Research And Design Based On PLC Sewage Treatment Control System And The Control Of PH Value

With the rapid growth in our economy, environmental protection plays anincreasingly important role in our lives. Water resource is a key element in ourecological system because it has a direct impact on the ecological circulation.There are multiple treatments to water protection and the most direct andeffective way among those would be wastewater treatment.Traditionalwastewater treatments mainly rely on manual operation and empirical control,which may have many drawbacks such as low efficiency, dispersed information,unsatisfactory real-time feedbacks and poor performance. As a consequence,with the technological advancement, it becomes urgently necessary to utilizeautomatic computer control system to treat wastewater and this helps to boostefficiency, improve safety and conserve resources.This paper introduces PLC wastewater automatic control system based onShaanxi Qishan wastewater treatment plant. This plant used to have a set oftraditional wastewater treatment equipment, substantially relying on manualoperation, which has many safety risks and low efficiency. Therefore it isnecessary to renovate the existing treatment system to a new system based on PLC wastewater automatic control system.The new system may perform thefollowing three control functions all at once: onsite manual control, remotemonitoring computer control and PLC automatic control. This paper introducesthe new system in three sections which are structures, components andapplications.Based on the technological processes of the wastewater treatmentplant, we firstly illustrate the software and hardware design of the PLC controlstation of the wastewater automatic control system. Secondly，we introduce thesoftware design of the computer monitoring system, using software Kingview todynamically design every parameters in the wastewater treatment process.Finally, we demonstrate the classic PID control method and fuzzy control(grey-prediction model) to realize the adjustment of the PH value of water andwe designed a sliding mode controller that possesses excellent anti-jammingproperties based on the complexity of the PH value of water and eventuallyachieved the goal of secondary recycling of the wastewater.This design usesRS-485to achieve the communication between the upper and lower systems.