Research On Multi-parameter Detection System Of Drinking Water Based On Ultraviolet-Visible Absorption Spectrum

Water resources,which bear the origin of life,are nature’s evolving ‘masterpiece’.The ubiquity and significance of water resources can be affirmed in all domains of life.However,with the rapid economic development in recent years,people have neglected the issue of water quality safety,especially the pollution of drinking water will seriously threaten the health and development of humans.Therefore,it is of great importance to timely,effectively,comprehensively and accurately acquire the water quality parameters for responding to sudden drinking water accidents and guaranteeing water safety.As the most effective analytical technology,water quality detection provides a scientific basis for water management,conservation and development planning.The paper is supported by the Jilin Province Environmental Protection Agency’s project “Research on Methods for On-site Emergency Monitoring of Water Quality at the Source of Drinking Water” and the Jilin Province Science and Technology Development Department’s planned project “Research on Drinking Water Safety Detector”.A real-time online multi-parameter water quality detection system was designed based on UV-visible absorption spectroscopy.The detection system has the advantages of energy saving,low cost,fast accuracy,automation,and good stability.Simultaneously it can also detect the concentrations of three important water quality parameters,including nitrate,COD and total phosphorus.And the detection system is suitable for real-time measurement of drinking water quality parameters in a low concentration range.The following aspects have been studied in the following aspects:(1)Based on the research background and significance of water quality detection,the common methods of water quality detection have been classified,and the principles of the UV-visible absorption spectroscopy and important significance of three drinking water parameters are also explored.Finally,combined with the research progress and problems existing at the present stage of UV-visible absorption spectroscopy detectors at home and abroad,the construction scheme of the detection system studied in this paper is determined.(2)The design of the overall hardware structure of the water quality detection system is consisted of the optical path and the circuit.Based on the principle of ultraviolet-visible absorption spectroscopy,the optical path structure of water quality detection system is mainly divided into four parts: light source,spectroscopic system,sample cell,and photodetector.In the circuit section,as the output of the photodetector,the weak signal is amplified by the amplification circuit.After the analog-to-digital conversion circuit collects and converts the data,it sends the data to the FPGA core control terminal.The final concentration value obtained by data processing and calculation is displayed on the LCD screen in real time.(3)We implemented software control for water quality detection system.The Verilog hardware description language is used for programming and control,to achieve accurate and efficient operation of data acquisition,numerical conversion,serial communication,LCD display,automatic sampling of peristaltic pumps and control of stepper motor to implement accurate wavelength scanning.(4)We utilized the detection system for water quality detection experiments.Based on the characteristics of the UV-visible absorption spectrum,the standard curve of the detection system was established and the measurement results of three important parameters were analyzed.Finally,the practicality and reliability of the detection system were verified by detecting the actual water samples.