Please remove the salt

Original post:  Aug 4, 2015

It's a bit ironic to be posting this as scattered thunderstorms pass over Mansfield. While the Northeast seems to fluctuate between overly wet and terribly dry spells, on balance we seem to have enough fresh water to go around. The same cannot be said for our fellow citizens out West. In California, persistent drought has forced the governor to declare a state of emergency. Everyone there has been asked to cut their water use up to 25%. There was even a story about famous stars being put on trial for poaching water!

California has easy access to a giant body of water--the Pacific Ocean. Unfortunately, no one can survive drinking salt water. There are now significant movements to start or revive efforts to build desalination facilities to provide fresh water.

This is not a new concept. Arid countries like Saudi Arabia, Israel, and Australia already employ industrial-size plants to augment their supplies. According to the International Desalinization Association, up to 300 million people get at least some of their water through desalinization.

This process is still more expensive than what consumers pay now. Desalinization has improved over the years.

Maloni says desalted water is slowly getting cheaper. The polyamide nylon membranes that remove marine salts and minerals last longer now—seven years instead of wearing out after three or four—and it now takes less pressure to push the water through because of technical improvements, including new ceramic pressure exchangers that boost the efficiency of the process.

The developers are building the plant next to a gas-fired power plant in Carlsbad, about 35 miles north of San Diego. That way it can take use some of the power station’s coolant water to dilute the salty brine discharge. After passing through several treatments to remove marine salts and bacteria, the water will go 10 miles inland to an aqueduct, where it’ll join the rest of the San Diego County Water Authority’s system. By 2020, desalted water is supposed to make up 7 percent of the total supply.

Despite the technical improvements to the process, desal water costs twice as much as existing imported water. San Diego ratepayers will fork over an extra $5 to $7 per month for the next 30 years to cover the difference.

Here is a link to the full article:  One Way to Fight California's Drought: Desalt the Ocean | WIRED