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Research and developments (R&D)

Land Pollution

Air Sparging

  • decrease the level of volatile constituents in petroleum products that are absorbed to soil and dissolved into groundwater, which involves the injection of contaminant free-air into subsurface saturated zone, enabling a transition from a dissolved state to a vapor phase
  • in combination with soil vapor extraction (SVE) which creates a negative pressure through a series of extraction wells to control the vapor plume migration
  • effective in decreasing levels of volatile organic compounds (VOC) which can either use vertical or horizontal sparge wells, depend on:
    • vapor/dissolved phase partitioning of the constituents determines the equilibrium distribution of a constituent between the dissolved phase and the vapor phase
    • permeability of soil determines rate of air injection into the saturated zone

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Low Temperature Thermal Desorption

  • ex situ technology which uses heat to split petroleum hydrocarbon from excavated soils through physical methods
  • effective in decreasing levels of petroleum products like gasoline, jet fuels, kerosene, diesel fuel, heating oils and lubricating oils
  • mechanism criterion: contaminated soils are excavated and transferred to stationary facilities; mobile units operate immediately on site
  • treatment modes:
    • rotary dryers
    • asphalt plant aggregate dryer
    • thermal screw
    • conveyor furnace

Soil Vapor Extraction (SVE)

  • in situ technology in reducing the level of volatile constituents in petroleum products absorbed to soil in the unsaturated (vadose) zone in which vacuum are introduced to wells near the source of pollution, where the evaporated vapors are drawn to the extraction well to be treated by carbon absorption before being released to atmosphere  
  • effective in use of volatile organic compounds (VOC) & certain semi volatile organic compounds (SVOC)
  • efficiency of SVE is determined by:
    • permeability of soil
    • soil structure and stratification
    • soil moisture
    • depth to groundwater

Soil Washing

  • elimination of hazardous waste and decrease the concentration to a minimum, which split the contaminated fine soil (silt and clay) from the coarse soil (sand and gravel)
  • upon completion, majority of fine silt and clay particles are further treated by bioremediation, incineration or disposed
  • effective with low presence of silt and clay, metals, gasoline, pesticide and fuel soils, with combinations of other treatment technology
  • important treatment mode is the soil scrubbing unit

Composting

  • Erosion control, turf remediation and landscaping
    • enhance plant growth
    • enhance soil compaction
    • control disease and pest infestation at plants
    • decrease rate of soil erosion and nutrient run off
  • Composting of soils and contaminated by explosives
    • contaminated soil is excavated, mixed with feed stocks and composted, thus producing contaminant free humus to improve landscaping and horticulture applications
  • Reforestation, wetlands restoration and habitat revitalization
    • provide tree seedlings added rigor for survival and growth

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