Nitrates and Nitrites

From Intec-America

What is Nitrate and what does it do?

Water Treatment Nitrate (NO3) can exist as an organic or inorganic compound, it can be natural or man made, and it is often found in drinking water supplies. Nitrates come in different forms such as ammonium nitrates (NH4NO), potassium nitrates (KNO3), and sodium nitrates (NaNO3). Nitrates can be expressed as nitrate as nitrogen (NO3-N), or nitrate as nitrate (NO3-NO3) on the water analysis. It is very important that the form of nitrate tested be identified on a water analysis test.

While nitrate itself is nontoxic, it is reduced to nitrite (NO2) by bacteria in the well or stomach. Nitrite passing into the bloodstream can be taken up by hemoglobin, reducing the blood’s ability to transport oxygen, causing oxygen deficiency anemia. Infants under six months of age are especially susceptible to this effect, causing the so-called “Blue baby” syndrome.

In poults, as with other infant monogastrics (single stomached system), their digestive systems contain nitrate-converting bacteria. Because of this, they are much more susceptible to methemoglobinemia. Fully grown monogastrics are not as susceptible to methemoglobinemia because their digestive system does not contain these bacteria. They are, however, susceptible to thyroid enlargement. Even so, it is believed that nitrate levels over 20 ppm are detrimental to performance. Nitrate levels as low as 3 ppm has been suspect in affecting broiler performance. It is also believed that heat stress and low pH compound the negative effects of nitrites in various breeds of birds.

As nitrates are produced during the final stage of decomposition of organic matter, nitrites are produced during intermediate stages of decomposition. Nitrites are toxic at much lower levels than nitrates as concentrations as low as 1 ppm can be toxic.

Nitrate in ground water has been known to be a potential health problem for more than 50 yrs. Depending on the form of nitrate, the USEPA maximum contaminant level (MCL) for humans in public drinking water varies from 45 ppm (NO3-NO3) down to 1 ppm (NO2-N). Water guidelines for poultry have set 25 ppm (NO3-N) as the maximum acceptable level which is substantially higher than the USEPA standards of drinking water of 10 ppm for the same form of nitrate. It is estimated by EPA’s 1990 National Pesticide Survey that over 5% of private water wells exceed the MCL for nitrates. The size of the animal is the main determinate of MCL in livestock.

Nitrates & Nitrites must be removed from private wells!
We need to be religious about keeping nitrates under control in our private wells (those used for drinking water for our family and our livestock). Just a few years ago, nitrate removal was not a problem for private wells, because there was no way to remove it. You can not oxidize it with chlorine nor filter it with sand or carbons. Using reverse osmosis or distillation would work but only for small volumes of water, but large volumes of water would make them cost prohibitive and labor intensive.

The past solution was to find a more promising location for a new, deeper well away from septic fields, cess-pools, hog wastes sprayed on fields for cultivation, poultry litter spread on fields for cultivation, inorganic fertilizers applied on row crops etc., and go to an aquifer deeper than the one presently used. Once nitrates have percolated into the aquifer, they can spread considerable distances. A deeper well may or may not solve the problem and it is a costly gamble at best. If your well is an old dug or drilled shallow well, the chances are high that a deeper well will be an improvement.

Today, there are nitrate-specific, anion resins manufactured primarily for nitrate removal (Water Softener). This resin does not remove nitrates only, but it does have a higher affinity for the nitrate versus the sulfate, tannins or bicarbonates.

Strong base anion resins will remove nitrates; however, they are actually more selective for sulfates over nitrates. If the sulfate ppm is high, it will preferentially collect sulfates over nitrates on the resin. If the resin is not regenerated and it becomes saturated or over exhausted, then the resin will release collected nitrates in exchange for sulfates causing a sharp rise in nitrate levels (nitrate dumping).

Sulfates must be considered when examining nitrate removal. Sulfates have been known to scar the intestinal tract of animals which effect the feed conversion, reduce body weight, and may cause a laxative affect. When removing nitrates, sulfates must also be removed. Choosing a nitrate-select resin could cause sulfate dumping.

The proper resin in the proper cubic footage and adequate regeneration will produce beneficial results. Other factors such as pH, the ppm of sulfates, and bicarbonates should also be considered in the selection of the resin and its volume.

In this type of treatment, a solution (usually sodium chloride) is introduced into the water to assist in the nitrate removal process. Chlorides are exchanged for nitrates and sulfates. The nitrates and sulfates are then captured in the adsorptive resin. Potassium may be used in place of salt if high sodium levels are a concern. It will require about 1.26 times as much potassium as salt, which makes it more expensive.


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