Due to the oxidation of NH4+-N, the dissolved oxygen concentration in the water body is reduced, resulting in black body odor and water quality, which affects the survival of aquatic animals and plants. Under favorable environmental conditions, the organic nitrogen contained in the wastewater will be converted into NH4+-N. NH4+-N is the most powerful inorganic nitrogen form and will be further converted into NO2–N and NO3–N.
Too much nitrogen in the water can lead to eutrophication of the water, which in turn leads to a series of serious consequences. Due to the presence of nitrogen, the number of photosynthetic microorganisms (mostly algae) is increased, that is, the eutrophication of the water body results in clogging of the filter tank, resulting in a shortened cycle of the filter tank, thereby increasing the cost of water treatment and impeding 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 the decay of algae, oxygen depletion occurs in the water.
NO2–N and NO3–N in water have a great harmful effect on humans and aquatic organisms. Long-term consumption of water with a NO3–N content of more than 10 mg/L may cause methemoglobinemia. When the methemoglobin content in the blood reaches 70 mg/L, suffocation occurs.
