Landfarming

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Landfarming
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What is Landfarming?

• Landfarming, also known as land treatment or land
  application, is an above-ground remediation
  technology for soils that reduces concentrations
  of petroleum constituents through biodegradation.
  As with other biological treatments, under proper
  conditions, landfarming can transform
  contaminants into non-hazardous substances.

Contaminated Soil Treatment in Fahud
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Bioremediation Technology
Source http//www.epa.gov/swertio1/download/citiz
ens/bioremediation.pdf

• It is a natural processes that cleans up harmful
  chemicals in the environment.
• Microscopic bugs or microbes that live in soil
  and groundwater like to eat certain harmful
  chemicals, such as those found in oil spills.
• When microbes completely digest these chemicals,
  they change them into water and harmless gases
  such as carbon dioxide.

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PDO Landfarms

• PDO operates 4 landfarms to treat contaminated
  soil/ sludge.
• Fahud/Qarn Alam operated by Al Khatherey
• Marmul/Nimr operated by GPS

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Application

• This technology usually involves spreading
  contaminated soils in a thin layer on the ground
  surface and stimulating aerobic microbial
  activity within the soils through aeration and/or
  the addition of minerals, nutrients, and
  moisture.
• Each strip shall be clearly marked on a board, by
  the Contractor, with the following information
• Date of spreading
• Treatment applied

Each strip is recorded by marking the date of
spreading treatment applied.
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Operation Principles

• The effectiveness of landfarming depends on
  parameters that may be grouped into four
  categories
• soil characteristics
• constituent characteristics
• climatic conditions
• Soil texture which may affects moisture content,
  and bulk density of the soil. For example, soils
  which tend to clump together (such as clays) are
  difficult to aerate and result in low oxygen
  concentrations. It is also difficult to uniformly
  distribute nutrients throughout these soils.
• Periodic soil samples are tested to check on how
  breakdown of the contaminants is progressing.

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Soil Condition

• Soil conditions are often controlled to optimize
  the rate of contaminant degradation. Conditions
  normally controlled include
• Moisture content (usually by irrigation or
  spraying).
• Aeration (by frequently tilling the soil, the
  soil is mixed and aerated).
• pH (buffered near neutral pH by adding crushed
  limestone or agricultural lime).
• Other adjustment (e.g., Soil bulking agents,
  nutrients, etc.).

Tilling of strip as part of landfarming
Watering of strip as part of landfarming
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System Design

• Landfarm Construction includes
• site preparation (grubbing, clearing and
  grading)
• liners (if necessary)
• leachate collection and treatment systems
• soil pretreatment methods (e.g., shredding,
  blending and pH control)
• vapour treatment facilities (where needed).
• To support bacterial growth, the soil pH should
  be within the 6 to 8 range, with a value of about
  7 (neutral) being optimal.
• Soil microorganisms require moisture for proper
  growth. Excessive soil moisture restricts the
  movement of air through the subsurface thereby
  reducing the availability of oxygen. In general,
  the soil should be moist but not wet or dripping
  wet.

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Advantages

• Simple to design and implement.
• Short treatment period (usually 6-9 months under
  optimal conditions).
• Effective organic constituents with slow
  biodegradation rates.

Treated soil healthy enough to grow plants
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Disadvantages

• May not be affective for high constituents
  concentration of hydrocarbon (greater than
  50,000ppm total petroleum hydrocarbon).
• Requires a large land area for treatment.
• May require bottom liner if leaching from the
  landfarm is a concern.
• Dust and vapour generation during landfarm
  aeration may pose air quality concerns.

Dust generated during tilling