TRANSFORMING BASE SUBSTANCES INTO GOLD
Contaminated Soil Remediation
Our soil, our water and the air we breathe are our most precious natural resources. Without them we cannot exist. Population growth and concomitant agriculture, transport and industrial activities have put a tremendous strain on our natural resources and this has led to contamination and depletion of our souls on a massive scale…
Common soil contaminants can be physical (all kinds of debris), of biological nature (bacteria, viruses), heavy metals (Such as Arsenic), organic industrial pollutants (such as petroleum products, herbicides, insecticides), acids, bases, volatile organic compounds, radio-nuclides or solvents (such as TCE which used to be used in Dry Laundry).
Soil treatment technologies include:
1. Chemical neutralization – using chemicals such as CaOH2 or Sodium Bi Sulphate to adjust the pH of the soil
2. Using oxidizing agents to oxidize POP’s (persistant organic pollutants). Common Oxidants are KMnO4 and H2O2
3. Aeration. Air can be pumped into the soil to encourage volatilization or to help bioremediating organisms breathe.
4. Bioremediation – using bacterial cultures to break down the pollutants
5. Phytoremediation: using plants to bioaccumulate certain pollutants such as Arsenic
6. Heating of soil
7. Pump and treat systems
8. Disinfection
9. Soil washing: Usually involves large machines that are caple of washing soil and conveying large amounts of earth.
Soil testing Laboratory tests often check for plant nutrients in three categories:
Major nutrients: nitrogen (N), phosphorus (P), and potassium (K)
Secondary nutrients: sulfur, calcium, magnesium
Minor nutrients: iron, manganese, copper, zinc, boron, molybdenum, chlorine
The soil is also tested for heavy metals. pH of the soil and the Salinity are also important indicators of the fertility of the soil. Soil texture testing indicates the amount of sand, silt and clay in the soil.
Below is a schematic with some of the techniques used in soil remediation:
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Compiled by Rami E. Kremesti M.Sc., CSci, CEnv, CWEM
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