By Penelope B. Grenoble
According to the US Conference of Mayors, local governments spent $105 billion in 2010 to provide water and wastewater services in this country. Although the figure includes infrastructure, there can be little doubt that a good chunk of that change went to meet federal and state drinking water standards and maintain water quality, a challenge that is becoming increasing complex.
As Mark LeChevallier, Director of Innovation and Environmental Stewardship for American Water, an investor-owned utility that serves some 15 million customers nationwide, puts it, “For 100 years or more the principle has been to find the highest quality water, then preserve and protect it as a drinking water supply. But in some places, those days are gone.”
And so the job of serving a commodity that must be consistent every day—365 days of the year—has become a complicated process, and decision-makers can sometimes feel caught up in a maze of conflicting obligations to regulatory agencies, boards of directors, ratepayers, and other stakeholders. To get a better idea of how decision-making takes place in the current water climate, in which budgets are tight and regulations are stiff, we went to a number of agencies and experts.
Here’s their list of what to consider:
- Be realistic about your source water.
- Keep up-to-date on technology and be ready to experiment.
- Be realistic; there’s no silver bullet
- Utilize stakeholders as allies.
- Keep your eye on the long-term.
The Best Tasting Water in the Country
Racine, WI, which earned the crown for best-tasting water in the country at the 2011 Conference of Mayors, has installed an innovative treatment train to assure this valuable commodity stays that way. The upgrade of its water treatment protocol began after the 1993 Milwaukee Cryptosporidiosis outbreak, which turned out to be the largest waterborne disease outbreak in US history. Over a two-week period an estimated 403,000 residents became ill with stomach cramps, fever, diarrhea, and dehydration, and 104 people died. The cause was subsequently traced to oocytes that passed through the filtration system in one of the city’s water treatment plants.
“That’s something you don’t want to have happen on your watch,” says Keith Haas, general manager of Racine’s water utility. “If you were someone who went through those boiled water orders, you’d want to be sure nothing like that ever happened again. We view ourselves as a public health agency with responsibility for producing a product that can be ingested safely by every one of our customers every day of the year. So when Milwaukee happened, the utility brought in the best people it could find to evaluate its plant and make recommendations.”
Membrane tanks at the Racine Water Treatment Plant
“Lake Michigan and the Great Lakes in general are excellent sources of drinking water, in terms of both quality and quantity,” says Racine Plant Superintendent Mike Kosterman. “They have their upset storm events, but for the most part, it is the almost-perfect water to treat. It’s moderately hard and very well buffered so you don’t make the water acidic during treatment, and with minimal pathogens. We have occasional algae blooms, but it’s not like what you see in a reservoir or on the Colorado River.
“After what happened in Milwaukee, a number of communities along the lake installed ozonation,” he continues. “UV [ultraviolet] technology was in its infancy, and membrane filtration was just not scaled large enough. We looked at all three of them from the standpoint of risk reduction cost and operations. We eliminated ozone and UV, because in order to inactive the organism, you have to make sure it’s exposed to the light or the chemical.
"Eventually we did some pilot testing with membrane filters,” explains Kosterman, “and in the early 2000s, we made the decision to go with immersed membrane technology from GE, because we saw it as an absolute barrier. As long as the membranes are intact, the pores are too small for any pathogens to get through.”
Reliable, high-quality water was the utility’s ultimate goal. Budget considerations were also essential—including preserving as much of the old system as possible. “We didn’t want to throw away our conventional plants,” he says. “During the pilot, somebody got the idea of instead of removing the sand out of our filters and putting membranes in our filter boxes, we should look at putting filtered water on some of the membranes as way to reduce long-term operational costs related to cleaning and chemicals. Now we include that as part of the process.”
As a result, the utility has now found a second life for its filter boxes: treating potable water via membrane filtration. “When membranes first came out, the philosophy was you can scrap your old plant and use membranes,” says Hass. “But we found that with filtered water the membranes foul less and we can purchase less membrane area, which brought the cost of own membrane plant down very low. Reducing fouling rates also reduces transmembrane pressure, which lowers permeate pump speeds, which means lower electricity use along with the decrease needed to chemically clean the membrane fibers.”
