≡ Categories

Recycled water: Next to new but new to you

Exporters complain about the amount of outflows fish require, calling that water “lost.” But for water that is really lost unnecessarily, we need to look at municipal waste water being discharged to the ocean after a single use: 3.5 million acre feet a year in LA, Riverside, San Bernardino and San Diego Counties, enough to supply 10 million people.

Last week, the Assembly Water Parks and Wildlife committee held an informational hearing on Water Re-use. The committee learned that use of recycled water (wastewater) by municipal users is now 669,000 acre feet (af), triple what it was in 1970. Most of this use is in Southern California, but 51 of 58 counties use recycled water. The goal is to produce 2 million acre feet (maf) of reused water by 2030 by treating about 30% of urban wastewater.

Permit processing time through the Department of Public Health and the State and Regional water boards has been about 10 years, but a new MOA promises shorter processing times.

Current projects in the North Bay (Solano-Marin), Orange County, and San Diego were reviewed. The North Bay project replaces water used in a marsh project, saving water that can then be used by agriculture.

The Orange County recycle projects stabilize water supply, improve water quality, meet or reduce costs of imported water, protect against natural disasters, and save energy costs of imported supplies. Some portion of the recycled water is injected along the coast to prevent salinity intrusion into the aquifers from which Orange County pumps. The costs, including reverse osmosis and ultraviolet-hydrogen peroxide treatment, were quoted at $461/acre foot, which is cheaper that State Water Project supplies.

San Diego is working on a project to supply treated waste water directly to potable uses by impounding the water in an expanded reservoir. Public acceptance of “toilet to tap” is increasing rapidly with the knowledge that there are already 361 waste water discharges “upstream” into San Diego’s water supplies.

Costs of treating wastewater depend on the constituents in the treated water supply and the degree of treatment necessary for the intended use.

The Central Delta Water Agency’s Tom Zuckerman thanked the committee for the hearing and noted that it is good to see “light at the end of the tunnel.” We know which tunnel he meant.

Leave a Comment

{ 0 comments… add one }