The invention provides a process for treating domestic
sewage with low CN (Carbon-
Nitrogen) ratio by use of an anaerobic / aerobic SNDPR (Simultaneous
Nitrification and
Denitrification Phosphorus Removal)
system capable of enriching
phosphorus-accumulating
bacteria and belongs to the field of biological
sewage treatment. After the domestic
sewage enters into an SNDPR SBR (
Sequencing Batch Reactor), delayed anoxic / anaerobic stirring is carried out firstly,
nitrogen removal by
denitrification is performed on NO3<-1>-N and NO2<-1>-N left in last cycle by use of
denitrifying bacteria and by utilizing organic carbon sources in the sewage, the anaerobic
phosphorus release is realized by use of the
phosphorus-accumulating
bacteria and by utilizing the organic carbon sources in the sewage, and stored substances are synthesized in the cells of the phosphorus-accumulating
bacteria. Due to delayed
anaerobic treatment, after PAOs phosphorus release is finished, the denitrifying
flora in the
system is still capable of taking full
advantage of organic matters in the sewage and storing the organic matters as an internal
carbon source. Hereafter, aerobic
aeration stirring is performed; as the concentration of dissolved
oxygen is controlled, endogenous SNDPR of the denitrifying
flora can be realized while phosphorus absorption of the phosphorus-accumulating bacteria is guaranteed. The method process for treating the domestic sewage with low CN ratio by use of the anaerobic / aerobic SNDPR
system capable of enriching phosphorus-accumulating bacteria has the advantages that deep
nitrogen and phosphorus removal of the sewage with low CN ratio is realized in one reactor, the process is simple, no external
carbon source needs to be added, and the
oxygen consumption and the
energy consumption are reduced.