CN108287140A - A kind of method and device for sewage treatment plant's real time on-line monitoring - Google Patents

Abstract

The invention provides a method and device for real-time on-line monitoring of sewage treatment plants - dual-mode detection of ultraviolet light spectroscopy and three-dimensional fluorescence spectroscopy. The ultraviolet light spectroscopy method includes a multi-wavelength ultraviolet light irradiation device, a water sample container and an absorption spectrum. The multi-wavelength ultraviolet light irradiation device can emit various wavelengths of ultraviolet light, the water sample container has a certain thickness b, and the absorption spectrum includes a full-band absorption Feature points and feature vectors of the spectrum; the three-dimensional fluorescence spectroscopy includes a multi-wavelength emission device, a water sample container and a fluorescence emission spectrum, the multi-wavelength emission device can continuously change the excitation wavelength, and the fluorescence emission spectrum includes emission spectra at each emission wavelength. Ultraviolet light spectrum and fluorescence spectrum have strong complementarity, and can jointly monitor the change of sewage water quality, including simultaneous analysis and measurement of various parameters such as NO ₂ , NO ₃ , COD, DOC, BOD, TOC and TSS.

Description

A method and device for real-time online monitoring of sewage treatment plants

technical field

The invention belongs to the field of environmental engineering, in particular to a method and device for real-time on-line monitoring of sewage treatment plants.

Background technique

Online monitoring of water quality is an important foundation and effective means to achieve water environment protection, drinking water safety assurance, sewage treatment and pollutant discharge control, and water resource management. In recent years, with the gradual increase in the real-time and monitoring frequency requirements for water quality monitoring, traditional laboratory manual analysis has been difficult to meet the monitoring needs, so that online monitoring has received widespread attention and rapid development, and more and more online monitoring instruments have been used Promote and apply to various fields of water quality monitoring. At present, the commonly used online water quality monitoring methods mainly include chemical methods, chromatography methods, and biological methods. The development of chemical method is relatively mature. It simulates the manual analysis process in the laboratory. With the help of sequential injection platform, it completes the processes of sampling, pretreatment, injection of reagents, reaction, analysis and inspection, and realizes online monitoring of water quality. The chemical method has a wide range of applications, accurate measurement, and efficient and rapid analysis. However, the chemical method relies on chemical reactions, and it is difficult to completely get rid of the inherent shortcomings of complex structure, consumption of reagents, and easy to cause secondary pollution. Chromatography distinguishes pollutants in a water sample based on the order in which different components separate in two phases. Chromatography has good selectivity and high sensitivity, and is suitable for the detection of trace or even trace organic pollutants. However, the detection cost of chromatography is high, and the analysis efficiency and degree of automation need to be further improved. It is difficult to play a role in water samples with complex components and rapid changes. The biological method monitors the comprehensive toxicity by observing the activity of fish, luminescent bacteria or human tissue cells in water. Comprehensive toxicity monitoring has good practicability and wide coverage, and the scope of monitoring includes pesticides, herbicides and other toxic and harmful pollutants. However, there are certain difficulties in the measurement and expression of biological activity, and organisms that lose their activity need to be replaced regularly.

In view of the problems existing in the existing water quality online monitoring methods, the research and application of water quality analysis methods and online monitoring equipment based on ultraviolet-visible light spectroscopy (ultraviolet-visible), UV-Vis and spectral technology has received widespread attention in recent years.

UV-Vis spectroscopic analysis is a method of analyzing and detecting water quality based on the absorption spectrum of water samples. Electromagnetic radiation (EMR) interacts with atoms and molecules in a discontinuous manner to produce characteristic absorption or emission distributions. UV-Vis radiation only includes a range of radiation along the electromagnetic spectrum with other forms of radio, infrared (IR) radiation, cosmic and X-rays. UV-Vis absorbance is a measure of the absorbance of this radiation at a wavelength according to the Beer-Lambert law. Since many organic pollutants in water and wastewater have strong absorption of ultraviolet radiation, UV-Vis is mainly used for the determination of COD and BOD ₅ . At present, the most widely used is the simple linear relationship between the absorbance at a single wavelength and a certain parameter value. For example, using the UV absorbance at 254nm to determine the COD value, it is found that 280 nm is the most suitable value for estimating the BOD ₅ value in domestic sewage and slurry wastewater The wavelength of nitrate between 200-210nm has a strong absorption spectrum. The market also follows this knowledge of in-situ optical sensors, which measure one or two wavelengths using relatively simple photometers. However, pollutant composition and concentration can change over time, causing a non-linear response between absorbance values. In view of this, recent research is using the entire absorption spectrum instead of a single wavelength, using principal component analysis (PCA) and partial least squares regression (PLS) to decompose the absorption spectrum of the water sample to be measured, and then complete the quantitative or qualitative analysis of water quality .

