Variant – 8

1. Pedosphere (a soil cover) as a part of biosphere

Phedosphere

The pedosphere (from Greek πέδον pedon "soil" or "earth" and σφαίρα sfaíra "sphere") is the outermost layer of the Earth that is composed of soil and subject to soil formation processes. It exists at the interface of the lithosphere, atmosphere, hydrosphere and biosphere. The sum total of all the organisms, soils, water and air is termed as the "pedosphere". The pedosphere is the skin of the Earth and only develops when there is a dynamic interaction between the atmosphere (air in and above the soil), biosphere (living organisms), lithosphere (unconsolidated regolith and consolidated bedrock) and the hydrosphere (water in, on and below the soil). The pedosphere is the foundation of life on this planet. There is a realization that the pedosphere needs to be distinctly recognized as a dynamic interface of all terrestrial ecosystems and be integrated into the Earth System Science knowledge base. Also, the pedosphere needs to be studied, valued, enhanced and treated in a sustainable and an ethical manner.

The pedosphere acts as the mediator of chemical and biogeochemical flux into and out of these respective systems and is made up of gaseous, mineralic, fluid and biologic components. The pedosphere lies within the Critical Zone, a broader interface that includes vegetation, pedosphere, groundwater aquifer systems, regolith and finally ends at some depth in the bedrock where the biosphere and hydrosphere cease to make significant changes to the chemistry at depth. As part of the larger global system, any particular environment in which soil forms is influenced solely by its geographic position on the globe as climatic, geologic, biologic and anthropogenic changes occur with changes inlongitude and latitude.

2. Wet dust removal equipment

Removal of particulate pollutants.

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.

Wet dust removal equipment

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.

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.

3. 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.