Water plant

As populations in US cities continue to grow, city planners have been hard put to increase supplies of drinking water, which face challenges from persistent drought and water shortages. It has not been easy getting projects approved. They are costly, and opponents raise formidable health issues and concerns.

* In October, San Diego’s city council approved a pilot plan to boost supplies in a drinking water reservoir using recycled sewer water. The mayor vetoed the project, but the Council may override the veto in December.
* In September, San Jose water officials revealed they would study the use of recycled water.
* In November, South Florida water managers approved plans to use recycled wastewater to replenish drinking water supplies.

On Nov. 30, one model will go into official service in Orange County Water District. It is said to be the largest plant in the world dedicated to purifying sewage water into drinking water. It will be a long, expensive process with filters, screens, reverse osmosis, peroxides and other purifying chemicals, ultraviolet light, and the long wait as water seeps through the ground to aquifers down below.

Projects like this will eventually emerge in places with severe water shortages. The Orange County plant is able to process 70 million gallons of sewage water a day, and water managers from other cities worldwide have visited the plant to see how they do it.

The finished product is technically clean, exceeding the highest drinking water standards. But it will not be piped directly into kitchens and bathrooms, in compliance with state regulations.

The purified water is injected underground. About half of the water will help to form a water barrier against seawater intrusions into groundwater reservoirs; the remaining half will filter gradually through the soil into aquifers. The plant established to do all these cost the county $481 million.

Treated sewage water, also called effluent, has for decades been discharged into the ocean and rivers, such as the Colorado and Mississippi, which are the source of drinking water for millions.

Opponents say there is no guarantee that the purifying process removes all contaminants from the water. The better alternative, in their view, is to control the growth in cities.

The mayor of San Diego justified his veto of the city council plan said the investment would be too big but the returns would be small. Yet, San Diego currently has to import 85 percent of its requirements for water due to a lack of aquifers.

Safety Tip:
* Cut your water use. You can help your water district by cutting water consumption. Earlier this year, San Diego officials asked residents to curtail water usage.