The invention relates to a method for starting and stably keeping the micro-expansion of
sludge in a synchronous biological
nitrogen and
phosphorus removal
system, belonging to the field of treating
sewage biochemically. A device for implementing the method is formed by connecting a water inlet
pool, anaerobic cells, hypoxic cells, aerobic cells and a secondary
settling pool in sequence. The wall of the secondary
settling pool is provided with a
sludge height mark so that the degree of expansion of the
sludge can be known in real time. Each aerobic
cell is provided with an independent dissolved-
oxygen probe, and the dissolved-
oxygen probe is connected with a dissolved-
oxygen instrument. The control platform of a PLC (
programmable logic controller) is used for controlling the concentration of the dissolved oxygen in each aerobic
cell accurately according to the parameter set value and the feedback
signal of the dissolved-oxygen instrument. The micro-expansion of the sludge in the synchronous biological
nitrogen and
phosphorus removal
system is started by reducing the concentration of the dissolved oxygen in each aerobic
cell to 0.8-1.0 mg / L, and the dissolved oxygen is regulated according to monitoring result of the SVI (
sludge volume index), the height of the sludge in the secondary
settling pool, the quality of the
effluent of the device and other parameters so as to keep the micro-expansion of the sludge stable. Due to the adoption of the method, the
pollutant removal rate is improved, the quality of the
effluent is guaranteed, the
aeration energy consumption of the water
plant is reduced, and the energy-efficient treatment of the
effluent is realized.