Variant – 26

1. Wet dust removal equipment

The dust removal equipment available may be divided into two large groups: Dry dust removal equipment and wet dust removal equipment. For both groups: A few representative examples will be discussed.

In wet dust removal equipment, the dust particles are captured by liquid drops introduced into the gas stream. The gas pollution problem is converted into a liquid pollution problem. This is acceptable when the volume of the contaminated water is small and when a waste water treatment plant is available.

There is a great variety of wet dust scrubbers available. Only three examples are selected for a brief discussion:

1. Packed column scrubber.

2. Vortex scrubber.

3. Venturi scrubber.

Fig. 3 schematically illustrates these scrubbers.

In the packed column scrubber, the water is distributed over the surface of various types of small packing elements and flowing downwards. The gas moves counter currently through the porous layer of packing elements, changing its flow direction according to the arrangement of the elements. Because of the inertia forces the particles, particularly the coarser ones, do not follow the gas flow, and impinge on the liquid surface.

In the vortex scrubber, the water drops are produced by the gas stream and carried into the vortex channel. The dust particles are captured during the period of drop movement inside the vortex channel. The efficiency of dust collection by drops depends on the relative velocity between drops and dust particles.

The Venturi scrubber is the most efficient wet dust scrubber. The water is introduced into the throat of the Venturi scrubber and there dispersed by the high-velocity gas steam. The pressure drop of the gas on its way through the Venturi scrubber is very high.

2. Soil protection and their rational use

Protecting the quality of our soils is as important as protecting the air we breathe and the water we drink. Protecting soil is critical to protecting our ecosystems and our ability to raise crops or maintain a backyard garden.

Soil quality can be a measure of soil productivity. Soil quality can also be linked to water quality.

Specifically, soil quality is “The capacity of soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health.”

Soil quality focuses not just on characteristics such as nutrient availability and total organic matter levels, but also focuses on overall soil biological activity, organic matter content, water infiltration, and soil structure.

Protecting and enhancing soil quality is accomplished through the use of soil conservation efforts; Best Management Practices for fertilizers and pesticides; and the proper use, handling and storage of agricultural chemicals, fertilizers, manures and soil amendments.

3. Ecological factors and their classification.

Ecological factors and their classification.

Inhabitancy is a part of the nature surrounding alive organisms and affecting on them. On our planet, alive organisms have assimilated 4 inhabitancies: water, ground- air, soil and organism. The water environment was the first. Then alive organisms have assimilated the ground-air environment, they have created and occupied soil. A soil inhabitancy means not only actually soil, but also rocks of a superficial part lithosphere. Organism environment was assimilated by parasites. Ecological factors are separate elements of inhabitancy which influence organisms. Each of inhabitancies is differed by features of influence of ecological factors. Ecological factors are divided into abiotic, biotic and anthropogenic ones.Abiotic factors are components of the lifeless nature. They are climatic (light, temperature, humidity, wind, pressure, etc.), geological are earthquakes, eruptions of volcanoes, movement of glaciers, radioactive radiation, etc.), orographical (lay of the ground), edaphic or soil-ground (density, structure, рН, granulometric composition, chemical composition, etc.), hydrological (water, flow, salinity, pressure, etc.). Otherwise, abiotic factors are divided into physical, chemical and edaphic ones.

Biotic factors are influence of alive organisms between each other (interaction between individuals in populations and between populations in communities). Thus mutual relations can be intraspecific (interactions among individuals of one species) and interspecific (between individuals different species). According to type of interaction there are symbiosis, mutualism, komensalism, intraspecific and interspecific competition, parasitism, predatoriness, amensalizm and neutralism. Depending on influencing organism biotic factors are divided into phytogenic (influence of plants), zoogenic (animals) and микробогенные (microorganisms).

Anthropogenous factors are activity of the person resulting in direct influence on alive organisms, or in change of inhabitancy (hunting, trapping, pollution, soil erosion etc.). Thus, it is necessary to differentiate a person activity as biological organism and his economic activities (technogenic factors).

Ecological factors can influence an organism directly and indirectly. Indirect influence is carried out through other ecological factors. For example, high temperature can cause a burn (direct action), and it can result in dewatering organism (indirect influence).

Different ecological factors possess various variability in space and in time. One of them are rather constant (for example, force of gravitation, solar radiation, salinity of ocean), others are very much inconstant (for example, temperature and humidity of air, force of a wind).

Changes of environment factors can be periodic and acyclic. Periodic factors are regularly repeated in time (for example, change of air temperature and light exposure within day or year). Acyclic factors have no periodicity (for example, volcano eruption, an attack of predator). Periodic factors are divided into primary and secondary ones. Primary periodic factors are connected with the space reasons (light exposure, inflow, low tide, etc.). Secondary periodic factors appear as consequence of action of primary factors (temperature, quantity of fall-out, a biomass, efficiency, etc.).

Ecological factors influence on alive organisms differently: limiting, irritating, modifying and alarm. Limiting influence does impossible existence in the present conditions. Irritable influence causes biochemical and physiological adaptations. Modification influence causes morphological and anatomic changes of organisms. Alarm influence informs about changes of other factors of environment.

In the nature, ecological factors operate jointly, that is, in a complex. A complex of factors under which action the basic vital processes of organisms are carried out, are called life conditions including normal evolution and breeding. Conditions in which breeding does not proceed, is called conditions of existence