NUTRIENTS Q&A    NEXT GEN         PRESENTATIONS    CONFERENCE
Chambers Creek
 

BC WATER NEWS

Oct. 7, 2013 — In 2011, after the EPA released a report about the large-scale environmental problems caused by nutrient pollution, stricter regulations were an emerging issue in states such as Florida and New York — with a nation of water professionals looking on. Today, utilities and water managers throughout the United States are knee-deep in the murky waters of nutrient reduction and integration strategies.

 

With excess nutrients being blamed for toxic algae blooms, hypoxia, acid rain, nitrogen saturation in forests and even climate change, the EPA has made this one of its top priorities in the fight for cleaner water and a better environment, and the agency continues to press state regulators and permit writers to take action.

So how is the industry responding? Utilities and stormwater agencies big and small — facing a full plate of challenges in addition to the nutrients issue — are beginning to find workable nutrient strategies and solutions. The good news is that nutrient goals often are in line with many municipalities’ overall water planning goals to build greener infrastructure and enrich communities. But the bad news is that compliance can be costly, and deadlines mean more investment up front on someone else’s timeline. Not to mention that some argue the science of nutrients is still evolving.

“Many of our members are seizing on the regulatory push for nutrient controls and turning it into an opportunity for more innovative solutions," says Chris Hornback, senior director of regulatory affairs for the National Association of Clean Water Agencies.

“In many regions, agencies are building coalitions and working together to assess the full regulatory impact of nutrient regulations and to plan ahead,” says Sarah Reeves, vice chairwoman of the 86th annual Water Environment Federation Technical Conference program committee. Reeves, a water resources compliance expert in Brown and Caldwell’s Denver office, is working with utility, industry, stormwater and agricultural leaders to create the Colorado Monitoring Framework, a group whose objective is to develop scientific evidence to deal with implementation of nutrient regulations on a regional level.

All of this means that the topic of nutrients is big on this year’s WEFTEC program in Chicago this week. From the latest research on nutrient removal and watershed approaches to successful treatment technologies and applied science, WEFTEC attendees will be able to sample emerging ideas for solving and managing the nutrient problems, including some solutions highlighted below.

 

 

 

 
Chambers Creek Regional Wastewater Treatment Plant will integrate the DEMON® nitrogen removal technology.
 
Sacramento's nutrient-removal pilot study is providing crucial data for the EchoWater Project.

 

Site-specific approaches move forward

“The current emphasis on developing water quality criteria for nitrogen and phosphorus presents tremendous challenges,” says Clifton Bell, Brown and Caldwell technical leader for watersheds and TMDLs. “We need to make progress in solving problems like hypoxia, algae blooms and degraded habitat. However, solving these issues can be complex and costly.”

Because no two water bodies are exactly alike and sometimes the rules fail to acknowledge this, the development of scientifically sound nutrient goals is one of the most high-profile challenges facing states and the regulated community. Efforts are being made to set reduction targets that are specific to a particular geographic region, taking into account that a body of water’s response to nutrient load often depends on a variety of characteristics.

In 2012, the Water Environment Research Foundation set out to create a toolbox that would serve as guidance for using models to set site-specific nutrient goals. In partnership with BC, Limno Tech and Tufts University, WERF is helping states and NPDES permit holders link nutrient management strategies to ecological response indicators for aquatic systems.

The resulting research report, Modeling Guidance for Developing Site-Specific Nutrient Goals, was the subject of a workshop Saturday during the conference. According to Bell, the Nutrient Modeling Toolbox contains 30 models capable of quantifying the relationship between nutrient loads and their impacts, as well as a Model Selection Decision Tool to help users select potential models for their specific site, condition, response indicators and available data and resources. The team also has developed technology-based and water quality-based approaches that might be applicable in cases where more complex methods are not feasible due to available data or cost.

Proven technology makes timelines possible

Sacramento’s effort to deal with lower nutrient requirements in its effluent permit will be featured in three sessions during WEFTEC. Faced with state mandates that it must construct and operate new treatment processes by 2021, the Sacramento Regional County Sanitation District decided to launch a $2 billion upgrade, known as the EchoWater Project. The more significant permit requirements include lower discharge limits for ammonia and nitrate and Title 22 or equivalent reclaimed water treatment standards, and requiring filtration and enhanced disinfection processes.

According to Kurt Ohlinger, EchoWater Project chief scientist, the short time-frame they had to work with was a major driver. “This really limited the alternatives we could consider to proven, mature technologies because there was no time to explore and test emerging nutrient removal technologies, such as shortcut nitrogen removal,” he says. “Viable alternatives had to be proven at large plants, be cost-effective, and be adaptable to meet anticipated future regulatory requirements.”

During the district’s comprehensive technology screening process, all options were on the table. Alternatives considered included keeping the high purity oxygen activated sludge system and achieving nitrogen removal in subsequent processes, as well as bioaugmentation of the HPOAS process. Suspended growth and fixed film process alternatives also were weighed.

“In the end, the primary drivers of mature technology at large plants, cost-effectiveness and adaptability to anticipated future treatment requirements drove the decision to select the air-activated sludge, biological nutrient removal (BNR) process,” Ohlinger says. In addition, he added, the new treatment processes will produce water that is reuse quality, which fits in nicely with the district’s water management plans.

