Arsenic and New Place

March 1, 2009

When it comes to age, Arizona cities, such as Buckeye, are rather young. Naturally, so are water treatment plants in the Phoenix, AZ, metropolitan area and elsewhere in the Southwest. As with older cities, though, one concern is getting arsenic out of the water. This nationwide problem is well documented in Arizona, so it was no surprise when builders in a master-planned community drawing water from four new 1,000-foot wells found that metallic element awaiting consumption. The levels proved significantly higher than federal standards, so something had to be done quickly. The solution? An arsenic removal system was added to the recently constructed water storage and pumping facility.

Generally, municipalities that fail to meet the new federal standards regarding arsenic haven’t much of a footprint to add another element to the existing treatment plant. Fortunately, the water campus in that part of Buckeye had more than enough room for expanding the system. The footprint needed for adding on an arsenic removal system was no problem. This also meant there was room enough for site workers to do their jobs without getting in the way of one another. Ditto for working on the edge of safety (which can prove more dangerous than drinking arsenic-contaminated water). Plus, a site already prepared for expansion as more homes and commercial buildings are constructed in this young community meant minimal change to the landscape. This kept further site preparation to a minimum, making it possible to meet the deadline for the addition.

“Sundance is a master planned community,” explains John Keenum, president of Buckeye Land Management Inc., which is a consortium of eight builders in the service area. He notes that he moved into the area when the project was already in the works. But that didn’t hinder him from contributing counsel when needed as construction proceeded. “I was involved in the engineering and construction phases,” he says. “Our quarterly meetings have to do with the complete water system, including water, wastewater, the sewer system, et cetera.”

With the mandate to meet federal specs, the developers are now using the system–which currently supplies water to 4,500 homes and 20 businesses–as an opportunity to build an additional arsenic removal facility. They hope to have the facility up and running as quickly as possible, so as not to disrupt current water delivery to area homeowners.

As with other large areas, arsenic levels can vary according to the locale. While a given area may meet the decreed levels, parts may need to add a removal facility to their treatment plant. This difference is even more pronounced in the Phoenix metro area that is half the size of Massachusetts. “In the Phoenix area, the northern half has clean water, but in the southwestern portion, arsenic in the water is more of an issue,” says Keenum, a holder of advanced degrees in construction management and finance. During his 20 years dealing with land and water development issues, Keenum has been involved in two other arsenic removal projects.

Constant Communication a Success Element
Keenum notes that he met 2–3 times a week with the design engineer, the contractor, and Buckeye’s water management people. All four major parties participated in the scheduled Wednesday meetings during the construction phase for the Sundance Arsenic Removal Facility. “Coordination and communication made a major difference,” says Keenum. “Nobody else does the same thing we did, because there were so many parties involved. Any issues were brought to the attention of others daily.” He then praised the professional level of Hunter Construction, who built the facility.

He cautions, “You need to keep dealing with water treatment needs at a minimum. For instance, blending well flows can lower the numbers, so there’s no need to treat for arsenic. Any time you make water treatment more technical, the more apt you’ll have problems. You want the most efficient system, one that’s as simple as possible.” This strategy also helps keep billing rates down.

Supervising Water Treatment
“Our water management area is 640 square miles,” reports Rick Morley, former Water Production Supervisor for the Town of Buckeye, which has 7,000 billing customers and five separate water systems. The Sundance Water Arsenic Removal Facility delivers metered water to just 4.5 square miles of residential and commercial sites. “We started delivering treated water at the end of the first quarter 2007,” he says. “Arsenic levels varied from 47 mcg [micrograms] to 27 mcg, in the best of the four wells. The national standard, which became law in 2006, calls for less than 10 mcg.”

Photo: RBF Consulting
A community development fund made possible the study of various removal processes.

Water Supervisor Explains System Used
Speaking from 18 years experience in dealing with water matters, Morley continues, “Well depths in this area tend to average 500 to 600 feet, with production ranging from 800 to 1,200 gpm [gallons per minute]. The challenge was to determine which would be the best removal system to use in this locale. We chose coagulation filtration, because it allows us to use a tank as a clarifier where we can concentrate the arsenic. With coagulation filtration, when bound with iron, arsenic becomes a sludge.

