BIOBAN CWT Brand of 25% Aqueous TRIS(HYDROXYMETHYL)NITROMETHANE Cooling Water Treatment Microbicide EPA Reg. No

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1 Product Information Brand of 25% Aqueous TRIS(HYDROXYMETHYL)NITROMETHANE Cooling Water Treatment Microbicide EPA Reg. No General BIOBAN CWT has been utilized successfully to control the growth of many different types of bacteria in cooling towers and evaporative condensers (including sulfate-reducing and slime-forming bacteria). In addition, possesses several additional attributes which enable it to overcome many of the drawbacks which historically have limited the use of traditional treatment programs: is effective over a broad ph range. In fact, its performance is actually enhanced in the alkaline ph range typified by many of today s cooling water systems. has proven to be a cost-effective bactericide, especially when compared to many other commonly-used microbiocides. has a quick speed of kill when compared to many other water treatment biocides. can be used in combination with other biocides and is especially effective in combination with isothiazolinones. is not a skin sensitizer. Nonionic and non-oxidizing, is compatible with other treatment chemicals, including charged polymeric and phosphorus-based dispersants and inhibitors. Even when slug fed to the system, will not cause ph fluctuations within the recirculating water. Consequently, operating conditions are more stable and program performance is improved. does not foam and is virtually odorless, important considerations from both an operational and product handling standpoint. has low mammalian, avian and aquatic toxicity and is compatible with sludge-activated waste water facilities, factors which help to further ease environmental concern. Laboratory Evaluation The inhibition of microbiological growth in the cooling system is dependent upon the concentration of antimicrobial activity in the treatment solution. Based upon more than 15 years of actual field experience, it has been determined that can be either slug fed or continuously applied to the system at a rate of ppm (as supplied) to achieve desired levels of microbiological control. Cooling systems operating at lower ph and temperature levels (i.e., less than 7.5 and 30 C, respectively) will require dosing in the upper portion of the recommended range as these conditions do not readily promote the release of formaldehyde from. 1 Not registered for use in the State of California. Page 1 of 6

2 A study utilizing Pseudomonas aeruginosa showed to be a quick kill biocide with faster performance at alkaline ph levels (Figures 1 and 2). Although some antimicrobial activity is provided by at a ph as low as 6.0, the product is most effective at a ph of 7.5 or higher, where the gradual release of formaldehyde provides continuous antimicrobial action for prolonged periods of time. At the more alkaline ph (8.5), 50 and 75 ppm active showed about a 2 log reduction in bacterial numbers by 4 hours, and about a 4 log reduction in bacterial numbers by 8 hours. Figure 1 at ph ppm active CWT 25 ppm active CWT 50 ppm active CWT 75 ppm active CWT Figure 2 at ph ppm active CWT 25 ppm active CWT 50 ppm active CWT 75 ppm active CWT Page 2 of 6

3 Laboratory tests utilizing mixed microbial populations from several cooling towers demonstrated that 150 ppm (active) reduces cooling tower bacterial viable counts by 99 percent within 24 hours and suppresses populations by percent after three days (Figure 3). Figure 3 Efficacy vs. Cooling Water Microflora Sample 1 Sample 2 Sample 3 Sample 4 Sample Day Each sample was treated with 150 ppm (active). Additional laboratory studies were conducted to evaluate efficacy against Legionella pneumophila, the causitive agent of Legionnaire s disease (Table 1). This demonstrates that is effective against Legionella pneumophila at concentrations as low as 10 ppm (active). Table 1 Effect of on survival of Legionella pneumophila (Active) 3 24 (ppm) Survivors Log Reduction Survivors Log Reduction x 1.0 x x 0.15 <20 > <20 > <20 > x 1.24 <20 > x <20 >3.70 Results of tests performed in ph 8 buffer at 37 C. has also been shown to be effective in combination with isothiazolinone chemistry, particularly 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and 2-methyl-4- isothiazolin-3-one (MIT). When used in combination with isothiazolinones, a broader spectrum of antimicrobial activity is achieved. In addition, a faster speed of kill is seen. Speed of kill is especially important in cooling water systems with short holding times and low cycles of concentration. Laboratory studies have demonstrated that 25 ppm active in combination with 0.5 ppm active CMIT/MIT shows equivalent antibacterial performance to 1 ppm CMIT/MIT alone (Figures 4 and 5). Faster speed of kill is seen with this combination especially at a ph level of 8.5 (Figure 5). Page 3 of 6