SRCSD recognized the value of piloting and included it within its 10-year plan for BNR implementation. A pilot plant was built in 10 months and operated for 11 months in order to evaluate the efficacy of new and existing technologies for nutrient removal from engineering and operations perspectives. It used deep aeration tanks and sufficiently large secondary clarifiers and minimum filter sizes to accurately mimic full-scale performance.

This ultimately allowed SRCSD to lower cost estimates for the upgrades and reduce its homeowner rate increase over seven years from $24 to $46 instead of the previously projected rate of $68. This pilot plant is providing crucial data for the district's 10-year implementation program for upgraded treatment facilities that ultimately will serve 1.4 million customers. BC, together with HDR, is leading the program management team working with SRCSD to implement the EchoWater Project.

New technology offers promising results

As wastewater technologies continue to advance, more municipal agencies are looking to apply new processes that help reduce costs, support decision making and meet future requirements.

Pierce County, Wash., successfully piloted and is implementing an Anammox sidestream treatment process (called DEMON®, short for DEamMONification) for anaerobic sludge dewatering centrate. Anammox, the cutting-edge nutrient removal technology, has been used in Europe for 10 years and is increasingly being used in the United States to efficiently remove nitrogen in ammonia-rich process streams.

This was the first U.S. pilot study of the DEMON® technology for "shortcut" nitrogen removal. Once completed, the Chambers Creek WWTP six miles outside of Tacoma, Wash., will be one of the largest North American installations of the DEMON® technology. The piloting work was presented on the podium at WEFTEC 2012.

Public interest in protecting Puget Sound created the impetus to move ahead with nutrient control investments before they became compliance issues in Pierce County. The county took advantage of the favorable economic climate and created a pro-active 30-year plan to accommodate looming capacity needs and regulatory requirements, including nitrogen removal. The $353 million expansion project will increase plant capacity from 28 to 50 mgd, introduce new technologies to protect the environment, and repair and replace aging infrastructure.

According to Chris Cleveland, senior vice president in BC’s Olympia, Wash., office, this proved to be cost-effective as well, because it eliminated potential sunk investments and provided overall opportunities to jointly manage countywide nutrient control responses with the surface water management group.

Now in its construction phase, Chambers Creek designers devised a strategy to adjust treatment performance for nutrient removal, water reclamation and “zero discharge,” and developed a capital improvement plan based on service and asset management principles. Addition of new unit processes, and upgrades to existing processes, can be expanded to accommodate additional needs so the county can speed up or slow down level-of-service improvements to correspond with the changing regulatory environment, public demand and available funding.

“Pierce County should be commended for their foresight and courage to take on this project,” Cleveland says. “The technologies, GC/CM process, financial planning and asset management practices are all on the forefront of what is happening in other sewer utilities across the country.”

This expansion will add 50 percent more capacity, provide the first steps for water recycling, and significantly increase the level of treatment using biological nutrient removal. As an added benefit, the design transformed the 180-acre utility site into a community asset by seamlessly integrating it into the master plan for a 920-acre regional waterfront park that includes a championship golf course. Work is expected to wrap up in 2016.

“One of my top priorities is creating livable communities, and having a cost-effective, environmentally responsible sanitary sewer system is a key part of that mission,” Pierce County Executive Pat McCarthy said. “The expansion will benefit this growing community for years to come, and the results truly support what it means to have livable communities.”

 

 

 

Coosa River Basin Initiative

Nutrient trading
gets simpler

Nampa, Idaho, is required to lower its wastewater phosphorus discharge by 2018.

 

Holistic planning for manageable compliance

About 20 miles west of Boise, Idaho, the city of Nampa is a town of about 80,000 people that’s growing by leaps and bounds. When word came that the city would be required to lower its wastewater phosphorus discharge to 0.5 mL per liter by 2018, and down to 0.07 mL by 2023, a big-picture approach based on the strategic vision for the city was taken. At present, the city discharges about 5 mL of phosphorus per liter of wastewater.

The first phase is a $28 million wastewater plant improvement project that will be completed in 2017. Facing significant decisions on how best to meet increasingly stringent NPDES permit limits, the city and its program management team have been working together during the past three years to screen the treated effluent discharge options that best manage current capital requirements as well as long-term risks and benefits from regulatory, technical, legal, and economic development perspectives.

The quantification of future risks and benefits associated with the various discharge options is the unique piece to the business case evaluation approach. It has allowed the city to better align the long-term decision-making process with strategic goals and level-of-service expectations from ratepayers.

By breaking the project into two parts, Nampa will be able to defer some of the more significant costs while still meeting all interim permit requirements, says Steve Burgos, BC’s program manager for the effort. More importantly, he says, this “just in time” upgrade approach allows Nampa to delay the larger capital expenditures until more clarity is gained on risks and benefits.

“This provides a foundation to build on as they work toward future goals,” Burgos says. “We are framing the current nutrient management issues in a more holistic, long-term fashion that considers how the wastewater program can support strategic level-of-service goals for Nampa.”

 

 

 

 
By breaking its wastewater plant improvement project into two parts, Nampa, Idaho, will be able to defer signifcant costs while still meeting interim permit requirements.
 

© 2013 BROWN AND CALDWELL