Physical treatments

The main purpose of the physical treatment process is to separate the waste material into like phases, usually in order to reduce the total waste volume or make treatment simpler. Whilst the number of physical treatment processes available is large the most commonly used ones tend to centre on various forms of filtration or distillation. Types of filtration processes include  

Traditional cloth filters as used in plate and frame filtration or pressure filtration these are relatively inexpensive and simple to use, and find wide application in the removal of medium and coarse particles in the range 10 to 1 mm. 

Centrifuges, which are highly efficient at removal of a wide range of particle sizes. 

Steam stripping is used to remove small amounts of volatile materials from aqueous waste. The steam is passed upwards through a distillation tower with the waste stream passing downwards. The volatile components are extracted into the steam, which is condensed to form a much more concentrated solution of the volatile component. Similarly air stripping is used for very low levels of contaminants where release of the volatile component to atmosphere would otherwise exceed permitted emission levels. 

Physical methods are employed to separate, reduce, or concentrate the waste. There are many physical methods available for waste treatment. Among them only a few have found application at the industrial level. Some methods are either in their infancy hke zone-refining, freezedrying, and electrophoresis, whereas others have found little potential appUcation on account of their operational cost. 

The most common processes today are sedimentation, filtration, flocculation, adsorption, distillation, and solvent evaporation. These treatment methods are used for phase or component separation purposes. 

Tb reduce or concentrate the waste volume, phase separation should he carried out for sludges, slurries, and emulsions. 

Separation of waste components containing large particles, filtration, centrifugation, or flotation may be used. Flocculation is carried out for colloidal systems. Removal of volatiles can be carried out by distillation or evaporation. 

Ion exchange, reverse osmosis, ultrafiltration, and air stripping can also be used for separating waste components, especially for waste-water treatment. 

In this section the stability and compatibility of petroleum will be discussed in terms of physical treatment such as distillation, deasphalting and diluent addition for pipeline transportation, and in terms of chemical treatment such as upgrading. 

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Cold- Water Swelling Starches. Special physical treatment produces starch granules that will sweU in water without heating. Molecular dispersions can be formed by appHcation of shear to the swoUen granules. 

Surface modification of a contact lens can be grouped into physical and chemical types of treatment. Physical treatments include plasma treatments with water vapor (siUcone lens) and oxygen (176) and plasma polymerization for which the material surface is exposed to the plasma in the presence of a reactive monomer (177). Surfaces are also altered with exposure to uv radiation (178) or bombardment with oxides of nitrogen (179). Ion implantation (qv) of RGP plastics (180) can greatiy increase the surface hardness and hence the scratch resistance without seriously affecting the transmission of light. 

Chemical Treatment. The most iavolved regeneration technique is chemical treatment (20) which often follows thermal or physical treatment, after the char and particulate matter has been removed. Acid solution soaks, glacial acetic acid, and oxalic acid are often used. The bed is then tinsed with water, lanced with air, and dried ia air. More iavolved is use of an alkaline solution such as potassium hydroxide, or the combination of acid washes and alkaline washes. The most complex treatment is a combination of water, alkaline, and acid washes followed by air lancing and dryiag. The catalyst should not be appreciably degraded by the particular chemical treatment used. 

P99 Other Physical Treatment milligrams of chemical/kilogram of air for particulates in air. If you have particulate concentrations (at standard... 

C01 Chemical Precipitation -- Lime or Sodium P99 Other Physical Treatment... 

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. 

Subsequently, biological/physical treatment of leachate with an activated carbon-enhanced sequencing batch bioreactor (PAC-SBR) was analyzed to determine whether the improved treatment by simultaneous adsorption and biodegradation in the SBR would produce an acceptable effluent without post-treatment in the existing granular activated carbon adsorber (Ying et al., 1986). 

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. 

Design and development of inherently safer process chemistry and physical treatment may be the most economical way to eliminate a... 

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. 

Reinforcing fibers can be modified by physical and chemical methods. Physical methods, such as stretching [22], calandering [23,24], thermotreatment [25], and the production of hybrid yarns [26,27] do not change the chemical composition of the fibers. Physical treatments change structural and surface properties of the fiber and thereby influence the mechanical bondings in the matrix. 

