Purple-Colored Conservation

Rain water, green water, gray water, black water: Whatever the source or color-code, it’s tending to be saved, treated, and quickly sent back into the supply stream, often by injection to our drinkable groundwater. Chronically parched regions have no choice; they’re embracing one reclamation strategy or another, selecting and applying technologies to clean every droplet. In the process, there often arise a range of issues to address, from health and safety to energy conservation, legal wrangling, and water politics. Here’s a brief survey of some notable recent challenges, solutions, and resulting cutting-edge projects.

them, if you will,” he recounts. Eventually, researchers discovered that “the vast majority of the estrogenic effect is coming from natural hormones that we all excrete, men and women, and also from pharmaceuticals—birth control pills and metabolites”, and other CECs, says Snyder, who is also on the National Academy of Sciences National Research Council Panel on Water Reuse.

Rather quickly after making this discovery, Snyder and SNWA began scrutinizing the lake in earnest for signs of these endocrine disruptors, to assess causes and effects and see how to mitigate them. As it turns out, although estrogen impacts are detectable on fish and wildlife, he says, “in terms of human health, I think that there’s not much data at all to support that estrogen chemicals in water would be a primary route of exposure.”

Whatever the threat may be, the mitigation of CECs is readily doable by any of three treatment methods: oxidation; physical separation using activated carbon or membranes and natural barriers, such as soil aquifer treatment infiltration; and ozone technology. All have been found to be highly efficient, he says.

One significant and practical result of this CEC research is SNWA’s new $122-million Southwest Water Reclamation Facility. Custom-made to mitigate the local contaminates, as well as to attain conventional IPR levels, it is now under construction in Henderson, NV, (population ca. 250,000) and set for commissioning in 2011.

A spokesperson for that city’s department of utility services, Kathleen Richards, lists some of the satellite plant’s features: First, it economizes by only treating liquid waste, as the solids can be done at the city’s existing plant, 7.5 miles away. For better energy conservation, she says, “basically, we’re siting the plant closer to our customers, so that we save on the pumping cost,” which face a 630-foot uphill elevation and very high power rates. First-year treatment costs are estimated at 74 cents per a thousand gallons, or just under a million-a-year total, including power and chemicals.

All of the community’s wastewater is eventually processed for reuse. The new one will ultimately yield 16 mgd; tertiary-treated outflow will be piped across town, primarily to keep local golf courses lush. What’s not sprinkled on fairways and greens will be deposited in Lake Meade—where its value turns out to surprisingly high. Under local water access rules, IPR sent there earns “return flow credits,” explains Richards. These enable Henderson to extract an equal volume of Lake water for drinking. Without having this exchange benefit, the city might be hard-pressed to meet its potable demand. “It’s huge for us,” she says.

On the technology side, Snyder points out that the plant will feature, centrally, “what will probably be one of the largest membrane bioreactors [MBRs] in the world.” Comparing this to top-of-the-line RO, as found in Florida and elsewhere, the big difference is reduced energy costs. By serially combining membranes, oxidation treatment, and ozone disinfection, this will typically prove much more cost-efficient for inland localites than will RO. He further suggests that this advantage perhaps is not yet as widely appreciated, as it should be. What’s gained in switching to membranes “is water that’s a very high purity—but without necessarily removing the salt.”

RO for coastal locales still makes sense though, he says, because the resulting briny outflow can be readily discharged into oceans, as opposed to inland sites, where disposal is often restricted. Also, coastal aquifers often need recharging with pure RO water to thwart seawater incursion.

As for CECs: The new Henderson plant is one of the first to target the above-mentioned contaminants such as pharmaceuticals and endocrine disrupters, using ozonation; and the SNWA research department is already planning to study the before-and-after effect of this purified water on local aquatic life. In addition, multi-stage processing will remove, he says, “the vast majority” of other unwanted elements, save for a few non-oxidizable ones.” It will be far superior to conventional treatment using chlorine or UV decontamination alone. Membrane filtration in pre-treatment will increase nutrient removal and reduce oxygen demand.

IPR, RO Abroad
Nevertheless, still RO remains the gold standard for purification; large treatment plants continue to sprout in water-challenged regions around the globe. Among the more prominent are a string of projects in Australia and Singapore, both of which have faced extraordinary needs and circumstances. Approaches to IPR solutions in both nations have also tended to differ somewhat from those typical in the US, says Soma Bhadra. As a water system engineer for Black & Veatch at the time, she participated in building some of the major membrane plants.

