The NO7 Nitrate Sensor measures the concentration of dissolved nitrate nitrogen (NO3 – -N) in water. The sensor uses two electrodes to determine the NO3 – -N concentration, a Nitrate Ion Electrode and a Chloride Ion Electrode. It is designed for use in all kinds of water. Typical applications include monitoring environmental waters, lakes, streams and wells as well as wastewater treatment in aeration basins and effluent.

Nitrogen primarily enters a municipal wastewater treatment plant as ammonia/ammonium compounds. Nitrification oxidizes the toxic ammonium ion into much less toxic nitrate ion using an aerobic activated sludge process. De-nitrification reduces the nitrate ion (NO3 – ) to nitrogen gas (N2) by an anoxic reaction in the same treatment basin or in a separate anaerobic digester. The NO3 – -N measurement can optimize the methanol being fed to the digester, minimizing cost, and also provide a trend of the total nitrogen (TN) in the effluent.

The Nitrate Ion Electrode provides the primary measurement. A second electrode measures the Chloride ions in the sample. The chloride ion due to their similar size and charge to the nitrate ion, cause a positive interference in the measurement. The Chloride Ion Electrode measures the chloride ion present in the sample and digital processor in the sensor subtracts a certain amount of signal contributed by the chloride ions from the Nitrate Measurement.

An option pH electrode is also available in the NO7 sensor. Although it is not required for the measurement, it can provide valuable information about the process. Temperature is also measured and used to compensate each of the measurements. Ion electrodes tend to be less well behaved than pH electrodes, so for the best results, please calibrate the sensor close to the process temperature.

The rugged NO7 sensor has a 1-1/2” NPT rear facing thread for attaching an extension/immersion tube for easy installation from catwalks or handrails. The NO7 sensor is submersible with an IP68 degree of ingress protection. A removable electrode guard facilitates easy electrode replacement when necessary. The sensor features an internal digital signal conditioning unit that allows the sensor to be mounted up to 300 meters from the GDC.

• AM7 Ammonium Sensor:
  1. Ammonium ISE electrode, K+, pH and Temp. electrodes.
  2. Fast and accurate Ammonium measurement NH4+ or NH4+-N; Fully compensated for pH, K+ interferences & Temperature.
• NO7 Nitrate Sensor:
  1. Nitrate ISE electrode, Cl- and Temp. electrodes.
  2. Fast and accurate Nitrate measurement NO3- or NO3-N; Fully compensated for Cl-interferences & Temperature (Optional pH electrode).
• The AN7 Ammonium/Nitrate Sensor is optional for both Ammonium & Nitrate measuring at same time.
• Rugged PVC design, Removable electrode guard for easy maintenance.
• Integral Spray Head Cleaner, Cleans the sensor in situ with pressurized water or air.
• Internal Signal Conditioning, RS485 Modbus Digital signals allow up to 300-meters long communication between the Sensor and the GDC