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How to Calculate Leaching From a Landfill

Landfills historically have not been situated in optimal environments for preventing waste leakage into nearby streams and rivers. Consequentially, the lack of foresight has inadvertently caused long-term pollution. Geologists and environmental engineers use their expertise to locate better spots for landfills, based on factors such as rock and soil type, vegetation, topographic elevation and the proximity to surface water and aquifers. Mathematical modeling is used to predict locations for new landfills and in remediation of old ones. You'll need lots of data and your own set of complicated algorithms to calculate leaching from a landfill, or get a free program from the EPA with plenty of documentation to guide you through.

Instructions

- 1
  Ascertain the type of landfill in question. Find out if it is composite-lined, clay-lined or unlined and surrounded by the natural landscape. Get dimensions for the length, width and depth of the landfill. Calculate the cubic volume of landfill space by multiplying those three parameters together.
- 2
  Know the soil chemistry for the base of the lined or unlined landfill. Perform soil analysis tests or acquire EPA charts that tell the soil chemistry and pH for your region or area. Categorize using geological terms such as sandy loam, silty loam and silty clay to describe soils.
- 3
  Locate regional topographic maps to get the geographical slope and elevation for the landfill site. Read elevation numbers and note the intervals between them to calculate the slope.
- 4
  Look at precipitation and evaporation rates for your area, or get data from the National Oceanic and Atmospheric Administration. Climate data are variables used for finding infiltration rates.
- 5
  Acquire hydrology data to input into your calculations to figure the infiltration rate. Obtain data for the amount of water that percolated through the landfill to the underlying soil. Get data values for the amount of water recharged through the soil to the outside aquifer.
- 6
  Use EPA database statistics, or your own measurements, to ascertain subsurface thickness, hydraulic conductivity, hydraulic gradient, thickness of saturated and unsaturated zones, at the landfill.
- 7
  Download and install computational software, such as the EPA's EPACMTP program. Get associated users guides to help navigate you through the types of data you need, and where to get it. Plug in the values from above to calculate the amount of leaching in the landfill. Review the range of tables, charts and statistics in the appendices to find values you need. Note the appropriate parameters specified for your location, climate and soil type.

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