March 2008, Vol. 20, No.3
Green, But at What Cost?
It doesn’t matter where you look. “Green” is everywhere: in the grocery store, around the office, at the wastewater treatment plant. That’s because green is in. Green is good. But it’s also got some people wondering: Is green always smart?
Consider the Toyota Prius, the automobile industry’s top-selling hybrid car. Embraced by the rich and environmentally conscious, the Prius combines an electric motor with a gas-fueled engine to create a fuel-efficient vehicle that gets 18.7 km/L (44 mi/gal). Besides having great fuel economy, it also causes less pollution and produces fewer carbon dioxide emissions than conventionally powered cars. Its batteries are also less toxic.
And yet, from a purely economic point of view, it makes absolutely no sense to buy one. According to Consumer Reports estimates, it would take nearly 25 years for the average driver to recover the Prius’ additional cost with the money saved at the gas pump.
Of course, saving the planet is more important than saving a few dollars, argue proponents of hybrids and other green technologies. Still, budget-minded utilities — like many budget-minded consumers — must ask themselves if “going green” is always worth it. Are there instances where energy management and energy efficiency technologies are more about political correctness than good business sense?
It depends on how you look at it, experts say.
“The conventional way to look at projects is to consider their cost-effectiveness at meeting a particular need,” explained Ray Ehrhard, a research associate in the Department of Energy, Environmental, and Chemical Engineering at Washington University (St. Louis).
Today, however, the boundaries of that economic evaluation are changing. “When a utility makes an environmental decision that impacts the public, you must look at the cost, not just to the utility, but to society and to the environment,” Ehrhard said. “You have to consider those who may reap the benefits or bear the brunt of your economic decisions.”
Utilities also have to recognize that their role in society is changing.
“There’s a little bit of denial in our profession to think that the things that worked for us when there were 2.5 billion people on the planet will work for the 9 or 10 billion people projected to be here by midcentury,” said Glen Daigger, senior vice president and chief technology officer at CH2M Hill (Englewood, Colo.).
“We need to realize our job isn’t just to treat wastewater but to provide water resources in a world that is more and more resource-constrained,” Daigger said. “Because we have essentially the same water supply to serve a much higher population, there will come a time when we are going to be using compromised water supplies that will need to be treated at higher levels, even as we work to reduce the environmental footprint.”
“There are definitely smart and not-so-smart ways to approach all these issues,” Daigger said. “There is a tendency to think of ‘green’ as something that requires less energy. But if you create more water for a growing population, you are also contributing to sustainability.”
And that is likely to cost more money than ratepayers are currently accustomed to paying. “We’ve undervalued the price of water and wastewater for a long time,” Ehrhard said. “No one thinks twice about paying $1 for a bottle of water, not remembering that we pay about the same amount for 1000 gallons [3785 L] of water delivered into our homes.”
Going Green on a Budget
Education may, over time, help ratepayers appreciate the challenges the water and wastewater industry faces with putting a greener face on our nation’s aging infrastructure. Meanwhile, what is a utility that wishes to “go green” on a budget to do?
The first step, said Jane Madden, a vice president at CDM (Cambridge, Mass.), “is to undertake an energy audit to understand current demand for electricity, natural gas, and heating fuel. This process will help to highlight the low-hanging fruit that can be addressed through low-cost operational adjustments or awareness-building activities.”
For the past 15 years, for example, the Phoenix Water Service Department has been implementing soft starts and variable-frequency drives on most of its electric motors, energy-saving strategies that help reduce peak electrical demand and minimize energy usage. At the time the program was begun, economics was the only consideration, according to Paul Kinshella, a treatment plant engineering superintendent for the department. “If we could save money by making a change, we went ahead and did it,” he said.
“As a nation, we are energy gluttons and can reduce consumption of electricity and natural gas by 20% by incorporating the simplest measures, sometimes just through a change in behavior or installing more energy-efficient equipment,” Madden said. Only after making these cost-justified upgrades does she suggest considering alternative or renewable energy sources, such as wind turbines, biofuels, and methane recovery, to further reduce consumption.
The decision-making process then grows more complicated. “A utility has to decide which tools are the least costly to implement — and which justify the rate increases that will be needed to achieve the environmental goals,” Kinshella said.
Regulatory requirements and government incentives play a role in nudging things along. Consider the digester gas — a low-quality methane — that is currently burned off in flares in Phoenix’s waste treatment process. “We have not used the gas for creating power because, historically, our electrical power costs have been less than the capital and operating costs to turn the digest gas into electricity,” Kinshella said. But that may be changing.
