Solids leaching

Leach test

Leach test can be used to determine the risk contaminated material poses to the environment when exposed to the elements. There are different leaching techniques, but the principle is the same for all of them. The material is exposed to a solution to see how much contaminants leaves the material and how much remains captured in the contaminated matrix.

To know the buffering ability of waste is also essential to understand how much acid rain the landfill can take before the metals and other contaminants starts leaching from the material.

ALS has performed leach test for over two decades and provides leach tests according to the local legislation. We have experience of client specific demands for complex matrices.

Shaking test

This method is good to understand the leaching on a medium to long time scale. This is often used as a quality control of the landfill.

The sample is sieved separated to the appropriate size according to the legislation and shaken for in deionized water for two different time periods. The solid material is removed and the leach waters are analyzed.

Column test, percolation test

Percolation test is used to understand how the material will act on a short to medium time scale. It is more complex as is can give you up to seven leach water to analyse. The material i sieved to the appropriate size and packed in a column. The material is then exposed to a liquid in 7 different steps. The quote between the liquid and the solid is increased in seven steps from 0,1 to 10. Leach water sample can be taken out a each of those steps and analyzed. .

Sequential leach test

Shaking test and percolation test are not always enough. A sequential leaching with different solutions can then be used to determine the risk of heavy metals.