The utility decided it was easier to build a new plant and install piping to transfer the filtered water over to the new membrane filter facility and then return it back for chlorine contact, rather than tear out the existing plant and retrofit the membranes into its sand filters. A switch from ferric sulfate to polyaluminum chloride in 2008 has resulted in reduction of iron carryover from the conventional treatment plant that adds additional help to reducing fouling on the membrane fibers.
“If we can continue to deliver good quality water in sufficient quantity,” says Hass, “it’s an enticement for businesses to come here rather than some other city that’s landlocked with either poor quality or quantity water.”
Risking New Technology
“People really undervalue water until they run out of it,” says Paul Schuler, GE Regional Executive for Engineered Systems Business. “Which means that not running out of it was top on the list at the Region of Peel in Ontario when it embarked on a proactive strategy to add capacity to its Lakeview Water Treatment Plant, which draws its source water from another Great Lake, Lake Ontario. Additional decision-making included the need to comply with Ontario’s Safe Drinking Water Act and the desire to preserve the regional water supply’s ‘aesthetic quality.’”
The Water Treatment Plant in Racine, WI, uses GE’s immersed membranes.
|GE ZeeWeed membranes being placed into membrane tanks at the Racine Water Treatment Plant
The $144 million expansion utilizes a multi-barrier, mixed treatment train that includes GE’s immersed ultrafiltration membranes in combination with ozonation and biologically active carbon contactors. The new system increased the plant’s capacity from 148 million gallons per day (MGD) to 217 MGD, making it the largest low-pressure, immersed ultrafiltration membrane plant in the world and the first to use ozone and biologically active carbon pretreatment on such a large scale. Space was another factor in the decision to use membranes—the compact plant footprint preserves green space that can be used for recreation.
On a much smaller scale, Monroe Township, NJ, has been fighting an expensive battle for water quality, in this case, against high sodium levels in its source water supply. New Jersey upped the federal standard of 250 miles per liter (mpL) to 50 mpL, which has placed a financial burden on a number of the state’s smaller utilities.
“This is especially true,” says Raymond Jones at Clayton, NJ-based Hungerford & Terry Inc., “where the utility doesn’t have access to multiple wells that would allow them to blend water or is dependent on aquifers that have high salinity.
In fact, this section of southern New Jersey, as well as other areas close to the Delaware River, is known for natural deposits that cause elevated sodium levels in the water supplies. Many south New Jersey communities have adopted high-cost reverse osmosis to strip the sodium out of the water but this also removes other beneficial (and taste producing) minerals like calcium and magnesium, which have to be added back—all at a high cost.
In an attempt to provide a lower cost solution, Hungerford and Terry partnered with local townships to give the municipalities a chance to test the ion exchange resin technology common in industrial use, wherein the sand-like beads attract sodium and exchange it for hydrogen. “We have a lot of customers that can see a tremendous cost savings, and we wanted to try it,” says Jones. “It’s the same basic technology as home water softeners, but based on a different form of the ion exchange resin. Instead of operating to a hardness break, we’re operating to a sodium break. Ion exchange resin technology is not an across-the-board solution to high sodium. Operating to a sodium break is going to be delicate especially in applications where you have high hardness ions. We’ll have to look at it case by case.”
In the meantime, the city had completed a three-month study, and the ball is in their park. Hunterford and Terry has done the preliminary documentation and published a paper on the technology, but the municipalities will have to see the new application approved by the state if they want to use it.
“We discussed this with the NJDEP [New Jersey Department of Environmental Protection] before we initiated the pilot to clarify the criteria they wanted to be covered and tested for,” says Jones. “They came out and inspected the facility. Now it’s up to them.”
The Role of Stakeholders
According to AWWA Director of Federal Regulations Alan Roberson, EPA is currently working on 12 different regulator actions that stem from 1996 Safe Drinking Water Amendments. Likewise, the Office of Groundwater and Drinking Waster is meeting safe drinking water act requirements for identifying new contaminants for regulatory consideration through the Contaminant Candidate List, as well as reviewing existing regulations through the Six Year Review process.