The Arizona Corporation Commission, which regulates the state’s utilities, is requiring that 15% of the energy sold in the state by 2025 come from renewable sources, up from 1.1% today. “We can sell our gas to a third party to generate electricity and not have to worry about the permitting and other complicating factors associated with producing it ourselves,” Kinshella explained. “That third party can in turn sell the power and the green credits it gets for producing it, which makes it financially feasible for them.”
Some utilities must also consider the “cap and trade” credits that organizations can buy and sell, depending on whether they’ve capped their emissions to meet regulatory limits. “The question we as a city have to ask is whether we want to let a third party offset or increase its greenhouse gas emissions by selling them credits we’ve earned by capping ours,” Kinshella noted.
While Phoenix is leaning toward selling its digester gases to third parties, other utilities want to generate their own power and are looking for additional organic matter they can turn into digester gas. In one case, edible kitchen grease from restaurants is being hauled to a wastewater treatment plant in Millbrae, Calif., where it’s being turned into biogas and used to meet 80% of the plant’s power needs. Developed by Chevron Energy Solutions (San Ramon, Calif.), the system is reported to consume more than 11,355 L/d (3000 gal/d) of grease while producing annual revenues and energy savings of $336,000.
Is it a politically correct solution? “Yes,” Ehrhard said. “But it also minimizes the plant’s energy purchases and solves a waste grease problem in the sewers.”
Not all green solutions can deliver those kinds of results, at least not yet. In some cases, in fact, green solutions not only cost more, they also increase power, chemical consumption, and carbon dioxide emissions. Stricter National Pollutant Discharge Elimination System permit requirements are sometimes the culprit behind the increases, Madden noted.
“I certainly understand the need to reduce nutrients from wastewater treatment facilities to a certain level,” Madden said. “Once you pass below a certain effluent limit, you get beyond the limits of a conventional biological — and sustainable — system and enter the realm where chemical addition and energy-intensive systems become necessary.”
While treating wastewater to extreme levels requires significant amounts of power and chemicals, the benefits might be negligible, Madden pointed out. “There is a need to look at water quality holistically,” she said, with permits written with the flexibility needed “to simultaneously achieve water quality goals while minimizing the resources needed.”
The Age of Localized Solutions
Whether it’s removing nutrients or addressing other treatment issues, Madden and others believe that site-specific solutions are the wave of the future.
“Our nation’s wastewater infrastructure was built in a planned way, and we’ve historically had prescriptive methods for solving problems associated with secondary and advanced treatment,” Erhard explained. “Now that it’s time to rebuild, we need multidisciplinary teams of engineers, biologists, architects, and economists to look at the impacts of our solutions and determine the best solution for a given need. It’s not about prescribing technologies but applying our accumulated knowledge to develop engineered solutions that are site-specific and that make the best use of our resources.”
One evolving trend is the development of localized treatment solutions that allow users to use water multiple times before “throwing it away.” According to Daigger, several Southern California communities are using “scalping” or “sewer mining” to do this. The approach involves locating small treatment plants along interceptor sewers near golf courses and other places where there is demand for reclaimed water.
“Membrane bioreactor technologies make it practical for utilities to build these small treatment systems that allow them to reduce their environmental footprint,” Daigger said. “Yes, these ‘plug-and-play’ systems take more energy to operate than conventional treatment, but they also require less pumping and reduce other impacts down the line.”
Around the globe, there are countless other efforts under way to tap into and create water resources at a local level. In Australia, “rainwater harvesting” is becoming a common practice in places facing water shortages, according to Daigger. With this approach, local water storage is created to capture rainwater for reuse in lawn irrigation, toilet flushing, and other uses.
Private business is increasingly getting into the act as well. The Solaire, a 27-story, 293-unit residential tower built along the Hudson River in New York City, is one of a growing number of real estate development projects that include onsite water treatment and reuse systems to supply its cooling tower and the building’s toilets with water.
“Historically, we’ve provided water resources by reducing the pollution in the natural environment,” Daigger said. “But that is no longer enough. As projects like this one demonstrate, we must bring not only our dedication and our good hearts but also brains and innovation to ‘create’ more water while reducing the environmental footprint.”
Sometimes, this might mean making decisions and doing things that look to some to be more about political correctness than good business sense.
