The Million Gallon Solution

Dec. 26, 2011

The small- to medium-sized water storage industry is seeing strong sales from the sustainability trend in water reclamation and decentralized wastewater treatment, and the locations aren’t just for those lonely tanks standing in a deserted field or far away hillsides. Water reclamation and wastewater treatment projects are part of sustainability efforts at major food processing sites, universities, swank retail locations, and sports stadiums. Decentralized wastewater treatment has even found a home in at least one luxury high-rise apartment building–the Solaire Apartments, located in Battery Park, one of the most prestigious sections of Manhattan, NY.

The Solaire defines many of the forces driving the small- to medium-sized water storage industry. With its water storage and treatment systems located in the basement, the Solaire recycles up to 25,000 gallons per day to supply toilet-flush water and cooling tower makeup. Additionally, a rainwater collection system irrigates 10,000 square feet of rooftop gardens. All told, the building uses 50% less water than a comparably sized residential tower, and its water efficiency helped in earning a Leadership in Energy and Environmental Design (LEED) Gold certification.

Using water storage for credits in the US Green Building Council’s LEED certification program is a growing trend, notes Tom Tietjen, president, Xerxes Corp., Minneapolis, MN. “This sensitivity to water supply and the adaptation of the LEED scoring system has really taken off. California has changed its greywater codes recently, and, though plumbing codes in other states have been slow to change, the use of systems where rainwater is collected and used inside of the building for toilet flushing and nonpotable water usage is growing.”

Other states, such as New Mexico and Arizona, have also adopted greywater codes that encourage reclamation projects, and some of these projects are very high-profile undertakings from major industries, such as Frito-Lay’s “near-net-zero” processing plant in Casa Grande, AZ. The goal of the snack food giant’s near-net-zero strategy was to redevelop an existing plant to operate as independently from the grid as possible, by using renewable energy sources and recycling 75% of its water.

Such projects show an ongoing trend for water storage, but Tietjen observes that when he talks to system designers and owners, the discussion often leans toward the material that Xerxes uses to build their tanks.

“Generally, in the industry, pouring concrete storage tanks above and below ground for water storage are typical, and fiberglass as a material for storage tanks isn’t necessarily familiar to a lot of design firms and owners,” says Tietjen. “Our primary market is petroleum storage, and we have installations at gas stations throughout the country with many tanks underground for well over 30 years. But when you move into the water industry, many larger engineering and design firms don’t necessarily have an awareness of fiberglass. So we have to get them comfortable with the fact that it’s lighter than concrete, yet strong enough, and doesn’t suffer from corrosion or require maintenance.”

New Ideas for an Old Institution
Tietjen mentions that plumbing codes have been slow to change, but that can’t be said about one of the country’s oldest institutions–the US Army. In April 2011, the Army announced that six locations were participating in a “net-zero” water pilot project. The sites stretch from coast-to-coast and include: Aberdeen Proving Ground, MD; Camp Rilea, OR; Fort Buchanan, Puerto Rico; Fort Riley, KS; Joint Base Lewis-McChord, WA; and Tobyhanna Army Depot, PA. Water is a critical asset and needs to be valued as highly as energy, according to a recent report issued by the Army in June 2011.

The report, “Water Reuse and Wastewater Recycling at US Army Installations,” was prepared for the US Army Environmental Policy Institute, and it finds that getting maximum efficiency from an available water supply and using water which would normally be discarded will enable the Army’s installations to meet long-term sustainability goals, and show immediate reductions in water consumption.

Along with sustainability, the report cites issues about security, quality, availability, affordability, and regulatory compliance. Those items could easily define most of water managers’ list of concerns about storing water, especially if they’re located in California, says Kevin Peacock, regional manager, DYK–Natgun, Divisions of DN Tanks, El Cajon, CA.

“Water in California is distributed over long distances, and that increases the cost per acre-foot,” says Peacock. “But water reuse can help reduce the cost of transported potable water by decreasing demand, and we’ve seen a trend in parks, schools, and golf courses where they are adding infrastructure storage, so the recycled water can be used via a separate distribution system to offset the potable water usage.”

The trend has resulted in a wide variety of reuse concrete tank projects for DYK-Natgun. Such as a 1-million-gallon tank in Santa Margarita, a 1.5-million-gallon tank in Corona, and a 0.66-million-gallon tank in Irvine.

“I’ve previously seen a predisposition that concrete tanks are suited for large tanks or for underground storage, but we are beginning to see more concrete tanks in smaller sizes, and in California,” explains Peacock. “Today, the construction of smaller concrete tanks can be achieved in an economical fashion without having to pay a large premium to get the lowest total cost over the lifespan of a product. Owners recognize the fact that we don’t have to coat the inside or outside of a concrete tank for corrosion protection. So the slight premium for a prestressed concrete will be paid for within all of our careers.”

The Tank Transformed to a Stage
No matter the application, Peacock notes that owners and engineers are concerned with how their tanks appear within a local environment.

“That’s one of the big benefits of concrete,” he says. “You can backfill the tank up to the roofline at very little additional cost. In addition, you can completely bury tanks and place parks, tennis courts, or parking lots on top.”

