A Non-point Source Contaminant Decreasing Device

摘要

The present invention relates to a nonpoint pollution reduction device for reducing a nonpoint pollution source contained in initial rainwater and, more specifically, to a downward-filtering nonpoint pollution reduction device using a standing filter medium, which allows initial rainwater to bypass and flow into the same through a rainwater pipe to filter out floating objects by using a screen of a preprocessing tank having the screen, reduces nonpoint pollution sources while rainwater from which the floating objects are removed passes through a filtering tank, allows the rainwater with reduced nonpoint pollution sources to flow into a backwashing water tank, and then supplies the rainwater back to a rainwater collecting well to use the rainwater to reduce nonpoint pollution sources contained in initial rainwater while downward-filtering in the filtering tank so as to improve filtering efficiency and, at the same time, uses the rainwater stored in the backwashing water tank to backwash the filtering tank if the filtering tank is overloaded when it does not rain or even while raining to improve backwashing efficiency.