Biological wastewater treatment. Wastewater treated with traditional biological methods contains large amounts of leftover biogenic substances (nitrogen and phosphorus compounds), which cause a lot of damage in natural water bodies.
The rapid growth of algae in the water causes secondary water pollution, intense coloration and reduction of oxygen concentration. Blooming water greatly complicates its use as drinking water for residences and industrial facilities. Therefore, the content of biogenic substances in wastewater is strictly limited.
There are many methods for wastewater treatment to remove biogenic substances: physico-chemical, biological, and chemical methods. The most efficient and inexpensive is the biological method for removing nitrogen and phosphorus compounds.
Biological purification of wastewater from nitrogen compounds is based on nitrification and denitrification. The essence of these processes is the oxidation of ammonia to nitrate (nitrification) and subsequent reduction of nitrates to nitrogen gas (denitrification). The nitrates containing oxygen reduce the amount of air needed for aeration of wastewater and, as a result, reduce the energy consumption.
The biological treatment of wastewater from phosphorus compounds is based on the ability of certain groups of bacteria (predominantly Acinetobacter) to remove significantly more phosphorus from the liquid phase in artificially created extreme temperature conditions (changing bacteria from anaerobic to aerobic). This process is also called “phosphorus absorption”.
Aerotanks can increase phosphorus removal rate by combining biological methods with chemical sedimentation.