Product Overview and Application Scenarios
Liquiline System CA80COD is an online analyzer that uses the wet chemical method for continuous determination of chemical oxygen demand (COD) in liquid media. It is suitable for the following typical scenarios:
- Monitoring at the inlet of wastewater treatment plants
- Process control in municipal wastewater treatment
- Industrial wastewater discharge monitoring
- Process control in industrial wastewater treatment
Core Functions and Expansion Capabilities
The instrument can connect up to four Memosens digital sensors, easily upgrading to a liquid analysis measurement station. Its high-precision sampling unit can automatically switch ranges within 10...5000 mg/l O2 and supports various digital fieldbus communications and web services.
- PROFINET
- PROFIBUS DP
- Modbus TCP / Modbus RS485
- Ethernet IP
Measurement Principle and Chemical Process
Chemical oxygen demand (COD) refers to the total amount of oxygen required to completely oxidize all oxidizable substances in a sample, and is a comprehensive indicator. Chloride ions interfere with the measurement results, so chloride ions must be removed first.
Digestion and Color Reaction
Chloride ions are removed by adding mercuric sulfate. After complete removal, sulfuric acid, silver sulfate, and potassium dichromate are added at 175 °C for sample digestion. Silver sulfate acts as a catalyst, and the high temperature and potassium dichromate (strong oxidant) ensure rapid and complete digestion of the sample, thereby shortening the digestion time. Note: These reagents are corrosive and require extra care during use.
The figure above shows the measurement unit: 1 is the LED light source (measurement/reference light source); 2 is the photometer reaction chamber (mixer and reaction vessel); 3 is the detector (measurement/reference).
During the chemical reaction, the color of the oxygen solution changes from orange to green. The chromate reduction reaction and color change are directly proportional to the concentration of oxidizable substances in the sample. Therefore, the optical quantification of the reduced chromate concentration can serve as an indicator of the chemical oxygen demand of the sample.
Key Technical Advantages
Precision Sampling and Anti-Contamination Design
CA80COD uses core precision syringe pump sampling technology, abandoning the pulse error of traditional peristaltic pumps to achieve microliter-level precise metering. Combined with a corrosion-resistant full-flow-path design and an intelligent liquid manager, it effectively prevents clogging and contamination from high-salinity and high-turbidity water samples, ensuring long-term stability under complex working conditions.
Fully Automated Operation and Maintenance
The fully automated design makes operation and maintenance easier. The instrument supports unattended automatic calibration, automatic cleaning, and automatic waste discharge. The built-in intelligent diagnostic system monitors each analysis step in real time. Once reagent shortage or a fault occurs, it immediately issues a warning, minimizing maintenance workload.
Summary
CA80COD is not just an analyzer, but a complete chemical oxygen demand online monitoring solution. For more information, you can add the WeChat below for consultation, or join the instrumentation exchange group, or call 153 2371 3323, and visit the official account or website http://ainstru.com/ for more content.