What is the significance of detecting ammonia nitrogen?
Harm to people: Ammonia nitrogen in water can be converted into nitrite under certain conditions. If you drink it for a long time, the nitrite in the water will combine with protein to form nitrosamines, which is a strong carcinogen and extremely harmful to human health . Long-term drinking of water with a nitrate nitrogen (NO3--N) content exceeding 10 mg/L will cause methemoglobinemia. When the methemoglobin content in the blood reaches 70 mg/L, suffocation will occur. The action of nitrous nitrogen (NO2--N) and amine in water will generate nitrosamines, and nitrosamines are "triple" substances. Ammonium nitrogen (NH4+-N) reacts with chlorine to form chloramine, which has a lower disinfection effect than free chlorine, so when ammonium nitrogen is present, the water treatment plant will need a larger amount of chlorine to increase treatment. cost.
In recent years, drinking water and even poisoning incidents caused by the random discharge of ammonia-containing nitrogen wastewater have occurred from time to time. China’s Yangtze River, Huaihe River, Qiantang River, Sichuan Tuojiang River and other river basins have reported that there have been millions of cases such as cyanobacterial pollution in the corresponding areas. The residents' drinking water is difficult, and the related waters have been "implicated" and other major events. Therefore, the removal of ammonia nitrogen in wastewater has become one of the hot spots of environmental workers.
Hazard to the ecological environment: Ammonia nitrogen is the main oxygen-consuming pollutant in water, which is toxic to fish and some aquatic organisms. Due to the oxidation of NH4+-N, the concentration of dissolved oxygen in the water body will be reduced, which will cause the water body to smell black and the water quality will decline, which will affect the survival of aquatic animals and plants. Under favorable environmental conditions, the organic nitrogen contained in the wastewater will be converted into NH4+-N, which is the most reducing form of inorganic nitrogen, and will be further converted into NO2--N and NO3--N. According to the biochemical reaction measurement relationship, 1gNH4+-N is oxidized to NO2--N and consumes 3.43 g of oxygen, and oxidizes to NO3--N and consumes 4.57g of oxygen.
At the same time, ammonia nitrogen is a nutrient in the water body. Due to the presence of nitrogen, the number of photosynthetic microorganisms (mostly algae) increases, that is, the water body is eutrophic, and the result is: block the filter, causing the filter cycle to shorten, thus increasing Water treatment costs; hinder water sports; the final product of algae metabolism can produce compounds that cause color and taste; due to toxins produced by blue-green algae, livestock damage and fish death; due to algae rot, it appears in the water body Oxygen deficiency phenomenon. Its toxicity is dozens of times greater than that of ammonium salt. The composition ratio of free ammonia (NH3) and ammonium salt (NH4+) depends on the PH value and temperature of water. When the PH value and temperature are higher, the proportion of free ammonia is higher, and vice versa The proportion of ammonium salts is higher.
Hazards to aquatic organisms: Ammonia is divided into acute and chronic. The hazards of chronic ammonia nitrogen poisoning are: reduced food intake, slow growth, tissue damage, and reduced oxygen transport between tissues. High ammonia nitrogen will damage the gills of fish and mussels. Above 0.5mg/L will cause inability to eat and breathe until death . The hazards of acute ammonia nitrogen poisoning are: aquatic organisms appear to be hyperactive, lose balance in the water, convulsions, and even die in severe cases. To protect freshwater aquatic life, the concentration of non-ionic ammonia in the water should be less than 0.02mg/L.