Fluorescence spectroscopy refers to the absorption of energy in the form of light when molecules (called fluorophores) are excited by a high-energy light source. At low concentrations, the measured peak intensity is directly proportional to the concentration of the responsible fluorophore in solution. It has strong complementarity with UV-Vis spectrum, and some pollutants with low discrimination or low detection limit in UV-Vis spectrum have obvious characteristics in fluorescence spectrum.

Three-dimensional fluorescence spectroscopy (EEM) is one of the main methods of fluorescence analysis. It uses the emitted light wavelength and the excited light wavelength as the horizontal and vertical coordinates, and the fluorescence intensity is projected on the plane in the form of contour lines. There are many fluorescent substances, such as oils, humic acids, proteins, surfactants, vitamins, phenols and other aromatic compounds, pesticide residues, etc. that often exist in sewage, and sewage contains many fluorescent substances. Therefore, his fluorescence spectrum will vary with the type and content of pollutants, and has the characteristics of one-to-one correspondence with water samples, so it is called "fluorescent fingerprint" of water quality. EEM technology has been important in providing the optical resolution needed to fingerprint individual or groups of fluorophores. Improvements in instrumentation have allowed the researchers to obtain fast, high-resolution data using sensors that provide data in situ, enabling EEM generation in about 1 minute. Furthermore, EEM offers multiple possibilities for data interpretation, from simple peak acquisition and integration of fluorescent regions to more complex parallel factor analysis (PARAFAC) and self-organizing mapping. Among these methods, peak picking and PARAFAC are the most popular in the research community.

Peak picking is a very simple tool for identifying components based on maximum intensity and corresponding excitation and emission wavelength combinations. Peak picking as an online real-time tool is a viable analytical technique, however, its applicability may be limited due to peak shifts, possible overlap and interference between peaks. Furthermore, when two excitation wavelengths are observed at a fluorescent component, it can lead to misleading observations by associating each peak with a specific fluorophore.

PARAFAC is a mathematical 3D model of EEM datasets that estimates the concentrations and spectra of underlying fluorescent components and can even reveal true spectra in the presence of uncalibrated spectral interferences.

Under the irradiation of short-wavelength radiation, some pollutants in the water sample will absorb energy and transition to an excited state. When the molecules transition back to the ground state, they will emit fluorescence with a longer wavelength. The characteristics and intensity of fluorescence spectrum are related to the molecular structure and concentration of pollutants. Accordingly, qualitative and quantitative analysis of pollutants can be carried out. The UV spectrum and the fluorescence spectrum are highly complementary, and some pollutants that are not highly distinguishable in the UV spectrum have obvious characteristics in the fluorescence spectrum.

Contents of the invention

The purpose of the present invention is to provide a technical solution for real-time on-line monitoring of sewage treatment plants - dual-mode detection of ultraviolet light spectroscopy and three-dimensional fluorescence spectroscopy. The ultraviolet light spectrum and fluorescence spectrum used in the present invention have strong complementarity, and can jointly monitor the change of sewage water quality, including simultaneous analysis of various parameters such as NO ₂ , NO ₃ , COD, DOC, BOD, TOC and TSS Measurement.

In order to achieve the above object, the technical solution adopted in the present invention is: to use ultraviolet light spectroscopy and three-dimensional fluorescence spectroscopy to monitor water samples in sewage treatment plants on-line in real time. Sample container and absorption spectrum, the multi-wavelength ultraviolet light irradiation device can emit multiple wavelengths of ultraviolet light, the water sample container has a certain thickness b, and the absorption spectrum includes feature points and feature vectors of the full-band absorption spectrum, so The three-dimensional fluorescence spectroscopy method includes a multi-wavelength emission device, a water sample container and a fluorescence emission spectrum. The multi-wavelength emission device can continuously change the excitation wavelength, and the fluorescence emission spectrum includes emission spectra at various emission wavelengths.

As a preferred embodiment of the present invention, the ultraviolet spectroscopy uses principal component analysis and partial least squares to analyze spectra.

As a preferred embodiment of the present invention, the three-dimensional fluorescence spectroscopy uses a parallel factor method to analyze spectra.

As a preferred embodiment of the present invention, the ultraviolet spectrometry and the three-dimensional fluorescence spectrometry are highly complementary and can be jointly monitored.

