Process of extended efficient aerobic bio-aeration of sewage

摘要

In the present invention there is disclosed a process of extended efficient aerobic bio-aeration of sewage, during which an optionally preliminary treated sewage is supplied into a biological tank containing both settled as well as suspended biomass and where phosphorus and nitrogen compounds are removed to a large extent biologically, whereby so treated sewage is then discharged from the biological tank. The invented process is characterized in that owing to a controlled introduction of oxygen in the biological tank during operation thereof there are maintained zones therein with different oxygen environment i.e. in the zone adjacent to the biological tank surface there is formed aerobic zone and on the bottom of the activation tank an anoxic zone and between those zones there is at least one transient zone. The content of the biomass, used as both settled and suspended biomass is greater than 3 kg of dry matter per one cubic meter of the biological tank utilized volume.