Seawater Greenhouse Turns Saltwater Into Fresh Drinking Water With Added Bonus
The lack of fresh, potable water in many areas of the world is increasing at an alarming rate. Even areas currently flush with the stuff are worried that won’t always be the case. For decades now we’ve been studying the problem and trying to figure out a solution. Time and again we come back to the idea of turning saltwater into drinking water. While we’ve found a way to do it, the amount of seawater you need to produce desalinated fresh water is 2 to 1. But that’s not a problem with rising ocean levels resulting from melting ice. It would seem like a no-brainer, especially when you consider we’re losing land because of it.
So far, the cost of desalinating seawater has made it cost prohibitive in the eyes of critics. Yes, it’s not cheap to produce, but what are our alternatives? Living, breathing creatures need it to survive, so how do we put a price tag on something that isn’t an option but rather a necessity? Now, a group known as Seawater Greenhouse Ltd. has developed greenhouses for the purpose of producing fresh drinking water that are not solely dedicated to the task but double as growing environments for plants inside and outside the structure. Their design enables the cultivation of crops in arid regions of the world that see extreme temperatures.
Desalinization vs. Evaporation
These structures are obviously well-suited to desert terrains, and they’re already in use in places like Tenerife, Qatar, Abu Dhabi, Oman and Australia. So, how does it work? First off, they’re not using a traditional desalinization process. They’re using an evaporative process to remove the salt. Ventilation air that is driven by wind is cooled, cleaned, sterilized and humidified by seawater evaporators. Only pure water evaporates. The seawater is then reduced to a concentrated brine form inside of the greenhouse and then further evaporated outside of the structure to yield salt and various other minerals.
Solving the Fresh Water Dilemma
The process of evaporating seawater while simultaneously cooling the air is actually much easier and less expensive than desalination. Ultimately, the outcome is the same if not better, because the volume of water lost through plant transpiration is reduced significantly. Plants that aren’t stressed through excessive transpiration are known to grow faster and produce higher yields. Transpiration is essentially evaporation of water from plant leaves. It’s the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is then released out into the atmosphere.
Because the system uses sunlight and seawater to enable the supply of food, energy and fresh water, the process is considered environmentally friendly and allows crops to thrive in areas which normally do not provide the right growing conditions due to high temps, a lack of fresh water, or both. This ambitious project has practical applications to some of the most water-stressed areas of the planet and could play a critical role in preventing future water- and food-based conflicts, which many analysts believe contributed to the further destabilization of the Middle East beginning in 2011.
Cost Effective Solutions to a Global Crisis
Seawater Greenhouse has noted that, while greenhouses by their nature carry with them high upfront capital costs, the company envisions that once the units are established “they will provide sufficient returns for investors.” Again, when it all comes down to it in the end, you can’t really put a price tag on survival, can you?