For hillside locations, concrete tanks can built directly into a hillside without the need for separate retaining walls because they can be designed to accommodate the lateral forces.

Agitation and mixing, or the lack of it, can affect water quality in tanks as large as the examples above and even small tanks that store water too long, but DYK–Natgun’s designers have engineered diffuser systems that force water to flow at high pressure to create agitation. Tank owners also have many other choices in aftermarket products to maintain agitation and water quality. (See Additional Content: “Water Quality: A Case of Mix and Match?”)

Texas shares many of the same water problems as California, especially aquifer depletion, and the state is racing to boost water reclamation projects. The Texas legislature exempted rainwater harvesting equipment from sales tax and allows local governments to exempt harvesting systems from property tax. Just counting the market in Central Texas, professional companies have installed more than 400 full-scale rainwater systems. Both residential and commercial markets are encouraged by the state’s incentives, and many smaller residential systems can crossover to small commercial applications, according to Dave Kelly, product manager for the Water Tank Division of Snyder Industries, Lincoln, NE.

“If there is a buzz in the water tank industry right now, it has to do with reclamation, and it’s in the residential market, but it’s even bigger in commercial,” says Kelly.

Snyder makes aboveground vertical tanks in sizes from 300–5,000 gallons, and basic collection packages include a tank, lid, strainer basket, and overflow assembly.

Belowground system sizes are available in 575, 1200, and 1700 low-profile designs.

“Let’s say you have a chain store with a lot of flat roofs, and, if there’s a yard center, that’s a lot of rain capture area to keep their inventory of plants growing,” says Kelly.

Overall, irrigation is one of the main benefits for many of the projects across Texas. For example, the Lady Bird Johnson Wildflower Research Center, in Austin, harvests 300,000 gallons of rainwater annually from a 19,000-square-foot roof collection area, and then it’s stored for irrigation in a 6,000-gallon stone cistern. At the Advanced Micro Devices semiconductor fabrication plant in Austin, captured rainwater maintains all of the site’s irrigation needs and saves $1.5 million per year in water costs.

Stormwater control also benefits from rainwater harvesting, and storage plays a role. For example, the Community Resource and Recreation Center, of Canyon Lake, TX, installed a rainwater harvesting system to meet a Texas Commission Environmental Quality requirement to control stormwater flow. The system collects rainwater from a 8,400-square-foot roof and stores it in a 12,500-gallon fiberglass tank until it is released at a rate to buffer the impact of the runoff.

Hot Savings From Cool Sources
In hot climates such as Texas, buildings incur much of their water cost from loss and consumption associated with cooling towers, says David Heiman, director of marketing at Containment Solutions Inc., Conroe, TX.

“Cooling towers are a very efficient means of transferring heat, but very inefficient in using water,” says Heiman. “With our tanks, we can store water from roofs, parking areas, condensation, and any number of different areas that can be collected and used for the cooling systems. So that takes a huge impact off the municipal water supply.”

Sizing for these collection systems vary, just as building sizes vary, and Containment Solutions has delivered tanks to supply systems as small as 600 gallons to several hundred-thousand gallons.

“Typically, in a larger system, we would connect several tanks with manifolds,” explains Heiman. “So it could be four 50,000-gallon tanks together for a 200,000-gallon system. It’s modular, but also gives you the flexibility to design different tanks in different ways to accept or treat different materials. So instead of one enormous system, you might have some tanks that are accepting greywater and some that are accepting reclaimed water from the parking area or the roof, which may need different filtration. You have the flexibility to custom design each of the tanks to accept different supplies, but still have one huge water source overall.”

Modular flexibility allows Binghamton University, in Upstate New York, to harvest rainwater and store it in four 50,000-gallon tanks from Containment Solutions. The system collects rainwater and runoff from buildings for flushing toilets and other nonpotable water uses in the university’s new ITC complex. At peak summertime temperatures, the university uses 100,000 gallons per week. Administrators cited a commitment to sustainability as a key factor in the project, and sustainability was also a factor in a storage project at California State University in Sacramento (CSUS).

Out of Date, Out of Capacity
In the case of CSUS, Containment Solutions provided a 33,000-gallon Flowtite Septic Tank as part of a schoolwide green building initiative to reduce harmful effects on the environment, as well as minimize the use of resources. A new holding tank and pump station replaced the original sewer system that was out of date and out of capacity. The CSUS project has much in common with the Solaire apartments, in that both are described as “green” and “sustainable,” yet, because they function as onsite wastewater, they could also be categorized as decentralized wastewater treatment. It’s another strong growth market for the water storage industry, and one that shows an equally strong backing from state and federal agencies.

In fact, among its many ongoing programs, EPA recently funded a $16 million program and contract to the Water Efficiency Research Foundation (WERF) and the Decentralized Water Resource Collaborative, to produce a report titled “When to Consider Distributed Systems in an Urban and Suburban Context.” Of the many benefits highlighted as points of consideration for state agencies, there is one that any water utility can appreciate: cost savings.

