Planning December 2014
The Tricky Business of On-Site Water Treatment and Reuse
It's time to rethink old assumptions about what can and can't be done.
By Vicki Elmer and Paula Kehoe
The 3Rs for solid waste — reduce, reuse, recycle — have been around since the 1970s, but the next big R is for water. Reuse of the wet stuff is on the rise.
On-site water treatment and reuse is turning up in commercial and residential buildings from Seattle to San Francisco, New York, Atlanta, and Portland.
Large water and wastewater utilities pioneered wastewater recycling — using it for irrigation in dry states. Today, local developers in both wet and dry states are getting in on the game with the goal of "net zero" or "net positive" water for individual building projects. Some of these projects also recover energy from wastewater and solid waste with integrated water-energy-waste systems.
The Living Building Challenge, LEED, and other rating systems are driving the current round of efforts toward water self-sufficiency. They take advantage of rainwater falling on the building and site, and reuse blackwater as well as graywater indoors and out. Even stormwater has the potential for reuse inside a building.
"Almost 50 percent of all the potable water used in a typical residential building is for nonpotable uses, like clothes washing or flushing the toilet. In commercial buildings, that percentage increases to around 95 percent," says Bill Worthen, an architect and sustainability consultant based in San Francisco. Treatment and reuse on-site is a valuable resource in water-stressed cities, and a way to address stormwater mitigation requirements.
Move forward
As a planner, you want your city to have a more sustainable and integrated approach to water. You've heard your mayor and your local water utility head talk about this issue a lot.
But local architects have told you hundreds of times that local plumbing and health codes prevent recycling water that has already been used within a building; that water, they say, cannot be used to flush toilets, do laundry, or irrigate the site. They've also said that local planning and health departments lack the performance standards or plan review guidelines needed to make a change. On top of that, your developers say that the cost of on-site water treatment and reuse doesn't pencil out no matter how wonderful the outcome.
So what is a planner to do? Fortunately, early adopters have pioneered a set of best practices to help you establish sustainable water policies to encourage water recycling, develop a local on-site reuse program, and promote integrated water-energy-waste systems at the district level.
Sustainable water practices
Your city may already have general sustainability policies in place for water. See what you have or could build on. Cities that are the furthest along with integrated water management have favorable general plan policies or sustainability plan objectives that were established as far back as the 1990s, such as San Francisco, Santa Monica, and New York City.
If you are updating a general plan, you're in luck. Otherwise good places to include these kinds of policies are sustainability plans, strategic plans, stormwater runoff plans, and climate change plans. You can also insert policies and performance standards into master plans, specific plans, and zoning ordinances. If you are in the midst of preparing a redevelopment plan or update, this is also an appropriate place for such a policy.
The following are some best practices for using water on-site as part of your policy. They mix and match the different kinds of "used" water. Some use conventional engineered systems for water treatment, while others rely on ecological engineering processes. Ecological processes take up more room and require vegetation maintenance but have a smaller carbon footprint. On the other hand, treatment equipment for conventional engineering systems also must be maintained.
Blackwater and rainwater — engineered systems in big multifamily projects. Planners were key players in making the on-site wastewater recycling process in Battery Park City work. The 92-acre site (similar to a redevelopment area) is on the southern tip of Manhattan in New York City. Agency planners included requirements for recycled water for all new development when the project's development guidelines were updated in 1999.
The result was the Solaire, a 293-unit residential building, the earliest and best known of the blackwater recycling efforts to use a mini treatment plant in the basement. Ten years later, the Solaire is one of six buildings in Battery Park City that use treated rainwater and recycled blackwater for toilet flushing, air conditioning, laundry, and park irrigation. Potable water demand has been reduced by 50 percent there.
Ed Clerico, who was the project engineer for Solaire, says, "Planners need to play an active role in setting the requirements for water infrastructure performance. Water is a key part of green building."
Blackwater, graywater, and rainwater — natural systems in commercial and educational buildings. Seattle's push toward sustainable water was sparked by problems with thermal pollution and contaminants from untreated wastewater discharges that hurt local salmon, fisheries, communities, wildlife, and recreational industries. Planners and nonprofit groups such as Sustainable Seattle and the International Living Future Institute have been working on these issues for two decades.
One result of a broad-based effort (including the city's innovative land-use code through the Living Building Pilot Program) is that Seattle is now home to two of the most ambitious on-site water reuse buildings in the country: the Bullitt Center and the Bertschi Science Wing. The first is a commercial office building; the second is part of a private school.
"These buildings are beautiful examples of integrated water management," notes Stacia Miller, policy manager for the International Living Future Institute. "In addressing on-site treatment and reuse, these projects capture critical resources and encourage community resilience in the face of a changing climate."
