Biochemical oxygen demand BOD5 is a mandatory item for water quality assessment and an important quality indicator for measuring organic matter pollution. The conventional BOD5 assay method uses a five-day dilution inoculation method. The method is cumbersome to operate, requires high experimental skills for the analysts, and the discreteness of the experimental data is large, often resulting in inaccurate experimental results.
The differential pressure method BOD measuring instrument test system adopts the differential pressure test method, and the pressure detecting head, the sample bottle and the CO2 absorbent constitute a sealed pressure measuring system, and the piezoelectric sensor in the pressure detecting head senses the change of the pressure.
Second, the working principle 1, the basic principle of B0D5
Biochemical Oxygen Demand (BOD) refers to the amount of dissolved oxygen consumed by the decomposition and respiration of aerobic microorganisms in water under specific conditions. The BOD5 value in water is usually expressed as the amount of dissolved oxygen (mg/L number) consumed by the sample to stand at 20 ° C for 5 days, and is referred to as "BOD5".
2. Instrument test principle When the microorganism in the sample to be tested carries out aerobic biochemical reaction, it will consume dissolved oxygen in the sample and release CO2. 21% of the oxygen in the air in the sample bottle will be continuously added to the solution to reach a new balance. And the released CO2 is absorbed by the CO2 absorbent. Therefore, the closed pressure system is in a negative pressure state. The BODTECH test system calculates the amount of O2 consumed by measuring the pressure change and converts it into a BOD value.
3. Advantages
Easy to learn, easy to operate, and can be mastered in half an hour
? Mercury-free pressure probe, safe and non-toxic, accurate measurement
The sample does not need to be diluted, making the BOD measurement more in line with the actual state of the sample biochemical process.
The electromagnetic stirrer continuously stirs to ensure that the oxygen is continuously replenished into the sample, so that the degradation of organic matter is closer to the natural environment.
? With automatic temperature compensation function, when the sample temperature is too high or too low, the instrument delays until the temperature tends to be constant
? Unit combination design, can be flexibly combined according to needs, failure of any unit does not affect the determination of other units
This article was published by Yingnuo Instruments (Shanghai) Co., Ltd.
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