TPNA-500, Automatic Total Nitrogen / Total Phosphorus Monitoring System, HORIBA

The TPNA-500 is HORIBA's latest automatic on-line monitoring system for simultaneous continuous measurement of total nitrogen (TN) and total phosphorus (TP) in wastewater and industrial effluent — designed to satisfy regulatory compliance requirements under Japan's Total Pollutant Load Control System and equivalent international frameworks. The latest model incorporates key improvements over previous generations: the reagent replacement cycle has been extended from one month to two months through development of more stable dedicated reagents; power consumption has been reduced by approximately 30%; pure water usage and waste liquid generation have been halved; and a new meniscus weighing method — resistant to contamination — has been adopted while maintaining the 1/10 reagent volume reduction achieved with previous models. Reduced use of mechanically driven components such as solenoid valves further improves long-term reliability. An optional third-component measurement (COD) and two-point metering capability are available for facilities requiring expanded monitoring. The system stores over one year of measurement data including daily and hourly reports, and communicates via RS-485/Modbus.

Key Features TPNA-500

• Extended 2-month reagent replacement cycle (vs 1 month on previous models) — reduced labour and consumable costs.
• ~30% reduction in power consumption; pure water usage and waste liquid volume halved — lower operating and environmental costs.
• New contamination-resistant meniscus weighing method — extended maintenance intervals and improved measurement stability.
• Reduced solenoid valve count — improved long-term mechanical reliability.
• Wide TN range: 0–2 to 1000 mg N/L; wide TP range: 0–0.5 to 250 mg P/L; repeatability ±3% FS (TN ≤50 mg N/L, TP ≤10 mg P/L) and ±5% FS (higher ranges).
• Optional 3rd-component COD measurement; optional 2-point metering for multi-location monitoring.
• Standard 4 analog outputs (4–20 mA) for TN/TP concentration and load output; 16 contact outputs; 9 contact inputs. RS-485 / Modbus communication.
• Data memory for over 1 year including daily/hourly reports, alarm history (500 events), calibration history (100 events); USB export.
• Turbidity compensation option for TN (275 nm correction wavelength).
• Compatible with older TPNA-300 and PN-100 series footprint — drop-in replacement at existing installations.

Applications

The TPNA-500 is suited to continuous automatic TN and TP monitoring at municipal wastewater treatment plants, industrial wastewater discharge points, and environmental water monitoring stations — particularly where regulatory compliance with Total Pollutant Load Control requirements mandates certified on-line measurement of nitrogen and phosphorus concentrations and loads.

Installation and Safety Notes

Install indoors on a flat, vibration-free surface at 2–40 °C; avoid dust, corrosive gases, direct sunlight. Power: 100–240 V AC ±10%, 50/60 Hz, 250 VA. Sample flow rate: 0.5–5 L/min (OF-3 overflow tank) or 5–20 L/min (OF-30). Sample temperature 2–40 °C; no metallic ions or interferents. Pure water usage: 43 L/month; supply pressure 0.1–0.5 MPa. Reagent replacement cycle: 2 months (conditions apply).

Technical Specifications