Chemical Oxygen Demand (COD) refers to the mass concentration of oxygen consumed by strong oxidants under specific conditions to oxidize organic and inorganic reducing substances in water samples. COD is a critical indicator reflecting the extent of water pollution caused by organic and inorganic reducing substances.

This analyzer is designed for long-term, unattended, automatic, and continuous operation based on field configurations. It is widely applicable to scenarios such as industrial pollution source wastewater discharge, industrial process wastewater, industrial wastewater treatment plant effluent, and municipal sewage treatment plant effluent. Depending on the complexity of on-site testing conditions, optional preprocessing systems can be integrated to ensure reliable testing processes, accurate results, and full compliance with diverse on-site requirements.

>>Features‌‌
A mixture of the water sample, potassium dichromate digestion solution, silver sulfate solution (added as a catalyst to enhance oxidation efficiency for straight-chain aliphatic compounds), and concentrated sulfuric acid is heated to 165°C. After the dichromate ions oxidize organic substances in the solution, a color change occurs. The analyzer detects this colorimetric change, converts it into a COD value output. The amount of dichromate ions consumed corresponds to the quantity of oxidizable organic matter, which is quantified as the COD value.

>>Technical Parameter

‌Test Method‌	Potassium dichromate oxidation spectrophotometric method
‌Measuring Range‌	0~5000mg/L (segmented measurement, expandable)
‌Indication Error‌	20% range standard solution: ≤±10% 50% range standard solution: ≤±8% 80% range standard solution: ≤±5%
‌Quantitative Lower Limit‌	≤15mg/L
‌Repeatability‌	≤5%
‌Drift (24h)‌	Low concentration drift: ±5mg/L High concentration drift: ≤5%
‌Masking Capacity‌	Up to 20,000mg/L Cl⁻
‌Measurement Time‌	<50min (digestion time adjustable)
‌Measurement Modes‌	Adjustable time interval, fixed time point, or triggered measurement
‌Calibration Modes‌	Automatic calibration (1~99 days adjustable) Manual calibration based on actual water samples
‌Maintenance Cycle‌	1 month per session; ~30min per maintenance
‌Human-Machine Interface‌	Touchscreen display and command input
‌Self-Diagnosis & Protection‌	Self-diagnoses operational status; retains data during anomalies/power outages Automatically clears residual reactants and resumes operation after reset/power recovery
‌Data Storage‌	5-year data capacity
‌Input Interface‌	Digital input
‌Output Interfaces‌	1× RS232, 1× RS485 2× 4~20mA analog outputs
‌Operating Environment‌	Indoor use; recommended temperature: 5~28℃, humidity ≤90% (non-condensing)
‌Power Supply‌	Voltage: AC 220±10% V Frequency: 50±0.5 Hz Power: ≤150W (excluding sampling pump)
‌Dimensions‌	520H × 370W × 265D (mm)

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products details

Online CODcr COD Water Quality Analyzer Potassium Dichromate Oxidation Spectrophotometric Method Monitor

Online Water Quality Monitor

Multi Parameter Water Quality Monitor

PH ORP Meter

Conductivity Meter

Dissolved Oxygen Meter

Ion-selective Meter

Residual Chlorine Meter

Turbidity Analyzer

TSS Analyzer

COD Analyzer

Optical Water Quality Sensor

Ultrasonic Meter

Water Quality Monitoring Accessories

Online Water Quality Monitor

Drinking Water Monitoring

Industrial Wastewater Monitoring

Aquaculture water Quality Monitoring

Boiler Water Monitoring

Multi Parameter Water Quality Monitor

PH ORP Meter

PH ORP Transmitter And Sensor

Portable PH ORP Meter

Desktop PH ORP Meter

Conductivity Meter

Conductivity Transmitter And Sensor

Portable Conductivity Meter

Desktop Conductivity Meter

Dissolved Oxygen Meter

Dissolved Oxygen Transmitter And Sensor

Portable Dissolved Oxygen Meter

Desktop Dissolved Oxygen Meter