How to use BOD5 tester to detect content

　　BOD5 instrument is a kind of instrument widely used in environmental science, which is used to detect the biological oxygen consumption in water, wastewater and other liquid samples. This test method is very important for monitoring and evaluating the health and pollution degree of water quality. This paper will introduce in detail how to use BOD5 tester to detect the content, and discuss the key steps and matters needing attention.

　　Dobby instrument -BOD5 tester

　　Let's know the working principle of BOD5 tester. BOD stands for biochemical oxygen demand, which refers to the amount of oxygen required by microorganisms to oxidize the body in a short period of time. BOD5 tester measures the content of organic matter in water by exposing the sample to a certain temperature and using the consumption of oxygen. This process is realized by collecting carbon dioxide generated after oxygen depletion in a sealed container. Some key steps are indispensable when conducting BOD5 test. First, you need to prepare a certain amount of samples, usually 500 ml. Then, transfer the sample to a sealed container that has been cleaned in advance to ensure that the sample does not contain oxygen. Next, the container is placed in a thermostatic bath to maintain a constant temperature (usually 20 degrees Celsius). Temperature control is very important for the accuracy of the results. Once the sample is put into a thermostatic bath, it is necessary to add a culture solution containing nutrients. This culture solution usually contains some common inorganic salts and nutrients to provide nutrients needed by microorganisms. By adding appropriate culture solution, the consumption of organic matter by microorganisms can be promoted, and the BOD5 content in the sample can be determined. Then, after the culture solution is completely and evenly mixed, it is necessary to measure the initial dissolved oxygen (DO). The initial DO measurement is to record the oxygen content of the sample before starting the test. This step is very important for the interpretation of subsequent results. By recording the initial DO value, the dissolved oxygen consumption of BOD5 can be calculated, so as to determine the content of organic matter in the sample. Next,The sample will continue to be placed in a thermostatic bath, which usually lasts for 5 days. During this time, the organic matter in the sample will be consumed by microorganisms, resulting in the reduction of dissolved oxygen. During the test, the dissolved oxygen content in the sample is measured regularly, usually once a day. These measurements will be used to calculate the BOD5 content in the sample. After the expiration of the 5-day BOD5 test, it is necessary to measure the concentration of dissolved oxygen again to determine the final dissolved oxygen content in the sample. By calculating the difference between the initial DO value and the final DO value, the consumption of organic matter in the sample can be obtained, so as to determine the BOD5 content. In the process of BOD5 determination, there are some matters needing attention. First of all, ensure that the sample collection and processing process is not polluted. Any foreign organic matter or microorganism may interfere with the test results. In addition, ensure that the temperature control of the thermostat is accurate to ensure the accuracy of the test results. Record and save the obtained data in time for future analysis and reference. It is a complicated and important work to detect the content with BOD5 tester. Only through accurate and detailed tests can reliable results be obtained. By following the correct operation steps and precautions, we can use BOD5 to monitor and evaluate the water quality, and provide strong support for environmental protection and water resources management.