SHARON process, short cut nitrification and denitrification process, is a new biological denitrification process proposed and developed by Delft University of technology in the Netherlands in 1997. The basic principle is that in the same reactor, under the condition of oxygen, autotrophic nitrous bacteria will convert NH3-N into NO2 -, and then under the condition of anoxia, heterotrophic denitrifying bacteria will convert NO2 - into N2 with organic matter as electronic donor and NO2 - as electronic acceptor. Its theoretical basis is nitrous nitrification and denitrification technology, and biochemical reaction can be expressed as follows

The key of the process is how to control the ammonia and oxygen in the nitrous acid stage and maintain the nitrite accumulation in a high concentration for a long time.

In this process, CSTR reactor without sludge stay is used to screen the population through "mud washing" under the condition of short HRT and 30-40 ℃. A large number of nitrite bacteria are produced. SHARON process is suitable for the treatment of high concentration ammonia (500mg / L) wastewater, especially for the pretreatment or bypass treatment with deamination requirements. Compared with the traditional process, this process can save 25% oxygen supply and 40% denitrification carbon source.