The microcomputer BOD analyzer (i.e. biochemical oxygen demand analyzer) is an instrument used to determine the amount of oxygen required for the degradation of organic matter in water samples. BOD (Biochemical Oxygen Demand) reflects the degree of organic pollution in water bodies and is one of the commonly used indicators in water quality monitoring. The microcomputer BOD analyzer simulates the biodegradation process of water samples under certain conditions to determine their biochemical oxygen demand.
Measurement method of microcomputer BOD analyzer
1. Sample preparation
Sampling: Collect water samples from the water body to be tested, usually with a collection volume of 300ml or less, to ensure uniform sampling and prevent external pollution.
Sample filtration: For water samples containing a large amount of suspended solids, filter with filter paper or membrane to remove insoluble substances and avoid affecting the measurement results.
Water sample pretreatment: Water samples can be pretreated as needed, such as adjusting the pH value, temperature, or adding appropriate amounts of nutrients to ensure that the testing conditions meet the standard requirements.
2. Add inoculation bacteria
The microcomputer BOD analyzer uses microbial inoculum (usually a specialized bacterial culture medium) during the measurement process, and the microorganisms in the inoculum will consume dissolved oxygen by decomposing organic matter in the water.
After adding the inoculum, stir evenly to ensure that the microorganisms in the water sample can fully decompose organic matter.
3. Set measurement conditions
Temperature control: Generally measured at a temperature of 20 ° C ± 1 ° C, as this temperature meets the growth needs of microorganisms.
Time setting: BOD measurement generally requires a cultivation period of 5 days (i.e. BOD5) or longer, and a 5-day cultivation period is usually set to observe the oxygen consumption in the water sample.
Instrument parameter setting: Set the measurement time and sampling frequency of the instrument to ensure accurate recording of oxygen consumption at each time point throughout the entire cultivation process.
4. BOD determination process
Closed cultivation: Place the treated water sample (with inoculum) into a BOD bottle, seal the bottle mouth, and ensure that there is no external oxygen interference.
Oxygen consumption measurement: Monitor dissolved oxygen at a set cultivation temperature. Microorganisms consume dissolved oxygen in water by decomposing organic matter. By measuring the changes in dissolved oxygen at different time points, the variation curve of biochemical oxygen demand (BOD) is obtained.
Continuous monitoring: The microcomputer BOD analyzer will automatically detect the dissolved oxygen value at each time period and record it. Measure dissolved oxygen concentration at regular intervals (e.g. every 24 hours) during the 5-day cultivation period.
5. Calculate BOD value
The microcomputer BOD analyzer will calculate the BOD value based on changes in dissolved oxygen. The BOD value is equal to the initial dissolved oxygen minus the remaining dissolved oxygen after 5 days of cultivation, and then corrected based on factors such as the volume and concentration of the water sample.
The microcomputer system will automatically process the data and output the final BOD value. The calculated BOD value can be directly used to determine the degree of water pollution.
6. Result analysis
BOD5: The common measurement cycle is 5 days, and different time periods can be selected as needed (such as BOD3, BOD7, etc.).
The relationship between BOD value and water quality: A high BOD value indicates that there are many organic pollutants in the water and the water quality is poor; A low BOD value indicates less organic pollution in the water and better water quality.
Advantages of microcomputer BOD analyzer
Efficient and accurate: The microcomputer BOD analyzer adopts automated control and data acquisition, greatly reducing manual operation and improving the accuracy and reliability of testing.
Real time monitoring: capable of real-time monitoring of dissolved oxygen changes in water samples, automatically recording data and outputting results, reducing human errors.
Easy to operate: The device is controlled by a microcomputer, with a simple and easy-to-use interface, suitable for routine monitoring in most laboratories.
Automatic calculation: The instrument can automatically perform data calculation and analysis, and the output results are concise and clear, saving experimental personnel's calculation time.
summary
The measurement method of the microcomputer BOD analyzer mainly includes sample preparation, inoculation, dissolved oxygen monitoring, data recording and calculation. By monitoring the consumption of oxygen during the degradation of organic matter in water samples, the degree of water pollution can be effectively evaluated. It is an accurate and convenient water quality analysis tool widely used in fields such as environmental protection, wastewater treatment, and water quality monitoring.