light industry

First, an overview
Water resources is an important factor of economic development and social sustainable development, urban sewage treatment rate has become an important symbol of regional civilization or not. Sewage treatment has been developed from the original natural treatment, simple first stage treatment to the use of advanced technology, advanced treatment of sewage, and reuse. Processing technology from the traditional activated sludge process, oxidation ditch process developed to a variety of processes, in order to achieve different requirements of the water.
Two, sewage treatment process
Secondary treatment method is mainly used in the general sewage treatment: the first stage is a mechanical processing, the grille and other machinery and equipment to filter sewage floating particles or larger material; second grade for biochemical treatment, according to the different processing requirements, excessive sewage contains a variety of silicon material or metal elements, hydro processing to meet the requirements of water equipment in the future, such as life with pure water, industrial boiler softening with the exception of saline.
Three, field conditions
Sewage collection pool in sewage by two sewage pump 1# sewage pump 2# water into the sedimentation tank, in order to prevent the precipitation pool overflow accident, precipitation pool is provided with a water level detecting device, when the actual water level exceeds the alarm water level control system automatically shut down grille at the front of the valve is to prevent the occurrence of water spill. The sewage in the sedimentation tank is then sent to the biochemical treatment pool by the biochemical water pump, and the biochemical treatment pool is also provided with a water level upper limit detection.
Four, transformation program
1, sedimentation tank two pumps by a frequency converter using one control two;
2, the high reliability of the PLC+ inverter;
Upper limit, lower limit water level, upper and lower limit alarm water level detection are arranged in the sedimentation tank. The control process when the water level reaches its limit, the water level detecting the signal sent to PLC, PLC frequency converter is switched on and the increase in frequency of the output signal to the inverter, when the inverter frequency up to 50 Hz at this time if the water level is still lower limit position, PLC sends out signal switching sewage pump 1# switch to power frequency operation, after a certain period of time delay by a frequency converter start sewage pump 2#. On the contrary, when the water level reaches the upper limit position stop sewage pump 1 PLC sends out the frequency decreased signal, if due to pump or other reasons caused by water level is lower than the lower or upper limit water level alarm, water level detector will alarm signal is sent to the PLC, the PLC output start alarm circuit alarm lamp and Bell), to prompt the operator to see why.
Aerator and the submersible pump is the core of wastewater treatment equipment and need to inverter (blower) blower aerator and submersible pump speed, air blower frequency conversion control: sewage treatment good oxygen dissolved oxygen concentration of processing results greatly affected, the dissolved oxygen concentration is too low, sewage is not compliance; dissolved concentration is too high, is not only a waste of energy may also make active sludge floating in the water also can not reach the standard, blower and transducer is to control the CASS tank dissolved oxygen concentrations stabilized at a constant value.
Five, conclusion
Sewage treatment plant after the transformation of frequency conversion not only improve the automation degree and control precision, but also greatly benefit in energy saving, comprehensive power saving rate of 35%, enterprise efficiency and social benefits synchronization significantly improve.