COD (Chemical Oxygen Demand) detection method and device based on multi-sensor information fusion

Abstract

The invention provides a COD (Chemical Oxygen Demand) detection method based on multi-sensor information fusion. The method comprises the following steps: performing oxidative digestion on a water sample to be detected by utilizing a COD detection device; recording the gas flow and the ozone concentration at an inlet of a reaction tube, the gas flow, the ozone concentration and the carbon dioxideconcentration at an outlet of the reaction tube as well as the temperature and the pressure in the reaction process in real time by multiple sensors; automatically judging whether the digestion is completed or not according to the change rate of the carbon dioxide concentration at the outlet, and if the digestion is completed, stopping digestion; then, calculating the dissolved oxygen demand and the dissolved carbon dioxide demand by utilizing a dissolved demand estimation model according to the related data measured by each sensor in the digestion process; and estimating the oxygen consumption demand according to physicochemical relation, and dividing the volume of the water sample to be detected so as to obtain the COD value of the water sample to be detected. The method and the device provided by the invention perfect the calculation process of COD detection and realize automatic judgment on digestion completion time of water samples with different concentrations or water samples containing different organic matters.

Description

technical field [0001] The invention belongs to the technical field of water quality detection, and is particularly suitable for on-line detection of chemical oxygen demand (COD) in an on-line monitoring system of environmental water quality. Background technique [0002] As one of the important comprehensive indicators to evaluate the degree of water pollution, COD mainly reflects the degree of water pollution by organic matter. The eutrophication pollution of lakes, reservoirs and other water bodies is closely related to the COD content in the water body. Excessive COD content will cause abnormal reproduction and growth of various aquatic plants. Large-scale cyanobacteria outbreaks have occurred in Taihu Lake, Chaohu Lake and other places, so the detection of COD content in water has important practical significance. [0003] At present, the detection of COD content in water mainly adopts the national standard potassium dichromate oxidation method (GB 11914-89) and perman...

AI Technical Summary

Problems solved by technology

Although the national standard method has high accuracy and good reproducibility, its operation is complicated, the digestion time is long, it is greatly affected by the chloride concentration, the cost is high, and the secondary pollution is serious

[0004] The existing invention (ZL201310537388.4) does not consider the influence of the gas generated during the digestion of organic matter on the COD measurement and the influence of the gas dissolved in the water sample during the digestion process on the COD measurement in terms of information fusion calculation, and there is uncertainty in the measurement error and the fixed digestion time in the original invention cannot automatically control the termination time of digestion of different water samples, resulting in the problem of incomplete digestion or low digestion efficiency

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