Water quality COD detection method and apparatus based on LED multi-feature wavelength

Abstract

The invention discloses a water quality COD detection method and an apparatus based on LED multi-feature wavelength. Light sources of N LED lamps with different characteristic wavelengths along a circumference direction are fixed, in an equal interval, on a front surface of a rotating disk; positioning teeth corresponding to the positions of the N LED lamps are arranged on a side surface of the rotating disk along the circumference direction; a convergent tube is arranged in front of the rotating disk, and a light source entrance is arranged on a rear end of the convergent tube; a first focusing mirror, a colorimetric ware containing water to be measured, a second focusing mirror and a photodiode are successively arranged with intervals right in front of the convergent tube; the colorimetric ware is arranged in a rectangular notch of a colorimetric ware rack; the photodiode converses a received optical signal into an electric signal, and amplifies and sends the electric signal to a one-chip microcomputer; an absorption light intensity of a sample to be measured at a first characteristic wavelength is measured, and absorbance is calculated out; the operations are repeated, and absorbance values at N characteristic wavelengths are put into a BP nerve network model; and a COD value of the water to be measured is calculated out, so as to realize rapid, accurate on-line measurement on the water quality COD value.

Description

technical field [0001] The invention relates to a water quality COD detection method and device based on LED ultraviolet multi-characteristic wavelengths. Background technique [0002] COD is the most important indicator of water pollution. Chemical oxygen demand (Chemical Oxygen [0003] Demand, COD) refers to the amount of oxidant consumed to oxidize reducing substances in 1L of water sample under certain conditions, and the result is converted into oxygen content. COD is a measure of the concentration of organic matter and inorganic oxides contained in water, reflecting the degree of pollution of water bodies, and is one of the important indicators for evaluating the quality of water bodies. Reducing substances in water include various organic substances, ferrous iron, nitrous acid, sulfide, etc. It is very common for water bodies to be polluted by organic matter. COD will excessively consume dissolved oxygen in water bodies, resulting in eutrophication of water bodies...

AI Technical Summary

Problems solved by technology

[0005] 1. The analysis cycle is long, the operation process is cumbersome, the pipeline system is complicated and easy to block, the reliability is poor, and the failure rate is high, so it is not suitable for real-time online monitoring

[0006] 2. The monitoring frequency is low, the sampling error is large, the monitoring data is inaccurate, and the sewage discharge status cannot be reflected in time;

[0007] 3. Chromium, silver and other precious metal reagents and mercury sulfate will cause secondary pollution to the environment, and the cost is high

[0009] 1. The organic components in the water body are different, and the maximum absorption peak is not all at 254nm;

[0010] 2. The interference of suspended matter on the absorbance will increase the value of COD;

[0011] 3. It is suitable for COD determination of sewage with relatively single composition and relatively stable composition. However, there are many practical applications, and different sewage has specific absorption peaks. It is very difficult to capture all organic matter with only 254nm, and its applicability is not wide enough.

However, there are many lens systems in the ultraviolet multispectral scanning device, the loss of light intensity is large, the structure is complex, the precision is high, and the cost is high

Images