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6.1.5 Land Farming
Land farming is a simple process that helps in the mixing and maintenance of soil
on flat land. Degrading wastes by the existing microbes in wet mud or sludge is
known as land farming. Light loamy soil is uniformly spread over a pad to the depth
of 0.5 foot. Residual liquid or oil sludge is collected from the soil and piled over the
loamy soil to a height of 1 foot. Phosphates, limestones, and nitrates are uniformly
spread over the mixture. Thereafter, the wet mud is watered to provide more than
30% water saturation in the pad. The mixture is turned over regularly to allow air to
mix with the excavated soil so that the microorganisms present in the soil will break
down. Microbial growth is maximum when the pH is between 7 and 8 and temperature is between 20 °C and 30 °C. In this method, the indigenous microbes degrade
60–70% of the soil wastes in the wet mud within 4 months. After complete degradation of wastes, the sludge material is excavated and replaced on the original field
from where it was excavated.
6.1.6 Composting
Decayed organic matter that is rich in microorganisms can degrade the wastes of
explosives which cannot be treated easily by any other methods. This process of
degrading explosive wastes is known as composting. Explosives such as trinitrotoluene (TNT), octahydro tetra nitro-tetra zocine (HNT), and hexahydro trinitrotriazine (RDX) are treated by composting. In a compost pit, liquid that contains the
explosives is added to a pile of decaying organic matter. Microbes present in the
organic matter will degrade the explosives and reduce their concentration in the
compost. At 50–60 °C, about 80–90% of wastes can be degraded within 70 days in
compost piles. By 150–170 days, the concentration of explosives in the soil will be
less than 1%. Thereafter, the compost pile is excavated from the pit and used to
fertilize the soil. This method of bioremediation is much cheaper when compared to
incineration of explosives. Composting allows maximizing the water levels and air
levels in which the microorganisms have more access. Composting is of three types:
static pile, in-vessel, and windrow composting methods.
6.1.7 Soil Bio-piles
In this procedure, heaps of soil are placed over the top of a vacuum siphon. The
vacuum siphon pulls air through the soil to enable oxygen to pass through the dirt to
the microorganisms. Contaminants that may transform into gas are effectively gathered as they are basically sucked with the airstream through the dirt.
R. Govindan et al.
6.1.5 Land Farming
Land farming is a simple process that helps in the mixing and maintenance of soil
on flat land. Degrading wastes by the existing microbes in wet mud or sludge is
known as land farming. Light loamy soil is uniformly spread over a pad to the depth
of 0.5 foot. Residual liquid or oil sludge is collected from the soil and piled over the
loamy soil to a height of 1 foot. Phosphates, limestones, and nitrates are uniformly
spread over the mixture. Thereafter, the wet mud is watered to provide more than
30% water saturation in the pad. The mixture is turned over regularly to allow air to
mix with the excavated soil so that the microorganisms present in the soil will break
down. Microbial growth is maximum when the pH is between 7 and 8 and temperature is between 20 °C and 30 °C. In this method, the indigenous microbes degrade
60–70% of the soil wastes in the wet mud within 4 months. After complete degradation of wastes, the sludge material is excavated and replaced on the original field
from where it was excavated.
6.1.6 Composting
Decayed organic matter that is rich in microorganisms can degrade the wastes of
explosives which cannot be treated easily by any other methods. This process of
degrading explosive wastes is known as composting. Explosives such as trinitrotoluene (TNT), octahydro tetra nitro-tetra zocine (HNT), and hexahydro trinitrotriazine (RDX) are treated by composting. In a compost pit, liquid that contains the
explosives is added to a pile of decaying organic matter. Microbes present in the
organic matter will degrade the explosives and reduce their concentration in the
compost. At 50–60 °C, about 80–90% of wastes can be degraded within 70 days in
compost piles. By 150–170 days, the concentration of explosives in the soil will be
less than 1%. Thereafter, the compost pile is excavated from the pit and used to
fertilize the soil. This method of bioremediation is much cheaper when compared to
incineration of explosives. Composting allows maximizing the water levels and air
levels in which the microorganisms have more access. Composting is of three types:
static pile, in-vessel, and windrow composting methods.
6.1.7 Soil Bio-piles
In this procedure, heaps of soil are placed over the top of a vacuum siphon. The
vacuum siphon pulls air through the soil to enable oxygen to pass through the dirt to
the microorganisms. Contaminants that may transform into gas are effectively gathered as they are basically sucked with the airstream through the dirt.
R. Govindan et al.