Detection System Of The Total Phosphorus In Water Based On Near Infrared Spectroscopy

In recent years,water quality around the world has been severely polluted,so that people care much more about the water environmental protection problem.As a very important way of protecting water resources,water quality testing has gradually become a hot research topic.Traditional detection methods,such as chemical methods and ion chromatography method,are so professional that they are difficult to be promoted to use.So it is really necessary to design and build a water quality detection system which takes less testing time but equips with a higher degree of automation.There are so many indicators to be detected,but only the total phosphorus is tested by the water quality detection system based on Near Infrared Spectroscopy detection technology built in this thesis.The contents of this thesis include:(1)The achievement of water detection system.In this thesis,we learned and compared the traditional water quality detection methods.And we decided to use the Near Infrared Spectroscopy detection technology at last,which can make the detection period shorter,operation easier.Then we built a hardware testing platform which was used to get the spectral information of the water samples,Moreover,we wrote a software to remote control the communication between the spectrum analyzer and PC.The platform and the software compose to the detection system.(2)The construction of prediction model.We learned and compared the traditional methods of processing the spectrum information,and raised a new method which is to use the spectrum information of both the Characteristic peaks and valleys.On the other hand,we also did a survey and compared the methods of building a prediction model,and we decided to use PLS to build our prediction model.(3)The testing experiment of water samples.Three water samples from three different lakes in Wuhan was sampled and they were used to get the spectral data through the system we just built.At last,we use our prediction model to calculate the total phosphorus content of the samples.By comparing with the official data,the result showed that the relative error of our system is lower than five percent,and the detection result is good.