Biochemical oxygen demand (BOD) is one of the important indicators to measure the ability of organic matter in water to be biochemically degraded by microorganisms, and is also a key indicator to evaluate the self-purification capacity of water and environmental conditions. With the acceleration of industrialization and the increase in population, the pollution of water environment has become increasingly serious, and the development of BOD detection has gradually improved.
The origin of BOD detection can be traced back to the end of the 18th century, when people began to pay attention to water quality issues. BOD is used to judge the amount of organic waste in water, that is, to measure its quality by measuring the ability of microorganisms in water to degrade organic matter. The initial BOD determination method was relatively simple, using the beam incubation method, that is, water samples and microorganisms were inoculated in a specific container for cultivation, and then the difference in dissolved oxygen in the solution before and after inoculation was measured, and the BOD value was calculated based on this.
However, the beam incubation method is time-consuming and complicated to operate, so there are many limitations. In the early 20th century, people began to seek a more convenient and accurate BOD determination method. In 1939, American chemist Edmonds proposed a new BOD determination method, which is to use inorganic nitrogen substances as inhibitors to block the replenishment of dissolved oxygen to reduce the determination time. This method has been widely used and has become one of the main methods for BOD determination.
With the advancement of modern science and technology and the development of instrumentation, the BOD determination method has also been further improved and perfected. In the 1950s, an automated BOD instrument appeared. The instrument uses a dissolved oxygen electrode and a temperature control system to achieve non-interference continuous determination of water samples, improving the accuracy and stability of the determination. In the 1960s, with the development of computer technology, a computer networked automatic data acquisition and analysis system appeared, which greatly improved the efficiency and reliability of BOD determination.
In the 21st century, BOD detection technology has made further progress. New instruments and analytical methods have been introduced to make BOD determination faster and more accurate. For example, new instruments such as microbial analyzers and fluorescence spectrometers can realize online monitoring and analysis of microbial activity and organic matter content in water samples. In addition, BOD detection methods based on biosensors and immunoassay technology have also been widely used. Biosensors can use biological materials and microbial enzymes to specifically detect organic matter, and have the characteristics of high sensitivity and stability. Immunoassay technology can quickly and accurately determine the content of specific organic matter in water samples by pairing specific antibodies.
In the past few decades, BOD detection methods have gone through a development process from beam culture to inorganic nitrogen inhibition method, and then to automated equipment and new instruments. With the advancement of science and technology and the deepening of research, BOD detection technology is still being improved and innovated. In the future, it can be foreseen that with the improvement of environmental awareness and the increase of regulatory requirements, BOD detection technology will continue to develop and become a more efficient and accurate means of water quality monitoring.
Post time: Jun-07-2024
