Location
In addition to preparing a good design for your brine pond that takes into consideration the specific purpose, it’s important to consider the location and the conditions in the area, since brine ponds don’t work in just any area. Brine ponds intended for mineral harvesting are intended to evaporate water as quickly as possible, for example, so they perform best in dry, relatively warm climates. Full exposure to sunlight dramatically increases the speed of evaporation and, as an added bonus, it can help control unwanted bacterial growth.
The next thing to consider is proximity to your source to minimize transportation complexities, including trucking or pipelines. If the brine is to be reused or requires additional processing, the pond should also be kept close to those facilities whenever possible. Still, if the activities are close to agricultural areas or places with high water tables, efforts should be made to move brine ponds further away. The intention is to reduce the risk of spills or floods of concentrated brine that could seriously damage the water table or render cropland unusable.
Locations that have reliably steady winds are excellent choices, but contamination from spray or waves from high winds also present significant risks that should be considered. The risks vs benefits of wind effects can be addressed in the choice of location, but also may be balanced by incorporating additional features in the pond’s design.
Construction
The project will probably involve construction of access roads, excavation for the pond areas, and may include fill dirt, depending on the properties of the excavated soil. A smooth, even bed that’s free of rocks, roots, or other sharp objects is necessary to protect the impermeable liner that will be placed. Many liners require an underlayment to provide additional protection from punctures, friction and other dangers, although a Reinforced Polyethylene (RPE) liner from BTL Liners is durable enough that underlayment is rarely necessary.
In addition to the pond excavation itself, berms or dikes must be constructed to prevent loss of caustic brines during storms or flooding events. These berms (and possibly the floor and walls of the pond itself) will need to be carefully stabilized. Depending on the hazard level of the brine involved, a secondary set of water control structures are likely a good investment. This second protective ring also needs to be lined - extra protection against environmental damage, potential fines, and risk to humans makes this an extra wise investment.
For ponds intended to contain contaminated brine or highly caustic concentrates, extra precautions are a necessity. Usually, that will include double lining with a thick layer of fine soil in between. Fine soil is characterized by a large percentage of clay and silt, which allows it to hold water effectively. The purpose of this soil layer is to create a cushion that can absorb spilled or leaked brine before it reaches the secondary layer. Leak sensors are often installed under single lined ponds, but they are absolutely necessary to include in the absorption layer so that seepage or leaks of the most dangerous brines are identified before they enter the environment.
Some large brine ponds, especially those intended for long-term storage, may be designed with a concrete liner (think swimming pool) to protect against problems with soil stability. Even with a concrete liner, though, an additional layer of protection is needed. Concrete is a porous material and can draw moisture up from the soil into the pond itself through capillary action. To avoid this incursion, an impermeable liner like RPE should be installed between the soil and the concrete.
Brine transportation to the pond(s) and potentially back for re-use need to be incorporated during construction. A non-reactive piping like HDPE or another appropriate material, should be specified in the design phase. Once again, it’s important to incorporate secondary containment strategies to protect against any potential leaks. Even if your transportation includes trucking, don’t neglect safety in the areas that will involve loading and unloading.
