Water Quality Indicators: Nitrogenous Compounds : Total Kjeldhal Nitrogen

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Nitrogen Compound Indicators


Nitrate and Nitrite

Ammonia Nitrogen

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Dissolved Oxygen

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How to use this page: This is an indicator page. Examine this page for detail on the indicator and use that information to establish a metric for the indication of water quality. This is the final step in examining a sustainable community for its environmental attributes, water sub-attributes, nitrogenous compounds sub-sub-attributes. After completing this page, please go back and review other indicators and see discern metrics and weights for the AHD process.


Why is Total Kjeldhal Nitrogen an indicator of water quality?

Total Kjeldhal Nitrogen (TKN) is the sum of organic nitrogen and ammonia in a water body and is measured in milligrams per liter (mg/L). High measurements of TKN typically results from sewage and manure discharges to water bodies. However, Total kjeldahl nitrogen (TKN) is an involved test that many wastewater treatment facility laboratories are not equipped to perform. This does not mean however, that nitrogen cycles should be neglected. The ammonia (NH3) values are approximately 60% of the Total kjeldahl nitrogen (TKN) values, and the organic nitrogen is generally removed in the settled sludge. Also, Total kjeldahl nitrogen (TKN) generally equals 15 - 20 % of the Biochemical Oxygen Demand (BOD) of the raw sewage.
What level of TKN is acceptable in a community?

TKN is a portion of the total nitrogen measurement. The presence of nitrogenous compounds at abnormal levels in surface water generally indicates pollution. You would not want the TKN level to excessively high because it would clearly indicate that the Total Nitrogen Level would be exceeding the levels mentioned on the nitrogenous compounds page.

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Where to go now that you have reviewed an indicator:

Now that you have reviewed an indicator you should create a metric (see Step 4 of the Analytical Hierarchy Processes) that indicates the importance of this indicator in your decision process. Keep this step in mind as you go through one of the other indicators below. Once you have chosen a metric for each of your indicators, you should decide how they collectively measure the sustainability of water by weighting each indicator (see Step 5 of the Analytical Hierarchy Process). These will be applied in an algorithm (see Step 6 of the Analytical Hierarchy Process) to give you the final measurement for Water and Sustainability.






Author: Shawn Dayson Shifflett