Posttreatment Section

In most plants that use reverse osmosis in the preparation of process water, the reject stream is routed directly to waste discharge without any additional posttreatment. In industrial plants that use reverse osmosis to treat industrial wastes, the reject stream may contain valuable materials and this stream would be sent back to the process. In other applications of industrial waste treatment by reverse osmosis, the reject stream may require additional treatment prior to ultimate discharge. In this case, the reverse osmosis unit will have provided a large volume of water that is disposable or can be reused (the product) and a smaller volume of reject which can be treated more economically. 

The product water from a reverse osmosis unit will have a low pH and most probably a high concentration of carbon dioxide. The carbon dioxide can be removed and the pH of the product increased by use of a decarbonator. A de-carbonator is a packed column in which product water is introduced at the top while either forced or induced air is introduced at the bottom. The air and water flow countercurrently over and around the column packing. The carbon dioxide is stripped from the water and exits from the decarbonator at the top in the air stream. In a well-designed decarbonator, the carbon dioxide content can be reduced to about 5 mg/C in the water effluent. 

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Fig. 4. (A and B) Breast tissue from the same patient, posttreatment. Section of the tumor bed posttreatment shows reactive changes consisting of cellular fibrous tissue with numerous vessels (granulation tissue) and infiltration by lymphocytes, plasma cells and numerous iron-loaded macrophages. No residual carcinoma cells are seen. (A) H E, magnification x200 (B) H E, magnification x400.

An industrial reverse osmosis plant usually will consist of three separate sections which are shown in Figure 4.2. The first section is the pretreatment section in which the feedwater is treated to meet the requirements of reverse osmosis element manufacturers and the dictates of good engineering practice. Following pretreatment, the feedwater is introduced into the reverse osmosis section where the feedwater is pressurized and routed to the reverse osmosis elements which are in pressure vessels. The feedwater flows across the membrane surface where product water permeates through the membrane and a predetermined amount remains behind as reject. The reject is discharged to waste while the product water is routed to the posttreatment section. The third or posttreatment section treats the product water to remove carbon dioxide and adds chemicals as required for industrial use of the product water. 

Similarly, posttreatment refers to similar process equipment after the boiler section (such as condensate polishing). 

Beyond peptides and proteins, MALDI MS imaging of tissue section for the detection of low-molecular-weight compounds can also be achieved. Of particular interest is the posttreatment location of pharmaceutical compounds in targeted tissues or organs. Further, in parallel to location, the effects of a drug on the local proteome can be observed as a function of dose or time. Variations in the proteome are indicative of drug efficacy.116... 

Most gas blacks are oxidatively posttreated to increase the concentration of acid groups on the surface even further (see Section 5.7.6.2.4). Due to their good dispersion properties, gas black is mainly used as pigment black in the paint and printing ink industries. 

Carbon blacks for black printing inks not only perform as black pigments, but also regulate the vi.scosity. Posttreatment adapts pigment blacks to particular binder systems (see Section 5.7.6.2.4). 

Steps 3 and 4 may sometimes move in front of step 2, particularly if the posttreatment involves spheronizing (see Section 4.2.2.6.8,b). 

The corrosion-protection metal layers, deposited on a substrate as described in the previous sections, are often subjected to some posttreatment. The following describes the most widely used procedures the formation of an additional organic film, or the formation of a conversion layer. 

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