Landfarming

1. Landfarming

2. What isLandfarming? 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

3. Bioremediation Technology Source: http://www.epa.gov/swertio1/download/citizens/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.

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

5. 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.

6. OperationPrinciples • 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.

7. 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.). Watering of strip as part of landfarming Tilling of strip as part of landfarming

8. 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.

9. 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

10. 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