At these two locales in particular, due to an almost existential necessity to produce clean water from waste, the respective governments’ commitment to RO has advanced “far, far ahead of us” here in the US, she says. In the case of Singapore—a tiny island nation hugging the Malay Peninsula—the need was spurred by a decision to gain independence, from an onerous sole-supplier relationship with a dominating northern neighbor. Singapore itself possesses no true freshwater aquifer; rather, it has had to rely on an expensive supply pipeline from the mainland.

In choosing to gain autonomy, the government proceeded to hire global engineering firms to launch a furious program of putting up desalination and stormwater and wastewater reuse treatment plants, and dam-building projects, to harness water from estuarine catchments. Behind this barrier, every drop of water is continually desalinated, reclaimed, and reused, to create what is perhaps the world’s first total water recycling microcosm. “The aim,” says Bhadra, “is that any drop that falls in Singapore from any source is captured and reused continuously.”

All sewage goes directly from its three-stage primary-secondary-tertiary treatment, to membrane treatment such as RO. Afterwards, “nothing is left in the water, and it comes out pure,” she says. In fact, it’s so unnaturally demineralized and ultra-pure, the water chemistry must be rebalanced to make it drinkable.

Although horribly energy-intensive to the tiny nation, she says, “they saw that they have no choice. They made their decision to become independent, and they are doing great job. Singapore treats water as a national security issue and is very serious about reducing reliance on outside sources and strengthening its own internal capacities.”

Australia, similarly, faced do-or-die commercial survival, spurring its RO plant-building program. The nation was thriving as a Pacific mining export powerhouse. For this, large volumes of process water are needed. But a multi-year drought hit, emptying reservoirs everywhere. “At that point, they started building desalination and water reuse plants all over the country,” says Bhadra.

In Brisbane, Australia, a 17.5-mgd site that she worked on, designed by Black & Veatch and built by Australian mining and construction firm Thiess, was remarkably fast-tracked; from inception to hand-over took an amazingly short two years. She comments:

“This was part of the 80-millon-gallon-per-day Western Corridor Recycled Water Project that aimed to meet the water supply needs for the City of Brisbane with a holistic approach, to capitalize on water available from six local wastewater treatment plants and to offset water demands on potable water supplies, by replenishing the water supply reservoir. A network of 200-kilometer pipeline was constructed to not only serve industrial needs and cooling towers, but also refill the Wivenhoe drinking water reservoir.”

At her present employment for a firm called Dudek, based in Encinitas near San Diego, CA, Bhadra offers a picture of contrast to ponder. Dudek recently bid on a modest 250,000-gpd reclamation plant for a desert town called Seeley, in Imperial County, CA. Reclaimed wastewater will support construction and operation of a new solar power farm down the road. For this inexpensive, low-intensity wastewater process, existing treatment lagoons will be converted into extended aeration ponds, using Biolac. Effluent will go to MBR tanks for filtration, then to UV disinfection, then to storage tanks, and then out through the purple pipe.

Yet, even at this remote small-scale site, an originally hoped-for delivery of service by mid-2010 was delayed many months by, perhaps, redundant environmental reviews, says Bhadra. Contrast this with gleaming mega-plants sprouting overnight across Singapore and Australia through sheer determination. “There are no endless hearings,” she says. “They just said, ‘Let’s do it’, and it’s done.”

LACSD, Reuse Criss-Crossing the Basin
Back in America, Los Angeles County Sanitation Districts (LACSD) are still “the largest sanitary district in world,” notes John Robinson, an enthusiastic beneficiary of LACSD in sharing and distributing its reuse water. He is the recycled water program manager for the Upper San Gabriel Valley Municipal Water District (USGVMWD) and, through a contract with MWH Americas Inc., has been the agency’s consultant for 17 years. All told, LACSD operates 11 wastewater treatment plants—10 do water reclamation to varying levels of quality, according to the agency’s Web site. Total output comes to over half a million acre-feet per year, or nearly half a billion gpd.

However, recycled output over the years has actually steadily shrunk. This is the happy result of huge success in County water conservation measures like low-flow toilets and such. Thus, surprisingly, LACSD wastewater treatment volumes remain equal to what they were in 1983, despite a population boom that has added millions more Los Angelenos.

On top of this, California’s drought of 2006–2009 has also eased in 2010; plenteous rainfall has returned and, with it, less practical need for reuse.

