What is Bioremediation

By Agropedia on 06 Apr 2016 | read
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Submitted by naipictuasdharwad

What Is Bioremediation?

Bioremediation can be defined as any process that uses microorganisms or their enzymes to return the environment altered by contaminants to its original condition. Bioremediation may be employed in order to attack specific contaminants, such as chlorinated pesticides that are degraded by bacteria, or a more general approach may be taken, such as oil spills that are broken down using multiple techniques including the addition of fertilizer to facilitate the decomposition of crude oil by bacteria.

ADVANTAGES TO BIOREMEDIATION

However, there are a number of advantages to bioremediation, which may be employed in areas which cannot be reached easily without excavation. For example, hydrocarbon spills (or more specific: gasoline) may contaminate groundwater well below the surface of the ground; injecting the right organisms, in conjunction with oxygen-forming compounds, may significantly reduce concentrations after a period of time. This is much less expensive than excavation followed by burial elsewhere or incineration, and reduces or eliminates the need for pumping and treatment, which is a common practice at sites where hydrocarbons have contaminated groundwater.

TYPES OF BIOREMEDIATION

Generally, bioremediation technologies can be classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site while ex situ involves the removal of the contaminated material to be treated elsewhere. Some examples of bioremediation technologies are bioventing, land farming, bioreactor, composting, bioaugmentation and biostimulation.

Compost is the decomposed remnants of organic materials (those with plant and animal origins). Compost is used in gardening and agriculture, mixed in with the soil. It improves soil structure, increases the amount of organic matter, and provides nutrients.

Compost is a common name for humus, which is the result of the decomposition of organic matter. Decomposition is performed primarily by microbes, although larger creatures such as worms and ants contribute to the process. Decomposition occurs naturally in all but the most hostile environments, such as buried in landfills or in extremely arid deserts, which prevent the microbes and other decomposers from thriving.

HEAVY METAL

A metal with a specific gravity greater than about 5.0, especially one that is poisonous, such as lead or mercury.

Effect of lead on soil

Lead is found to accumulate on the top layer of the forest soil. The forest soil is rich in humic content. Presence of this lead in forest soils have reduced the humic by 29% within ten years 1977-1987 reported by soil scientist (mayer). Indicating the lead has converted the humic soil in to mineral soil.

PESTICIDES AND POLLUTION OF THE SOIL

Pesticides decrease biodiversity in the soil because the do not just kill the intended pest; they often kill many of the other small organisms present.

When life in the soil is killed off, the soil quality deteriorates and this has a knock on effect upon the retention of water. This is a problem for farmers particularly in times of drought. At such times, organic farms have been found to have yields 20-40% higher than conventional farms.

Soil fertility is affected in other ways. too. When pesticides kill off most of the active soil organisms, the interactions which result ion good fertility break down.

LAND QUALITY INDICATORS

1. INDICATOR

(a) name of the indicator: Land use change.

(b) brief definition of the indicator: Change with time of distribution of land uses within country.

(c) unit in which the indicator is measured: Proportion of change of given land use per unit time.

2. PLACEMENT IN THE FRAMEWORK

(a) chapter of Agenda 21: Chapter 10, Planning and management of land resources.

(b) type of indicator (Driving Force, State or Response): Response (mainly).

3. SIGNIFICANCE

(a) purpose of the indicator (the phenomenon it is meant to represent): Highlight changes in productive or protective uses of the land resources.

(b) policy relevance: Consequent changes in volume of produce available; and in scope for providing services such as tourism or environment.

(c) relevance of the phenomenon to sustainable/unsustainable development (interpretation, value, movement): Evident from 3(b).

(d) close linkages between this indicator and other indicators in the list e.g. is this indicator better interpreted if paired or combined with (an) other indicator (s)?: With land condition change (Chapters 10 and 14).

(e) targets (do international targets exist? does the indicator lend itself to the establishment of national targets? how does this indicator relate to existing targets?): No. Except for establishing certain minimal contiguous extent, or proportions of total, for certain needed or desirable land uses.

(f) reference to international conventions or agreements.


 

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