“The timing is such,” says Roberson in a March 2012 regulatory update, “that many of these regulatory actions may converge over the next few years.” Among what he calls “The Drinking Water Dozen,” any one of which has the potential to stir up public controversy, are fluoride, hexavalent chromium (Cr-6), perchlorate, carcinogenic volatile organic compounds (cVOCs), arsenic, and nitrosamines.
“There are a number of ways you can go about meeting regulatory compliance, and they all have advantages and disadvantages,” says Ed Means, senior consultant at Malcolm Pirnie /ARCADIS US Inc. and former water quality director at the Metropolitan Water District of Southern California. “Some folks have gone so far as to try to actually capture risk reduction. The challenge with that is it works contaminant by contaminant, but when you’re dealing with multiple contaminants, there are some false equivalencies that can come into it. Bladder cancer doesn’t equal other kinds of cancer, for example. And when you try to break it down into numeric comparisons, you can very quickly get yourself in a quagmire.
“One of the best examples of where these sort of relative analysis fail is cryptosporidium, which would be much a much greater concern from a public health standpoint in a community like San Francisco where there is a large immuno-compromised segment in the population that might include gays, young people, or the very elderly. So it’s almost that these issues have to be weighed by both technical and lay people.”
Which brings us to stakeholders. “At the end of day, it’s the ratepayers who will pay the price of standards compliance,” says Means. “And because of that, I think they deserve at least an attempt to help them understand the pathways that are going to affect their water bill. In fact, I think we’re going to need these processes more and more as we move into a more and more complicated political environment and we have significant shortfalls in revenues. It’s becoming more expensive to get incremental risk reduction in an economy where there’s a lot more resistance to the kind of rate increases that are often necessary. Stakeholder involvement is not the easiest or cheapest pathway, but it’s better to invest the money upfront and have a sustainable solution than trying to do it quick and dirty and have the political wheels fall off at the end.”
Aerial view of Racine's Water Treatment Plant
That being said, Means thinks utilities must adopt individualized decisions about stakeholder engagement. “If you can convey that value proposition short of a big stakeholder process, go for it. Maybe you’ve got really good communication with the community and you don’t have to do anything but the typical kind of public outreach. But if it looks like the issue is going to be controversial from a rate standpoint or a public health standpoint . . . at least you will have the opportunity to articulate what the challenges are, and when you go to your decision-making body, you’ll be able to know where the opposition will be coming from and you can articulate why the direction you’re taking is the right direction, whether the public is supportive or not.”
Just such an outreach project was undertaken by the Army Corps of Engineers for the Washington Aqueduct, the water wholesaler that serves, among others, the nation’s capital. The goal was to develop consensus around issues such as emerging contaminants, disinfection byproduct risk, and in general plans about improvements to the resiliency of the system and performance optimization. To facilitate the discussion managers brought together the public with a panel of experts who could lay out the issues, the risk management opportunities, available technologies to manage those risks, and ultimately what it would cost to go down different compliance pathways. The two public workshops, which Means facilitated, resulted in a draft plan for the utility to guide long-term planning. He points out that this kind of stakeholder involvement was critical for a utility that serves agencies of the national government and in a region that has developed an active group of non-government organizations, which take a keen interest in how it operates.
A Futuristic Orientation
In Arizona the City of Glendale may have had a little more public feedback than it may have liked—600 to 800 complaints a year about taste and odors related to the algae in its water supply. The water in the 30- to 150-mile-long uncovered canals that deliver surface water to Glendale’s treatment plants can rise to 102°F in summer. Evaporation during transportation also elevates high mineral concentrations in this source water, resulting in high total dissolved solids and hardness. As if this wasn’t enough, there was the need to comply with EPA’s Stage 2 Disinfectant and Disinfectant Byproducts Rule.
To address these challenges, the city opted for a comprehensive facilities planning and design project that ultimately led to both improvements in two older facilities and development of a new treatment plant. The city’s three water facilities serve water to 300,000 people in the city itself, 55,000 residents of Peoria, and approximately 1,500 in Phoenix. Its Cholla facility (rated at 30 MGD) and new Oasis Water Campus (12.5 MGD) treat water from the Salt River Project Arizona Canal, with the Oasis facility also equipped to take in and mix groundwater into the potable water supply.
