| Water resource protection is becoming an important globalization problem becauseit is able to influence the subsistence and development of human society. Our country isshort of water resources per capita, and the security situation of water resourceenvironment is very austere, which has become a serious restrictive factor for nationaleconomic and social sustainable development. Water quality monitoring is importanttechnical means and scientific basis that can reflect the variation of water quality andthe status of water pollution. So it is basis for the water resources protection andmanagement, and our country is paying attention to it.In view of the grim situation that the domestic instruments aren’t able to meet thedemands of quality monitoring for water resource environment, the status and trends ofwater quality monitoring technologies had been researched, and the existed problemshad been analyzed too. Aiming at water quality monitoring network’s urgent demandsfor the multi-parameter water quality monitoring instruments with high performance,low power consumption and small volume, a multi-parameter water quality detectingsystem based on micro spectrometer had been put forward, which can on linemonitoring such water quality parameters as COD, total phosphorus, ammonia nitrogen,hexavalent chromium, lead, anionic surfactants and volatile phenol. The theory andmethod based on micro spectrometer for multi-parameter water quality detecting hadbeen researched. The key technologies such as multifunction samples reacting anddetecting system, the control system of on line sample chemical pretreatment, the flowsystem of water quality parameter’s sequential detecting, control system and thespectrum signal processing system for on line water quality detecting had been broughtthrough. And the key technology of rapid digestion and detection for COD and totalphosphorus at normal temperature and pressure had been also brought through. On linemulti-parameter water quality detecting had been realized by spectrum analysis insteadof various analytical methods. The mathematical model for spectrum signal processinghad been established, and the systematic error processing method based on the ratio of thelight intensity at two wavelengths is put forward, and then the spectrum signal processingsystem for on line water quality detecting had been formed. Combining theoreticalanalysis and experimental research, the basic method of multi-parameter water qualitydetecting had been acquired. Prototype of multi-parameter water quality detecting system had been successfully researched, which met the technical requirements.The main research work is as the fellow:①On the basis of the research background of this dissertation, the technicalcharacteristics of several kinds of water quality detecting instruments had beencompared. Aiming at the water quality detecting technology based on spectrum analysis,the status and trends of multi-parameter water quality monitoring technologies had beenresearched, and the existed problems had been analyzed too. The new idea and structureof multi-parameter water quality detecting system based on micro spectrometer hadbeen put forward.②Based on Lambert Bill law, theory and method for multi-parameter waterquality detecting system based on micro spectrometer had been researched. Aiming atCOD (chemical oxygen demand) and other six important water quality parameters, theefficient sample chemical pretreatment had been researched too. Because the sevenimportant water quality parameters can be measured by micro spectrometer accurately,the design idea of multi-parameter water quality detecting system based on microspectrometer had been put forward.③Based on micro spectrometer and in order to meet the demands of instrument’sminiaturization and on line multi-parameter water quality detecting, the new structure ofmulti-parameter water quality detecting system had been put forward. The keytechnologies such as multifunction samples reacting and detecting system, the controlsystem of on line sample chemical pretreatment, the flow system of water qualityparameter’s sequential detecting, control system and the spectrum signal processingsystem for on line water quality detecting had been brought through. Prototype ofmulti-parameter water quality detecting system had been researched.④The spectrum signal characteristics of on line water quality detecting based onsample chemical pretreatment had been researched. The mathematical model forspectrum signal processing had been established. And spectrum signal processingmethod had been researched. The system error of the spectrum signal had beeneliminated by the application of the invariance of the ratio of the light intensity at anytwo wavelengths within micro spectrometer’s wavelength range. The characteristicwavelengths of the sample reaction system while detecting COD (chemical oxygendemand) and other six important water quality parameters had analyzed, accordingly thebackground interference had been eliminated by multi-wavelength spectrum analysismethod. All of the above had formed the spectrum signal processing system for on line water quality detecting.⑤Based on Lambert Bill law and end-point method, the control conditions of online sample chemical pretreatment for accurate measuring COD and other six importantwater quality parameters had been determined. And the key technology of rapiddigestion and detection for COD and total phosphorus at normal temperature andpressure had been also successfully brought through. The experimental researches ofinstrument’s calibration, quality control and test of Accuracy and reproducibility hadbeen carried out. So the main performance parameters had been acquired.⑥Aiming at on line monitoring surface water quality and wastewater quality, thecontrast test between multi-parameter water quality detecting system and China nationalstandard analysis method had been carried out. And the results had showed thatsystem’s key technical index such as LOD(limit of detection), sensitivity,repeatability(10%) and accuracy(±10%) had met technical requirements of nationalenvironmental protection standards.Finally, we summarize our research work and the innovation points. We also givethe suggestion for the future work. |
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