Biochemical incubator - How to conduct BOD5 measurement experiments in a biochemical incubator

BOD5 (Biochemical Oxygen Demand at 5 days) measurement is an indicator used to measure the degree of organic matter degradation in water. A biochemical incubator can provide a constant environment to support microorganisms in degrading organic matter in water samples over a certain period of time. By measuring the difference in dissolved oxygen concentration before and after degradation, the BOD5 value can be calculated.

The following are the basic steps for conducting BOD5 determination experiments in a biochemical incubator:

Biochemical incubator - How to conduct BOD5 measurement experiments in a biochemical incubator

Experimental preparation:

Sample collection: Collect water samples and ensure that they are kept cool before being collected in the laboratory to avoid natural degradation of organic matter.

PH adjustment: If the pH value of the water sample is not within the appropriate range (usually 6-9), appropriate pH adjustment should be carried out.

Preparation of biochemical culture medium: Prepare a biochemical culture medium suitable for BOD5 determination. This usually includes organic carbon sources, nitrogen sources, phosphorus sources, etc., to provide the nutrients needed for microbial growth.

Biochemical incubator - How to conduct BOD5 measurement experiments in a biochemical incubator

Experimental steps:

Sample packaging: Divide the water sample into appropriately sized glass bottles, and the sample volume in each bottle should be sufficient to support a 5-day microbial degradation process.

Add biochemical culture medium: Add pre prepared biochemical culture medium to each bottle to ensure sufficient nutrients are provided to support microbial growth.

Biochemical incubator setting: Set the temperature of the biochemical incubator to a range suitable for microbial growth, usually between 20-25 degrees Celsius.

Aeration: Adequate oxygen is provided by injecting air into the culture bottle or through the gas exchange membrane on the bottle cap.

Cultivation: Place the bottle into a biochemical incubator and conduct a 5-day cultivation process. During this period, microorganisms will utilize organic matter in the water sample to consume dissolved oxygen.

Dissolved oxygen measurement: After the cultivation is completed, use a dissolved oxygen meter to measure the dissolved oxygen concentration in the water sample before and after cultivation. The calculation of BOD5 is based on the difference in dissolved oxygen at these two time points.