Power generation plants, natural gas extraction sites and hydraulic fracturing all require groundwater for cooling or processing. After the water has been used, it’s usually contaminated in some way and requires careful handling and storage until it’s processed or drained into a permanent sealed well. Solution mining, in which salts or minerals like lithium are dissolved for pumping and evaporation, requires a large amount of groundwater for the initial work. Groundwater storage lagoons are usually at high risk for environmental damage if there’s a leak or seepage due to an unlined structure. Freshly pumped groundwater, ready for use in mining and processing, can be stored in any pond designed for freshwater. Wastewater, that comes back out of the ground, requires special handling with the right lagoon design.
Types of Waste Groundwater
The properties of different wastewater mixtures determine the type of storage lagoon needed. Some groundwater supplies are highly acidic or corrosive, making it difficult to store the water in metal or concrete structures. Other groundwater supplies need double lining systems with spill monitoring equipment built in. Compare the requirements of the most common types of waste groundwater to determine what’s necessary for your project.
Natural Brine and Mineral Concentrations
As groundwater passes through dozens of layers of sand, soil, and rock, it can accumulate plenty of natural dissolved minerals. Groundwater high in iron, lithium, or salt isn’t always safe to use for drinking or agricultural purposes. Pumping a concentrated brine or mineral-rich groundwater deposit into a storage lagoon can protect nearby drinking water supplies from contamination. These mineral-rich groundwater deposits are also useful for mineral extraction through evaporation, creating a double purpose for extracted water. Naturally formed groundwater deposits, that need storage, are often corrosive and may require cover to ensure animals and birds can’t reach the surface.
Groundwater Contaminated by Spills and Seepage
When a septic system becomes damaged or toxic waste is spilled on the soil’s surface, the groundwater deep below is often also affected. Contaminated groundwater should be pumped out of its aquifer area and purified or processed in some way, so it doesn’t seep into other nearby water supplies. Shallow groundwater supplies are particularly prone to surface runoff contamination. Contamination can happen anywhere from urban roadways to remote processing or construction sites.
Natural Gas Mining and Pumping Wastewater
Extracting natural gas and removing it from underground storage areas requires the use of thousands of gallons of groundwater. Most of this water remains trapped underground in the original aquifer, but some rises to the surface with the natural gas as it’s extracted. Since this groundwater is mixed with residues from the gas, processing chemicals and additives, and other contaminants, it’s essential to keep it stored properly until it can be reused or evaporated. Lagoons for storing natural gas wastewater must have durable liners from a supplier like BTL Liners to prevent the chemicals from reaching the soil and water below the surface.
Hydraulic Fracturing Wastewater
Hydraulic fracturing, also commonly called fracking, is another common source of contaminated groundwater. Known as produced water, this liquid is a combination of fracturing additives, leftover hydrocarbons, and water. Every type of oil and gas extraction requires groundwater and produces wastewater, but fracking creates a particularly large volume of water to store. Many sources estimate that anywhere from 40 to 50 million gallons of groundwater are required for each horizontal fracturing well. With just a small fraction of that exiting the well along with the oil or gas, you’re dealing with thousands of gallons of water that need proper storage. Fracking wastewater often causes reactions that weaken certain plastic lagoon liner materials, requiring special selection when planning the pond. The water also tends to have extremely high salinity, increasing the risk of corrosion when the water is stored in metal tanks. Flexible liners that won’t react with the hydrocarbons are the best choice for lining these lagoons.
Sewage Processing and Landfill Runoff
Spills and runoff from sewage processing plants, septic tanks, and landfills can contaminate the groundwater over a large area. Gathering this runoff into a detention or retention pond is the best way to prevent contamination, but the runoff or leachate often isn’t discovered until it’s already mixed with a groundwater supply. At that point, the best option is to pump the water into a new pond and process it like any other form of wastewater. The high levels of bacteria in this type of groundwater makes it necessary to use covers in many cases or at least the implementation of access control methods; like fencing around the lagoon.
While all of these forms of waste groundwater may need secure containment and pose risks upon exposure, their specific properties vary greatly depending on the exact mixture and source. Make sure you’re choosing the right liner for your project by requesting advice and help from our team here at BTL Liners.