As desalination becomes more widespread, committing to safe brine disposal is becoming more important than ever
As more communities turn to desalination and brackish water treatment to address water scarcity, concerns about brine disposal are growing. But responsible engineering and real-world data show that it’s possible to protect both the water supply and marine ecosystems. From creek-safe discharges in Alice, Texas, to carefully monitored ocean outfalls in Trinidad, Seven Seas Water Group is helping chart a sustainable path forward. To celebrate World Oceans Day this month, we’re taking a closer look at how brine can be managed with science, safeguards, and stewardship.
The Desalination Dilemma
The oceans play an important role in influencing our climate, they provide us with a wide variety of seafood, as well as an abundant supply of seawater that can be turned into a valuable source of drinking water. As the world faces intensifying water scarcity, desalination and brackish water treatment are offering a lifeline, especially in regions where supplies of fresh water are dwindling. But while saline water offers a sustainable long-term solution in terms of availability, the brine left behind at the end of the process poses an environmental challenge. This raises the question: Can desalination coexist with ocean and freshwater ecosystems?
What Brine Is and Why It Matters
During the desalination process, saline water, whether sourced from surface water bodies or groundwater, is forced through reverse osmosis (RO) membranes with tiny pores (0.001-0.0001 microns) that allow water molecules to pass through while rejecting salt and other impurities. The desalinated water, or permeate, that passes through the membrane is fresh and potable, while the remaining brine consists of highly concentrated salt water. This hypersaline byproduct not only contains excess salinity but may also contain traces of pretreatment chemicals, such as chlorine, acids, or antifoulants, and can be warmer or more acidic than the source water.
Without proper handling, this mixture poses a potential risk to aquatic life, especially benthic organisms that live on the ocean floor. Inland, inadequate brine disposal practices can lead to the contamination of soil and groundwater, jeopardizing the integrity of aquifers and the broader ecosystem. There is also growing concern over the cumulative long-term impact of improperly managed brine disposal on environmental and human health.
Real-World Safeguards in Practice
The good news is that desalination can coexist with environmental stewardship. With smart design, real-world monitoring, and a commitment to sustainability, responsible brine management is not just possible, it’s already happening.
Brackish RO in Alice, Texas
In the city of Alice, Texas, a new brackish reverse osmosis plant from Seven Seas will soon deliver critical water supplies without harming the surrounding environment. Unlike many inland desalination systems that rely on deep-well injection or groundwater discharge, which can lead to contamination of local aquifers, this facility is taking a different approach to discharge disposal. The concentrate stream will be discharged into a local creek that flows into Baffin Bay. As the discharge is less salty than the bay itself, it potentially provides a diluting effect rather than increasing salinity. This case study provides a real-world example of how careful design can allow inland desalination to coexist with sensitive ecosystems.
Seawater RO in Trinidad
Seven Seas operates a seawater reverse osmosis plant in Trinidad, providing clean water to surrounding communities while minimizing environmental impact.
At Guapo Bay, Point Fortin, on the Caribbean island of Trinidad, Seven Seas runs a seawater reverse osmosis plant that provides clean water to surrounding communities. The plant incorporates ocean-friendly safeguards into its brine management. Seven Seas initiated benthic fauna surveys to monitor the effect of brine on marine organisms, making necessary adjustments to protect these ecosystems. Additionally, two independent environmental firms regularly monitor water quality nearly a kilometer offshore from the discharge point, checking salinity levels, temperature, and alkalinity. Operators adjust discharge rates in real time to avoid ecological disruption. The site has been recognized for its low-impact siting and commitment to responsible ocean stewardship while providing high-quality potable water to island inhabitants.
Engineering for Responsible Brine Management
Not all brine is created equal, and neither are the ecosystems where it may be discharged. Consequently, there’s no one-size-fits-all solution. Because effective brine management depends on local geography, hydrology, and ecological sensitivity, location-specific design is key. Possible scenarios include:
- Surface water discharge: If the brine meets discharge regulatory requirements and a surface water body is located nearby, discharging brine into surface waters can be a cost-effective disposal option. If the brine does not comply with discharge requirements, diluting it before disposal can help meet those requirements.
- Subsurface ocean discharge: Environmental impact studies should guide the placement of brine outfalls, with diffusers incorporated to dilute and spread out the brine. Advanced modeling can help pinpoint the best location for the outfall, ensuring the brine is disposed of in an area with a strong current to aid in dispersal.
- Deep-well injection: In suitable geological formations where there is porous space within the subsurface rock formation, brine can be injected underground. While this method can safely contain brine underground, it requires conducting the necessary site evaluations and obtaining the required permits, as well as drilling and maintaining the wells.
- Evaporation ponds or land application: In arid inland regions with limited discharge options, evaporation ponds offer a simple and effective method of concentrating brine further as the water component evaporates. The brine can also be applied to soil or used to irrigate salt-tolerant crops to enhance crop growth.
No matter which approach you opt for, rigorous planning is essential. This entails:
- Hydrodynamic modeling of ocean currents and discharge flows to ensure outfalls are optimally sited
- Conducting thorough environmental impact assessments to determine the location of sensitive ecosystems and how to avoid disrupting them
- Continuous feedback through real-time monitoring systems that allow operators to make adjustments when necessary
When executed well, these safeguards ensure that brine is dispersed safely into the ocean, protecting sensitive marine species and ecosystems.
Designing With Oceans in Mind
The demand for desalination is growing steadily, especially in coastal and arid regions where water stress is becoming the new normal. But this growth must be met with responsibility.
Seven Seas is committed to advancing sustainable desalination practices that minimize environmental impact, particularly through improved brine and concentrate stream disposal. Our primary goal is to enhance water security by delivering a reliable supply of clean water to communities — without compromising the health of surrounding ecosystems.
Desalination can provide an alternative source of potable water, offering a lifeline for water-stressed regions. However, to ensure it’s truly sustainable, stakeholders, from city planners to engineers, must factor brine and concentrate discharge management into early project planning.
Contact Seven Seas to learn more about our approach to sustainable desalination.
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