As part of its long-range system retrofit, the Cholla plant converted four conventional anthracite sand filters to deep bed reagglomerated granular activation carbon (GAC) and added two additional GAC filters, along with new solids removal equipment, sedimentation basins, and chemical feed to control pH during water treatment. The new Oasis plant was designed from the start for deep bed mono-media GAC filters.
As part of the planning process, the city did almost two years of piloting in which it evaluated a range of options including chloramines and ozone. Water Plant Superintendent Rick Scott says the decision not to go with chloramines was based on concern about controlling renitrification; also that two of the other municipalities the city serves have free chorine systems, and either wouldn’t be able to accept the city’s water or would have to convert to chloramines, which neither was interested in doing. It tested ozone among other treatment technologies, but because the city’s surface water contained so many bromated species, the water ended up over the maximum contaminant level for bromates.
Eventually, the city settled on carbon filters and set up test beds to compare available types: reagglomerated coal-based carbon (which lasted for the six-month life of the pilot with residual capacity), coconut- and wood-based carbons (both of which lasted four to four-and-a-half months), and carbon imported from China (two-and-a-half months). It ultimately chose deep bed reagglomerated granular activated carbon from Calgon Carbon to solve both its taste and odor problem and comply with EPA’s Stage 2 mandate.
Scott reports that the goal in choosing the 8 x 20 mesh reagglomerated bituminous coal-base virgin activated carbon from Calgon included life-cycle savings, upfront capital cost construction, and lower operation and materials expenses. In addition, the technology will make it possible for the city to treat for chemicals EPA hasn’t yet regulated, including personal care products and pharmaceuticals. With a total of 220,000 pounds of spent carbon to dispose of, the city turned to reactivation wherein the spent carbon is removed for reactivation and then delivered back to the original facility. Because of material lost during reactivation, the city is now using a combination of 80% reactivated and 20% virgin carbon. Scott notes that the reactivated carbon does a better job than virgin in filtering turbidly levels.
The type of planning and analysis the City of Glendale undertook to solve its water quality and standards compliance challenges fits the profile of what Schuler at GE calls a business as opposed to utility orientation.
Right on, says LeChevallier at American Water. “What we’re really talking about is integrated water resource management, which means having a holistic look at our water supply and managing it as an entire cycle, source water, treated potable water, and wastewater,” he says. “This includes looking at the energy footprint. We’re using technology that allows us to increase or decrease our pumping based on the availability of real-time measurements of electricity in the electric grid, because the more sustainable we are in managing the electric grid, the less greenhouse gases to impact that overall water cycle.
“One of the biggest challenges for most water supplies is algae during the summer,” he adds. “The two compounds that cause the odor and taste are hard to treat. You have to go to use ozone or UV hydrogen peroxide technologies that are very energy-intensive, but we’ve found that biologically active filtration breaks down these odor compounds. It allows the microbes to grow on the filter media and do the job. So instead of regenerating the carbon in granulated activated carbon filters, we’re moving toward leaving the carbon in place and allowing the microbes to do the job.
LeChevallier continues, “The water industry is conservative for good reason. It recognizes the important role that it plays in public health. But we’ve got to find a way of thinking, and testing, and evaluating new technology—that if it looks good, we can find an avenue to take advantage of it.”
“In terms of regulatory compliance,” says Means, “I think a targeted action plan is the best. It brings together the engineering, operations, and water quality staff—maybe planning as well. Together you dissect the regulation and evaluate each implication across the entire organization. Then, you develop a specific set of actions necessary to either implement whatever information you have, or get the information you need. This may include pilot studies, demonstration studies, or maybe simply paper desktop studies, but essentially it articulates and identifies every step that has to be taken to get to an answer. Then, each and every one of those steps is given a specific sponsor and a timeframe and a budget, and the final action plan is crafted in a fashion that it’s a decision document, which can go from the organization up to senior management.”
Penelope B. Grenoble writes on issues concerning resource management and technology.