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6 Bioremediation of Pesticides Containing Soil and Water

Composting is a natural process that occurs in soil where organic waste components

are degraded by the microorganisms. During artificial ways of composting, temper-

atures are kept higher in soil which results in amplified solubility of contaminants

and display greater metabolic endeavor. Co-metabolism of organic contaminants can

exist at higher levels of substrate in the compost. Mechanical treatment of unwanted

nondegradable materials such as metals, plastic, stones, and glass makes it easy for

the biological treatment to take place. Nature of organic contaminants, compost-

ing standards, protocols, microbial population, and incubation period act as major

factors which will impact the total operation of the compost methodology [32].

6.5.2.2

Land farming

It is an overhead ground remediation skill which is also called as land treatment.

This method comprises spreading of contaminated soil in slender layers up to 0.4 m

thickness on terrain surface and accelerating aerobic microbial activity in the soil by

adding nutrients and aeration. It demands a large treatment area as the soil is spread

into thin layers. To increase the degradation process, oxygen supply and mixing

(plowing, milling, and harrowing) at regular intervals of time are done.

6.5.2.3

Biopiles

It is the combination of composting and land farming. Here, evacuated soils are

combined with soil amendments and positioned on treatment areas. They are

bioremediated by obligated aeration and thereby completely convert toxins into

carbon dioxide and water. The mentioned system comprehends aeration system,

treatment bed, nutrient or irrigation organization and leachate assembly. The soil

piles are up to 20 ft and enclosed by plastic to avoid the runoff, volatilization, and

evaporation. Biopiles offer a favorable atmosphere for the indigenous anaerobic

and aerobic microbes.

6.5.2.4

Bioreactors

Here polluted soil is treated in slurry or solid status. The principle of solid-state appa-

ratus is systematic mechanical decomposition of the soil by the intensive mixing

and enabling of mechanisms in the locked system. This makes sure that the toxins,

microorganisms, water, and nutrients are in lasting contact. The slurry state biore-

actors may be elucidated as contaminant system and apparatus is used to produce a

three-phase (solid, liquid, and gas) mixing. As compared to in situ or solid-state sys-

tems, the rate of biodegradation is superior in the slurry bioreactor scheme because

the environment is manageable and foreseeable. The contaminated soil requires pre-

treatment by soil washing and physical extraction before feeding into the bioreactor.

6.6

Bioremediation Process Using Biological Mediators

6.6.1

Bacterial Remediation

Biodegradation of pesticides (including micro-pollutants) comprises the oxidation of

parent compound which forms carbon dioxide and water [33]. During the process,

the contaminants provide energy and carbon for the growth and multiplication of