All water used on-site in these two buildings is required to stay on-site. Wastewater treatment consists of composting units that convert human waste into a beneficial byproduct. Graywater is treated by a recirculating vegetative system before it is used for irrigation on-site. While the owners have not yet obtained a permit, they have a clearly identified pathway for using rainwater for drinking. Once the building manager — and engineer — passes the required tests, they will be certified as an independent water district.
Graywater nonpotable reuse for a community center. Graywater reuse for irrigation at the site level occurs frequently in the U.S., but recycling graywater from the building to use it again inside is still tricky. The Bud Clark Commons Transition Center in Portland, Oregon, opened in June 2014 with a hygiene center for the homeless, who can shower and do laundry there. The wastewater from these activities is treated to meet State Department of Environmental Quality standards for nonpotable reuse and used again on-site for toilet flushing. This was the first reuse of graywater inside a building in Portland, and is being followed by a mixed use residential and commercial project.
Rainwater and stormwater reuse for single-family housing. Reusing stormwater indoors is a good way to mitigate urban runoff impacts. The Los Angeles County Department of Health recently established guidelines for harvesting rainwater, stormwater, and urban runoff for indoor and outdoor nonpotable uses; the county is working with the city of Santa Monica and two local nonprofits.
The next challenge is reusing rainwater as potable water. Santa Monica has included goals for locally obtained potable water into its sustainability plan, pending further code changes for implementation.
Georgia passed one of the most comprehensive on-site water ordinances in the country for single-family homes during a serious drought in 2011. In addition to the use of graywater on-site for nonpotable uses, the home owner may install a treatment mechanism and use rainwater as drinking water.
Oregon, Washington, Hawaii, and Ohio, among other states, also allow home owners to install treatment facilities so that rainwater can be used as a source of residential drinking water in single-family homes. Texas does not preclude potable rainwater use in single-family homes but defers to county health and building departments for regulation.
Develop a local on-site program
Some suggestions about how to proceed:
Find a friend in the water business! The first step is to reach out to staff in your local water agencies: water supply, wastewater treatment, and stormwater. Identify and involve those who have jurisdiction over the permits. Possibly involve interested nonprofits as well.
Decide on the alternative water sources and end uses. You, the water utility, and the health department need to determine this depending on different development patterns. You may also want to address the carbon footprint for different treatment systems.
Address cost factors. Urban water reuse systems are more competitive in places where water and sewer rates are high and the project is large enough to have economies of scale. On-site recycled water may also be less expensive than central utility provision due to the smaller size of pipes and connection fees.
To incentivize on-site water reuse, municipalities could waive or lower permit fees or reduce property taxes, stormwater fees, water fees, and other sewer charges. A city or the utility could also offer loans or on-bill financing, grants, and rebates.
Several locales have embraced on-site water systems.
- New York City provides wastewater allowances to qualified properties with on-site water systems.
- San Francisco Public Utilities Commission's grant program provides up to $250,000 for an individual building and up to $500,000 for multiple buildings using on-site water systems.
- Santa Monica, California, waives building permit fees for on-site water systems.
- Minnesota recently made decentralized and on-site systems eligible for low-interest loans from federally provided revolving loan funds.
- San Marcos, Texas, offers rebates of up to $5,000 for rainwater harvesting systems in single-family homes and up to $20,000 for commercial systems.
Make changes to regulations and planning documents. Currently, most health codes do not permit on-site or district level reuse of wastewater. Other local building codes and permit processes likewise hold back these innovations. But help is on the way!
In 2011, the San Francisco Public Utilities Commission initiated a revolutionary effort to facilitate on-site integrated water management that includes on-site treatment and reuse. Events were triggered by the rebuild of the commission's headquarters and the agency's desire to reclaim and treat the building's wastewater to provide all the daily water needed for toilet and urinal flushing.
In addition to a 25,000-gallon rainwater harvesting cistern, SFPUC management wanted to treat the building's blackwater by filtering it through a constructed wetland as part of a green strip outside the building and in the building lobby. Regulations stood in the way.
Undaunted, the SFPUC reached out to the city's building department and the local health department to develop an integrated ordinance that sets standards for water quality for different uses inside and outside of buildings. The ordinance, signed into law in 2012, was enthusiastically received by local officials and has since been expanded to permit district and neighborhood reuse projects. It also contains provisions for plan review procedures and postconstruction monitoring and operations.
SFPUC also developed a manual and technical assistance program for developers that included financial incentives to promote on-site reuse. In the past two years, 20 projects have participated in the program. The agency estimates that together these projects will offset eight million gallons of potable water demand a year.
