Recycled Water in Demand

The ongoing drought has driven interest in using recycled water instead of drinking-quality water wherever possible, but making that happen depends largely on where the "purple pipes" run

Wastewater treatment agencies in the East Bay have been selling (or giving away) the water that runs through those purple pipes -- essentially wastewater that has been treated to a lesser degree than water purified for drinking and other domestic purposes -- for uses ranging from watering home gardens to helping cool down a power plant.

Even if the drought comes to a wet, El Niño-fueled end, cities, industries, and school and park districts will increasingly rely on recycled water. And that will require spending to expand the network of all-important purple pipes that, by state law, carry only "disinfected tertiary" water. Although it isn't safe for humans and animals to drink, it can be used on virtually any food crop and for irrigation of parks and playgrounds, school fields and golf courses.

"Moving recycled water requires separate infrastructure running to the various facilities, and that is very expensive," said Jennifer Allen, director of public affairs for the Contra Costa Water District. Bringing that water to more Contra Costa County industries, she said, will require wastewater agencies and the industries to pay for those purple pipelines and associated equipment.

Antioch-based Delta Diablo recently started supplying recycled water to Contra Costa Waste Services' Loveridge Road transfer station in Pittsburg for ongoing dust control needs, related mainly to recycling construction waste.

"Instead of the (transfer) station using drinking water for dust control, they're using recycled water," said Angela Lowrey, Delta Diablo's public information manager. "It's a matter of addressing the drought and preserving drinking water."

The cost of a gallon of recycled water is approximately one-quarter that of a gallon of drinking water, which is good news for the transfer station, operated by Concord-based Garaventa Enterprises. Sal Evola, a Pittsburg city councilman and a Garaventa governmental affairs officer, said it also plays into the transfer station's main mission.

"Our philosophy is to not waste things; for us, it's all about recovery," he said.

It also helps that the Loveridge Road facility is near an existing Delta Diablo "purple pipe," one the agency hopes will soon serve more industries, Lowrey said.

Even pre-drought, wastewater agencies supplied cities, school districts, park districts and other entities with recycled water. Delta Diablo, which has sold recycled water since 2000, can also serve industrial customers, thanks largely to its location on the East Contra Costa waterfront. Its first industrial client was the Calpine power plant a stone's throw away.

The Central Contra Costa Sanitary District, based near Concord, has had preliminary talks with CCWD and others about making more recycled water available for the area's industrial businesses and refineries.

"Are we looking at doing this? Definitely," said Emily Barnett, the sanitary district's intergovernmental affairs manager. "But other entities have to be involved for there to be a solution."

Part of that solution, she said, is creating projects large enough to be financially practical for both the wastewater agencies and the industries.

Many newer neighborhoods in San Ramon and Brentwood, among other places, have purple pipes as part of the original infrastructure. Concord's remade former Naval Weapons Station land will be built with such pipes, too.

Whether the expense of retrofit work in older, established neighborhoods is justified is a case-by-case matter, said Paul Eldredge, general manager of the Union Sanitary District, which serves Fremont, Union City and Newark.

"We'd have to determine whether the expense, and subsequent ratepayer hikes, would be worth it," he said. A partnership between his agency and the Alameda County Water District to pursue expanding recycled-water service has been discussed but would be at least two to three years away, he said.

The Tri-Valley has little industry, but the Dublin San Ramon Services District provides recycled water to construction companies for dust control. Far more of the district's recycled water goes to the cities of San Ramon and Dublin, the latter of which uses recycled water for 82 percent of its needs, said spokeswoman Sue Stephenson.

"Dublin has been a poster child for recycled water use," said Stephenson, noting that her agency is on the lookout for other bulk users.

Source: Contra Costa Times News

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• Water Reuse & Recycling
• Industrial Water Treatment
• Industrial Water Managment
• Water Recycling