This method is applicable to wastewater with total nitrogen concentrations within the range of 0-300 mg/L.

1. Measurement Method: Potassium persulfate resorcinol spectrophotometric method
2. Measurement Range: 0-300 mg/L
3. Accuracy: ≤±10%
4. Repeatability: ≤±5%
5. Measurement Cycle: Minimum cycle is 45 minutes; color development time can be adjusted flexibly between 5-30 min based on environmental conditions.
6. Sampling Cycle: Adjustable time interval (10-9999 min) or on-the-hour measurement mode.
7. Calibration Cycle: Adjustable at any interval from 1-99 days.
8. Maintenance Cycle: ≥168 hours, with each maintenance lasting ~1 hour.
9. Reagent Consumption: <0.50 CNY per sample.
10. Outputs: RS-232, 4mA-20mA, RS-485.
11. Environmental Requirements: Temperature-controlled indoor environment (recommended: 5-40°C); humidity 45%-85%.
12. Power Supply: AC 220±10% V, 50±1% Hz, 5A.
13. Dimensions: Height 1500 × Width 500 × Depth 450 mm.
14. Additional Features:

• Data retention during abnormal alarms or power outages.
• Touchscreen display and command input.
• Automatic discharge of residual reactants and resumption of operation after power restoration or system reset.

Unique Design: This product features a distinctive design that ensures lower failure rates, reduced maintenance requirements, minimal reagent consumption, and higher cost-effectiveness compared to similar products.

1. Selector Valve Assembly:

   • Enables flexible reagent sampling timing and diverse channel configurations.
   • Minimizes dead volume for easy maintenance and extended service life.

2. Micro-Dosing Unit:

   • Utilizes a visual photoelectric system for precise reagent measurement, eliminating quantitative errors caused by peristaltic pump tube wear.
   • Achieves accurate micro-dosing with 0.7 mL per dose, significantly reducing reagent usage.

3. Sample Introduction Unit:

   • Employs a peristaltic pump with negative pressure suction, creating an air buffer zone between reagents and the pump tube to prevent corrosion.
   • Simplifies and enhances flexibility in reagent mixing.

4. Sealed Digestion Unit:

   • Operates under high-temperature and high-pressure conditions to accelerate reactions.
   • Eliminates corrosion risks from volatile gases in open systems.

5. Reagent Tubing:

   • Uses imported modified PTFE (polytetrafluoroethylene) transparent tubing with an inner diameter >1.5 mm to minimize clogging by particulate matter in water samples.