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Feature wateronline.com ■ Water Online The Magazine 16 Most utilities will be starting from scratch, however, from a learning standpoint. "There's quite a bit of training and chemical handling," noted Kolisz. "A process like this is a lot more challenging than just replacing the media. When you start getting into pH control and those chemicals, there's a certain level of operator that you would want to have working on the system." Safety training is equally important. Operators need to exercise caution when working with sodium hydroxide and sulfuric acid. They need to be trained in safe use and handling, and always wear proper personal protective equipment (PPE). The effluent produced from the regeneration process is also dangerous, at least from an environmental perspective. Twentynine Palms, which is not connected to a centralized sewer system, was initially forced to haul the effluent for offsite industrial treatment, which cut into its savings considerably. Much of the savings was recouped once the utility began treating the wastewater onsite — using ferric chloride to precipitate arsenic from the effluent — after which only a small amount of residual needed to be disposed. Though Kolisz called disposal "a major cost," it's worthy of mention that when Twentynine Palms was paying for wastewater removal, the entire media regeneration process was still 60 percent less expensive than repurchasing. Communities and water agencies that are piped into the sewer system are in better shape, as sewers are deemed an appropriate and acceptable discharge point. A third factor to consider before adopting regeneration is attaining proper permission. "Any time you change a process, you have to get state approval," the EPA's Tom Sorg reminded. The approval and success at Twentynine Palms should bode well for others, however. Referencing the California Department of Health's strict reputation, Sorg commented, "If you can get California to approve something, then you can get almost any other state to do it." A final point of consideration, submitted by both Sorg and Battelle research scientist Vivek Lal, is the acknowledgment of a "break point" where operations would be too small to realize the value of media regeneration — where replacement is the less expensive option. "I suspect that the break point would be between 25 and 50 ft 3 " of media volume," estimates Sorg. The Bottom Line The cost-saving opportunity from regeneration is variable depending on the amount of media typically used and frequency of replacement, but Twentynine Palms Water District serves as a good gauge of potential. With each regeneration performed in lieu of repurchase, Twentynine Palms saves nearly $15,000. The utility reports the cost of media replacement to be $20,500 per tank for Well 11, compared to chemical expenses of just $1,000 per tank and current disposal costs of around $5,000. Even with the initial, one-time investment for minor pipe modifications and design work (less than $5,000) coupled with the former disposal cost of $10,000 (prior to instituting on-site treatment), Twentynine Palms saved $5,000 on its very first media regeneration. "It saves us quite a bit of money," said Kolisz. That is perhaps more understatement, considering that Kolisz's colleagues — the EPA's Sorg and Battelle's Lal — attested to the rising costs for adsorptive media. As the price continues to climb, utilities will save even more. And, again (amazingly), Twentynine Palms is still seeing no degradation in the regenerated media. Could it be that they will never purchase media again? While the true potential for this new process has yet to be determined, the opportunity to take advantage of its proven benefits is readily available to water agencies right now. "We're trying to get the word out that this can be done, and it can save you a whole heck of a lot of money," said Kolisz. "It's up to the agencies to use the data and resources they have to make that decision." Sodium hydroxide is prepared for regeneration. For traditional treatment, the biggest expense is purchasing new media. 1 4 _ V E R T _ 0 5 1 4 C l e a n w a t e r _ F e a t u r e _ D G . i n d d 3 14_VERT_0514 Cleanwater_Feature_DG.indd 3 4 / 2 1 / 2 0 1 4 3 : 5 2 : 5 5 P M 4/21/2014 3:52:55 PM