Жас ғалымдар, магистранттар, студенттер мен мектеп оқушыларының «хxi сәтбаев оқулары»

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«XXI Сәтбаев оқулары»
«СТУДЕНТТЕР»
сериясы
For the treatment of domestic and industrial wastewater, the 
following methods are used: mechanical, chemical, physico-chemical, 
biological.
Mechanical treatment is the separation of undissolved coarse 
impurities of mineral and organic nature from wastewater. To do this, 
the following methods are used: straining, settling, filtering.
Straining-retention of the largest contaminants and partially 
suspended substances on grates and sieves;
Sedimentation-separation of suspended substances from wastewater 
by gravity on sand traps, sedimentation tanks, as well as on oil traps;
Filtration-the retention of a very fine suspension in the suspended 
state on mesh and granular filters. 
Mechanical cleaning is used for the separation of insoluble mineral 
and organic impurities from wastewater [4, p. 4].
The main methods of chemical treatment of industrial wastewater 
are neutralization and oxidation. Electrochemical treatment also applies 
to oxidative methods. 
Chemical treatment can be used as an independent method before 
the supply of industrial wastewater to the recycling water supply system, 
as well as before their discharge into a reservoir or into the city sewer 
network. The use of chemical cleaning in some cases is advisable (as a 
preliminary) before biological or physico-chemical cleaning. Chemical 
treatment is also used as a method of deep purification of industrial 
wastewater for the purpose of disinfection, discoloration or extraction 
of various components from them. In most cases, chemical methods are 
preferred for the local treatment of industrial wastewater [1, p. 102].
The oxidative treatment method is used to neutralize industrial 
wastewater containing toxic impurities (cyanides, complex cyanides 
of copper and zinc) or compounds that are impractical to extract from 
wastewater, as well as to purify by other methods (hydrogen sulfide, 
sulfides). Such types of waste water are found in machine-building 
(electroplating shops), mining (processing plants of lead-zinc and copper 
ores), petrochemical (oil refineries and petrochemical plants), pulp and 
paper (pulp cooking shops) and other industries [1, p. 113].
A neutralization reaction is a chemical reaction between substances 
that have the properties of an acid and a base, which leads to the loss 
of the characteristic properties of both compounds. The most typical 
neutralization reaction in aqueous solutions occurs between hydrated 
hydrogen ions and hydroxide ions contained in strong acids and bases, 
respectively [1, p. 102].
Physical and chemical methods play a significant role in the 
treatment of industrial wastewater. They are used both independently 
and in combination with mechanical, chemical and biological methods. 
In recent years, the field of application of physico-chemical methods 
of purification is expanding, and their share among other methods of 
purification is increasing. 
Physical and chemical purification methods include coagulation, 
flocculation, sorption, flotation, extraction, ion exchange, hyperfiltration, 
dialysis, evaporation, evaporation, crystallization, magnetic treatment, 
as well as methods associated with the imposition of an electric field-
electrocoagulation, electroflotation [1, p. 124].
Coagulation is the process of aggregation of dispersed particles 
due to their interaction and integration into aggregates. Small 
(primary) particles in such aggregates are connected by the forces of 
intermolecular interaction. The clumping of homogeneous particles 
is called homocoagulation, and heterogeneous particles are called 
heterocoagulation. Substances that can cause particle coagulation.
they are generally called coagulants, and in water treatment-coagulants 
or hydrolyzable coagulants. The latter not only cause coagulation of 
pollution particles, but also form, hydrolyzing, slightly soluble products 
that can combine into large flakes [2, p. 136].
Flocculation is the process of aggregation of dispersed particles 
under the action of high-molecular compounds called flocculants. 
Flocculants are used to expand the optimal coagulation ranges 
(pH and temperature), as well as to increase the density and strength of 
the resulting flakes and reduce the consumption of coagulants, which 
increases the reliability and throughput of treatment facilities [2, p. 145].
Sorption is the process of absorbing a substance from the 
environment by a solid or liquid called sorbents. The absorbed substance 
is called sorbate. During the absorption of a substance (adsorbate), the 
latter is absorbed in the entire volume of the liquid or solid absorbent. 
Absorption is due to both the process of diffusion of the absorbent into 
the absorbate and the processes of dissolution. Adsorption is understood 
as the process of absorption of substances (adsorbates) located in gases 
and liquids, occurring on the surface of solids (adsorbents). Sorption, 
accompanied by the chemical interaction of the sorbent with the absorbed 
substance, is called chemisorption. 
Sorption treatment is recommended for wastewater contaminated 
with aromatic compounds, weak electrolytes or non-electrolytes, dyes, 
unsaturated compounds, hydrophobic aliphatic compounds [2, p. 149].

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