“We still have a lot to learn about the best ways to do things,” Ehrhard said. “Our field is going to change.”
— Mary Bufe, WE&T
Improving Mississippi River Water Quality
A recent U.S. National Research Council report calls for a systemwide approach
Along with spring melt and rains, nutrients and sediments again are being flushed off agricultural lands, making their way into tributaries that feed into the Mississippi River as it flows 3700 km (2300 mi) from Minnesota’s Lake Itasca to the Gulf of Mexico. An interagency federal–state action plan, in place since 2000, was supposed to gain better control over these pollutant loadings, but 8 years later, most of the plan’s goals have not been met. Recently, a U.S. National Research Council (NRC) panel said that if the river’s water quality is to improve, the U.S. Environmental Protection Agency (EPA) must take a stronger leadership role in implementing the Clean Water Act (CWA).
To date, EPA has failed to use its authority under CWA to adequately coordinate and oversee state activities along the Mississippi and ensure progress toward the act’s goal of “fishable and swimmable” waters, according to the NRC report titled Mississippi River Water Quality and the Clean Water Act: Progress, Challenges, and Opportunities, which was released in October. In fact, the lack of such leadership, as well as limited interstate coordination, has rendered the river an “orphan” in terms of monitoring and assessment of its water quality, the panel found.
“The limited attention being given to monitoring and managing the Mississippi’s water quality does not match the river’s significant economic, ecological, and cultural importance,” said panel chair David Dzombak, an environmental engineer and director of the Steinbrenner Institute for Environmental Education and Research at Carnegie Mellon University (Pittsburgh).
The Upper Mississippi River Basin Association (St. Paul, Minn.), an interstate regional collaborative representing Illinois, Iowa, Minnesota, Missouri, and Wisconsin, said the report “presented an excellent summary of the current environmental and institutional challenges to improving water quality” on the river. In a Dec. 13 letter to EPA, however, the group also cautioned that further improvements “will require a layered, interwoven approach of local, state, regional, and federal actions … where success is not overly reliant on EPA.”
EPA also welcomed the report and is committed to increasing efforts with all its partners to improve water quality and monitoring of the Mississippi River basin, said Benjamin Grumbles, assistant administrator for the agency’s Office of Water. EPA is using NRC’s recommendations to revise a draft Gulf Hypoxia Action Plan, which, at press time, was expected to be finalized in March, according to Grumbles.
Systemwide Monitoring Needed
The NRC report evaluates efforts undertaken to implement CWA along the Mississippi, noting that these measures have significantly reduced much of the point source pollution coming from such sources as factories and wastewater treatment plants. Cutting back remaining pollutant loadings — particularly nutrients and sediments leaching off of Midwestern agricultural operations — will be “crucial to further improving water quality in the Mississippi River,” Dzombak said.
Excess nutrients, especially nitrogen, are feeding the growth of the so-called dead zone in coastal waters off Louisiana and Texas. To date, measures to reduce nonpoint source loadings have been hampered by inconsistencies among the river corridor states in their water quality standards and monitoring programs, according to NRC. EPA, the panel added, has failed to use its CWA authority to provide adequate oversight of state water quality activities. Greater effort is needed, according to the report, to ensure that the river is monitored and evaluated as a single system.
The NRC panel acknowledged that CWA addresses nonpoint source pollution in only a limited fashion but maintained that its provisions, if comprehensively implemented, could effectively address much of the river’s pollution problems.
For starters, water quality standards for nutrients, which have yet to be established for most of the Mississippi River, must be implemented, Dzombak said. With such standards in place, he added, the total maximum daily load (TMDL) process could be triggered, establishing the amount of pollutants the waterbody can accept and still meet its water quality standards. Also, given the interstate nature of the Mississippi, “it is essential that the effects of interstate pollutant loadings be fully considered in developing the TMDL,” according to the report. CWA assigns most interstate water quality coordination authority to EPA, the NRC panel noted, recommending that EPA work with the states to develop a federal TMDL, or its equivalent, for nutrient pollutants for the river and the northern gulf.
Using the Chesapeake Bay Model
To illustrate the type of EPA leadership called for in the Mississippi basin, the NRC panel pointed to water quality management efforts in the Chesapeake Bay watershed as a model to be emulated for the Mississippi.
