News

Voluntary Security Guidelines Open for Utility Review

Steps necessary to improve security at drinking water, wastewater, and stormwater facilities became clearer with the release of the nation’s first standardized physical security guidelines in December. Recommended safety practices are designed to protect the water and wastewater infrastructure against a wide range of threats, including terrorist attacks, but also other sources of potential harm, such as accidents, vandals, criminals, dangerous microbes, chemical contamination, and natural disasters.

The draft set of voluntary guidelines — jointly developed by the American Society of Civil Engineers (ASCE; Reston, Va.) and American Water Works Association (AWWA; Denver), with technical assistance from the Water Environment Federation (WEF; Alexandria, Va.) — are the result of Phase 3 of the Water Infrastructure Security Enhancements (WISE) program funded by the U.S. Environmental Protection Agency (EPA). These organizations are inviting utilities nationwide to review and test the guidelines and submit comments on them until the end of June.

“We want people to check them out and give us feedback as to whether they’re useful,” said Stacy Passaro, a senior environmental engineer at WEF. “Are there circumstances that we didn’t cover in the guidelines that would be good to add? Is there too much or not enough information? — and so on.”

Once finalized, the guidelines will be forwarded to the American National Standards Institute (Washington, D.C.) for accreditation as a voluntary national standard.

“Our society depends on a safe and reliable water supply, not only for human consumption but also for other needs, such as industry, agriculture, and even fire protection,” said Patrick Natale, ASCE executive director, in a statement on the guidelines’ release. “These risk-reduction standards for water, wastewater, and stormwater systems are an essential part of protecting our nation’s infrastructure from potential terrorist threats and allowing it to continue supporting our economy and health.”

Bill Bertera, WEF executive director, added that “WEF is pleased to partner with organizations like AWWA and ASCE. Incorporating WEF’s technical expertise in wastewater into the development of their standards jointly serves the professionals who design and operate water infrastructure.”

No One Size Fits All
The guidelines spell out scores of tangible steps that utilities can take to protect new and existing facilities of all sizes but essentially leave it up to the individual utility to decide whether and how to implement them.

Titled Guidelines for the Physical Security of Water Utilities and Guidelines for the Physical Security of Wastewater/Stormwater Utilities, the documents contain best engineering practices based on the collective experience and judgment of ASCE, AWWA, and WEF. The water utility guidelines cover raw water facilities, wells and pumping stations, water treatment plants, water storage facilities, distribution systems, and support facilities. The guidelines for wastewater and stormwater facilities focus on collection systems, pump stations, wastewater treatment plants, and support facilities.

Because utilities vary greatly from one community to the next, the flexibility offered by the guidelines enables them to consider their unique circumstances and threats, Passaro noted. The disadvantage is that the same flexibility makes it more difficult to determine how much safety and security is needed or appropriate in each situation.

“This was a challenge when we first started this project,” Passaro admitted. “The whole premise of security is that you can’t mandate everybody to use the same thing, because then it’s basically useless.” Such information, of course, has to be distributed widely, meaning that the chances are good that it could fall into the wrong hands. “If you know exactly what you’re dealing with,” Passaro explained, “it’s easy to defeat almost any kind of system.”

Utilities have to start the process by defining what sort of threat they need to defend against, according to Passaro. Large utilities that store chemicals onsite in heavily populated areas, for example, would need to guard against a sophisticated terrorist threat. A small plant in the middle of Iowa, on the other hand, is more likely to be worried about vandals or possibly a disgruntled employee damaging equipment.

“Each utility has to first look at its own situation and determine what would be reasonable for the type of threat they need to defend against,” Passaro said. Once such threats are defined, the next step is for utilities to conduct a vulnerability assessment. “That’s where they actually look at their plant and determine what kinds of chemicals ... they have onsite that potentially could be a threat to public health and what equipment in their plant is critical to the function of their plant,” Passaro noted. Those then become the critical pieces that a utility would need to focus on.

“It really takes a lot of upfront work first to find your threat and define what your critical assets are that you need to protect,” Passaro acknowledged. “Once you’ve completed that piece, you still have to figure out what changes you’re going to make at your plant to improve security,” and that is where the new guidelines kick in.

Assessing Vulnerability
The Public Health Security and Bioterrorism Preparedness and Response Act of 2002 requires U.S. drinking water utilities to conduct vulnerability assessments of their systems, but no such national requirement exists for wastewater utilities.

In March 2006, the U.S. Government Accountability Office (GAO) completed a survey of more than 200 large wastewater facilities to assess whether such utilities are following through on their own or whether regulatory incentives might be needed. GAO found that most of the surveyed facilities had completed, had under way, or planned to complete some kind of security assessment. Similarly, more than half indicated that they did not use potentially dangerous gaseous chlorine as a wastewater disinfectant.

Other security measures taken after the Sept. 11 attacks generally focused on controlling access to the treatment plant through improvements in visual surveillance, security lighting, and employee and visitor identification, according to GAO. What stood out in the report, however, is that wastewater utilities have made little effort to address collection system vulnerabilities.

