased as the pressure and flow rate increased, but the percent volume of overflow showed an opposite behavior. The concentration of total suspended solids (TSS) in underflow increased as a function of increasing pressure while it decreased in overflow. The TSS separation efficiency was evaluated based on mass balance. It ranged from 30% to 90% with the pressure ranging from 2 to 10 meters, and it was proportional to pressure and flow rate. The analysis of water balance indicated that around 13% of total runoff was captured by the separator as a first flush, and this runoff was separated as underflow and overflow with the respective percent volume of 29% and 71%. The pollutants budget was also examined based on mass balance. The results showed that the percent of TSS, COD(cr), TN and TP in underflow were 73%, 59%, 7.6% and 49%, respectively. |