Toxicity

All three nitrogenous ions can be toxicity to aquatic life, especially fish. Ammonium ions and nitrite ions are extremely toxic, and nitrite ions are the most toxic of the three nitrogenous ions.

TABLE 1.2 Permit Requirements for Nitrification and Denitrification

Requirement

Description

Nitrification/Denitrification

NH3

Ammonia

Nitrification

NH+

Ammonium ion

Nitrification

nBOD

Nitrogenous biochemical oxygen

Nitrification/denitrification

demand

NOD

Nitrogenous oxygen demand

Nitrification/denitrification

TKN

Total kjeldahl nitrogen

Nitrification/denitrification

Figure 1.1 Oxidation of ammonium ions and oxidation of nitrite ions. Under appropriate conditions nitrification occurs when oxygen is removed from water, or a water film, and added to ammonium ions to produce nitrite ions, or added to nitrite ions to produce nitrate ions. Although many organisms such as algae, bacteria, fungi, and protozoa are capable of nitrifying ammonium ions and nitrite ions, a specialized group of nitrifying bacteria is primarily responsible for nitrification in water and soil.

Figure 1.1 Oxidation of ammonium ions and oxidation of nitrite ions. Under appropriate conditions nitrification occurs when oxygen is removed from water, or a water film, and added to ammonium ions to produce nitrite ions, or added to nitrite ions to produce nitrate ions. Although many organisms such as algae, bacteria, fungi, and protozoa are capable of nitrifying ammonium ions and nitrite ions, a specialized group of nitrifying bacteria is primarily responsible for nitrification in water and soil.

Although ammonium ions are the preferred nitrogen nutrient for most organisms, ammonium ions are converted to ammonia with increasing pH (Figure 1.3). It is the ammonia at an elevated pH that is toxic to aquatic life.

Was this article helpful?

0 0
Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

Get My Free Ebook


Post a comment