Application of frequency converter in sewage treatment equipment 1

Application of frequency converter in sewage treatment equipment 1

Application of frequency converter in blower

The best power-saving occasion of sewage treatment plant is the blower of aerator (some of which are aerated by mixer), which has a higher power-saving rate. The equipment of sewage treatment plant runs all the day, and the aerator and submersible pump are the core equipment of sewage treatment. It is necessary to use frequency converter to regulate the speed of the blower and submersible pump of aerator.

Frequency conversion control of blower:

The concentration of dissolved oxygen in the aerobic part of sewage treatment has great influence on the treatment results: the concentration of dissolved oxygen is too low, and the sewage can't meet the standard; If the solution concentration is too high, it will not only waste electric energy, but also make the activated sludge float up, to make the treated water not meet the standard. The purpose of adding frequency converter to blower is to control the concentration of dissolved oxygen in CASS pool to be stable at a constant value.

Considering that in practical application, only one fan can operate with frequency conversion, and the other one can stop or operate at power frequency. At the same time, in order to reduce the investment in fixed assets, two fans are designed to be controlled by only one frequency converter. At the beginning of aeration, one fan operates with frequency conversion. If the dissolved oxygen concentration of the fan still does not reach the set value after running at 50Hz, the fan will automatically switch to power frequency (50Hz) to continue its operation, and the other fan will automatically switch to frequency conversion operation, which will be controlled by PID until the dissolved oxygen concentration is stable at the set value. When the dissolved oxygen concentration is greater than the set value, and the frequency of the frequency conversion fan is lower than a certain frequency, the power frequency fan is automatically cut off, and only the frequency conversion fan operates.