Chemical Oxygen Demand – COD Sensors

Ultraviolet absorption spectroscopy is based on the determination of the water content of organic matter, based on the Lambert-Beer law to establish a linear relationship between the absorption signal and COD, and determine the corresponding water quality COD value.

This process mainly uses the absorption of organic matter by ultraviolet spectroscopy, and reflects the content of organic matter through a special absorption relationship.

The advantage of using this technology is that it is low in cost and fast in speed, and it is not easy to cause secondary pollution.

UVD method for the determination of COD can not detect all the organic matter, but can avoid the problem of chloride interference in chemical methods.

It can also detect benzene series, pyridine, etc. which cannot be detected by chemical method. It is an objective and comprehensive method for COD detection in water.

Specifically, it is measured by the absorption of ultraviolet light at 254 nm by most of the organic matter in the water.

However, due to the large amount of suspended solids in the general water body, the scattering effect of these suspended solids will affect the absorbance of organic matter in the water at this wavelength, resulting in a large deviation between the measured results and the actual values.

In order to reduce the scattering effect of suspended solids in water on the absorbance of water at 254 nm, the absorbance at other wavelengths is usually used to compensate, that is, the absorbance with less influence of scattering is used as another input variable.

This product uses the water absorbance at 546 nm wavelength to apply to the compensation modeling of different test environments, and the resulting modeling results.

This effectively proves that the dual-wavelength measurement method based on this can effectively eliminate the interference caused by suspended scattering in water on COD measurement.