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What is BOD?

by:BOQU     2021-05-03


Under the influence of microorganisms, the degradation process of general organic matter can be divided into two stages. The stage is the process of converting organic matter into CO2, NH3 and H2O. The second stage is the nitrification process where NH3 is further converted into nitrite and nitrate. Since NH3 is already an inorganic substance, the biochemical oxygen demand of sewage generally only refers to the amount of oxygen required by the organic matter in the stage of a biochemical reaction.

The degradation of organic matter by microorganisms is related to temperature. Generally, 20°C is used as the standard temperature for the determination of biochemical oxygen demand. Under the conditions of sufficient oxygen and constant agitation, it usually takes 20 days for organic matter to basically complete the stage of oxidative differentiation about 99%. The 20-day BOD value is often regarded as the standard BOD value, namely BOD20.

But 20 days is difficult to achieve in actual work. Therefore, there is a standard time, generally, 5 days, called the five-day biochemical oxygen demand, commonly known as BOD5. BOD5 is about 70% of BOD20.

The BOD5 of general rivers does not exceed 2mg/L. If it is higher than 10mg/L, it will emit a foul smell. my country summarizes the rules of sewage discharge standards. At the factory outlet, the allowable concentration of the second-level BOD standard for the biochemical oxygen demand of wastewater is 60mg/L, and the surface water biochemical oxygen demand BOD must not exceed 4mg/L.

Lovibond? Biochemical oxygen demand BOD measurement and constant temperature incubator are best combined to form a biochemical oxygen demand BOD analysis and measurement system, using breathing pressure method of biochemical oxygen demand BOD measurement principle, highly environmentally friendly and mercury-free measurement, user can set Biochemical oxygen demand BOD cultivation cycle (1 to 28 days), with a variety of biochemical oxygen demand BOD ranges to choose from, the smallest range is 0 to 40mg/L, the maximum range is 0 to 4000 mg/L, large screen display, continuous reading And the graph shows the change of the measurement process in real-time, and it has the function of the active opening. After the temperature of the sample is balanced, the measurement is automatically opened, and the BOD value is automatically stored in the sensor.

Equipped with a dedicated remote control, users can quickly retrieve data at any time, USB, SD flash card interface, can quickly and computer data transmission and processing, in line with APHA, AWWA, WFF standard method 5210 D and DIN 38 409-H 52 standard methods, widely used in surface water, daily sewage and industrial sewage, etc.

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