“Currently, we collect that sludge in a storage tank and put it into the sewer system at a rate that matches the diurnal Sewer flow,” he adds. “This helps ensure that the sludge isn’t pumped into the sewage system in one removal cycle. Doing that could overpower the ability of sewage treatment plants to deal with the sludge.”

Time Flow and Iron
Morley says that such a system includes adding the proper amounts of free chlorine, which almost instantaneously changes the valence of the arsenic, giving it an affinity for iron. “When we add the ferric chloride, the iron and arsenic combine. The treated water then goes through a filter where the iron and arsenic are removed, giving users potable water with an arsenic level that meets the stricter federal specs.”

How successful has this system been? Morley confesses, “It’s not designed for complete removal, but the arsenic in the treated water has dropped to at least eight micrograms, which is two micrograms under the Maximum contaminant levels. The last quarterly sample had just 1.5 micrograms of arsenic. Lower numbers aid in assuring the Regulatory Agencies that the Sundance Arsenic Removal Facility will easily pass periodic inspections.”

Morley reports a community development fund made possible the study of the various removal processes. “RBF Consulting is a civil engineering, land planning, and surveying firm,” he says. “They had a full report for evaluation in less than 90 days.”

Buckeye monitors the operation because the facility was built for them to own and operate. Cost of operations is funded by revenue from the users. “There have been no changes to billing due to the operation of this system,” he adds.

Photo: RBF Consulting
It took engineers just 90 days to draw up plans for the Sundance Arsenic Removal Facility, with RBF Consulting handling the specifications.

Fourteen Months to Completion
Buckeye’s water production supervisor monitored the construction phases for this addition to an existing removal system. That took 14 months from the go-ahead to the finish. “The material supply all worked out,” says Morley. “There were some minor obstacles. For example, we have several automated valves on the site, and micro switches in some of the valves were not operating as planned, so it took some time to resolve the problem. Challenges need to be overcome in most major projects, as they were on this project. However, with creative solutions, our timelines were met for the delivery of the water.”

He notes that the facility is located in the middle of the community and has its own service area. A five-acre water campus, with storage tanks and booster facilities, is all the space it takes to provide safe drinking water. “Water out of the ground ranges from 94°F to 96°F year-round, so in a summer environment it is difficult to cool water back down. Fortunately, with nighttime temperatures of 85°F even in the midst of summer, the storage tanks get significant cooling before dawn.”

Communication Made for Greater Progress and Smaller Obstacles
Like Keenum, Morley comments that the standout success of the Sundance Arsenic Removal Facility included great communication among all four major entities involved. “In essence, we met often enough to make sure all big picture elements were in focus. Hunter Construction handled the job, and I met daily with the construction superintendent to see what we could do to help each other,” he says. “We all helped each other anticipate problems.”

One problem, unseen even by the equipment supplier, was checking the chlorine levels. “Maricopa County provides a solution of chlorine and checks the level in the treated water,” says Morley. “But they never could get a residual reading, because the filter would absorb the chlorine.”

A post chlorination injection point was added downstream of the filter equipment. That was the only surprise in the project, and it took just 10 days to solve the problem. Best of all, finding that solution didn’t affect construction progress.

Easy Access
Because the eight developers in the affected area built the original plant with an eye to saving enough room for future construction, security, site traffic, and safety concerns were fairly minimal. “At the peak, there were about 25 people on the site at the same time, says Morley. “Very little piping and electrical work was needed and very, very little trenching, thanks to the first phase planning.”

Automated Success
Morley reports the life expectancy of all components to be at least 20 years. It’s a fully automated system, and daily walkthroughs to ensure that everything is working correctly take about 45 minutes. Rapid growth of this city from 5,000 to 60,000 in the past decade presents challenges to this water production supervisor and his three assistants. “First and foremost is diligence in delivering the finest water we can to make sure water coming out of the faucet is safe,” he says.

In the Beginning…
As mentioned, it took the engineers just 90 days to draw up the plans for Sundance Arsenic Removal Facility. RBF Consulting, of Phoenix, handled the specifications, says Ryan Christensen, water and wastewater engineer for that project. “Good communication helped facilitate the project,” he reiterates. “Besides the arsenic removal facility, we designed the storage reservoirs, consisting of two reclaimed water reservoirs and two finished water tanks. The reclaimed water reservoirs hold about 200,000 gallons each, while the storage tanks hold 2.7 million gallons and 1.5 million.”

