Better water technology is on tap

The drought in many parts of the U.S. so far this summer points out the preciousness of water supplies. There’s greater demand for waste-minimization and recycle-and-reuse technologies as well as more awareness of utility usage and the impact of life-cycle costs on water-treatment operations. Here’s a look at new technologies that will help.

By C. Kenna Amos, contributing editor

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The drought in many parts of the U.S. so far this summer points out the preciousness of water supplies. The chemical industry cer-tainly didn’t need the weather to sensitize it to the importance of optimizing water use (see www.chemicalprocessing.com/articles/2005/571.html). There’s greater demand for waste-minimization and recycle-and-reuse technologies, says Hari Gupta, Schaumburg, Ill.-based director of application engineering for the build-own-operate group within Siemens Water Technologies Corp., Warrendale, Pa. There’s also more awareness of utility usage and the impact of life-cycle costs on water-treatment operations, he adds.

Meanwhile, another summer hot button, the high price of gasoline, spurred at least in part by refinery output limitations, is adding to the driving force for water initiatives at refineries. “The refining industry faces issues with aging infrastructures, increasing capacity,” notes Tom Sandy, principal technologist and global wa-ter-and-process-practice leader in CH2M Hill’s energy and indus-trial-systems business unit, Charlotte, N.C.

So, it’s not surprising there’s a flood of new technology for water treatment. Here’s a rundown on some noteworthy develop-ments.

Tackling transients

Nalco Co., Naperville, Ill., has enhanced its well-established Trasar technology to better detect and compensate for changes in water-treatment systems subject to varying conditions or frequent upsets. It launched 3D Trasar for once-through cooling this year (Figure 1), with commercialization of 3D Trasar for reverse osmo-sis (RO) planned for later this year and 3D Trasar for boilers ex-pected to debut in 2008.

Figure 1. Using tagged polymer and taking measurements every six seconds afford better control in highly variable systems. Source: Nalco.
Figure 1. Using tagged polymer and taking measurements every six seconds afford better control in highly variable systems. Source: Nalco.

All three use a fluorescent “tagged” polymer that, when added to the water, reacts with dehydrogenase, an enzyme pro-duced by living organisms, explains Daniel M. Cicero, senior product manager with Nalco’s cooling-water programs and tech-nology group. When tag-containing water passes through an in-line fluorometer, measured fluorescence directly correlates to concen-tration of treatment chemical, i.e., scale or corrosion inhibitor, or dispersant, he says. The Trasar controller gives analyses every six seconds. The measurements provide an ongoing indication of the scale-forming stress on the system and are said to allow much bet-ter control in highly variable systems.

To eliminate guesstimating, Nalco’s technology suite incor-porates a chemical modeling tool. “Users input the local water conditions, variability, special operational realities and other data,” Cicero says. “The program analyzes the data and offers treatment and control guidance.” This may involve suggestions both as to dosage and changes in operation.

“We have documented many cases where performance im-proved or the causes of problems were uncovered as a result of 3D Trasar technology,” Cicero notes. Before using the technology, it was often unclear that any improvement was even possible, he adds. For instance, with many U.S. refineries trying to maximize output, scaling or fouling of heat exchangers can be a real worry. “3D Trasar has identified ways to avoid the expense of mechanical changes [on exchangers] and eliminate the operational problems,” he says.

The suite also contains 3D Trasar Web, to which controllers upload data hourly. It can produce graphs, retrieve data and, when normal operating limits are exceeded, generate alarms that can be sent via e-mail, digital paging or text messaging. “Many users op-erate several cooling systems in different locations. 3D Trasar Web gives them consistent visibility on every one,” Cicero explains. Systems can be benchmarked against each other, improving trou-bleshooting, maintenance and performance evaluation.

Continuous corrections

Ciba Specialty Chemicals, Basel, Switz., is currently testing online cationic demand control (OCDC) at a German municipal water treatment plant. Ciba hopes to launch this technology, which will be called Ciba Aquawatch, later this year.

“You measure and adjust the dosage continuously,” explains Doug Chamberlin, head of Ciba’s global industry market center for water solutions, Bradford, U.K. In the German municipal applica-tion, the focus is organic colloids, which tend to have a negative electric charge. “We add a combination of coagulants, which dis-rupt the charge, and then flocculants to make a bigger particle,” he says. That eases and speeds sludge dewatering and creates a drier sludge cake.

Chamberlin believes the OCDC technology can be deployed to reduce chemical oxygen demand and biological oxygen demand in industrial wastewaters.

Meanwhile, Ciba in late 2006 in Europe launched Irgatreat MF443, a corrosion inhibitor that finds use in heat exchangers, pasteurizers and chillers. “Irgatreat MF443 contains organics, which have much less impact on environment because they’re bio-degradable,” Chamberlin notes. Ciba hopes to launch the technol-ogy in the U.S. in early 2008, he adds.

Fractal-based flowpath

Figure 2. New treatment system halved deionization chemical us-age and reduced water loss to 2% of total water treated. Source: Rohm and Haas.
Figure 2. New treatment system halved deionization chemical us-age and reduced water loss to 2% of total water treated. Source: Rohm and Haas.

The Advanced Amberpack system, introduced in 2004 by Rohm and Haas Co., Philadelphia, Pa., already has proven itself in min-ing and power generation. A six-month demonstration of this skid-mounted, fully automated technology ended in May at an Ana-darko Petroleum Corp. coal-bed methane (CBM) production site in Wyoming’s Powder River Basin. “The water produced with the methane has to be treated before release to the environment,” ex-plains Jay Miers, market development manager with Rohm and Haas’ ion-exchange resins group.

Another successful application is halfway around the globe in Siberia. In January of this year, OJSC Novosibirskenergo installed the technology at its Novosibirsk Power Plant No. 4 (Figure 2). This allowed the power company to cut deionization chemical us-age by 50% and water loss from 10% of total water treated to 2%. “No major issues [have been] encountered during operation,” notes power plant manager Sergei Miroshnokov, who predicts that “we can do maintenance once a year.”

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