4 Figure 4 / ISOTHIAZOLINE (ITZ) Combinations at ph 7.5 (All biocides ppm active) ITZ 1.0 ppm ITZ/CWT 0.5/25 ppm ITZ/CWT 1.0/25 ppm Figure 5 / ISOTHIAZOLINE (ITZ) Combinations at ph 8.5 (All biocides ppm active) ITZ 1.0 ppm ITZ/CWT 0.5/25 ppm ITZ/CWT 1.0/25 ppm Field Trials Trial 1 is equally effective in the field. A 10,000 gallon open recirculating cooling water system operating with a crossflow tower and the following characteristics was shock fed with 600 ppm (150 ppm active). Water Characteristics ph: 8.5 Conductivity, (as µ mhos/cm): 1,150 Total Hardness, (ppm as CaCO 3 ): 155 Total Alkalinity, (ppm as CaCO 3 ): 350 Chlorides, (ppm as CI): 140 Maximum Water Temperature, ( C): 40 Cycles of Concentration, (by chlorides): 4.2 Page 4 of 6

5 Samples were analyzed for bacterial levels and concentration. The data presented (Figure 6) indicate bacterial populations were reduced by 90 percent within 30 minutes and were controlled (>99% inhibition) for the duration of the test. Concurrent analysis of formaldehyde in the air space above the system (Figure 7) shows that formaldehyde concentration never approached the OSHA action level (0.5 ppm). Figure 6 in Cooling Tower Percent Inhibition Percent Inhibition ppm Active ppm Active TIME () Figure 7 Formaldehyde in Air Above Cooling Tower Treated with ppm Formaldehyde in Air OSHA Action Level 1 Actual TIME ( Since Treatment) Note: 1) At OSHA Action Level, Monitoring is Required Trial 2 Another four-month field trial was conducted in a 10,000 gallon open recirculating cooling water system containing water with the following characteristics: This system circulated 3600 gpm to a 1000 ton absorption chiller. It was treated with 300 ppm of twice weekly. Water Characteristics ph: 8.2 Cotal Alkalinity, (ppm as CaCO3): 250 Total Hardness, (ppm as CaCO3): 150 Conductivity, (as µ mhos/cm): 1,080 Chlorides, (ppm as CI): 30 Throughout the four-month study, bacterial levels remained well below the 1 x CFU/mL criterion level (Figure 8). Visual inspections revealed that the tower structure remained free of microbiological deposits. Moreover, feeding the highly-concentrated product to the system in moderate quantities only twice per week reduced chemical consumption rates and associated treatment costs by over 80 percent when compared to the previous program. The use of a liquid product also greatly improved plant safety by allowing for the automatic Page 5 of 6

6 addition of biocide to the system, an advantage that was quickly recognized and adopted by management personnel for use throughout the plant site. Figure 8 Field Trial Microbiological Analysis Bacterial Count Limit /1 12/15 1/1 1/15 2/1 2/15 3/1 3/15 4/1 4/15 Dates Conclusion provides broad-spectrum, cost-effective microbial contamination control in cooling water. A versatile antimicrobial, is virtually free of environmental, health and safety problems. In addition, shows excellent efficacy when used in combination with isothiazolinones (CMIT/MIT). Complete instructions on the handling and use of are given in DOW Technical Information Sheet No , available on request. For further information visit our website: or call United States (phone) and Canada: (phone) (fax) Europe: (phone) (phone) Pacific: (fax) (phone) (fax) Latin America: (phone) (fax) Other Global (phone) Areas: (fax) NOTICE: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer s use and for ensuring that Customer s workplace and disposal practices are in compliance with applicable laws and other governmental enactments. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED. Page 6 of 6 Printed in U.S.A. *Trademark of The Dow Chemical Company