As potable water becomes ever more scarce, North Bay organizations and governments are investing in water recycling projects to ease the demand.
Since then, water recycling has evolved into a sophisticated technology that’s become a necessity for cities and public agencies throughout the North Bay. As water purveyors grapple with impending long-term water shortages brought about by population growth, fish protection and climate change, the highly treated water from treatment plants is no longer something to be disposed of into the nearest creek or river but a valuable commodity that can stretch precious drinking water supplies and provide a range of beneficial uses.
When it reaches the steam fields, the recycled water is injected deep into the geothermal wells, where it’s transformed into steam and used to produce electricity. The recycled water pumped daily into the steam fields increases electricity production by about 100 megawatts per year, or enough to power 100 households.
Not only is the recycled water producing clean power, it’s reusing millions of gallons instead of discharging it to the Russian River. In 2008 and 2009, Santa Rosa didn’t discharge any treated wastewater into the river. In addition to the Geysers Project, the city is also building an urban reuse project that will use recycled water for landscape irrigation. The city has had an agricultural reuse program for many years. Currently, nearly a third of Santa Rosa’s 8.1 billion gallons of recycled water is used to irrigate more than 5,800 acres of agricultural land.
Water in Windsor
The town of Windsor has an equally impressive track record when it comes to innovative uses for recycled water. In the early 1990s, Condiotti Enterprises wanted to build 475 homes in the Vintage Greens subdivision, but Windsor’s growth controls allocated only 150 units per year for the entire town. Under the terms of a development agreement, the developer had the rights to half the allocation each year. In exchange, Condiotti agreed to several conditions to benefit the town, one of which was installed pipelines for the use of recycled water to irrigate both the front and back yards of the new homes.
“We saw it as an opportunity to enter into a public-private partnership where the town would get some additional amenities and benefits, and one of those was to make recycled water available to all the homes in the new Vintage Greens subdivision,” says Matt Mullan, Windsor’s town manager. In addition to the recycled water being made available, the developer also built a lighted soccer field.
The recycled water is free to Vintage Greens homeowners until the year 2012, when the town council will set rates for recycled water. The town estimates 25 million gallons of drinking water are saved each year by using recycled water for outdoor irrigation in the 473 homes in the subdivision. The Windsor Golf Course, which the town leases to a private operator, also uses recycled water for irrigation. Mullan says the course uses about 100 million gallons per year.
When Windsor High School was built, school and town officials had the foresight to use recycled water to flush the school’s toilets and water its playing fields and landscaping. The school, which was completed in fall of 2000, is located directly across Windsor Road from the town’s wastewater treatment plant. Mullan credits the Town Council with having the vision to see the benefit of using recycled water at the new school.
“It takes a town council that sees the long-term benefits and is willing to step out of its comfort zone to be the first community to use recycled water for toilet flushing in a public school,” he says. “It’s easy to irrigate athletic fields, but it’s another thing to use it to flush toilets. The town council’s vision and commitment has made Windsor a leader in recycled water use in Sonoma County—and in the state.”
When the Town Green was built, the lawn area was plumbed for recycled water, and later, the linear fountain that stretches along the southern edge of what’s become the town’s gathering place was converted to recycled water. If one takes into account the golf course, Vintage Greens, the Town Green and Windsor High School, “you’re talking about hundreds of millions of gallons of recycled water being used in town,” says Mullan. “For every gallon of water that’s reused, a gallon of potable water is saved, year after year.”
For Windsor and the majority of cities in Sonoma County that rely on the Russian River for their drinking water supply, conserving every gallon of water has become critical. Within the past decade, the availability of that water has come into serious question. “When we started our recycled water project in 2000, there weren’t the concerns about availability of water in the Russian River,” says Mullan. “Now you have flow regimes, fishery issues, drought—all these factors that have resulted in the availability of water in the river being severely constricted. Recycled water helps us meet our demand for potable water. You hear a lot these days about sustainability. We believe our recycled water program is contributing to the sustainability of our community and its resources.”