Because of their nature, “collection systems are hard to secure,” Passaro explained. “They’re spread out over a large area and have many access points” from storm drains, manholes, and underground piping and conveyances. GAO recommended that utilities place additional emphasis on collection systems but noted that a “lack of funding and federal security guidelines remain a concern for many wastewater facility managers.”

The new guidelines offer several options for providing better security for these systems, such as installing manhole locks or sensors to detect toxics or other biochemical threats. They also address risks from construction and design perspectives.

“We’re trying to work both angles on this,” Passaro said, “of making utility people more aware, as well as designers.” Previously, plants were designed to minimize footprints or pipe runs, with cost-saving measures a priority. Now, however, “we want security to be another [criterion] that they consider when they’re doing design work,” Passaro added.

What’s Next?
The latest guidelines make up Phase 3 of EPA’s WISE program. The program was launched in 2003 and funded by a multiyear EPA grant to support water and wastewater utilities in mitigating vulnerabilities from man-made threats and natural disasters in existing systems and throughout the design, construction, and operation of new systems.

The Phase 3 guidelines will be factored into the National Infrastructure Protection Plan (NIPP) being developed by the U.S. Department of Homeland Security (DHS), according to Alan Roberson, AWWA’s director of security and regulatory affairs. “As part of that, they’re trying to develop metrics for water security, so that we’ll be able to benchmark and evaluate improvements in security effectiveness,” he said.

Water and wastewater infrastructure is one of 17 critical infrastructure and key resource sectors identified under the Homeland Security Act of 2002 that require protective measures against a terrorist attack or other hazards. Other sectors include agriculture and food; energy; public health and health care; banking and finance; information technology; telecommunications; postal and shipping; transportation systems, including mass transit, aviation, maritime, ground or surface, and rail and pipeline systems; chemical facilities; commercial facilities; government facilities; emergency services; dams; nuclear reactors, materials, and waste; the defense industrial base; and national monuments and icons.

“The NIPP formalizes and strengthens existing critical infrastructure partnerships and creates the baseline for how the public and private sectors will work together to build a safer, more secure, and resilient America,” said George Foresman, DHS undersecretary for preparedness, in a statement issued in June when NIPP was completed. Sector-specific plans that complement NIPP and detail the risk management framework will be released in coming months, according to DHS. These plans will address unique characteristics and risk landscapes and will be developed in collaboration with sector-specific security partners, according to DHS.

The Phase 3 WISE guidelines are expected to remain voluntary, Roberson noted. “The science behind water security is still evolving,” he pointed out. “DHS is doing a pretty good job of trying to get some uniformity on security across all of the critical infrastructure sectors, but we don’t really have the intelligence on what the most likely threat might be.”

Nevertheless, EPA, WEF, AWWA, and ASCE are encouraging utilities to implement the guidelines not only to reduce the risk of malevolent acts but also potentially to reduce the risk associated with natural events.

Copies of the draft standards for trial use are available free on each organization’s Web site at www.wef.org, www.awwa.org, and www.asce.org, respectively.  Comments can be submitted to any of the three participating organizations.

— Kris Christen, WE&T

The U.S. Environmental Protection Agency’s nutrient criteria are driving a push toward ever lower discharge limits on nitrogen and phosphorus, and in the wake, many wastewater treatment plants are struggling to keep up. Now, a new research development could give water quality experts a leg up in re-engineering existing plants and designing more efficient and reliable ones in the future for removal of nutrients, particularly phosphorus.

In the first ever metagenomic study of an activated sludge wastewater treatment process, researchers from the U.S. Department of Energy’s Joint Genome Institute (JGI), University of Wisconsin–Madison (UWM), and University of Queensland, Australia (Brisbane), were able to obtain a nearly complete DNA blueprint of the bacterial species Accumulibacter phosphatis, a key player in phosphorus removal. This step opens the door to better understanding the mechanisms involved in that removal, potentially leading to an early warning system of treatment plant failure, said Philip Hugenholtz, head of JGI’s Microbial Ecology Program and co-author of a paper on the study published in the Sept. 24 online edition of Nature Biotechnology.

Enhanced biological phosphorus removal (EBPR) is widely used at wastewater treatment plants and is one of the best studied microbially mediated biotechnology processes on the planet, according to the paper. Yet the process is not well understood at the metabolic level, and consequently, many questions surround the mechanisms that make it work.

“Engineers and microbiologists have been trying for 35 years to grow this microbe, with no success,” said Katherine McMahon, an assistant professor of civil and environmental engineering at UWM and one of the paper’s co-authors. “Remarkably, through metagenomic techniques, we were able to isolate and acquire the genome sequence of A. phosphatis without a pure culture of the organism, which, like most microbes, eludes laboratory culture.”

