Abstract: Thickening method and apparatus includes conventional settling vessel with moving rake and pickets at the bottom thereof to promote sludge settling and compression and a plurality of inclined passageways for upwardly flowing liquid. Upflowing liquid from the hindered settling feed is clarified in the inclined passageways from which a presettled semisolid mass flows downwardly into a detention zone of compressive thickening sludge. This interrelationship of inclined passageways and compressively thickening zone enhances the effectiveness of the thickening process.

Abstract: Apparatus assembly including continuous particle forming means, such as pelletizer, mounted on mobile platform, adapted to deposit compression formed particles as they are formed substantially throughout a large curing area to permit at least partial hardening of the particles prior to further handling. Preferably, rail mounted longitudinal and transverse supports permit movement of the pellitizer both transversely and longitudinally through predetermined paths. Most preferably, pelletizer is also mounted with elevation means to permit raising and lowering and thereby to control the drop of freshly formed particles and to permit their disposition with minimum drop as inventory of formed particles accumulates.

Abstract: Digested sewage sludge resulting from sewage plant treatment of municipal sewage is disposed of and used in an ecologically acceptable manner by the incorporation of such sludge in hardenable compositions further including, for example, lime, fly ash and, in some cases, alkaline earth metal sulfates and/or soil or other inert or complimentary additives. These hardenable compositions may be emplaced in an area open to the atmosphere and permitted to cure over a period of time to act as land fill or as road base materials.

Abstract: A roll pelletizer as disclosed and claimed in U.S. Patent Number 3,561,051 with rolls consisting of a helically wound strip of resilient material having a reduced depth portion along its length providing grooves in adjacent wraps of the strip, the remaining non-reduced depth portion of the strip defining lands. Opposed compressive rolls of this invention are helically wound with opposite hands so that lands of one roll intermesh or mate with grooves of an opposed roll. In preferred forms of this invention, a thin, non-yieldable (generally metal) strip is helically wound on a cylindrical base member with the helically wound resilient strip interposed between adjacent wraps thereof. The non-yieldable strip may include right angle tabs spaced at intervals along the length thereof which mate with spaces provided therefor in the grooved portions of the resilient strip.