San Francisco realized that other cities would have a harder go if they wanted to encourage on-site water recycling, since most health departments operate at the county or state level. National interest resulted in a meeting last spring, hosted by SFPUC, that brought together water and health departments from around the country; they formed the Innovations in Urban Water Systems group with funding from the Water Environment Research Foundation.
The urban water systems group has produced a guide, The Blueprint for Onsite Water Systems, to assist communities in developing programs to manage and oversee on-site water systems that protect public health. In addition, it convened a multistate working group, consisting of public health officials and city agencies, to develop guidelines for water quality standards for alternate water sources.
Integrated systems
Just as the solid waste recycling movement added resource recovery centers to the three Rs, the fourth R in the water field also emphasizes recovery. Well-known in Europe, many sustainable district plans (eco-districts) include designs for waste (both solid and liquid) systems in concert with water and energy programs to recapture water, energy, and nutrients while minimizing carbon emissions, energy use, and discharges to local water bodies.
Eco-districts also include walkable communities, mass transit, and local food production, and they emphasize equity and local job generation. The recent Living Communities initiative of the International Living Future Institute encourages U.S. planners to think holistically about communities, including the role of "blue-green streets" in achieving integrated water management as a public benefit.
In North America, we are just starting to think about "water-waste-energy" as an integrated infrastructure system that is possible at the site or district level. Several individual projects have pioneered aspects of these systems, the best known being the False Creek system in Vancouver, Canada. This district-level system recovers warmth from the wastewater system through the use of a heat pump for heating residential units.
Others around the country note that water reuse is only one aspect of a wider spectrum of water-waste-energy projects possible at the site and district level. A retrofit is on the drawing board in New York City, while a project that integrates district energy and direct potable reuse is under way in Fort Murray, Canada.
"Capturing latent energy from warm wastewater can provide economic and environmental benefits and increase the cost-benefit of water reuse," says Ed Clerico. "At the district level, biodegradable wastes from the solid waste stream can be used in anaerobic digesters to produce biogas as a renewable source of energy."
The San Francisco Eco-District Plan, approved by the city's board of supervisors in 2013, also calls for integrated infrastructure planning at the site and district level (along with the traditional elements of an eco-district noted above). One of the project consultants, Bry Sarte, says that "SFPUC's district water program is one of the best innovations in the country in terms of laying the critical groundwork to support district infrastructure as a backbone for an eco-district."
The Central Corridor Eco-District around the new central subway line that will serve Moscone Center, San Francisco's downtown conference and event space, is currently under design. Along with green and walkable streets, and watershed and flood management elements, the plan envisions district-scale nonpotable reuse; on-site water recycling, water capture, and reuse; and two thermal energy plants where energy and wastewater systems are integrated.
Stepping up
Planners have to be silo busters — to help the larger community understand the benefits (including economic) to overcoming barriers that keep water, energy, and waste infrastructure bound to traditional centralized utilities. The experts interviewed for this article offer the following recommendations for planners:
- Integrate on-site requirements for water into planning documents at all levels.
- Implement requirements for integrated resource recovery systems at the building, district, and city scale.
- Support nonprofit efforts to build community capacity in support of integrated water reuse projects.
- Reach out to the local water, wastewater, and stormwater agencies as well as health departments to build coalitions for innovation.
Vicki Elmer is a former planning director who teaches in the Planning, Public Policy and Management department at the University of Oregon. Her book, Infrastructure Planning and Finance: A Smart and Sustainable Guide for Local Practitioners, was published by Routledge in 2013. Paula Kehoe is the director of water resources for the San Francisco Public Utilities Commission.
