Project Background
The Longjiang Middle Road Wastewater Management Office in Longwen District, Zhangzhou, Fujian, is responsible for regional wastewater treatment and discharge supervision. To improve water quality monitoring capabilities, the office deployed a complete online monitoring instrument system for real-time monitoring of key water quality indicators.
Since being put into operation, the system has run stably, providing a reliable data foundation for process control and environmental compliance.
Monitoring Parameters and Instrument Configuration
The project covers six core water quality parameters: pH, SS, COD, ammonia nitrogen, total phosphorus, and total nitrogen. Based on the characteristics of each parameter, the following instrument models were selected:
| Monitoring Parameter | Instrument Model |
|---|---|
| pH | PM8202S pH |
| SS (Suspended Solids) | PM8202S SS |
| COD | PhotoTek 6000 COD |
| Ammonia Nitrogen | PhotoTek 6000 Ammonia Nitrogen |
| Total Phosphorus | PhotoTek 6000 Total Phosphorus |
| Total Nitrogen | PhotoTek 6000 Total Nitrogen |
Instrument Technical Features
PM8202S Series (pH/SS)
- PM8202S pH: Uses the glass electrode method, measuring range 0-14 pH, accuracy ±0.01 pH, suitable for continuous monitoring of wastewater acidity and alkalinity.
- PM8202S SS: Based on infrared scattering principle, range 0-5000 mg/L, effectively handling fluctuations in wastewater suspended solids concentration.
- Both instruments feature automatic temperature compensation and RS485 output, making integration into the central control system easy.
PhotoTek 6000 Series (COD/Ammonia Nitrogen/Total Phosphorus/Total Nitrogen)
- PhotoTek 6000 COD: Uses UV absorption method, reagent-free, low maintenance, range 0-1000 mg/L.
- PhotoTek 6000 Ammonia Nitrogen: Ion-selective electrode method, fast response, range 0-100 mg/L.
- PhotoTek 6000 Total Phosphorus: Ammonium molybdate spectrophotometric method, range 0-50 mg/L.
- PhotoTek 6000 Total Nitrogen: Potassium persulfate digestion-UV spectrophotometric method, range 0-100 mg/L.
- The entire series supports automatic cleaning and remote calibration, suitable for unattended stations.
System Operation and Maintenance
To ensure accurate and reliable monitoring data, the project established a standardized operation and maintenance process:
- Daily Inspection: Check instrument display, pipeline patency, and reagent levels.
- Regular Calibration: Perform standard solution verification every 1-2 weeks according to operating conditions.
- Cleaning and Maintenance: Manually clean sensors and flow cells monthly.
- Data Review: Remotely check data daily and promptly investigate abnormal values.
Through these measures, the instruments exhibit minimal drift during long-term operation, with a data availability rate of over 95%.
Application Results
Since being put into operation, the online monitoring system has provided continuous and accurate water quality data for the Longjiang Middle Road Wastewater Management Office. Managers can grasp real-time changes in influent and effluent water quality, optimize process parameters, and ensure compliant discharge.
At the same time, the system data has been connected to the environmental protection regulatory platform, meeting the requirements of pollutant discharge permits and total quantity control, and improving the efficiency of regional water environment supervision.