McMahon and her colleagues expect that the genome sequence will enable biologists and engineers to understand why and how these organisms accumulate phosphorus, allowing for major advances in optimizing and controlling the EBPR wastewater treatment process. “In particular, it makes possible further research into why some wastewater treatment plants occasionally fail,” she added.

Scope of the Issue
When EBPR works, it performs beautifully, but when it fails, excess nutrients can get washed out, potentially leading to serious pollution of lakes, rivers, and estuaries, McMahon noted. With more than 117 million m3 (31 billion gal) of wastewater being treated daily in the United States alone, any improvement in existing methods will offer treatment plants relief in meeting the increasingly stringent discharge limits for phosphorus that are expected in the future.

Microorganisms are well-equipped to do the job, but activated sludge has long been a black box mystery. EBPR systems are prone to unpredictable failures due to the loss or reduced activity of the microbial populations responsible for phosphorus removal, according to the paper. This incomplete understanding of the microbial ecology found in sludge has forced design engineers to rely on highly empirical observations.

Sequencing Step Forward
To shed some light on the challenge, the researchers compared sludge samples from wastewater plants in Madison, Wis., and Brisbane, Australia, that they maintained in laboratory-scale bioreactors to control and monitor the status of the sludge microbial communities.

Applying a metagenomic strategy directly to the sludge samples, they were able to use high throughput sequencing to get an overview of the entire microbial population contained therein and not just the sequence data for particular bacteria, as is done with genomics. In this way, “you also get DNA from organisms that aren’t doing phosphorus removal, but the key is that if you sequence enough, then ultimately you can assemble and stitch together the genome sequence of each organism in the community, rather than going organism by organism,” McMahon explained.

Subsequent analysis of the sequence data showed that despite significant differences in operating conditions, including different volatile fatty acid feeds, sludge volume, and sludge residence time, Accumulibacter species dominated both sludges, comprising roughly 80% of the biomass in the U.S. sludge and 60% in the Australian sludge, respectively, according to the paper.

Some of the initial findings reported in this study on the organism’s capabilities call into question a few previous empirical observations of how the EBPR system works, said David Jenkins, professor emeritus of civil and environmental engineering at the University of California–Berkeley. Other findings support some of these observations.

For example, in order to accumulate massive amounts of phosphorus, the organism has to shuttle the nutrient across its cell walls. It does this using transporters, which are a type of enzyme, Jenkins explained. As it turns out, the findings show that the organism has two transporters: a high-affinity one and a low-affinity one. The latter “works when it’s pretty easy to transport it — that is, when there’s a lot of phosphorus around the outside of the cell,” Jenkins noted. “When the phosphorus starts to run out, you get down to very low concentrations outside the cell,” and the high-affinity transporter, which requires a lot more energy to function, kicks in to grab the phosphorus and transport it across. “Effectively, you can get down to very low concentrations using a combination of these two transporters,” Jenkins said.

Comparatively, empirical observations have shown that plant designs using a series of compartments in the aerobic treatment zone do better than simply using one big tank of the same volume. This now makes sense, Jenkins pointed out, “because if you have a completely mixed tank, the phosphorus concentrations are the same all over.” If, on the other hand, “you have a system with a series of compartments, then at each succeeding compartment towards the effluent end, the phosphorus concentration gets lower and lower, forcing this organism to turn on its high-affinity transporter,” he said. In this way, “you go down further than you’d be able to with the low-energy one.”

What It All Means
Until now, phosphorus removal research has been limited by the lack of having a pure culture of A. phosphatis, Jenkins said. This sequence data “provides the first real way we’ve had to see what this organism can actually do, because if you know its sequence and genetic material, you can tell what enzymes it can produce and, therefore, what reactions it can catalyze,” he noted.
Of course, the genetic blueprint is just the first step toward further fundamental investigations of these bugs, but an important one.

“Now that we know all of the genes this organism has, we can use that information to design new experiments to look for the expression of the genes that we think are involved in phosphorus removal and pick apart the biochemical mechanisms that are responsible for each step in the process,” McMahon noted. “When you do that, you can begin on a much more fundamental level to understand why the bacteria store phosphorus, under what conditions they’ll stop storing phosphorus, and maybe ways to make them store more.”

Additionally, the researchers said they are hopeful the findings will lead to the development of an early warning system that could alert treatment plant operators of an impending crash or failure. “If you can get information a couple of days ahead of a crash, where you’re seeing changes in the microbial population or the organism starting to express particular shock proteins, you can maybe set about taking some actions to head it off,” Hugenholtz pointed out, allowing for a more preemptive response, rather than a reactive one.

Overall, “the findings and tools described in this landmark paper will allow the resolution of many of the questions that have arisen concerning the mechanism by which the enhanced removal of phosphate from wastewater occurs,” Jenkins said. “Understanding these mechanisms will undoubtedly lead to more efficient operation of the process and to the development of more robust designs.”

— Kris Christen, WE&T

©2007 Water Environment Federation. All rights reserved.