Measuring Technology And Instrument Development Of Sewage COD By Electrochemical Method

This topic is derived from the project of Shandong Science and Technology Breakthrough Program"Instrument Development of Sewage COD based on Electrochemical Method"undertaken by the Institute ofOceanographic Instrumentation, Shandong Academy of Sciences. This paper mainly introduces the measuring technology for sewage COD and the present situation and development tendency of related instruments. For solving the deficiency of sewage COD measuring instrument, this paper innovatively proposes sewage COD measuring technology and successfully develops a measuring instrument based on three-electrode electrochemical method. The instrument is composed of automatic sampling system, chemical measurement pool, three-electrode sensor, signal acquisition system, control and data processing system. With independent intellectual property rights, this instrument is a novel intelligent online COD measuring instrument which can measure sewage COD fast and reliably without secondary pollution. With hydroxyl radicals (·OH) as an oxidant, and electrochemical method as measuring means, the sewage COD measuring instrument is developed on the basis of structured design pattern. The errors from the electric potential detection, signal acquisition, data processing system, and the error elimination methods are analyzed. Consequently the optimal analysis conditions are confirmed, and the on-site contrast tests are conducted to check the accuracy of sewage COD measuring based on electrochemical method. The testing results show that the measuring method is simple, fast, and the measuring sensitivity is high. The measured results of actual samples coincide very well with the results by the methods regulated by National Standards. The measuring instrument is suitable for online automatic sewage COD analysis and test. The first chapter of this paper mainly introduces the research background and significance, research contents and target. The second chapter analyses present COD measuring technology and the current situation and characteristics of related instruments. The sewage COD measuring principle of Electrochemical Method is also described. The third chapter introduces in detail the design of sewage COD measuring instrument based on electrochemical method, including the overall structure, sampling system, chemical measuring system and hardware control systems. The fourth chapter presents the design process of system software, upper computer function module, interface design and anti-interference measures. The fifth chapter analyses the experimental data, and draws scientific and reasonable conclusion. The sixth chapter summarizes the whole paper and puts forwards the prospect.