이중층 토양 여과시설을 이용한 도로 강우 유출수 처리성능 평가 (Ⅰ) - 시설 설계인자 결정을 중심으로 -

Abstract

This manuscript covers the results of field investigation and lab-scale experiments to design a double-layered biofilter system to control urban storm runoff. The biofilter system consisted of a coarse soil layer (CSL) for filtration and fine soil layer (FSL) for adsorption and biological degradation. The variations of flow rate and water quality of runoff from a local expressway were monitored for seven storm events. Laboratory coatmn experiments were p evented using seven kinds of soil and mulch to maximize poalutants remoora. The site mean concentration (SMC) of storm runoff from the drainage area (runoff coefficient: 0.92) was measured to be 203 mg/L for SS, 307 mg/L for TCODCr, 12.3 mg/L for TN, 7.3 mg/L for NH4+-N, and 0.79 mg/L for TP, respectively. This study employed a new design concept, to cover the maximum rainfral intensity with one month recurrence interora. Effective storms for last ten years (1998-2007) i raeoul suggested the design rainfral intensity to be 8.8 mm/hr.raingle layer soil coatmn showed the maximum remoora rate of poalutants lsoilwhen the univentity coefficient of CSL was 1.58 and the silt/clay contents of FSL was virtually 7%. The remoora efficiency during op eory coatmdxperimlayer soil coatmn was 98% for SS and turbidity, 75% for TCODCr, 56% for NH4+-N, 87% for TP, and 73-91% for heavy metals. The hydraulic conductivity of the soil coatmn, 0.023 cm/sec, suggested that the suevatalsrea of the biofilter system should be about 1% of the drainage area to treat the rainfall intensity of one month recurrence interval.