A desalination plant is able to create freshwater resources from a saltwater source, such as the ocean. Once it goes online, the facility is able to provide a water supply that is immune to drought, offering drinking water to an entire region. The Tampa Bay Seawater Desalination facility, located in Florida, provides up to 25 million gallons of drinking water per day to the region.
The primary benefit which desalination plants provide is proven technology. Reverse osmosis is used in many desalination plants, which creates high-quality drinking water on small or large scales. Homeowners can even hook-up a reverse osmosis filter to their own plumbing system to create a better water supply.
The disadvantage of desalination plants, however, is their cost. Although several factors can dramatically change the final price of construction, a 2010 report estimated that a new desalination plant in Texas would cost $658 million to achieve 100 million gallons per day of freshwater supplies. Even at 2.5 million gallons per day, the plant would cost $32 million to build.
Here are some addition desalination plants pros and cons to think about and discuss.
Pros of Desalination Plants
1. It is a predictable resource.
Desalination plants produce consistent levels of freshwater to consume once operational. There are few factors that are deemed to be “uncontrollable” with this technology. Whether the plant is working with brackish water or sea water, the resource does not require precipitation, annual snowfall, or some other form of unpredictable water resource to operate. The ocean is not going anywhere.
2. It solves the worry of a water shortage.
With the presence of a desalination plant, water shortages have a reduced impact, even during critical times, such as a drought. In many areas of our planet, irrigation is the only reason why there are fertile croplands available for agricultural work. Not having a crop produce an expected yield does more than create a food shortage emergency. It also creates an economic emergency, as farmers and agricultural workers can no longer support themselves and their families.
3. Desalination plants may reduce energy costs.
In the United States, there is an infrastructure to distribute water just as there are road networks, wastewater networks, and oil pipelines. There is a specific energy cost which is associated with the movement of water. Pumps must be used to ensure communities receive an adequate supply. By lacing desalination plants strategically, it would be possible to offset the environmental impact of the facility by lessening the current infrastructure costs which are required for freshwater movement.
4. It could create a freshwater reserve.
There are times when freshwater resources are plentiful. During those times, the desalination plant could continue to operate, producing a healthy reserve of water that could be used at a later time. That would allow habitats and agricultural efforts to be maintained, potentially over a period of several years, which could reduce or eliminate the changing economic and agricultural conditions that drought could provide.
5. Desalination plants offer independence.
Many communities purchase their water supply from others. By building a desalination plant, coastal communities or those with access to a large brackish water supply could become more independent with freshwater access. Although the cost of the facility could be extensive, it would reduce the regular payments require for freshwater access. That means, for some communities, a desalination plant could eventually pay for itself.
6. It stops water diversions.
Most communities get their freshwater resources from local lakes, rivers, or groundwater supplies. Over time, diverting this water changes those habitats. If carefully constructed, a desalination plant could maintain those habitats while also providing a needed source of water for thousands of households.
7. It creates diversification.
Water diversification is closely linked with economic stability. Stable water access creates stable pricing structures for utility customers. Having higher levels of reliable availability supports human productivity. When a community is connected to a desalination plant, it no longer relies on any one source for its water.
Cons of Desalination Plants
1. Desalination plants may contaminate groundwater supplies.
Desalination is known to create a high-quality supply of freshwater that can be used for drinking water. It may also introduce certain contaminants into the local water supply. Chemical, biological, or mineral contaminants can alter groundwater supplies, which would affect crop growth, water access, and water-related issues with such a change. It would depend on how the water was treated within the plant, so the process must be constantly monitored to protect the water supply.
2. The salt must go somewhere.
To create freshwater resources from a saltwater resource, the desalination plant removes the salt which is found within the water. The process of salt removal creates a concentrated product called “brine.” Salt is naturally corrosive, so concentrated salts can be potentially deadly. Consistent contact with brine has been known to kill vegetation, harm wildlife, and is even potentially harmful to certain individuals.
3. It takes the minerals out of the water.
Water has some bad minerals in it that the reverse osmosis process of desalination can remove. Taking arsenic, lead, and barium out of the water supply seems like a good thing. At the same time, however, there are certain “good” minerals, such as magnesium, potassium, and calcium, that are also found in water supplies. These minerals are easier to absorb when they are naturally included in the water being consumed. Reverse osmosis takes out the bad, but it also takes out the good too.
4. Desalination plants create pollution.
Although a desalination plant is able to create additional freshwater resources, it does so at a cost. Fossil fuels must be consumed to create the filters, screens, and equipment that are required to create the freshwater resource that is healthy enough to drink. That negative contribution to the atmosphere may be minimal compared to other industries, but it is still present nonetheless.
5. It is an energy-intensive solution.
The amount of energy that is required from a desalination plant to create drinkable water is higher than any other water supply option that is currently available. In Tampa Bay, the cost of desalinated brackish water can be up to $2.60 for every 1,000 gallons of water produced. Desalinated seawater can cost up to $5.80 per 1,000 gallons of water.
6. The return is minimal.
A typical system that is reliant on reverse osmosis will return as little as 5% of the water that is pushed through the system. The remaining water is often sent to the local wastewater facility for further processing and treatment.
These desalination plants pros and cons offer communities the benefit of having freshwater resources available when needed, but there are certain costs that must be paid to do so. Some are economic, some are environmental, and some are unpredictable. Are desalination plants worth their cost?