Sludge, settling properties

One particularly important parameter for the influent to an activated sludge system in a refinery is oil and grease, which can lower floe density to a level where the sludge-settling properties are destroyed. A study conducted for USEPA [47] indicated that an activated sludge... 

Similarly to gaseous fuels, an important role is played by the instrumentation allowing for precise measurements of process values. However, in comparison with gaseous fuels, there are much higher requirements for the robustness of individual measuring instruments, especially as regards to pressure sensors and flow rate meters that not only have to be resistant to pressure shocks but also have to resist temperatures and physical-chemical properties of liquids. In the case of manometers and pressure sensors it is necessary to avoid that sludge settles down and solidifies inside their bodies. Separators filled with silicon oil are used for that purpose. 

Namer, J. and Ganezarezyk, J.J. (1993). Settling properties of digested sludge particle aggregates. Water Res., 21,1285-1294. 

Flocculation Where dispersants are present at too high an active level in a boiler (say, when the actives exceed 80-100 ppm or possibly up to 120 ppm), the dispersant may exhibit flocculating properties normally dispersed sludges then settle out on boiler surfaces. 

The calcium sulfite or sulfate solids are allowed to settle from the solution. The regenerated solution is returned to the absorber. The solids are concentrated to around 70%. Because these solids are not a mixture of the sulfite and sulfate, their properties are far superior to lime or limestone process sludge (unless oxidation is used) and disposal should be easier. 

The transport properties of aggregates are of interest in a number of processes such as sedimentation, filtration, and electrophoresis whenever they are charged and submitted to an external electric field. Industrial applications include the determination of the settling velocity of sludge particle aggregates [47-49]. 

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