Electric discharge (corona, cold plasma) is another method of physical treatment. Corona treatment is one of the most interesting techniques for surface oxidation activation. This process changes the surface energy of the cellulose fibers [28]. In the case of wood surface activation it increases the amount of aldehyde groups [291. 

MEEP/(IiX)n electrolytes, which can be processed into thin films without physical treatment or addition of a second polymer, have been obtained by Abraham [610]by dissolving MEEP and IiAlCl4 in acetonitrile. The complexes MEEP/(LiAlCl4)o.i3 and MEEP/(IiCL04)o.25 have almost the same conductivity at 25 °C, 1.2x10 and 1.7x10" S cm, respectively. 

Formation from Template Surfaces Recently, a new method for the preparation of LUV was reported by Lasic et al. (1988). The method is based on a simple procedure which leads to the formation of homogeneous populations of LUV with a diameter of around L vim. Upon addition of solvent to a dry phospholipid film deposited on a template surface, vesicles are formed instantly without any chemical or physical treatment. The formation of multilamellar structures is prevented by inducing a surface charge on the bilayers. The size of the vesicles is controlled by the topography of the template surface on which the phospholipid film was deposited (Lasic, 1988). 

Indeed, apple pomace, beet pulp or citrus peels contain pectins (3). Chemicals, enzymes, microorganisms, or physical treatments can be used for thextraction (4). 

The use of chemicals, essentially acid, is the method of choice for the extraction of pectins, at least at an industrial level (3,4). Enzymes such as "protopectinases", polygalacturonases, rhamnogalacturonases, have been tentatively used at a laboratory scale but their industrial interest is still an open question (4,5,6). There are only some reports on the use physical treatment such as various heat treatments. 

The same methods (chemicals, enzymes, physical treatments) can be also applied on the cell wall materials not with the aim of extracting polysaccharides but with the aim of obtaining modified fibres. New properties concerning for exemple fermentability, ratio soluble/insoluble dietary fibre, hydration., can be obtained (1). 

For the sake of completeness, attention is drawn to physical procedures for removal of contaminants and for their chemical destruction. A valuable review by Hamby (1996) summarizes chemical and physical treatments of soils and contaminated ground and surface waters. Examples include the following ... 

Texturization is not measured directly but is inferred from the degree of denaturation or decrease of solubility of proteins. The quantities are determined by the difference in rates of moisture uptake between the native protein and the texturized protein (Kilara, 1984), or by a dyebinding assay (Bradford, 1976). Protein denaturation may be measured by determining changes in heat capacity, but it is more practical to measure the amount of insoluble fractions and differences in solubility after physical treatment (Kilara, 1984). The different rates of water absorption are presumed to relate to the degree of texturization as texturized proteins absorb water at different rates. The insolubility test for denaturation is therefore sometimes used as substitute for direct measurement of texturization. Protein solubility is affected by surface hydrophobicity, which is directly related to the extent of protein-protein interactions, an intrinsic property of the denatured state of the proteins (Damodaran, 1989 Vojdani, 1996). 

MeV a-particles and used the Au/Ir source after annealing without any further chemical or physical treatment. Commercially available sources are produced via Pt(p, n) Au. The most popular source matrix into which Au is diffused is platinum metal although it has the disadvantage of being a resonant matrix - natural platinum contains 33.6% of Pt. Using copper and iridium foils as host matrices for the Au parent nuclide, Buym et al. [327] observed natural line widths and reasonable resonance absorption of a few percent at 4.2 K. 

Physical treatments scrubbing, settling, absorption and adsorption. 

This is very similar to the flotation procedure described under basic physical treatments. In the case of foam fractionation, not only are the pollutants raised to the surface where they can be skimmed off, but a froth, like beer foam, is produced in which the pollutants become concentrated. The key to the process is the adsorption of the pollutants onto the surface-active agents that cause the froth to form. Sometimes a surfactant is added so that non-surface-active components can be removed. 

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