| Nowadays the operation optimization and energy saving of wastewater treatmentplants are important problems in China. To ensure normal and effective operation ofwastewater treatment plants, developing and applying the automatic control system arevery necessary. Due to the wastewater treatment system is a complex process, thedesign and operation of control system should be considered from the perspective of thewhole plant, and then the effect of the control system should be evaluatedcomprehensively through a scientific and reliable method to improve theimplementation of control strategy. This research develops a control strategy and systemfor a wastewater treatment plant, and develops a comprehensive performance evaluationsystem for the control system. The conclusions are as follows:(1)This research analyzes the process operating characteristics of the typicalwastewater treatment plants from two points: the interference factors and thecharacteristics of energy and material consumption. The influent loading as anexternal interference factor, shows a significant seasonal characteristics and periodicityof diurnal variation. And the influent flow is the most significant factor to causefluctuations in the influent loading. Biochemical process as the main unit of energyconsumption, accounts for about60%of the energy consumption of the whole plant.And the blower is the major energy consuming equipment of it. The follow unit ofenergy consumption is pretreatment process, which accounts for about30%of theenergy consumption of the whole plant. Its major energy consuming equipment is thepump. Chemical phosphorus removal process and carbon addition process, followed bysludge treatment process is the main material consumption unit.(2) This research proposes a control strategy based on the influent loadingdynamic changes from the perspective of the whole plant. The core unit includes a liftpump timing feed-forward-Cascade feedback control, feed-forward compensation ofthe aeration process-Cascade feedback control strategydrug and chemical phosphorusremoval and feed-forward compensation-feedback control strategy. This controlstrategy directs the design and implementation of WWTP’s control system.(3) In older to solve the problem during the operation of the control system,this research studies the performance of the key equipment which can affect the control system, and propose measures to improve it. On the basis of preprocessingof the instrument’s signal, a warning system has been established and the problem indaily operation has been solved.(4) This research establishes a practical valuable WWTP’s comprehensiveperformance’s evaluation system from the view of combining the operation process andautomatic control. The evaluation system is divided into three aspects as following:standard operation, energy&material saving and control performance capability. Bysetting up6second-level indicators and12third-level indicators, the evaluation systemcould make an effective evaluation on the automatic control performance form differentlevels containing whole plant, unit and equipment. The evaluate system not only canfind the problem for every part but also can evaluate the automatic control systemeffectively. Practice show that the evaluate system provide a good support forimproving the WWTP’s.operation. |
