AERATION

From Big Medical Encyclopedia

AERATION (grech, aer air) — process of natural receipt or mechanical administration of free air to residential, public and production buildings, water, the soil and other environments. And. finds broad application at implementation of sanitary actions: improvement of quality of water by deferrization, deodorizations (see), intensifications of sewage treatment (see. Bacteria beds ),

And. influences a condition of the air basin of the settlement, a microclimate of dwellings and public places. At design of the industrial enterprises, zones a dignity. gaps and during the calculations And. territories of the housing estate use data on repeatability and average speeds of wind in the directions taking into account a relief, gardening. Character of the housing estate exerts impact on a condition of the air basin of spaces between buildings since. And. depends on their interposition and placement in relation to winds. And. industrial buildings — the organized managed natural air exchange in workshops for the purpose of creation in them favorable microclimatic conditions — happens to considerable heat releases under the influence of thermal or thermal and wind pressure. Natural inflow of fresh air is carried out through the apertures in longitudinal walls of the building supplied with shutters: during the warm period — through all apertures of the lower tier, aeration and transport apertures directly in a working zone; in cold — through shutters of an upper tier, height of an arrangement to-rykh decides by efficiency of heating of an incoming air due to hashing on warm air of the workshop (not lower than 4 m from a floor). Removal of a polluted air happens through apertures of aeration or aeratsionno-light lamps of not blown type. And. demands special calculations for automatic control of the area of stitched openings taking into account temperature of fresh air, intensity of heat releases and the device of air curtains, etc. For organized management A. stitched and exhaust apertures shall be equipped with mechanisms with distance steering. Efficiency And. depends on configuration and the sizes of the equipment generating heat and gases, architectural and construction registration of the building. Calculation And. workshops with warm and gas-allocations it is made taking into account the thermal pressure and sufficiency of natural air exchange for dilution of gases to maximum allowable concentrations. Calculation And. hot workshops it is made on the maximum heat releases.

Aeration in microbiology — process of mechanical administration of free air in liquid cultures of microorganisms for the strengthened supply with their oxygen. Method A. it is widely applied by production of bacteriological drugs, antibiotics, vitamins, enzymes, amino acids and other biologically active compounds, and also at synthesis of protein and production of bacterial fertilizers.

With a growth in fluid mediums the need of microbes for oxygen is satisfied at first at the expense of the oxygen dissolved in a medium and then, in process of its use, at the expense of the oxygen arriving from the atmosphere. Due to the small solubility of oxygen (0,2 mm on 1 l of broth at t ° 25 °) reproduction of bacteria, pleseny and actinomycetes stops owing to deficit of oxygen still in the presence in the environment of nutrients. For ensuring further reproduction of microorganisms it is recommended And., edges it is best of all carried out by blowing off of sterile air through cultural liquid with its simultaneous hashing.

Degree And. cultures it is considered to equal unit if through a certain volume of the environment in 1 min. the same air volume is blown. The amount of the oxygen consumed by 1 ml of culture is equal to the work of the quantity consumed by one cell on number of the cells which are contained in 1 ml of culture. With growth of culture requirement it increases in oxygen and reaches a maximum by the end of a logarithmic (exponential) growth phase.

Under the influence of aeration there is an acceleration of reproduction of microbes and increase in a harvest of cells (biomass of culture). The changes in metabolism of bacteria which are expressed increase in intensity of digestion of nutrients by them and accumulation of products of exchange therefore at submerged cultivation of microbes it is necessary to pick up among the balanced combination of intensity are at the same time noted And. and concentration of sources of carbon and nitrogen. Partial pressure of oxygen at And. shall correspond to the need for it of this culture. 4 Reduction of degree And., as well as its excessive increase, has an adverse effect on reproduction of microbes and an exit of products of their life activity. Short breaks in And. cultures lead to falloff of biosynthesis, to disturbance of life activity of acetic-acid bacteriums.

At excessive And. there can occur braking and even the termination of reproduction of aerobes. Small increase in partial pressure of oxygen in comparison with optimum for this species of a microbe causes frustration in its exchange. Industrial cultivation of microbes is carried out in reactors (reactors) of various capacity (to 100 000 l of the environment). High economic effect of cultivation of microorganisms in reactors provided modern progress of industrial production of vaccines, antibiotics, enzymes, vitamins and other biologically active and valuable organic compounds.


Bibliography: Didenko S. Yu. To a question of «temperature overlapping», Vodosnab. and dignity. tekhn., No. 6, page 6, 1968; Shtromberg Ya. A. Aeration of hot workshops with an uneven arrangement of sources of heat, in the same place, No. 2, page 1; about N e, Shielding of thermal sources in hot workshops, in the same place, No. 2, page 24, 1969.

And. in microbiology — Egorov N. S. Bases of the doctrine about antibiotics, page 423, M., 1969, bibliogr.; Zhdanov V. M. Quantitative patterns of growth and reproduction of bacteria, Mnogotomn. the management on mikr., wedge, and epidy. infek. diseases, under the editorship of H. N. Shukova-Verezh-nikova, t. 1, page 153, M., 1962, bibliogr.; Meynell Dzh. and Meynell E. Experimental microbiology, the lane with English, page 84, M., 1967; Fedorov M. V. Metabolism of bacteria, food and breath, Mnogotomn. the management on mikr., wedge, and epidy. infekts. diseases, under the editorship of H. N. Zhukova-Verezhnikov, t. 1, page 203, M., 1962, bibliogr.; Brown D. E. Aeration in the submerged culture of microorganisms, in book: Methods in microbiol., ed. by J. R. Norris a. D. W. Ribbons, v. 2, p. 125, L. — N. Y., 1970, bibliogr.; Continuous cultivation of microorganisms, Proc. 4-th symposium, Prague, 1969; Gottlieb S. P. Effect of hyperbaric oxygen on microorganisms, Ann. Rev. Microbiol., v. 25, p. Ill, 1971, bibliogr.

L K. Kvartovkina; A.B. Ponomarev (mikr.).

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