Ammonia Nitrogen Test In Wastewater

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Ammonia Nitrogen

Tim Loftus

Nitrogen is an essential ingredient in the germination of proteins for cell growth. From complex organisms like animals to the simple bacteria used to treat wastes in an activated sludge handling facility, every living matter needs some grade of nitrogen to survive.

But also much nitrogen freely available in the environment can be a bad affair. Excess nitrogen discharged into our waterways can contribute to eutrophication, the gradual change of water bodies into marshes, meadows, then forests. It can likewise contribute to massive algae blooms leading to oxygen depletion in water and its associated problems. Certain forms of nitrogen can cause specific problems likewise. Ammonia is toxic to fish, and nitrates at loftier plenty dosages in the drinking water cause methemoglobinemia in infants (Nitrates catechumen to nitrites in the stomach. These nitrites then interfere with the oxygen-conveying chapters of the hemoglobin in blood).

In the wastewater field we are concerned with several forms of nitrogen: ammonia, organic, nitrate, and nitrite. Nether the correct weather condition, each of these forms is biologically convertible to i of the other forms. This creates certain challenges in the treatment of nitrogen in wastewater. Because of these challenges, it is important to properly collect, preserve, and analyze samples for the specific forms of nitrogen then that the appropriate treatment of these wastes tin can be made. I�ll forgo the explanations of how the biological processes converts one course of nitrogen to some other, leaving that to the wastewater treatment books. Instead, I volition focus on the lab aspect of nitrogen analyses � specifically on ammonia-nitrogen.

As with any sample, the accuracy of the ammonia event starts with sample collection. To help keep the sample from biologically or chemically degrading, y'all must add together sulfuric acrid to a pH of less than ii and to cool the sample to 4oC. A sample for ammonia analysis preserved this mode volition keep up to 28 days. If a sample is analyzed afterwards that amount of time, its results cannot be reported for NPDES purposes. As well, residual chlorine reacts with ammonia. If residual chlorine is present, immediately dechlorinate using sodium thiosulfate. Always neutralize samples with potassium hydroxide or sodium hydroxide before analyses.

Prior to ammonia assay a sample must first be distilled to remove annihilation that may interfere with the test method. The sample�s pH is adjusted to pH 9.five using a borate buffer. This solution is so distilled into a receiving solution of either boric acid (for the nesslerization and titration test methods) or into sulfuric acid (for the electrode and phenate methods).

However, distillation may not exist needed if certain conditions can be met. According to Affiliate 40 of the Lawmaking of Federal Regulations, part 136, Table1B, �distillation is non required if comparability data on representative effluent samples are on company file to prove that this preliminary distillation step is non necessary�� Unnecessary distillation will subtract the accuracy of the overall ammonia analysis procedure. If you chose the choice of non distilling samples for ammonia analyses, brand sure you have the documentation demonstrating that the results of distilled versus nondistilled samples are statistically the same. For more information on performing a comparability study, refer to an earlier cavalcade, �A Applied Awarding of the Student�southward t-Test.�

Like many of the constituents in wastewater, ammonia concentrations can exist measured using many different test methods. But for NPDES reporting purposes, simply certain canonical examination methods tin be used. The list of canonical methods is found in 40 CFR 136 Tabular array 1B.

The ammonia concentration of a sample can be measured colorimetrically, by titration, or by an ammonia-selective electrode.

Colorimetrically, the ammonia concentration can be determined two ways. The nesslerization procedure uses a potassium/mercury/iodine chemical that reacts with ammonia, creating a yellow to brown-colored compound. The phenate method reacts phenol and hypochlorite with ammonia to create a blue-colored compound. In both methods, the colour intensity is proportional to the ammonia concentration.

In the titration procedure, a color indicator is added to a sample. This sample is titrated using 0.02N sulfuric acid until the indicator turns to a pale lavander color. The amount of acid used to the color alter is proportional to the ammonia present.

The ammonia-selective electrode method is probably the easiest to perform. Later a pH aligning to 11, the ammonia in solution diffuses through a special membrane at the tip of the electrode. The alter in electric potential at the electrode is proportional to the ammonia concentration.

Finally, before reporting the results for NPDES purposes, make sure the measured values are in the proper units. Sometimes the ammonia concentration may be measured as ammonia and other times it may be measured as ammonia-nitrogen. One milligram per liter of ammonia-nitrogen is equivalent to 1.22 mg/L of ammonia. Confusion on this can result in reporting an ammonia violation when, in fact, there may not be a violation at all.

The adjacent article will deal with the other forms of nitrogen that we are concerned with in the wastewater field: nitrate, nitrite, and organic nitrogen.

The information in this article is very full general. As usual, check your federal, country, and local regulations. You may take additional requirements that you must meet.

If you have any questions, suggestions, or comments, contact NEWEA Lab Practices Commission Chair Tim Loftus at (508) 949-3865 timloftus@msn.com. For more information on the NEWEA Laboratory Practices Committee, delight contact Tim Loftus or Elizabeth Cutone, NEWEA Executive Director, 100 Tower Role Park, Woburn, MA 01801, (781) 939-0908, ecutone@newea.org.