Characteristics of Coagulants Distribution by the Pumping Rate in Pump Diffusion Mixer

This study collected the latest 30-year (1976~2005) continuous rainfall data hourly recorded at 61 meterological observatories in Korea, and the continuous rainfall data was divided into individual rainfall events. In addition, distribution charts of average rainfall event-depth were created to facilitate the application to the overflow risk-based design of detention storage basin. This study shows that 4 hour is appropriate for SST (storm separation time) to separate individual rainfall events from the continuous rainfall data, and the one-parameter exponential distribution is suitable for the frequency distribution of rainfall event depths for the domestic rainfall data. The analysis of the domestic rainfall data using SST of 4 hour showed that the individual rainfall event was 1380 to 2031 times, the average rainfall event-depth was 19.1 to 32.4mm, and ranged between 0.877 and 0.926. Distribution charts of average rainfall event-depth were created for 4hour and 6 hour of SST, respectively. The inland Gyeongsangbuk-do, Western coastal area and inland of Jeollabuk-do had relatively lower average rainfall event-depth, whereas Southern coastal area, such as Namhae, Yeosu, and Jeju-do had relatively higher average rainfall event-depth.

Pump Diffusion Mixer에서 압력수량에 따른 응집제 확산분포 특성

급속 혼화공정에서 응집제의 동력학적 수화반응 특성을 고려하여 1초 이내의 순간혼합을 제시하고 있으며, 이러한 이론에 근거하여 설치된 Pump Diffusion Mixer(PDM)의 관내 응집제 확산 분포특성을 조사하였다. D=1,200mm 관경에서 압력수 유량비에 따라 응집제 주입지점으로부터 4.5D되는 지점에서 관 단면의 지점별 제타 전위를 측정하여 평가한 결과, 압력수의 유량비가 2%에서는 분사속도가 낮아 관 단면에 응집제가 골고루 분사되지 못하는 것으로 조사되었다. 그러나 압력수 유량비가 4% 이상이 되면 비교적 균등하게 혼합되며, 8%에서는 관 단면 전체에 균등하게 확산 분포되는 것으로 나타났다.