Groundwater in one of those things we generally don't think too much about until an emergency arises, yet it's something that affects us every day. According the the U.K. Groundwater Forum, about one-third of all residents in England and Wales are provided their tap water from the ground. In Northern Ireland the amount is 6% and in Scotland 3%. Groundwater is also used for irrigation, livestock, manufacturing, medical purposes, and countless other uses. But what happens when that supply gets contaminated?
Polluted groundwater can indeed be dealt with through a process which either removes the contaminants or contains the water so further contamination doesn't take place. "Groundwater remediation" is what we call the task of dealing with polluted water, regardless of the process used. Since groundwater occurs naturally in very different places, it can sometimes be complicated to find the source of the pollution and then deal with the water.
There are a number of methods for cleaning polluted water which fall into two categories; the first being biological. In this category there five basic methods: bioaugmentation, bioventing, biosparging, bioslurping, phytoremediation. In the first four processes micro organisms are introduced to the contaminated water which then, in essence, break down and disintegrate the contaminants. In phytoremediation, the roots of specific plants and trees will absorb and eliminate the unwanted material.
In chemical processes, various agents or compounds are used to react with pollutants, ether absorbing them for later filtering or changing their composition to make them water soluble. Pumps and filters remove the absorbing agents and any other remaining residue. A third category of groundwater remediation uses physical means rather than chemical or biological. Air sparging and dual phase extraction are two examples of this kind of remediation.
It is not abnormal in a groundwater remediation scenario to also find contaminated soil as well. Sometimes the contaminants have reached groundwater by draining through the soil above while other times, soil is contaminated in the other direction as the polluted water moves through it. Regardless of the case, soil remediation methods are similar to groundwater methods. The two are often employed together in a comprehensive remediation plan.
In the U.K., water quality has diminished over the last fifty to sixty years due to the increase use of pesticides, petroleum-based products, and industrial chemicals. Fortunately, though nitrate levels have increased there hasn't been much of a problem with disease causing germs, known as pathogens. In order to provide enough clean drinking water for U.K. residents, massive water treatment plants have been constructed throughout the country.
You can help by doing your part to avoid accidental contamination of water and soil. If you pollute purposely, understand that it's illegal in most places, and just bad form everywhere. And next time you reach for a cold glass of water, remember that lots of people had a hand in making sure it is clean.
So next time you each for the tap to get a cold glass of water, remember that someone, somewhere, probably was involved in cleaning that water for your consumption. Try also to remember that knowingly contaminating water is illegal in most places. Oh, and it's just poor form too.
Katherine D Peacock is a consultant and writer specializing in contaminated land remediation. For more information regarding groundwater or soil remedition, please visit her website.