NATURAL BALANCE TYPE FILTRATION DEVICE AND METHOD OF CLEANING FILTER MEDIA LAYER THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a natural balance type filtration device adaptable to existing equipment and cleaning filter media layer efficiently and a method of cleaning the filter media layer. SOLUTION: The natural balance type filtration device is provided with 2 reversely U-shaped waste water siphon pipes 48 and 50 for connecting a filter pond 12 having the filter media layer 40 to a waste water flow-out part 14. The filter media layer 40 is cleaned by the reflux water flowing in the filter pond 14 through each waste water siphon pipe 48 and 50 respectively and the filter media layer 40.