Double wavelengths ultraviolet absorption method for organic wastewater COD measurement and its instrument design
双波长紫外吸收法有机废水COD测量技术与仪器设计

Ultraviolet absorption method for organic wastewater COD measurement is a green nondestructive testing method, which has the advantages of no reagent application, no sample preparation, and no secondary pollution, but in practical application, the measurement results are greatly influenced by the suspended solids in organic wastewater. The operation method of double wavelengths ultraviolet absorption for COD measurement and the principle of eliminating interference of suspended solids were discussed in this paper, which based on the actual wastewater sample, and online COD measuring instrument was discussed as well which was designed based on this method. The embedded computer system was used in this instrument to collect and process the real-time data, and the COD was calculated quickly according to the effective ultraviolet absorbance which was in the condition of double wavelengths measurement of practical wastewater sample, the testing results show that the instrument has characteristics of rapid, accurate and no pollution.