In Robinson’s idiom, if there’s one keyword to describe, overall, the regional reuse strategy, it would probably be collaboration, and this of a kind occurring from natural necessity. Collaboration or partnering, as he says, is the only way to deal with a sprawling urban milieu in which all manner of water—raining, pooling, piped, gathered, dirty, reclaimed, etc.—tends to cross several jurisdictional bounds, and thus engages multiple budgets and agencies, myriad purveyors public and private, and end-users large and small.

To achieve more efficient outcomes in this jungle, participants sometimes blur distinctions and act as one. Basically, he says, to run its three purple pipe systems for irrigating sites like schools, industries, and the 1,500-acre Rose Hill Cemetery (largest in the world), USGVMWD partners with LACSD and other entities all over town. Among recent collaborations in this arrangement are:

• Shared pump stations. The Central Basin Municipal Water District (MWD) got a “piggy back” and avoided having to build their own. Another colocated station with LACSD treatment plant serves the Whittier Narrows reclamation project, saving on land acquisition costs. Operators share and combine duties. Similarly, Central Basin MWD colocated a pump station; so one site now handles purple and blue pipes, to respective customers.
• Shared personnel. “We teamed up with a local purveyor, San Gabriel Valley Water Company, so instead of hiring additional staff, we hired the local purveyor—who drives the pipeline alignment anyway—to be our operator,” says Robinson.
• Building departments. The agency checks with permitting offices to see who is planning what and might turn into a “new reuser”; thus, dual plumbing can be installed efficiently, long before ground breaking.
• Regulators. Rose Hill Cemetery was using roughly 1,800 acre-feet of groundwater per year. Half of this was shifted to recycled. The groundwater was then leased back to a local purveyor. In the course of this came an appeal to ease some provisions of Title 22, to allow recycled water into hose bibs (i.e., to water visitors’ flowers). So far, regulators seem accommodating.
• Educational Administrators. “The key thing for efficiency there was, instead of building a recycled water system throughout [Rio Hondo College], we looked to see where we could hook up a majority of reuse water and minimize infrastructure,” says Robinson. This resulted in 75% to 80% of the campus getting reuse, with minimal digging or expense.
• A “Let EPA do it” strategy. Los Angeles Parks and Recreation Department’s irrigation was extracting contaminated groundwater. Robinson’s department talked them out of this, and into leaving it in the ground and letting EPA perform its cleanup mandate. The Parks staff switched to reuse water, which otherwise would have been wasted.
• Collaborative treatment. The West Basin MWD won permission from Los Angeles (L.A.) to take secondary effluent from the Hyperion plant, transport it elsewhere, add tertiary treatment, and feed it to a purple pipe.
• Water swaps and horse trading. The San Gabriel Valley Water Recycling Project Upper District direct reuse project will supply 1,800 acre-feet of recycled water to irrigation customers in the Whittier Narrows area. Recycled IPR replaces groundwater and saves costly imported potable water. Reclaimed water is bought from the Central Basin MWD, who get it from the San Jose Creek Water Reclamation Plant, operated by LACSD. Recycled water is wholesaled to San Gabriel Valley Water Company, who resell it to landscape irrigators. San Gabriel Valley Water Company will design, construct, and operate the distribution pipeline for the Upper District. (Did you get all that?)
• Apply for federal Recovery Act bucks strategy. USGVMWD community and government affairs manager Peter Rodriguez notes still another cooperative effort: “We’ve just completed the first recycled water project west of the Mississippi that had stimulus funds,” he says. With it, they’re now extending reclaimed water to a large park and golf course and have signed up several local corporate headquarters; schools; a Wal-Mart; and a huge, 16-million-gallons-of-potable-water-per-year commercial sports park, for purple pipe.

IPR and L.A. Aquifer Injection
Across the Basin from San Gabriel Valley and nearer the ocean, Kraig Erickson has been collaborating with Los Angeles Water and Power to develop its recycled water master plan. Erickson is a project manager with RMC Water and Environment, a California-based engineering firm with seven locations. In this undertaking, he explains, both non-potable reuse and IPR are being steadily extended to the heart of L.A. Local reuse customers are fed by four water reclamation plants, delivering irrigation to Griffith Park, local cemeteries, and Universal Studios. Purple lines are being run southward “to get them into the downtown metro area, Dodger Stadium, and Legion Park,” he says.

One of his roles in the process is to talk-up reuse to hundreds of potential customers. It’s turning out to be a relatively easy sale, as it were. Prospective reusers fully understand the drought-driven urgency; typically, they’re eager to sign up. Erickson says their main question is usually, “When are you going to get it here, and how fast can you get the pipe in the ground so I can hook up to it?”

