Vitamin C for Chlorine/Chloramine Removal


Vitamin C was originally discovered and selected as our utility’s chemical of choice in 1989 at the suggestion of a kidney dialysis physician1 who furnished medical references for this author to review. Since the use of vitamin C was documented to be an effective technique, preparations were taken to adapt this method into the waterworks field. The Public Utility District of Skagit County is believed to be the first utility to use vitamin C to neutralize chlorinated water in order to protect fish during large-scale flushing operations.

In the beginning, there were few reasons to select vitamin C, other than the fact that it was recommended by a medical professional. Since then, the author has realized numerous new reasons for choosing ascorbic acid to dechlorinate water during flushing operations. What follows are some of them.

Vitamin C boosts the fish’s immune system.

It was not an easy task to find a source for ascorbic acid at a reasonable price or as a powder ready to mix with water. While placing the initial order, the sales representative commented about the large quantities that he also sells to manufacturers of fish food pellets used at fish hatcheries. It turns out that vitamin C is an essential nutrient for fish and actually boosts their immune system. It is essential for their life, and hatchery trout develop cataracts without vitamin C in their diet.

Vitamin C is environmentally logical.

Environmentally, it makes good sense to use a reagent that is beneficial to fish (by strengthening their immune system) to eliminate a deadly pollutant that will kill fish at very low doses (0.011 milligrams per liter chronic level). Use something good to remove something bad. Not only do fish benefit, but all forms of biodiversity found in streams and lakes become stronger and suffer less routine physical distress with increasing levels of vitamin C. Fish have been found to be attracted to it.

Ascorbic acid is comprised of hydrogen, oxygen, and carbon, which after chlorine neutralization, results in a milder and safer reaction consisting of inorganic chloride and dehydroascorbic acid2. The latter byproduct is still a nutritional benefit to living organisms. If ammonia is present in the water to be treated, as found in chloraminated water supplies, another byproduct, ammonium chloride, can be detected. (Ammonium chloride from chloraminated water supplies is thought to be a byproduct with all chemical dechlorination reagents.)

Sulfur-based byproducts that are produced during dechlorination, other than hydrochloric acid, are not commonly known.

Vitamin C is a proven reducing agent.

The Environmental Protection Agency published a report3 in 1989, which listed ascorbic acid as a dechlorination reagent worth considering. Today, water-testing laboratories use ascorbic acid to quench chlorine from a field water sample, which has been drawn for VOC testing at a distant laboratory.

The medical field has used ascorbic acid to neutralize chlorine since the early 1970s. Free chlorine and chloramines were found to destroy the reverse osmosis membrane used during hemodialysis. Today, many doctors prefer large carbon block filters to remove chlorine prior to kidney patient treatment.

Recently, water utilities have also demonstrated effective results in the field. In December of1998, AWWA’s monthly publication, Opflow published an article4 on early vitamin C technology.

A recent American Water Works Research Foundation (AwwaRF) study5 documented the effect of various compounds on oxygen levels. Their findings, which were based on field measurements, indicated that water treated with vitamin C somehow increased the oxygen levels of the sampled water. While this cannot be accepted as the norm, it does reveal that vitamin C imparts less of an effect on oxygen levels when compared to the other sulfur-based reagents that were included in the study.

There is more to vitamin C than ascorbic acid.

The most cost-effective form of vitamin C is in the form of pure ascorbic acid. Vitamin C can also be purchased as sodium ascorbate. Certain utilities prefer sodium ascorbate because of its higher pH. Sodium ascorbate has a pH of approximately 7.8 while compared to ascorbic acid, which yields a pH of approximately 3. Utilities with poorly buffered supplies have noticed a slight decrease in pH when using ascorbic acid, whereas upon switching to sodium ascorbate, no pH drop was detected.

Sodium ascorbate is slightly more expensive than ascorbic acid and approximately 11% more is required to match the same effectiveness of pure ascorbic acid.

The shelf life for vitamin C is reported to be in excess of one year if kept in a dry, cool, dark storage area.

The most common question asked is where vitamin C can be purchased. Integra Chemical6 (800-322-6646) will provide small samples (150 grams) for testing purposes as well as sell multiple 55 pound boxes of pure ascorbic acid. They are experienced with vitamin C technology.


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