Research And Application Of Precise Aeration Control System For Sewage Treatment

As an important part of sewage treatment,the effect of biological treatment on nitrogen and phosphorus removal is particularly critical.The key of biological treatment is the control of dissolved oxygen,which has many control problems such as non-linearity,multivariate,lag and so on.Therefore,automatic control is difficult.Taking the reconstruction and expansion project of the West Wastewater Treatment Plant in Jimo,Qingdao as an example,this paper starts with the control system,studies the VACOMASS system,understands the advanced control equipment and control concepts abroad,and establishes the control strategy and control system construction scheme of the aeration transformation.1)The aeration control strategy adopts a single aeration area control strategy,that is,each aeration tank is a control loop,each aeration tank operates independently and does not interfere with each other.2)According to the aeration strategy,the equipment selection and installation are completed.The DO fluorescence probe is selected,the rhombic valve is equipped with multi-rotary actuator,and the hot gas flowmeter is added.3)Finally,the program of dissolved oxygen flow PID control,flow valve proportional linear algorithm,air pressure calculation of blower,ammonia nitrogen compensation is compiled in PLC.The control system adopts the communication mode of ethernet.The upper computer establishes the operation monitoring and control screen of the precise aeration system through WINCC software.The parameters of the precise aeration system can be monitored and modified in the central control room.In addition,the historical curve and alarm function can be established.The research results improved the treatment efficiency of biochemical pond,ensured the control of total phosphorus and nitrogen in the effluent of biochemical pond at the lowest point,saved the cost of dosing in the later period,optimized the control of blower,improved the stability of main pressure,greatly reduced power consumption,and met the control requirements of precise aeration.