By switching to reuse water, customers “gain freedom from all the time-of-use constraints they are under,” due to conservation mandates. They also lop 20 to 40% off their potable water bills. Customers must first incur some hookup charges—a meter, backflow preventers, and conversion—but they’re typically getting a two- or three-year payback, Erickson finds.

The timeframe to get pipes extended can range from two years to 20, depending on the project scale. Here’s an impressively short turn-around: The City of Lancaster, CA, took “just two or three years, from planning to design, construction, and hookups,” to build a 5-mile spur, albeit hastened by state regulatory pressure.

As for reuse water being returned to the ground supply as IPR,

Erickson’s colleague Brian Dietrick, also a project manager, notes that L.A. has done this kind of thing for decades—not for drinking, but to protect the coastal aquifers. Inland, likewise, replenishment with stormwater has been ongoing. What’s relatively new these days, Dietrick says, is that blending of “fresh” potable with disinfected reuse water is increasing. An original 50-50 formula has been increased to allow 75% reuse, “and the hope,” says Dietrick, “is that we’ll be getting to 100% reuse water eventually, so we don’t have to use any [very costly] imported water.”

The Color Purple???!!!
This final item concerns not a project or locality, but the common denominator in all (or most): purple piping. This refers, of course, to the standard color recognized internationally for reuse water conduit—right?

Not quite. After water reuse began mushrooming, the industry belatedly discovered that the US is still, in some ways, a patchwork of quirky regulatory fiefdoms. Specifically, from place to place, pipe color conventions and standards are inconsistent. Multiple organizations and territories do not agree. In fact, they occasionally don’t know each other exists. Also, real standards turn out to be somewhat nonexistent and/or inconsistent.

A move to correct the situation began about two years ago, and still faces another two years or so before some resolution may be attained, suggests Don Vandertulip, P.E. Professionally, he is with the El Paso, TX, office of CDM, a consulting, engineering, construction, and operations firm with offices worldwide. As chair of the Water Environment Federation Water Reuse Committee, president of the WateReuse Texas Section, and a board member of the WateReuse Association and of the AWWA Water Reuse Committee, he is one ringleader confronting the lack of coherence and standardization.

Several issues are in play here, he says. First, pipe installation is overseen by states, most of which take their guidance typically from one of two rival code organizations: International Association of Plumbing and Mechanical Officials, issuers of the Uniform Plumbing Code (UPC); and the International Code Council, who publish the International Plumbing Code. “Both codes,” notes Vandertulip, “call for green as the designated color onsite for potable water.”

Green is the color code for local private construction. On the other hand, public utilities—guided by the American National Standards Institute and American Public Utility Association—have established blue as the potable water code, and green pipe signifies wastewater. Purple, in this province, “means reclaimed water.” In other words, literally, when you cross the border from public sector to private property, the color codings change.

From here, things go steadily downhill. In 2006, the UPC specified using not purple, but yellow pipe with black lettering, for reclaimed water—not realizing that this combination already was in use by the gas industry to indicate flammability. In other words, a plumber, thinking a pipe carries reuse water, might cut it or blowtorch it and blow himself up.

What’s worse: Such risks are not merely theoretical. Foul-ups happen frequently. Google the phrase “cross-connections” and see for yourself. For one recent example, in North Carolina, a builder had connected several homes to reclaimed water meant for irrigation. After some time, a resident complained of odd taste and odors from faucets. Investigation revealed crossed pipes.

Another dimension here is that water grades are evolving. Future plumbing codes and water systems might soon enumerate multiple grades of reuse quality, thereby multiplying the potential for pipe-crossing before the glacial pace of code-revision catches up, Vandertulip adds.

Besides this disparity in coding, there’s no unanimity about tubing materials—PVC versus copper. Competing commercial interests come to bear.

Water departments, too, have idiosyncrasies. “Some like the idea of every pipe being purple and only needing to look for one color of pipe to know that it’s not potable,” says Vandertulip. “Others don’t mind so much that one color fits all.” And they may or may not readily yield to an externally imposed standard.

There’s also inconsistency on the quality and varieties of reuse water inside the pipe, whatever the conduit’s pigmentation. Some states define a single reuse water; but Texas has two, for instance, and there’s a jurisdiction called the West Basin Water District, in California, with six.

What’s the solution? Currently, the two plumbing groups are gathering public comment in advance of issuing new codes in 2012. But, lacking a more comprehensive outreach and perspective, it seems unlikely that either will soon resolve the question of what exactly goes into which pipe, of whatever color.