| Definitions |
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Rainwater: Precipitation collected from roofs or other man-made, above-grade surfaces Stormwater: Precipitation collected from at- or below-grade surfaces Graywater: Wastewater from bathroom sinks, bathtubs, showers, and washing machines Blackwater: Wastewater from toilets, dishwashers, kitchen sinks, and utility sinks Source: the Innovations in Urban Water Systems Working Group |
| In a Dry State |
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By Allen Best A photo taken in 1977 says it all: An ordinary telephone pole near Mendota, California, marked how much the land had subsided after groundwater pumping began in 1925. The answer: 30 feet. Mendota is in the 450-mile-long Central Valley, which provides a third of the nation's food. Subsidence has continued there and in other parts of California that depend on groundwater — disrupting roads, irrigation ditches, and other infrastructure. Even in the 1970s, California's governor was being called on to limit groundwater pumping. The governor — Jerry Brown, then and now — did just that this past August, signing a trio of laws that create a framework for managing the aquifers. Asked to explain what had changed over the intervening 36 years, Brown suggested that California's unprecedented drought might just have provided political cover for bold steps. As it happens, California is dead last among Western states in adopting more rigorous limits to groundwater mining. In all, 85 percent of Californians depend on groundwater for a least part of their drinking water. Some 30 percent of all water for farms, exurban homes, and cities comes from groundwater in normal times. In recent drought years, it's up to 60 percent, according to the California Department of Water Resources. Drawing on that groundwater has been likened to writing blank checks. "Now we must balance that checkbook," says Andrew Fahlund, deputy director of the California Water Foundation, of the new legislation. Previous laws adopted since 1991 give local agencies latitude for linking water resources and land-use decisions. The new laws shift the onus. By 2017, groundwater management agencies must be created across California. By 2020, the 56 sub-basins that are overdrafted must have plans to replenish the aquifers as rapidly as they are depleted.
Local agencies are offered some carrots and sticks. Pumping will be metered, as already occurs in other states, but in California the information will not be publicly disclosed. By 2022, all of California's 515 basins must have sustainability plans, and if they don't, the state's Water Resources Control Board will step in. By 2040, the account must be reconciled (to continue the checkbook metaphor): Each aquifer must be recharged at the same rate it is depleted. These new laws give local planners "a few more tools" to link sustainable water to land use, says Leon F. Szeptycki, executive director of the Water in the West program at Stanford Woods Institute for the Environment. But exactly what this means at the permitting level has yet to be worked out. One possible outcome: more recycling of water, which is already happening in Los Angeles and San Diego. California previously required that water sources for new development be identified, but did not specify that the sources be sustainable. All groundwater below private land was considered free for the taking by the surface owner. In fact, water underground doesn't stay in one place. Overpumping on one parcel could draw water from neighboring properties. There was no inherent motivation for conservation or efficiency. That sounds like a classic case of the tragedy of the commons — an economic theory that explains how individual actions can deplete a shared resource. James Caruso says that's exactly what happened in San Luis Obispo County, 200 miles south of San Francisco, where he is a senior planner. It's a place of expanding vineyards and exurban homes; some 40 to 45 percent of residents live outside municipalities. By 2013, the water table had dropped 200 feet in places, causing some wells to go dry. In July 2013, the county board of supervisors adopted an emergency ordinance requiring every new development, every new house, and every new vineyard to offset its groundwater withdrawal with some new source. This puts a premium on plumbing retrofits and other efficiency measures, says Caruso. The county prevailed in three lawsuits, defending the county's ordinance as a government police power, the same legal foundation for zoning and other land-use authority. Still unclear, says Caruso, is whether the county has authority to limit pumping begun before the ordinance's adoption. With drought as the backdrop, California voters in November approved $7.5 billion in bonding for water storage projects, watershed restoration, water recycling, and other measures, including $100 million for groundwater management. One thing it won't do is create more water. Allen Best is a freelance writer based in metropolitan Denver and the publisher of the e-zine Mountain Town News. |
Resources
Images: Top — Eco-roofs, a stormwater treatment system, and a graywater recycling system have reduced regulated potable water usage at Bud Clark Commons by 53 percent. Photo by Holst Architecture. Middle — Photos by Sian Kennedy/The New York Times. Bottom — The 55-story, mixed use tower at 181 Fremont is the first building to receive an on-site water system grant from the San Francisco Public Utilities Commission. In addition to other design features that are expected to earn the building a LEED Platinum rating, the building is proposing to install a graywater system for toilet flushing. Photo by Steelblue.
Blueprint for Onsite Water Systems: http://sfwater.org/modules/showdocument.aspx?documentid=6057
Innovation in Urban Water Systems: http://sfwater.org/np/iuws
International Living Future Institute — Living Building Challenge, Living Community Challenge: www.living-future.org
"Distributed Water Infrastructure for Sustainable Communities," Water Environment Research Foundation: www.decentralizedwater.org/research_project_DEC3R06.asp
The International Future Living Institute's Living Building Challenge (includes requirements for net-positive water): http://living-future.org/lbc
Experts who contributed to this article include John Scarpulla, urban watershed planner at the San Francisco Public Utilities Commission; Ed Clerico, a water-waste-energy consultant with Natural Systems Utilities LLC, EClerico@clerico.biz; S. Bry Sarte, the author of Sustainable Infrastructure: A Guide to Green Engineering and Design, bsarte@sherwoodengineers.com; Bill Worthen, principal at the sustainability consulting and communications firm Urban Fabrick, Inc., www.urbanfabrick.com.