For industrial wastewater, there are various parameters that need to be detected, and TOC is just one of them. In this chapter, let’s briefly understand the application issues of TOC analyzers in industrial wastewater with the editor.

Taking the large-scale thermal power industry as an example, there are various types of sewage treatment equipment in some large-scale thermal power plants in China, mainly including clarifiers, activated carbon filters, filter tanks, reverse osmosis and other types of equipment. In the wastewater pretreatment system of thermal power industry, the water vapor system in the furnace and the desalination system all need to use TOC online analyzers to detect the total organic carbon in the water in real time. So how does this instrument detect the TOC value?

Hangzhou Moody has produced a TOC-8000 – TOC online analyzer, which is precisely used to measure the total organic carbon content in water. The non-dispersive infrared (NDIR) colorimetric method was used. After the water sample was pre-treated, it was injected into the ultraviolet digestion device by an injection pump. In this way, the inorganic carbon in the water sample would be converted into carbon dioxide at the action line of strong acid and escape from the gas/liquid to the outside of the separator. At this point, the TOC in the water sample in the reactor undergoes an oxidation reaction with the strong oxidant in the reagent. Then, the TOC is converted into carbon dioxide gas, which is carried by the carrier gas to enter the condenser. After condensation, the carbon dioxide gas is filtered out to remove solid particles and interfering objects that may exist in the carbon dioxide gas. Then, it is sent into the non-dispersive infrared NDIR gas measurement chamber for photoelectric signal measurement. The signal output by NDIR is closely related to the concentration of carbon dioxide gas and also to the TOC in the water sample. Then, by measuring this signal, we can directly determine the TOC content in the water.