Suspending fine and

Acid Recovery. In the manufacture of every pound of cellulose acetate, about 4 lb of acetic acid is produced in 30-35 percent aqueous solution. The accumulated acid contains a small amount of suspended fines and some dissolved cellulose esters. To remove the suspended material, the acid is passed slowly through settling tanks. Then it is mixed with organic solvents, so that the acid becomes concentrated in an organic layer, which is decanted. Distillation separates the acid from the organic solvent. 

Density of suspended fines and carrier liquid in the upper layer of the two-layer model... 

The punishment should fit the crime. Low levels of speeding should be treated with low-level fines. Perhaps the first offence should result in a suspended fine and a warning letter, with a second low-level offence attracting the suspended fine from the first offence plus a fine for the second offence, plus the allocation of demerit points. We are not proposing this as the ideal system, but simply pointing out that we need to convince the motoring public that our interest is not in revenue but in speed moderation for safety. 

Ultrafiltration. Ultrafiltration was described under pretreatment methods. It is used to remove finely divided suspended solids, and when used as a tertiary treatment, it can remove virtually all the BOD remaining after secondary treatment. 

Some companies have used the Merseburg process to manufacture ammonium sulfate from gypsum, but the process is only economically attractive where sulfur is unavailable or very expensive (32), and is thus not used in the United States. Ammonium carbonate, formed by the reaction of ammonia and carbon dioxide in an aqueous medium, reacts with suspended, finely ground gypsum. Insoluble calcium carbonate and an ammonium sulfate solution are formed. 

Process water streams from vinyl chloride manufacture are typically steam-stripped to remove volatile organics, neutralized, and then treated in an activated sludge system to remove any nonvolatile organics. If fluidized-bed oxychlorination is used, the process wastewater may also contain suspended catalyst fines and dissolved metals. The former can easily be removed by sedimentation, and the latter by precipitation. Depending on the specific catalyst formulation and outfall limitations, tertiary treatment may be needed to reduce dissolved metals to acceptable levels. 

Flotation Air flotation has proved to be successful in concentrating secondaiy sludges to about 4 percent solids. The incoming solids are normally saturated with air at 275 to 350 kPa (40 to 50 psig) prior to being released in the flotation tank. As the air comes out of solution, the fine bubbles are trapped under the suspended solids and cany... 

Granular bed filters are used in porcelain enameling wastewater treatment to remove residual solids from clarifier effluent (sedimentation effluent or flotation effluent). Filtration polishes the effluent and reduces suspended solids and insoluble precipitated metals to very low levels. Fine sand and coal are media commonly utilized in granular bed filtration. The filter is backwashed after becoming loaded with solids and the backwash is returned to the treatment plant influent for removal of solids in the clarification step.10-12... 

Preliminaries. The combustion of suspended dusts and powders is quite complex and only imperfectly understood. The complexity stems from both fundamental and practical considerations. On the fundamental side, the ignition of suspensions of finely divided solids is influenced by hard-to-quantify factors such as the time-varying concentration of solids, the chemical activity and morphology of the particulate, and the degree of confinement provided by the vessel. On the practical side, industrial conditions are seldom sufficiently well-controlled or characterized to justify application of existing theoretical models. For all the above reasons, this chapter can provide only a very abbreviated coverage of ignition basics. The reader is referred to other sources for in-depth treatment of dust and powder explosions (Bodurtha, 1980 Bartknecht, 1981 Bartknecht, 1987). 

Watson, J. G., Chemical element balance receptor model methodology for assessing the sources of fine and total suspended particulate matter in Portland, Oregon, PhD Thesis, Oregon Graduate Center, Beaverton, Oregon, 1979. 

The need to remove suspended dust and mist from a gas arises not only in the treatment of effluent gas from a plant before it is discharged into the atmosphere, but also in processes where solids or liquids are carried over in the vapour or gas stream. For example, in an evaporator it is frequently necessary to eliminate droplets which become entrained in the vapour, and in a plant involving a fluidised solid the removal of fine particles is necessary, first to prevent loss of material, and secondly to prevent contamination of the gaseous product. Further, in all pneumatic conveying plants, some form of separator must be provided at the downstream end. 

When water flows over a contaminated land surface, pollutants released from higher elevations are transported, as dissolved solute or adsorbed on suspended particles, and accumulate at lower elevations. This behavior is reflected in the spatial variability of contaminant concentration, which affects contaminant redistribution with depth following leaching. If a sorbed contaminant is not of uniform concentration across all soil-size ranges but is higher in the fine sediment fraction, the deposition of this soil fraction controls contaminant redistribution in the subsurface. 

A stream of fully suspended fine solids (v = 1 mVmin) passes through two mixed flow reactors in series, each containing 1 m of slurry. As soon as a particle enters the reactors, conversion to product begins and is complete after two minutes in the reactors. When a particle leaves the reactors, reaction stops. What fraction of particles is completely converted to product in this system ... 

U.S. Congress passes the Armed Career Criminal Act, amending the Gun Control Act of 1968. It imposes stiff fines and prison terms for felons and other prohibited classes of persons who receive, possess, or transport a firearm. An appropriation bill passed by Congress eliminates probation or suspended sentences for persons committing a federal felony with any firearm and imposes an add-on 15-year sentence for possession of a firearm by a robber or burglar who is a repeat offender. 

Watson, J.G., Jr., (1979) "Chemical Element Balance Receptor Model Methodology for Assessing the Sources of Fine and Total Suspended Particulate Matter in Portland, Oregon," Thesis, Ph.D., Department of Chemistry, Oregon Graduate Center, Beaverton, OR. 

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