In certain applications it may be desirable to use an entirely different chemical reagent to destroy the chlorine, this reagent is ascorbic acid, commonly known as, Vitamin C or our Tramfloc Ascorbic Granules. Ascorbic acid is applied as a granular material (Tramfloc Ascorbic Granules) to create a solution which is fed to a chlorinated stream to destroy the chlorine. In certain regulatory environments, ascorbic acid is the preferred dechlorinating agent because our material is so benign and is beneficial to aquatic plants and animals. The end-user would be wise to consult the regulators in his locality to determine which of our reagents would be the most acceptable in a specific dechlorination application. We use a stoichiometric dosage of 4 ppm granules/1 ppm Cl2. For feeding techniques and dosage information, please contact Tramfloc, Inc.

For additional information about these three dechlorination reagents, please see our Dechlorination Chemicals section on the home page and review both the Tramfloc MSDS and Technical Information Bulletins. Please contact our technical department for recommendations for your specific application details, product dosage, and project cost estimates. Regulators are increasingly requiring contractors to apply on ascorbic acid granules due to safety and environmental concerns about other chemical reagents, even if these other chemicals are known to be benign. While treatment costs with ascorbic acid, Tramfloc Ascorbic Granules tend to be higher than our tablet or liquid, the regulators usually always give their unqualified preference and approval to this special “Vitamin C” reagent.

Please be sure to review the home page menu about our “H2O Neutralizer Device” which is used to deliver the dechlorinating solution made from liquid Tramfloc® 905, Dechlorination Tablets or Dechlorination Ascorbic Granules/Tablets. This device is used to accurately apply the selected dechlorinating solution at the optimum dosage rate to produce complete chlorine destruction with the lowest reagent usage to control your costs.

COMPARISON: Tramfloc® Ascorbic Granules versus sulfates, sulfites, bisulfites, metbisulfites, thiosulfates)

Tramfloc® Ascorbic Granules Sulfur-based Products
Oxygen: No Yes
Un-dissolved Solids (tablet form) No Yes
Reaction Time with Cl Instantaneous Slow – several minutes
Product Raw Material Grade Food Grade Industrial Chemical
Benefit to Aquatic Life Yes No
Human Toxicity Little to none Minor to very hazardous

COMPARISON: Tramfloc® Ascorbic Granules versus sulfates, sulfites, bisulfites, metabisulfites, thiosulfates)

Chemical Form Dissolved Oxygen Scavenger DOT Rating Aquatic Toxicity
Sulfur Dioxide Gas Strong Poison NA
Sodium Bisulfite Powder/Crystal Strong Corrosive Toxic
Sodium Metabisulfite Powder/Crystal Strong Corrosive Toxic
Sodium Sulfite Powder/Tablet Moderate Non-Hazardous Toxic
**Sodium Thiosulfate Powder/Crystal Moderate Non-Hazardous LC50-7.3 g/l
*Calcium Thiosulfate Powder/Crystal Weak Non-Hazardous LC50-7.3 g/l
TFL Ascorbic Acid Powder/Tablet No Non-Hazardous N/A
Sodium Ascorbate Powder Powder No Non-Hazardous N/A

*Calcium Thiosulfate (CaS2O3)

Calcium thiosulfate is a clear crystalline substance, with little color, a faintly sulfurous odor, and near neutral pH. It reacts with free as well as combined chlorine.

One concern with using calcium thiosulfate is that dechlorination reactions using stoichiometric concentrations require nearly five minutes for complete neutralization (6). Over-dosing of calcium thiosulfate may produce milky-colored suspended solids, causing turbidity violations. Also, excess thiosulfate release may promote thiobacillus bacterial growth.

**Sodium Thiosulfate (Na2S2O3)

Sodium thiosulfate is a colorless, transparent monoclinic crystal widely used by municipalities for dechlorination. It undergoes multiple reactions with free and combined chlorine, depending on solution pH (1,3).

Sodium thiosulfate is a skin, eye, nose and throat irritant. It has an NFPA Rating of 1,0, 0 for health, fire and reactivity, respectively. An EPA toxicity study indicated that sodium thiosulfate is not very toxic to aquatic species. Sodium thiosulfate may react slowly with chlorine under some conditions and requires more time for dechlorination than most dechlorination chemicals (4). Over-dechlorination with sodium thiosulfate may encourage thiobacillus and some other bacterial growth in receiving streams, particularly during low flow conditions.

(*) and (**) From Guidance Manual for Disposal of Chlorinated Water, AWWA Research Foundation

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