Photo: RBF Consulting
Since the system is fully automated, a daily, 45-minute walkthrough is completed to ensure that everything is working correctly.

Care, communication, and storage helped ensure that no one in town was without treated water. The public received protection at all times. “It took 20 months from raw land to the finished removal plant,” he says. “We were able to work with the contractor on the design.”

Christensen explains that the arsenic removal system was designed to efficiently recover over 99% of the backwash water. “The contractor sourced the materials for coagulation filtration from Pureflow in Whittier [CA]. Their design and product quality minimizes overall maintenance.”

Like the others, Christensen emphasizes the major key was getting all the parties involved, to have parties communicate with one another. “Basically, it was a matter of getting everyone on board and being involved up front,” he says. “This made for successful completion in the time frame allowed, because it kept surprises to a minimum. This is one of the primary reasons that it turned out to be a highly successful project.”

Qualifications Help Contractor
But, how does one get the best contractor for the project? The secret is rather than negotiating for bids to ensure the lowest price, to select by the reputation of the contractor, instead. In this case, the contractor brought on board was Hunter Contracting Company, headquartered in Gilbert, AZ, a community in the southeastern part of the metropolitan area. This heavy construction company includes water and wastewater treatment construction in its host of different kinds of construction, and has built a number of general water treatment plants in Arizona. “Still, the price has to be within budget,” emphasizes Gary Hornberger, superintendent for Hunter Contracting. “The contractor, engineer, and owner work together. It is not an adversarial relationship, but working together as partners; that is a wonderful practice.”

Plans were at 30% completion when the company began working with the others. They broke ground in June 2005 and had the plant up and running September 2006. Hornberger also notes the booster plant had to add on the arsenic removal portion in order to supply water meeting the acceptable limits of the new federal standards for arsenic. At the same time, they added some additional water storage to handle future growth in the area.

They also had to get the work done safely. “Safety is our number one goal,” says Hornberger. “We have an incident ratio well below the industry average. We had zero injuries on the Sundance project.”

Standard safety measures include specialized training as needed, as well as a hazard analysis before construction begins. They also employ the buddy system. In all, the Industrial Division of Hunter Contracting Company has worked over 600,000 man-hours without a lost-time injury.

One focus was to avoid the expense of early purchase, and to limit cluttering the site with materials that would not be used rather quickly; delays were not a major problem. “We had to modify the schedule a few times, and material delivery was one reason,” says Hornberger. “All products had to be approved before they could be purchased. This was a unique job, but we were able to meet the deadline.” During construction, Hunter had a maximum of 35 employees onsite, averaging a dozen workers in all. While it was a unique project, standard backhoes, loaders, and cranes were sufficient for the job at hand.

Crew Experience Counts
One of Hunter Contracting’s strengths is the experience and the diverse abilities of its workers. “It was mostly standard construction,” says Hornberger. “We utilized subcontractors for some of the special trades such as building tanks and the electrical, but we handled the other elements of the project ourselves.”

Hornberger agrees effective communication helped keep the job within budget and on time.  “We had weekly meetings with the engineer, Buckeye’s water manager, and the developer to discuss any problems or areas that would hinder the project,” he says. “Our weekly meetings were chiefly at the engineer’s office because of the central location. From time to time, we met onsite. Most of the time, the problem was settled during those meetings. We didn’t have to table problems; we were able to go ahead with the game plan.” Excellent communication helped save time and avoids conflicts that would have added to the cost of the project.

Resolving Conflicts
Despite continued communications, now and then a conflict arose. For example, while excavation was kept to a minimum, some utilities were in place right where we needed to dig. The problem was resolved on the spot. Hornberger comments, “There were design changes to make construction more feasible. Those changes were brought to the table and were agreed upon, which saved time and money for the project. Sometimes there was not that much money involved, but it saved time that maintained the schedule of the project.”

Overall, each party’s background and experience–along with cooperation and communication–ensured timely and correct construction. In the end, the long-term winners are those who pay their monthly water bills as timely as construction of the Sundance Arsenic Removal System.

About the Author

Joseph Lynn Tilton

Journalist Joseph Lynn Tilton specializes in land and building issues.

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