Floated sludge

Anaerobic Contact. This process can be considered as an anaerobic activated sludge because sludge is recycled from a clarifier or separator to the reactor. Siace the material leaving the reactor is a gas—Hquid—soHd mixture, a vacuum degasifier is required to separate the gas and avoid floating sludge ia the clarifier. 

Fats and, through the use of lignosiilfonic acid, proteins can be Rotated from the wastewaters of slaughterhouses and other food-processing installations [Hopwood, Jn.st. Chem. Eng. Symp. Ser, 41, Ml (1975)]. After further treatment, the floated sludge has been fed to swine. 

The spiral scoop that is shown in Figures 27.6 and 27.7 as a part of the patented structure takes up the floated sludge, pouring it into the stationary center section where it is discharged by gravity for either recycling or disposal. 

It can be seen that comparatively the floated sludge will have higher DO content, higher total solids consistency, less sludge volume, and a much lower SVI. In conclusion, the quality of the floated sludges is better than that of settled sludges. 

The floated sludge, which frequently contains 95 per cent of the solids, forms a blanket on the liquid surface and may be continuously removed by means of slowly moving brushes or scrapers mounted across the top of the tank. 

At the end of the digestion period, the top cover is removed, tap water at 15 is added to float the oil particles in the form of a froth. The steam feed hose is disconnected, and the air feed valve closed. A very mild air stream is drawn into the digested floating sludge from ambient atmosphere. The... 

Float or Floated Sludge The concentrated material scooped or skimmed from the top of the flotation unit. The concentration is measured in percent solids, or mg/L. 

Float Characteristics. The bubble-particle system that accumulates on the surfoce of the tank is termed the float. Prediction of the solids concentration of the float is a con lex matter. Bratby and Marais [1977] indicate from their e>q)erimental work that generally the floating sludge solids concentration is directfy proportional to the depth of the float and inversely related to the solids loading rate. They give equations which involve five enq>iiical coefficients. 

For activated sludge, for exan le, the floating sludge solids concentration, Cf (% w/v) is given by the equation ... 

Oily "floating" sludge from effluent treatments... 

Flotation units are normally designed for a feed-flow detention period of 15 min and an overflow rate of 1.5 to 4.0 gal/(min)(fF) [760 to 2025 L/(day)(m )]. Increased detention time is needed if floated sludge must be thickened since surface area is based on the loading rate of solids. 

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