Groundwater is a resource that people rely on daily for drinking water, refilling lakes and rivers, industrial processes, agriculture and much more. In this article we take a look at how to pump out groundwater correctly to enable it to be used in these processes.
You may not be familiar with what exactly groundwater is and where it comes from. Groundwater is the water that sits below the ground, it can either sit between rocks, soil and other particles or be contained in aquifers. Aquifers are underground bodies of water that can be harnessed and used as a water source. Groundwater is considered water that goes beyond the top layer of ground known as the unsaturated zone and into the saturated zone. You may have also heard the term water table, this is the top level of groundwater, so essentially the depth below the ground where the saturation zone starts.
It is important to test groundwater quality and contamination levels before using it to drink, supply agricultural land, or in an industrial process. Groundwater can become contaminated and be left unusable if it has been in contact with contaminated materials. Landfills, overuse of fertilizers and leaks in underground gas tanks can all result in contaminated groundwater. Groundwater testing is a simple process of extracting some of the water through a well or borehole using a pump. The extracted water is then sent off for testing in a laboratory where it can be determined if the water is suitable for use.
At QED we offer groundwater sampling equipment that can be used to collect samples from different well and borehole depths and sizes. Find out more about how QED can assist you with groundwater sampling.
Groundwater pumping is the process of extracting the groundwater from the aquifer or saturated zone and transporting it to the surface where it can be used for the various applications previously discussed. This process is fairly simple, if a well isn't present in the ground then a borehole is created. This is a hole that travels deep into the ground to extract the groundwater. Boreholes can be made quickly with the right equipment, they are only very small in diameter typically 6 inches wide.
Once the borehole has been created it will fill up with water. A pump is inserted into the borehole to extract this water out into a holding tank. The pumps that are typically used are electric pumps, electricity rotates propellers which drive the water up through the pump pipe and into the holding tank. As the water is pumped out of the borehole or well the level will fall, and the pump may need to be lowered in order for it to reach groundwater.
Depending on what the groundwater is needed for, it may need to be filtered before being used. There are several methods of filtration which can remove the particles, bacteria and contaminants from the water. The filtration methods need to be combined to remove the necessary contaminants to make the water safe for its intended use. Examples of filtration methods include; activated carbon filters, reverse osmosis filters and micro filtration membrane filters.
Once the groundwater has been filtered it may also need to go through a disinfection process. UV light can be used to remove bacteria and viruses from the water. The light does not require any chemicals to be added but does need to have a power supply. Chlorine may also be added to the water to disinfect and remove any bacteria and viruses. Chlorine needs a minimum contact time with the water in order to be effective. Large tanks are therefore needed for this type of water disinfection.
Many see groundwater as a sustainable source of water; however, groundwater can take thousands of years to replenish if aquifers are completely drained. Polluted groundwater is also an issue for sustainability, when a groundwater source becomes polluted it needs to be effectively cleaned. It can take a considerable amount of time and money before the source can be used again. In order for groundwater to be a sustainable source of water the extraction rates need to be carefully managed and controlled. Groundwater near potential pollutants also needs to be carefully managed to avoid contamination.
