Hossein Ashktorab, Ph.D. and Jeannine Larabee

Advances in Water Recycling
 
Hossein Ashktorab, Water Utility Planning Unit Manager, and
Jeannine Larabee, water conservation specialist, are with the
Santa Clara Valley Water District (SCVWD), the organization
that manages water resources (watersheds, reservoirs, streams
and groundwater basins) and provides flood protection throughout
Santa Clara County. Earlier this year, the SCVWD Board of Directors
approved two agreements with the City of San Jose to build an
advanced water treatment facility that will divert a portion of the
treated water from the San Jose/Santa Clara Water Pollution
Control Plant to produce highly purified recycled water for
non-potable uses.
 
Hossein and Jeannine will describe the planned facility’s use
of advanced treatment methods (e.g., microfiltration, reverse
osmosis and ultraviolet disinfection) to produce up to 8 million
gallons per day of highly purified water, of near-distilled water
quality. While this project is being built for non-potable uses in
irrigation and industry, Hossein and Jeannine will describe how
the same technology is being used worldwide to produce
highly purified water for drinking, and the prospects for
producing potable water using these technologies here.


Hossein began by finding out the backgrounds of the crowd. One by one we mentioned technical and political backgrounds, with special interests for the talk in things like gray water use. He was the first speaker in a long time to get us to do that.

Then he explained that the Santa Clara Valley Water District (SCVWD) serves two million customers. 55% of the water is imported, and 30% comes from our rivers and lakes. The rest is ground water. The imported water is mostly Hetch-Hetchy water that we get via San Francisco's system. After using the water we send it to the treatment plants, which processes 100,000,000 gallons every day.

Our water resources are completely allocated. Every drop of water that flows into the Sacramento River delta system is needed by the fish. Every drop that is diverted for Southern California and agriculture is needed, and they are looking for more. The same is true of Hetch-Hetchy, and our local rivers.  To look for more supply conservation and recycling are the only options that seem feasible.

The SCVWD has a very active conservation program. Rebate programs are available for water saving installations, including automatic systems for lawn watering and free low flow shower heads. Consultants are available to help homeowners get involved with the program.

Recycling starts with water as it comes out of the treatment plant. First it is run through a microfilter that catches most of the solids remaining, and then it is pushed through a reverse osmosis barrier. It comes out such pure water that stuff must be added to it to keep it from corroding pipes on the way to being used. 85% of the water pushed into the recycling plant comes out clean, the rest is flushed as brine.

Recycled water is distributed in purple pipes to destinations like golf courses and parks that use a lot of water for landscaping. The main expense is laying the pipe to the customer, after that recycled water is cheap. In 2003 Santa Clara County recycled about 14,000 acre feet of water, since then consumption has gone up by a third and is growing rapidly.

Tian Harter