Physical processing wastes

The treatment of waste is the third element of the hierarchy and should be utilized only in the absence of feasible source reduction or recychng opportunities. Waste treatment involves the use of chemical, biological, or physical processes to reduce or eliminate waste material. The incineration of wastes is included in this categoiy and is considered preferable to other treatment methods (i.e., chemical, biological, and physical) because incineration can permanently destroy the hazardous components in waste materials (Ref. 4). It can also be employed to reduce the volume of waste to be treated. 

Landfarming Landfarming is a waste-disposal method in which the biological, chemical, and physical processes that occur in the surface of the soil are used to treat biodegradable industrial wastes. Wastes to be treated are either apphed on top of the laud which has... 

End-of-pipe treatment refers to the application of chemical, biological, and physical processes to reduce the toxicity or volume of downstream waste. Treatment options include biological systems, chemical precipitation, flocculation, coagulation, and incineration as well as boilers and industrial furnaces (BIFs). 

Ammonia stripping also removes cyanide, phenols, and other VOCs typically found in cokemaking wastewater. Phenols may also be removed by conversion into nonodorous compounds or into crude phenol or sodium phenolate by either biological means (phenol concentration <25 mg/L) or by physical processes.21 However, the Koppers dephenolization process is considered to be quite effective as it lowers the phenol content by 80 to 90% in ammonia still wastes. In this process a stream stripping process followed by mixing in a solution of caustic soda results in renewal of pure phenol with the flue gas.8... 

DSP wherein waste can be stabilized by biological or physical process... 

Chevron WWT [Waste water treatment] An integrated process for treating sour water from oil refineries, particularly for removing ammonia, hydrogen sulfide, and carbon dioxide. Only physical processes are used—volatilization and condensation under various conditions. Developed by Chevron Research Company and used in 14 plants worldwide in 1985. Martinez, D., in Chemical Waste Handling and Treatment, Muller, K. R., Ed., Springer-Verlag, Berlin, 1986, 180. 

Introduction Chemical reactivity is the tendency of substances to undergo chemical change. A chemical reactivity hazard is a situation with the potential for an uncontrolled chemical reaction that can result directly or indirectly in serious harm to people, property, or the environment. A chemical reaction can get out of control whenever the reaction environment is not able to safely absorb the energy and products released by the reaction. The possibility of such situations should be anticipated not only in the reaction step of chemical processes but also in storage, mixing, physical processing, purification, waste treatment, environmental control systems, and any other areas where reactive materials are handled or reactive interactions are possible. 

Physical aging, defined, 10 424 Physical analysis, of wine, 26 324 Physical bonding processes, 17 496 Physical-chemical waste treatment,... 

Is any heat generated during the mixing or physical processing of substances NO No indication of exothermic behavior when premixing wastes... 

Thermal desorption is a physical separation process. Waste is heated to volatilize water and organic contaminants. A carrier gas or vacuum system transports volatilized water and organics to the gas treatment system. The bed temperatures and residence times designed for these systems will volatilize selected contaminants without oxidation. Three types of thermal desorption are available ... 

Stratified random sampling, which is a variation of simple random sampling, is used for media that are stratified with respect to their chemical and physical properties. Each stratum is identified and randomly sampled. The number of grab samples and the sampling point selection depend on the nature of contaminant distribution within each stratum. Stratified random sampling is used for the characterization of multiphase liquid wastes or process waste batches that undergo stratification over time and/or space. 

Solidification and stabilization are generic names applied to a wide range of discrete technologies that are closely related in that both use chemical and/or physical processes to reduce potential adverse impacts on the environment from the disposal of radioactive, hazardous, and mixed wastes [16-18]. 

Chemical/physical treatment processes are those in which a chemical reaction is used to alter or destroy a hazardous waste component. Chemical treatment techniques can be applied to both organic and inorganic wastes, and may be formulated to address specific target compounds in a mixed waste. Typical chemical treatment processes include oxidation-reduction reactions such as ozonation, alkaline chlorination, electrolytic oxidation and chemical dechlorination. Physical treatment processes separate waste component by either applying physical force or changing the physical form of the waste. Various physical processes include adsorption, distillation, or filtration. Physical treatment is applicable to a wide variety of waste streams but further treatment is usually required. 

Flotation. This method is used to remove suspended organic and inorganic solids from waste streams or slurries. This technique is basically a physical process in which solutions carrying suspended particles are agitated with the stream of air bubbles or a mechanical agitator. A froth forms at the surface of the liquid or slurry, which is then removed by skimmers or scrapers. Individual or combinations of similar materials may be removed by this method from wastewater streams. 

The following section provides detailed information concerning the transport of radionuclides associated with two very different field analogues the Chernobyl reactor accident and the Oklo Natural Reactor. These examples span wide temporal and spatial scales and include the rapid geochemical and physical processes important to nuclear reactor accidents or industrial discharges as well as the slower processes important to the geologic disposal of nuclear waste. 

Efforts are being made to reduce waste water by recycling in the milling process and to decrease its environmental pollution by treatment with biological or physical processes prior to its discharge (22). A number of alternative technologies are available for waste water purification (18-21) however, they are costly and difficult to apply. 

For instance, urea, the product of protein digestion from which the term urine is derived, must be removed. Other waste products of metabolism must be removed. Any toxins produced by bacteria must be removed. Any drug residue or other unusable material must be removed. Any excess hormone must be removed. Glucose, on the other hand, should not be eliminated and proteins should not be secreted. Vitamins need to be saved, as does calcium and a certain amount of sodium and other minerals. However, water must be regulated. Too much water in the blood would be bad because if blood were too dilute, then not enough nutrients would be transported to the cell. If blood had too little water, then the physical process of pumping the blood around would be... 

Options 8 and 9. Other Effluent Treatments. Reverse osmosis is a physical process by which the majority of the effluent water is cleansed of polluting ions. However, a highly polluted reject-water stream also is produced. This reject stream is normally sent to evaporation ponds for further concentration and ultimate disposal of the pollutant solids. Ion exchange is a physiochemical process that similarly produces a pure-water stream and a lower volume stream of concentrated waste that must be evaporated. Both processes are more expensive than is Option 7, have the same general drawbacks, and have the additional problem of disposing their concentrated waste streams. 

Many of the macroscale and mesoscale P2 approaches rely on a molecular-level understanding of chemical and physical process at the microscale. For example, the synthesis of new catalysts to achieve higher yields with less wastes relies on a fundamental understanding of surface chemistry. There are a large number of methods available for undertaking P2 at the microscale via the molecular-level redesign of chemical products and processes. In line with the emergence... 

When the wastewater arrives at the treatment plant, it moves through a series of processes which remove the waste from the water and reduce its threat to public health. Treatment at the plant consists of p re-treatment, primary treatment, and secondary treatment. Pre-treatment physically screens out large debris, and removes sand, gravel, and oil. Primary treatment removes settled and floating materials. Secondary treatment involves biological, chemical, and physical processes which remove suspended and dissolved solids secondary treatment also kills pathogenic organisms. 

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