I. Current Major BOD Measurement Methods
BOD stands for Biochemical Oxygen Demand. Common detection methods include the coulometric method, dilution and seeding method, activated sludge method, microbial electrode method, mercury-based differential pressure method, and mercury-free differential pressure method. Among these, the dilution and seeding method is the national standard; it involves diluting the water sample to a specific concentration, incubating it at a constant 20°C for five days, and measuring the dissolved oxygen levels before and after incubation to calculate the BOD value (specifically, BOD5).
II. Lianhua’s BOD Solutions
Lianhua Technology currently offers two methods for BOD measurement: the mercury-free differential pressure method and the microbial electrode method. The first, the mercury-free differential pressure method, operates on the principle of respirometry: the depletion of oxygen within a sealed space creates a pressure difference that is detected by a pressure sensor. In this closed system, microorganisms in the sample consume oxygen and produce carbon dioxide; the generated carbon dioxide is absorbed by sodium hydroxide, causing a change in air pressure. A pressure sensor measures this change and converts it into a BOD value. Recommended model: Biochemical Oxygen Demand (BOD) Analyzer LH-BOD712.
The second method, the microbial electrode method, operates on the following principle: the water sample and air are introduced into a flow-through measurement cell at a constant flow rate, bringing them into contact with a microbial sensor. Soluble, biodegradable organic matter in the sample is acted upon by microorganisms in the microbial membrane, reducing the amount of oxygen diffusing to the surface of the oxygen electrode. When the diffusion rate of the biodegradable organic matter into the microbial membrane stabilizes, the oxygen diffusion rate to the electrode surface also stabilizes, generating a constant current. Since there is a quantitative relationship between this current and the amount of oxygen consumed (reflecting the biodegradable organic matter content), the sample’s biochemical oxygen demand can be calculated. Typically, a BOD5 standard sample is used for comparison to determine the sample’s BOD5 value. Recommended model: LH-BODK81 BOD microbial sensor rapid analyzer.
Post time: Sep-17-2026
