Physical waste treatment

Selected physical properties of oxygen are included in Table 9.24. It is a colourless, odourless and tasteless gas which is essential for life and considered to be non-toxic at atmospheric pressure. It is somewhat soluble in water and is slightly heavier than air. Important uses are in the steel and glass industries, oxyacetylene welding, as a chemical intermediate, waste-water treatment, fuel cells, underwater operations and medical applications. 

Table 4 allows a generic identification of the various technology options suitable for treating wastes based on their hazardous characteristics and physical form Table 4 also identifies the kinds of data which must be collected to perform a valid evaluation of those technologies. The physical treatment data needs for different media shown in Table 5 are typically required in addition to those presented in Table 4. 

In applying these general criteria, one should focus on the intended application. In wastewater treatment applications, filtration can be applied at various stages. It can be applied as a pretreatment method, in which case the objective is often to remove coarse, gritty materials from the waste-stream. This is a preconditioning step for waste waters which will undergo further chemical and physical treatment downstream. 

To control water pollution, a waste stream can be subjected to at least one, or perhaps a combination, of chemical, biological, and physical treatments. Some of these processes are discussed below. 

Pretreatment is a series of physical and chemical processes to precondition the wastewater and remove some wastes. The treatment is usually arranged in the following sequence screening flow equalization and neutralization optional fat, oil, and grease (FOG) separator optional acidification ... 

An industrial treatment system may require some chemical pretreatment before biological treatment even some physical treatment may be desirable. Also, smce the concentrations of the pollutants are usually greater and more predictable than those in municipal wastes, the engineer can design a more specific system than is possible for municipal treatment plants.64 In this case all possibilities must be carefully evaluated by the process engineer. 

Assess both scenarios Landfill Waste indnerafion Assess shreddingfmilling - scenario and Check exduston of recyding gn if processes are covered by earlier lifecyde stage or Assess relevant MR-scenarios Assess relevant scenarios Thermal treatment coandneratlon Chemical physical treatment Re-Disfillation... 

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. 

Stabilization/solidification (S/S) is a proven technology for the in sitn or ex situ treatment of hazardous wastes and hazardous waste sites. It uses additives or processes to physically and/or chemically immobilize the hazardous constituents of contaminated soils, sludges, sediments, or even hquid wastes. The object of this technology is to prevent the migration of contaminants into the environment by forming a sohd mass. Contaminants are trapped and immobilized within the existing medium, rather than removed via chemical or physical treatments. 

The most commonly used waste water treatment procedures are not sufficient to remove these dyes. Considerable efforts are therefore made to improve the efficiency of the physical, chemical and biological treatment procedures. However, in order to achieve this aim, reliable analytical methods for the identification and quantification of the azo dyes and their by- and degradation products are required. Since most of the dyes are non-volatile and thermally labile, LC-NMR and LC-MS are the methods of choice. 

Depolymerizing modification of starch usually involves the use of enzymes, acid- (and less frequently base-) catalyzed hydrolysis, and thermolysis alone and thermolysis combined with acid-catalyzed hydrolysis (see a recent survey in this Series2). Despite several studies, the physical treatment of starch has not yet resulted in major practical applications. The aim of this Chapter is to review physical methods as tools for the treatment of starch which deliver amounts of energy suitable for depolymerizing starch to target products. It should be noted that the duration of such processes does not need to exceed that for conventional, namely enzymic, chemical, and thermal modifications. Moreover, a potential advantage of nonconventional physical treatments is the fact that they generate no waste products. 

Kotz R, Stucki S, Career B. Electrochemical waste water treatment using high overvoltage anodes Part I. Physical and electrochemical properties of Sn02 anodes. J Appl Electrochem 1991 21 14—20. 

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. 

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