Heron in its natural environment
Water sampling in the natural environment is subject to strict regulations and routine hydrogeological studies aim to guarantee the integrity of the resource. Underground aquifers fed by water in the soil are among the most heavily called-upon natural resources.
Due to pipe breakages and rain water containing agricultural or industrial pollutants (notably hydrocarbons) the water table becomes degraded to the detriment of the environment.
It is therefore necessary to artificially replenish the ground water and treat the polluted water well before its arrival at the treatment facility. Activated carbons play a key role in this situation.
Bore holes are sunk to address hydrocarbon contamination which tends to float on the surface of the water; then the water itself can be treated, which may contain dissolved hydrocarbons and other pollutants such as pesticides. The recovered water is passed through a bed of activated granular carbons to eliminate contaminants and then released into the underground aquifer.
For this type of treatment, PICA recommends the use of coconut shell based GACs which can be placed in fixed or mobile units.
Soils containing polluted water (notably volatile organic compounds (VOCs)) are purified by aspirating air from the soil and passing it through a bed of GAC before releasing the air into the atmosphere.
Another effective method entails combining purification of both soil and underground aquifers by re-introducing the pumped and treated water into the aquifer through the soil.
The impurities contained in the soil will settle in the aquifer and the water will be re-pumped and treated to ensure the pollution has been eliminated.