Apparatus for treating rainwater

PURPOSE: An initial rainwater treatment apparatus is provided to improve the water treatment efficiency for preventing the contamination of lakes and rivers by nonpoint pollutants mixed with initial rainwater. CONSTITUTION: An initial rainwater treatment apparatus comprises an undercurrent space unit for storing initial rainwater. The undercurrent space unit includes an undercurrent tank main body formed with a pre-treatment tank(110), a detritus tank(120), a settling tank(130), and a discharge tub(140). A swirl screen is installed on the pre-treatment tank for dividing minute foreign substances and soil from the initial rainwater.