Ammonia nitrogen properties
Ammonia nitrogen refers to nitrogen present in water in the form of free ammonia (NH3) and ammonium ions (NH4). The nitrogen content of animal organic matter is generally higher than that of plant organic matter. At the same time, nitrogen-containing organic matter in human and animal manure is unstable and easily decomposes into ammonia. Therefore, when the ammonia nitrogen content in the water is increased, it refers to the combined ammonia existing in the form of ammonia or ammonium ions.
Source of ammonia nitrogen
(1) Urban domestic sewage
The source of ammonia nitrogen in water is mainly the decomposition products of nitrogen-containing organic matter in domestic sewage under the action of microorganisms.
In addition, ammonia nitrogen is also generated during the growth of crops and the use of nitrogen fertilizer, and is discharged into the urban sewage treatment plant or directly into the water body with the sewage.
(2) Ammonia and nitrite can be converted into each other
Ammonia in water can form nitrite under the action of oxygen, and further form nitrate. At the same time, nitrite in water can also be converted into ammonia by microbial action under anaerobic conditions.
(3) Certain industrial wastewater, such as coking wastewater and synthetic ammonia plant wastewater.
Chemical plants such as fertilizer plants, power plants, and cement plants emit ammonia-containing gases, dust, and smog into the environment; with the continuous improvement of people's living standards, there are more and more private cars, a large number of private cars and various models of Vehicles such as trucks also emit a certain amount of automobile exhaust containing ammonia into the ambient air. The ammonia in these gases dissolves in water to form ammonia nitrogen, which pollutes the water body.
Impact of ammonia nitrogen on ecological environment
The main harmful effects of ammonia nitrogen on aquatic organisms are free ammonia, which is tens of times more toxic than ammonium salts, and increases with increasing alkalinity. Ammonia nitrogen toxicity is closely related to the pH and water temperature of the pool water. In general, the higher the pH and water temperature, the stronger the toxicity. The harm to fish is similar to nitrite.
The harm of ammonia nitrogen to aquatic organisms is divided into acute and chronic. The hazards of chronic ammonia nitrogen poisoning are: reduced food intake, slowed growth, tissue damage, and reduced oxygen transport between tissues. Fish are sensitive to ammonia nitrogen in the water, and when the ammonia nitrogen content is high, fish will die. The hazards of acute ammonia nitrogen poisoning are: aquatic organisms show excitement, loss of balance in water, convulsions, and even severe death.