Recovery device and recovery method for recovering specific material from sludge
A recovery device is configured to recover specific material as a dewatering aid from sludge generated in a sewage treatment process. The recovery device includes: a grinder configured to fragment a solid in the sludge to obtain prepared sludge; a separator configured to separate hardly decomposable organic matter and easily decomposable organic matter from the prepared sludge; and an extractor configured to continuously extract hardly decomposable organic matter having specific properties as the dewatering aid from the hardly decomposable organic matter separated by the separator.
1. A method of separating fibrous material from sewage sludge for subsequent use as a dewatering aid, said method comprising:
introducing raw sewage sludge from a sewage treatment process into a grinder including a stationary disk and a rotary disk rotatably arranged to face the stationary disk and defining a recessed portion therebetween, the rotary disk having a supply port in fluid communication with the recessed portion for receiving said raw sewage sludge;
grinding solids contained in said raw sewage sludge to produce a prepared sludge;
separating fibrous material having fiber lengths of 0.1 mm to 5 mm and fiber diameters of 1 micron to 50 microns from said prepared sludge by introducing said prepared sludge into a proximate end of a rotary cylindrical screen having a distal open end through which separated fibrous material exits, said introduced, prepared sludge, being sprayed by pressurized water directed at said cylindrical screen to aid in separation; and
collecting said separated fibrous material which has exited said distal open end of said rotary cylindrical screen.