Xorazm ma ’ mun akademiyasi axborotnomasi – /2020 Ўзбекистон республикаси фанлар

 
 
Introduction 
Thermal Power Plant 
Active sources of environmental pollution with PAHs include enterprises of energy industries, 
especially great thermal stations [19, 25, 28]. The Angren Power Plant is a 2100-megawatt coal-
fired. This is an enterprise of hazard class 1, which was set in operation in 1957-1963. At present, it 
includes eight working blocks and is the main source of electrical energy in Uzbekistan. Coal 
(lignite) and natural gas are the major fuel types for the station. The height of the first chimneystack 
is 185 m; the three other stacks are 250 m high. The New Angren300 megawatt coal -fired and it 
was set in operation in 1985-2000. The height of the first chimneystack is 185 m; the three other 
stacks are 250 m high [26]. 
Phytoremediation 
Heavy metals are defined as natural atoms, which are five times higher than those with high 
atomic weight and density, and are toxic or toxic at low concentrations. The heavy metals are 
defined as naturally occurring elements that have a high atomic weight and density five times 
higher than that of water and is toxic or poisonous even at very low concentration [7]. To compare 
other pollutants, heavy metals are non-biodegradable, and so they persist for long time in the 
environment [20, 7, 27].
There are also chemical technologies and physical methods that can help eliminate heavy 
metal contamination, but their use is technically difficult and expensive, creating massive amounts 
of sludge and thus polluting the environment [17].
The phytoremediation has become increasingly important for the economical, effective and 
non-invasive method of reducing pollutants from water and soil [10] without showing any negative 
effect on the environment.
The phytoremediation, on the other hand, is very useful because it uses sunlight as a source of 
energy and to cleanse natural pollutants in soil conditions. In addition, this process does not contain 
or remove secondary contaminants as it immobilizes them, thereby preventing them from entering 
the groundwater, thereby protecting the soil profile and improving soil quality and preventing soil 
stocks [14,15].
Phytoremediating plants can turn large and very toxic substances into fine and non-toxic 
substances, but this ability varies greatly from species to species. Phytoremediating plants have 
variable properties due to their growth rates, biomass, root zone depth, and the potential for 
groundwater transfer into the atmosphere [14,15].
In addition to all the advantages, phytoremediation has a number of disadvantages as it is time 
consuming to eliminate soil contamination and is limited by climatic, geological conditions and soil 
type in the area. There are different processes involved in phytoremediation [4, 12, 16, 18]:
 
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Phytoextraction is the process of collecting soil pollutants during the process of 
absorption by plants and their accumulation in the buds and harvests of the root. The best members 

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