Explain clearly at one time what COD, BOD and TOC are?-Yuanlai Water Treatment

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Explain clearly at one time what COD, BOD and TOC are?

Released Date: Aug 17,2015 Article Source: Yuanlai Water Treatment

There are many types of organic substances in natural water that cannot be detected separately; only the total amount of organic matter can be tested. The detection indicators for total organic matter include: Chemical Oxygen Demand (COD), biological oxygen demand (BOD), and total organic carbon (TOC). Now let's talk about what COD, BOD and TOC are. Chemical Oxygen Demand (COD) refers to the amount of oxidant consumed when treating water samples under certain conditions with a certain strong oxidant, with the unit being mg/L. It is an indicator representing the content of reductive substances in water. In addition to various organic substances, the reducing substances mentioned in the book also include nitrite, sulfide, ferrous salt, etc., but organic substances account for the vast majority. Therefore, chemical oxygen demand (COD) is often used as an indicator to measure the amount of organic matter in water. There are two methods for COD determination: one is potassium dichromate

Chemical Oxygen demandCODIt refers to the amount of oxidant consumed when treating water samples under certain conditions with a certain strong oxidant, with the unit beingmg/L. It is an indicator representing the content of reductive substances in water. In addition to various organic substances, the reducing substances mentioned in the book also include nitrite, sulfide, ferrous salt, etc., but organic substances account for the vast majority. Therefore, chemical oxygen demandCODIt is often used as an indicator to measure the amount of organic matter in water.CODThere are two methods for the determination: one is the potassium dichromate method, which usesCODCrIt is indicated, abbreviated as the chromium method; Another one is the potassium permanganate method, which usesCODMnIt indicates that it is used for contaminated surface water or wastewaterCODCrIndicated. Generally, one water sample is usedCODCrThe value is expressed as "use"CODMnRepresented by a value2~10"Multiple, thus characterizing.CODWhen specifying parameters, indicate the method to be used.

Biological oxygen demandBODIt reflects the amount of oxygen consumed when organic substances that can be decomposed in water are decomposed under aerobic conditions due to the action of microorganisms. It is the amount of dissolved oxygen that decreases after a water sample is stored in a sealed container at a certain temperature for a certain period of time.mg/LIt is expressed by). The general temperature is20℃Yes, it is needed.20~100Only natural substances can undergo oxidation and decomposition processes. The current regulations are20℃Below, cultivate5The day is used as the standard for determining biological oxygen demandBOD5The same goes for unitsmg/L.CODwithBODThere is no fixed relationship among the values of the quantities, and in most casesCODCr＞BOD5.

Total organic carbonTOCThe content of organic substances is expressed by the amount of carbon, the main element in organic substances. in950℃At high temperatures, the organic matter in the water sample vaporizes and burns, generatingCO2The generated product is determined through an infrared analyzerCO2The total amount can be used to determine the total organic carbon content.

Keywords: Water Softening Equipment Automatic Water Softener Reverse Osmosis Equipment Manufacturer of Water Treatment Equipment

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