Study On COD Detection System Based On Variable-Range Ladder Dosing

With the rapid development of the economy and the acceleration of the industrialization process,the number of discharged and industrial effluents has continued to increase,leading to the deterioration of water quality and the adverse effects on the sustainable use of water resources.Therefore,the effective detection and monitoring of water pollution targets is imminent.Chemical oxygen demand(COD)is one of the important indexes to evaluate the degree of water pollution.Potassium dichromate is commonly used as an oxidizing agent in the current COD detection method,and potassium dichromate is a toxic and carcinogenic substance.Commonly used COD detection system through a one-time addition of excess potassium dichromate for COD digestion detection operation,and one-time dosing method is likely to cause the use of waste and secondary pollution.Therefore,it is important to study a COD detection system which can control the amount of potassium dichromate.Based on the analysis of commonly used COD detection system at home and abroad,a COD detection system based on variable range ladder dosing was studied.The main research contents are as follows:(1)Aiming at the extensive use of potassium dichromate in the current COD detection system,a method of COD dosing is proposed to effectively control the amount of potassium dichromate,Reduce secondary pollution.(2)Based on the theoretical analysis,this paper studies a specific method of ladder dosing in the process of stepping dosing and segmentation in the process of stepping dosing.(3)To build COD site inspection system of the experimental platform to complete the relevant hardware and software design.The hardware circuit mainly includes: photoelectric detection,temperature detection and heating drive,motor drive and valve switch control and microprocessor and A/D and other units;software part mainly includes: range switching,PID temperature control and A/D unit data transmission.(4)The design of COD monitoring data remote monitoring system,including wireless transceiver unit and host computer monitoring software,you can achieve the data remote real-time display,storage and query functions.(5)In the construction of the experimental platform,complete the relevant experiments,and pharmacy savings and system performance analysis.The experimental results show that the system can accurately and reliably detect the COD value of the water sample to be measured,and can effectively reduce the amount of potassium dichromate,especially in the low concentration COD water sample test,compared with the one-time dosing experiment,The added savings of about 40%,greatly reducing the secondary pollution.