Decentralized wastewater systems help to avoid large, upfront capital investments typically required of a large centralized system and can be built on a “pay-as-you-grow” basis when needed to meet demands. Additional benefits that would incorporate water storage include opportunities for improving watershed management, aquifer recharge, and water reclamation and reuse.

By using a pay-as-you-grow plan, the LOTT Alliance, Olympia, WA, expects to save about $87 million over the course of a 20-year Capital Improvement Program. The plan calls for three satellite reclaimed water treatment plants, and includes promoting wastewater reclamation and reuse, plus ongoing adoption of new technology that’s introduced over the next 20 years.

In another related project, the Mobile Area Water Sewer System, Mobile, AL, chose a decentralized plan to cope with growth beyond city limits and an aging infrastructure. The plan relies on 15 cluster systems serving residential, commercial, and school properties. EPA also pitched in with funding for a sewer mining reclamation project that provides reclaimed water for landscape irrigation.

Maintaining Rural Character
Sometimes a decentralized system can actually fund itself, as seen in Loudoun County, VA, where the utility has implemented a strategy to purchase capacity from a centralized plant, plus a satellite water reclamation facility and several small community cluster systems. Maintaining the area’s rural character was important to the county’s citizens, and the cluster approach was less obtrusive. Maintaining a budget was equally important, so the county had developers design and construct cluster facilities at their own cost and transfer ownership to Loudoun Water for continued maintenance. The program funds itself through rates structured to cover the expenses.

For cities with growth and infrastructure issues, onsite wastewater treatment does indeed offer the ideal solution, according to Joe Brown, vice president of Roth Global Plastics, Syracuse, NY.

“Even though the short-term housing market is slow, in general, the long-term decentralized wastewater industry has a very bright future when housing recovers,” he says.

Roth tanks are made from polyethylene, a material that doesn’t react with wastewater. The tanks incorporate an NSF 61 lining, a food grade resin qualified for water holding tanks, greywater storage, rainwater collection, or wastewater reception.

Finding the Funding
We’ve seen that decentralized systems can save utilities money, but there’s more to be saved by investigating EPA’s Clean Water State Revolving Fund (CWSRF) as an economical resource of funding for decentralized water treatment projects. Qualifying categories include all types of nonpoint source, watershed protection or restoration, and estuary management projects, as well as more traditional municipal wastewater treatment projects.

Under the CWSRF, states have a variety of assistance options: loans, refinancing, purchasing, or guaranteeing local debt and purchasing bond insurance, with repayment periods of up to 20 years. Also, states may customize loan terms to meet the needs of small and disadvantaged communities.

With these and other funding methods, state and local water agencies are booking projects, according to Bill Neighbors, president of Tank Connection, Parsons, KS.

“Any tank manufacturer that actually provides value-added services is very busy now,” says Neighbors. “We are seeing some trends in replacement, and even though we are a manufacturer of welded and bolted tanks, the bolted steel market is growing faster due to cost efficiency, because they install in one-third the time of a steel-welded tank. When you’re talking about two different specifications, just imagine you’re in the field and paying prevailing wage labor, which is applicable at all municipalities–now you have a need to minimize the amount of labor.”

Further savings can be found in another trend in water storage: aluminum dome covers. “No matter what the design of the tank, everyone is using aluminum dome covers,” says Neighbors. “The big reason is these covers fit any type of tank, and you have something that’s a maintenance-free item. They’re not expensive; there are no coating issues; and they have a great track record.”

Tight budgets and labor costs are common worries for university projects, so it’s not surprising that Tank Connection was chosen by The Ohio State University and Ohio Agricultural Research and Development Center to supply tanks for an anaerobic digestion system in the BioHio Research Park on the Wooster, OH, campus. Tank Connection designs, manufactures, and installs four types of steel digester tank designs, including bolted RTP (rolled, tapered panel), field-weld, shop-weld, and hybrid tank construction.

High-tech companies are building a solid market for Tank Connection and other storage tank manufactures. And the industry can expect another boost from multi-national giants such as GE Energy. The company’s Advanced Water Recycling business unit supplies its ZeeWeed MBR systems at the Solaire Apartments and at a much larger project, the Gillette Stadium, Foxborough, MA. The stadium’s system recycles nonpotable water for toilet flushing and depends on two tanks: a 600,000-gallon ground-level unit and a 500,000-gallon elevated unit.

Not surprisingly, as the industry expands, other technology suppliers are entering the market, such as Nalco Company, Naperville, IL. Nalco recently introduced 3D TRASAR, an automation technology to continuously monitor water conditions and add treatment as needed. The system extends cooling tower operations and makes it easier to use nonpotable quality water.

Looking ahead, with major companies such as GE Energy pushing projects of the size and scope we’ve seen at the Solaire and the Gillette Stadium, it’s fair to say that this is just the beginning of a new era in water conservation technology. Yet one of the oldest and most basic of methods–storage–is well positioned to continue its role as an essential component of sustainable water usage. All told, it looks as if tank manufacturers have a busy future to look forward to. 
About the Author

Ed Ritchie

Ed Ritchie specializes in energy, transportation, and communication technologies.

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