The technical scheme of the present invention for real-time on-line monitoring of sewage treatment plants has at least the following advantages: (1) no need to add chemical reagents; (2) no or little need to process water samples, and few water samples are required for analysis The structure of the instrument is simple, which reduces the cost of installation, operation and maintenance; (3) The detection speed is fast, and a large amount of data can be generated and analyzed in a short time, and multiple parameters can be detected at the same time, including simultaneous detection of NO ₂ , NO ₃ , COD, DOC, BOD, TOC and TSS and other parameters for analysis and measurement.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following examples.

The technical solution of the invention for real-time on-line monitoring of sewage treatment plants includes a water sample collection device, a multi-wavelength ultraviolet light emitting device, and a receiving spectrum device.

Absorption spectra received when using UV spectroscopy are analyzed using principal component analysis or partial least squares.

Received fluorescence spectroscopy when using 3D fluorescence spectroscopy analyzes the spectra using the parallel factor method.

Ultraviolet light spectroscopy and three-dimensional fluorescence spectroscopy are highly complementary and can be jointly monitored.

As can be seen from the above, the technical solution of the present invention for real-time online monitoring of sewage treatment plants, as a brand-new water quality analysis and detection method, has irreplaceable advantages of traditional methods in the fields of rapid water quality detection, multi-parameter analysis, water quality classification, water quality alarm, etc. .

The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent transformation of the technical solution of the present invention adopted by those of ordinary skill in the art by reading the description of the present invention is the right of the present invention. covered by the requirements.

Claims (7)

1. a kind of method for sewage treatment plant's real time on-line monitoring, which is characterized in that include the following steps：

The ultra-violet absorption spectrum that water sample is measured using ultraviolet spectrum method carries out the ingredient in water sample according to ultra-violet absorption spectrum Qualitative and quantitative analysis；And

Using the three-dimensional fluorescence spectrum of three-dimensional fluorescence spectrum method for measuring water sample, according to three-dimensional fluorescence spectrum to the ingredient in water sample into Row qualitative and quantitative analysis；And

The monitoring result obtained using ultraviolet spectrum method is combined with the monitoring result obtained using three-dimensional fluorescence spectrum method, Monitor the ingredient in water sample on-line.

2. the method for being used for sewage treatment plant's real time on-line monitoring as described in claim 1, it is characterised in that：The ultraviolet light Spectroscopic methodology uses Principal Component Analysis and Partial Least Squares Method spectrum.

3. the method for being used for sewage treatment plant's real time on-line monitoring as described in claim 1, it is characterised in that：The three-dimensional is glimmering Light spectroscopic methodology analyzes spectrum using parallel factor method.

4. the method for being used for sewage treatment plant's real time on-line monitoring as claimed in claim 2 or claim 3, it is characterised in that：The purple Outer spectrum has very strong complementarity with fluorescence spectrum, can combined monitoring.

5. sewage treatment plant real time on-line monitoring device of the one kind for any one of claim 1 ~ 4 the method, feature exist In, including：

Ultra-violet absorption spectrum detection device, including multi-wavelength UV curing apparatus, water sample container A and ultraviolet spectra detector； The ultraviolet light wave that multi-wavelength UV curing apparatus generates generates the ultra-violet absorption spectrum of water sample, the ultraviolet suction through water sample container A It receives spectrum and obtains the characteristic point and feature vector of all band absorption spectrum through ultraviolet spectra detector；And

Three-dimensional fluorescence spectrum detection device, including multi-wavelength emission device, water sample container B and fluorescence emission spectrum detector；Institute Excitation wavelength can constantly be changed by stating multi-wavelength emission device, and water sample contained substance is in the sharp of corresponding excitation wavelength in water sample container B Generation fluorescence emission spectrum is given, the fluorescence emission spectrum detector is used to detect the fluorescence emission of different emission Spectrum.

6. sewage treatment plant's real time on-line monitoring device as claimed in claim 5, which is characterized in that further include data processing dress It sets, which uses Principal Component Analysis and Partial Least Squares ultra-violet absorption spectrum, and uses parallel factor method Analyzing three-dimensional fluorescence spectrum；The data processing equipment is according to the characteristic point and feature vector and three-dimensional fluorescence of ultra-violet absorption spectrum In spectrum analysis water sample at being allocated as Qualitative and quantitative analysis.

7. such as sewage treatment plant's real time on-line monitoring device described in claim 5 or 6, which is characterized in that the water sample container A, water sample container B is respectively provided at least one set of chamber wall being mutually parallel, and the chamber wall being mutually parallel uses transparent material, For allowing light wave to pass through water sample to be monitored and container.