| With the rapid development of China’s economy, the issues of environment are increasingly prominent. The growing pollution of water affects human’s life and development seriously. The important indicators of measuring water pollution are chemical oxygen demand(COD), chlorophyll content, turbidity, etc. The traditional methods of measuring these indicators are complicated to operate, long time measuring,high cost and easy to cause secondary pollution.This paper proposes the program of COD concentration detection using the seawater spectral data. At the same time, a single wavelength real-time and online detection system based on the theory of photoelectric detection is designed. This paper includes the following:Firstly, the paper analyzes the background and the significance of the research and describes the methods and the research status of marine environmental detection domestic and international. The advantages and disadvantages of traditional detection methods are analyzed. The spectrum detection method of COD, chlorophyll, turbidity and the single wavelength photoelectric detection method of COD are put forward.Secondly, the paper introduces the theory of spectrophotometry and researches the algorithm of spectral data. The spectral data model of COD standard solution are built by partial least squares(PLS) and the prediction models are obtained. At the same time, the prediction models are tested and the error analysis and the experimental results are given. The quantitative model impacting the results was established.Again, The scheme design and theoretical analysis of real-time and online detection system for marine environmental spectrum method are built. The system includes a package design, optical simulation, circuit simulation, schematic drawing,PCB board set up, set up control circuit.At the same time, the quantitative model impacting the results was established. The system is re-scaled to improve the COD concentration detection accuracy.Finally, the paper introduces the designer for detecting the concentration of CODwhich uses a single wavelength to achieve the real-time online detection. The part of optical and the part of circuit are repeatedly tested and improved. The PC interface is programmed. Then, the calibration models is established to eliminate the factors. |