The era of water limits
Among the environmental benefits of recycled water is the reduced demand on surface waters, such as the Russian River, where the protection of endangered species has severely limited the amount of water that can be diverted. This scenario mirrors others throughout the state, according Dr. Dave Smith, a recycled water consultant with a background in the technical and regulatory issues with recycled water. He also serves as the managing director of the California Section of the WateReuse Association.
“Californians have reached or exceeded the sustainable yield of traditional water supplies, such as rivers and groundwater, in most of the state,” says Smith, who was among the consultants who worked on the Santa Rosa Geysers Recharge Project. “For most of the last century of population and economic growth, water supply planners determined how much water could be diverted for use and built the facilities necessary to divert it.”
At the end of the century, Smith notes, two factors came into play. “Regulators have recognized the need to allocate water for fish protection, and climate change may be reducing water supplies,” he says. “Both of these factors have effectively reduced the amount of water available for diversion.”
Enter recycled water, which provides a reliable, drought-proof source of water for a variety of uses.
The treatment process
Recycled water is approved by the California Department of Public Health for use in irrigating urban and agricultural land. It’s being used safely in hundreds of communities throughout the state for irrigation in agriculture, parks, golf courses, public space landscaping, wetland habitat restoration and industrial uses. Recycled water for these uses must be treated to what’s called a “tertiary” level. The process involves aeration that assists microorganisms in removing pollutants, filtration to remove treatment microorganisms and either chlorine or ultraviolet treatment to remove bacteria, viruses and other pathogens.
The national WateReuse Association estimates 332 agencies, counties and cities recycle water in California. According to the Department of Water Resources (DWR), about 650,000 acre-feet of water is reused per year, three times what was recycled in 1970. The state’s Recycled Water Task Force in 2003 estimated that a potential of about 1.4 to 1.7 million acre-feet of additional water supply annually could be realized though water recycling by 2030.
An acre-foot of water is 325,000 gallons, or enough water to cover an acre of land in a foot of water. By comparison, the water supply capacity of Lake Sonoma is 245,000 acre-feet. The water supply capacity of Lake Shasta is about 4 million acre-feet.
DWR estimates that two-thirds of all recycled municipal wastewater in California is used for irrigation, including 46 percent for agriculture and 21 percent for landscaping. In addition to irrigation, other uses include industrial uses, groundwater recharge and indirect potable water sources (which is the use of highly treated recycled water to augment drinking water supplies).
Smith points out that while Sonoma County already recycles most of its wastewater, there is a huge untapped source of recycled water that’s currently not being put to use. “Californians discharge about 4 million acre-feet of wastewater to the ocean with no apparent beneficial effect,” he says. “This water could be further treated and then recycled, which would represent the only new source of fresh water in the state.”
Projects abound
The city of Healdsburg has taken a huge first step to join the recycled water party with a brand new, $32 million, state-of-the-art tertiary treatment plant. With plans for a $10 to $15 million distribution system in the works, the small city along the banks of the Russian River has put itself on the water reuse map.
It was a long, circuitous path that led to construction of the treatment plant, which replaces the former plant that treated the wastewater to a secondary level, which is suitable only for limited recycling uses.
During floods in 1995 and 1997, breaches occurred in the levee separating the Russian River from the adjacent former gravel pit, where treated wastewater is discharged and stored. As a result, treated wastewater flowed to the Russian River. “It was a something we knew we were facing because of the breaches of the levee,” says City Councilmember Gary Plass. “When those occurred, we knew water quality [Regional Water Quality Control Board] was taking a look at what we were doing.”
Prompted by orders from regulators, the city started a seven-year process of planning and building the new plant, which uses a combination of aeration, membrane ultra-filtration, denitrification and UV disinfection treatment to create high-quality recycled water. “We knew if we were going to do this, we were going to build a state-of-the-art tertiary facility,” says Plass. “And we knew there had to be a recycling component,” since water quality officials told the city it had to stop summer discharge of its wastewater into the gravel pit storage pond.
