Applications waste water purification

Tsygankov, A.A., Fedorov, A.S., Talipova, I.V., Laurinavichene, T.V., Miyake, J., Gogotov, I.N. (1998a). Application of immobilised phototrophic bacteria for waste water purification and hydrogen production. Appl. Biochem. Microbiol. 34,362-366. 

The principal advantages of this type of cyclic system with transient operating techniques are apparent in bioprocesses whose maximum productivity is in a transient region. The products of secondary metabolism (Pirt, 1974) are a typical example of this group of processes. Another group consists of processes whose optimal operation requires an optimal substrate concentration— biomass production with bakers yeast, for example (Aiba et al., 1976)—or where the process is subject to substrate inhibition. An important area of application for this is in biological waste water purification. These periodic modes of operation generally show increased productivity. More systematic and detailed study is needed in this area. 

Applications RO is primarily used for water purification seawater desalination (35,000 to 50,000 mg/L salt, 5.6 to 10.5 MPa operation), brackish water treatment (5000 to 10,000 mg/L, 1.4 to 4.2 MPa operation), and low-pressure RO (LPRO) (500 mg/L, 0.3 to 1.4 MPa operation). A list of U.S. plants can be found at www2.hawaii.edu, and a 26 Ggal/yr desalination plant is under construction in Ashkelon, Israel. Purified water product is recovered as permeate while the concentrated retentate is discarded as waste. Drinking water specifications of total dissolved solids (TDS) < 500 mg/L are published by the U.S. EPA and of < 1500 mg/L by the WHO [Williams et ak, chap. 24 in Membrane Handbook, Ho and Sirkar (eds.). Van Nostrand, New York, 1992]. Application of RO to drinking water is summarized in Eisenberg and Middlebrooks (Reverse Osmosis Treatment of Drinking Water, Butterworth, Boston, 1986). 

Today their initial work on the preparation of suitable asymmetric membranes has touched nearly every aspect of life including uses in water purification, food technology, biological separations, waste treatment, medical applications, and bioengineering, and this appears to be just the beginning. 

The main fields of application for directed crystallization as a purification (separation) technology are organic-chemical separation and purification (2), fruit juice or liquid food concentration (3.4, waste water treatment (1) ... 

The traditional application of adsorption in the process industries has been as a means of removing trace impurities from gas or liquid streams. Examples include the removal of H2S from hydrocarbon streams before processing, the drying and removal of C02 from natural gas, and the removal of organic compounds from waste water. In these examples the adsorbed component has little value and is generally not recovered. Such processes are generally referred to as purification processes, as distinct from bulk separations, in which a mixture is separated into two (or more) streams, each enriched in a valuable component, which is recovered. The application of adsorption to bulk separations is a more recent development that was stimulated to a significant extent by the rapid... 

It has been demonstrated that membrane separation processes can be successfully used in the removal of radioactive substances, with some distinct advantages over conventional processes. Following the development of suitable membrane materials and their long-term verification in conventional water purification, membrane processes have been adopted by the nuclear industry as a viable alternative for the treatment of radioactive liquid wastes [1]. In most applications, membrane processes are used as one or more of the treatment steps in complex waste treatment systems, which combine both conventional and membrane treatment technologies. These combined systems have proved more efficient and effective for similar tasks than conventional methods alone. 

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