EDITORIAL
High-tech desalination may be in our future
| • | It's premature to start splashing out |
During these hot days when we are advised to conserve water as a defense against depleting our aquifer, it is only natural that folks are thinking of alternative sources.
One of the most mentioned — and potentially promising — alternatives is desalination of seawater.
Such plants already exist, most notably in Saudi Arabia, which is rich in cheap energy but poor in fresh water.
Smaller plants can be found around the world. In fact, a prototype plant for O'ahu is being tested at Kalaeloa on the 'Ewa coast. Eventually, the $45 million project could be producing up to 35 million gallons a day of fresh water.
But desalination is no cure. It is expensive and poses certain environmental risks.
However, improvements in technology in the desalination plants and increased costs associated with naturally occurring water make desalination worth another look.
One place to start might be the California Coastal Commission, which has been studying the merits and drawbacks of desalination plants for several years.
There are already about a dozen working desalination plants in California, and 20 or more are being planned.
But the commission's study warns that it takes a large amount of energy to push the saltwater through the process that converts it to fresh. In oil-dependent Hawai'i, this could be a problem.
One possibility here is ocean thermal technology. It is possible that seawater could be converted to fresh using the energy generated by an all-in-one ocean thermal plant.
But the California study also noted environmental concerns. One is "biofouling" of the pipes needed to bring the seawater to the plant. Ocean thermal experimenters at Keahole are familiar with this.
Another concern is the concentrated brine that is left after the conversion process. What impact might that have on the ocean environment?
Systems would also have to be developed to prevent marine life from being sucked into the system.
Surely, none of these problems should stop us from exploring this source of fresh water for our thirsty Islands. But while those efforts go forward, the easiest way to sustain our supply is through straightforward conservation, as the editorial below points out.