The recycled water distribution system will send the water to the city-owned Tayman Park Golf Course, school fields and other city parks. “Our goal is to bring it back into the community so we can use it on the golf course, and public parks and playgrounds,” says Plass.
Healdsburg’s treatment plant is unique in a number of ways, says Jim Flugum, deputy director of public works. The city’s treatment process uses additional aeration to “supercharge” the biological process, which relies on a rich “soup” of microorganisms that break down the pollutants in wastewater, he says. Then the filtration step uses a very fine membrane screen with microscopic pores that screen out bacteria and many viruses. The third unique aspect of the plant is the denitrification process that removes nitrate compounds. This will produce water with nitrate levels comparable with potable water, says Flugum. The final step is the ultraviolet light disinfection, which kills disease-causing pathogens and has allowed the city to eliminate the use of hazardous chlorine gas in the disinfection process.
Plass says the city is also planning for an agricultural reuse component, with at least one grape grower interested in using the water to irrigate vineyards. “The ag component is great because it’s really close to the plant,” he says. “At some point, it’s going to be a supply and demand issue.”
It also provides savings to customers and to the city in potable water use. “The first benefit is you’re taking less water from the aquifer and the river and you’re saving groundwater,” says Plass. “The second benefit is you’re discharging less into the aquifer and the river.”
How enthusiastic is Plass about recycled water? “When I replastered my pool, I wanted to refill it with recycled water,” he says. City officials, however, told him it was currently not a permitted use.
Recycling with authority
A more recent project got underway in 2005 when the North Bay Water Reuse Authority (NBWRA) was formed by the Sonoma County Water Agency, Napa Sanitation District, Sonoma Valley County Sanitation District, Las Gallinas Valley Sanitary District (Marin County) and Novato Sanitary District. That agency is in the first phase of a water recycling project that will eventually deliver 3,800 acre-feet of water annually to agricultural sites including vineyards, large commercial landscapes and a salt marsh restoration project in Napa.
The NBWRA was formed “to maximize the use of resources, become more efficient with operations and to become a stronger regional voice,” says Chuck Weir, the agency’s project manager.
“As we all know, there aren’t really any new sources of water,” he says. “We have to maximize the use of whatever’s there by using efficiency measures and recycled water. Recycled water is sustainable, and it’s not subject to drought.”
Recycled water is less expensive and more energy-efficient, reducing a community’s carbon footprint. “The water is being treated anyway, so the cost is to build pump stations and pipelines. In the whole scheme of things, it’s certainly a lot cheaper than trying to find a new water supply, building a dam or buying it from other sources. In fact, there really may not be any other reliable sources available at any cost.”
Phase I of the NBRWA has a $100 million price tag, with about $25 million expected from the federal government. It’s a very cost-effective program. “Everyone expects that once it’s being delivered, there are going to be a lot of folks who are going to be wanting this water,” he says.
As the North Bay faces its water future, there are those who believe recycled water will provide the key to coping with water supply shortages. “Recycled water will make up the difference between current supply—which has been reduced by the need to protect fish and possibly climate change—and future demand,” says Smith. “Recycled water can be treated to comply with all regulatory standards for all uses of groundwater and Russian River supplies, including landscape irrigation, agricultural irrigation, frost protection, industrial processes and potable supply.”
With the exception of potable reuse, all those uses are in place in Northern California today. Smith notes that several large potable reuse projects are operating successfully in Southern California, but none have been implemented in the North Bay. A facility in Orange County treats wastewater to drinking water quality using a reverse osmosis process and injects the water into the groundwater aquifer, where it’s later pumped out to supplement drinking water supplies.
Given the probability that climate change and the need to protect endangered species will reduce future water supplies, the demand for recycled water will continue to increase. When you consider that only 25 years ago, North Bay residents were sending most of their wastewater to the ocean and now most of it is recycled for beneficial uses, the idea of potable reuse may not be too far off.