“Those efforts were clearly basinwide, involving all the states, with EPA as the focal point,” said Tracy Mehan, a former EPA assistant administrator for Water who is now a principal at The Cadmus Group (Arlington, Va.), an environmental consulting firm. Mehan was also on the NRC report panel. The result in the Chesapeake region has been “cutting-edge water quality criteria, which are now a standard throughout the basin,” Mehan added. “That’s now backing up into National Pollutant Discharge Elimination System permits, and, to the extent more progress can be made on addressing point source discharges, it will be very beneficial.”
The NRC panel also recommended that EPA’s administrator ensure coordination among the agency’s four regional offices with jurisdiction over various parts of the Mississippi River and work more closely with the U.S. Department of Agriculture (USDA) to reduce harmful runoff from agriculture.
“USDA has an important role to play through its land and water conservation programs,” Dzombak explained, adding that these programs should be more closely targeted to specific geographical areas that are providing most of the nutrients and sediments.
Incentive-based programs, such as USDA’s Conservation Reserve Program, Environmental Quality Incentive Program, and Conservation Security Program, are designed to help farmers implement best management practices (BMPs) that reduce levels of nutrient and sediment inputs and runoff. In a May 16, 2007, letter to the U.S. Congress, the Water Environment Federation (Alexandria, Va.), along with 11 other water sector groups, urged legislators to not only promote more funding for such conservation programs but also to ensure that the new Farm Bill makes water quality a top priority for program funding.
Action Plan Too Little, Too Late?
The interagency federal and state hypoxia task force led by EPA released a new draft action plan in November that revises the goals set in its 2000 plan. Scientists interviewed for this story, however, said the new plan falls short.
“It calls for states to take the lead, but without strong federal leadership; I think it’s going to be hard to get effective strategies in place,” Dzombak said.
Additionally, the plan steps back from its original goal to reduce the dead zone’s size to less than 5000 km² by 2015, noted Donald Boesch, president of the University of Maryland Center for Environmental Science (Cambridge). This target, according to the draft plan, “may no longer be possible to achieve … by 2015,” so the task force instead is now committed to making “significant progress” toward this goal.
“This isn’t something you can just put off,” Boesch said, noting that the 2007 hypoxic zone in the gulf was the third largest since measurements began. He pointed to another recent report by EPA’s Science Advisory Board (SAB) showing that the Gulf of Mexico system has become more susceptible over time as oxygen depletion has diminished its capacity to assimilate nitrogen loads. The SAB report, finalized in December, assesses the current state of the science surrounding the gulf’s hypoxic zone, as well as potential options for reducing its size. “This lost resilience will make it more difficult in the future to restore the system,” Boesch said, noting that SAB also recommended 45% reduction targets for both nitrogen and phosphorus loads to the Mississippi River system. The task force’s draft action plan does not specify any such load reductions.
“It’s hard to imagine how you would implement a plan that results in nutrient load reductions when nobody knows how much you have to reduce and how those reductions are to be apportioned among the various tributaries of the river,” Boesch stated. “It seems like we’re going the wrong direction if we’re serious about addressing this problem.”
EPA is looking at ways to bring multiple levels of government and different jurisdictions within the Mississippi River basin toward a common goal and objectives, Grumbles said. “One of the key challenges in making real, meaningful progress is the fact that this is such large basin,” he noted. Nevertheless, EPA is focusing on a wide range of actions.
One of those Grumbles outlined is accelerating the development of numeric criteria for nutrients, thereby helping to create a market for innovative, cost-effective approaches, such as water quality trading. Another priority action, Grumbles noted, is working with USDA as it implements Farm Bill programs. “We think the key to progress is to work with them to provide incentives for BMPs to be put in place and maybe even add money to farmers’ pockets,” he said.
EPA also is working closely with other agencies, such as the U.S. Geological Survey, on modeling efforts to identify watersheds within the basin with the highest nutrient loadings.
“We’re going to see a lot of innovative approaches and solutions — such as water quality trading, carbon banking, and nitrogen farming — to help reduce erosion and phosphorus and nitrogen going into rivers, and that’ll help us make significant progress toward the goals,” Grumbles said.
For more information, the NRC report is accessible at books.nap.edu/catalog.php?record_id=12051, and EPA’s draft 2008 action plan is available at www.epa.gov/msbasin/taskforce/pdf/2008draft_actionplan.pdf. The SAB report is available at yosemite.epa.gov/sab/sabpeople.nsf/WebCommittees/BOARD (search for “hypoxia in the northern Gulf of Mexico”).
— Kris Christen, WE&T