OFT
O
FT series of internally-fed Rotary drum sludge thickeners have cylindrical drums with progressive series of screen elements that are mounted horizontally on four shaft-mounted wheels and supported in a structural housing.
The smallest openings are used to screen the influent sludge, followed by coarser elements as the sludge thickness. The screening element is either woven mesh or wedgewire. The screens are used to remove free liquids from a variety of sludges, including those with appreciable amounts of microbial particles, sludge containing 0.5%--3% solids can be thickened to 5%--15%, depending on the type of the sludge.
Options
- 316 stainless steel construction
- Full support base
- Internal spray bar
- Wedgewire or mesh panels
- Control panel
- VFD
Method of operation
Sludge is normally pumped to the thickener, while polymer is injected prior to sludge entering tank. The tank has a vertically mounted mechanical mixer, the polymer is gently agitated for up to 1 minute to aggregate the fine solids into tightly held floc. The conditioned sludge overflows into the distribution headbox and is fed gently on the inside surface of the screen cylinder.
The floc are retained on the screen surface as the liquid flows rapidly through the screen opening.
The liquid filtrate is collected and directed to an outlet on the bottom of the discharge pan, the solids are transported by flights along the cylinder and discharged out the open end and exiting through the discharge chute. The thickened sludge attains high levels of consistency as the rotation induces the free liquid to drain away. A shower bar along the to section applies an intermittent cleaning shower to keep screen openings clean.
