Filtration device

A filtering device comprising:

• a filter tank comprising a first sidewall and a second sidewall opposed to each other;
• a flow passage which supplies a fluid containing therein an object to be removed to the filter tank;
• a sludge takeout passage formed between a discharging outlet provided at a position higher than a fluid surface of the filter tank and a bottom portion of the filter tank;
• a conveyor comprising a lower portion moving from the sludge takeout passage toward the discharging outlet;
• a first drum filter comprising a first end portion supported on the first sidewall and a second end portion supported on the second sidewall and which filters the fluid supplied from the flow passage to the filter tank;
• a cantilever second drum filter comprising an end portion on the supported side supported on the first sidewall, arranged between the first drum filter and the sludge takeout passage, and which filters the fluid inside the filter tank;
• a fluid inflow passage formed between the first drum filter and the second drum filter and communicating with a fluid flow passage on the lower surface side of the first drum filter;
• a communicating passage formed between an end portion of the second drum filter on the non-supported side and the second sidewall and communicating with the fluid inflow passage;
• a fluid-retention passage communicating with the communicating passage and facing the sludge takeout passage;
• a drive mechanism which rotates the first drum filter and the second drum filter;
• a first jetting structure comprising a first jet nozzle and a fluid supply system, wherein the first jet nozzle jets a fluid supplied by the fluid supply system against an outer circumferential surface of the first drum filter;
• and
• a second jetting structure comprising a second jet nozzle and the fluid supply system, wherein the second jet nozzle jets the fluid supplied by the fluid supply system against an outer circumferential surface of the second drum filter.