Sensor Measures Dissolved Nitrate In Water
Featuring a precision nitrate ISE electrode sensor with an integral self-cleaning sprayer, the new HYDRA Nitrate Analyzer System from Electro-Chemical Devices, Inc. (ECD), offers superior measurement, monitoring and control with virtually no maintenance.
The highly intelligent HYDRA Nitrate Analyzer System measures the concentration of dissolved nitrate as 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. An optional electrode is also available for pH measurement.
The system’s HYDRA Analyzer is configured to periodically actuate a cleaning cycle using the integral spray cleaner in the nitrate sensor, minimizing the formation of biofilms or other coatings on the electrodes and keeping maintenance to a minimum. The cleaning cycles feature a user configurable period and duration. During the cleaning cycle the 4-20 mA output is held at either a preset value or the last value.
While useful in all types of water treatment applications, the HYDRA Nitrate Analyzer System is especially well suited for municipal wastewater treatment plants. Nitrogen primarily enters a municipal wastewater system as ammonia/ammonium compounds. Nitrification oxidizes the toxic ammonium ion into a much less toxic nitrate ion using an aerobic activated sludge process.
De-nitrification reduces the nitrate ion (NO3-) to nitrogen gas (N2) through an anoxic reaction in the same treatment basin or in a separate anaerobic digester. The NO3–N measurement helps optimize the methanol being fed to the digester, which minimizes cost and provides trend measurement 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 HYDRA Analyzer subtracts the appropriate amount of signal from the nitrate measurement for accurate monitoring. The sensor also detects temperature, and the analyzer provides a temperature-compensation calculation for superior measurement accuracy.
The rugged nitrate sensor offers 1.25-inch NPT rear facing threads for attaching an extension/immersion tube for easy installation from catwalks or handrails. Internal signal conditioning allows the sensor to be mounted up to 200 meters from the analyzer. The sensor is extremely low-maintenance, featuring a movable electrode guard to facilitate easy electrode replacement when necessary.
ECD’s HYDRA Nitrate Analyzer System measures nitrate and chloride in concentrations from 0.1 to 1000 ppm, pH from 0 to 14 and temperature from 0 to 50°C (32 to 122°F). Accuracy is ±3 percent of reading with a response time of T90 1 minute.
Featuring a backlit LCD display that provides up to 4 lines of text and graphics, the HYDRA Analyzer includes two 4-20 mA outputs with two SPDT alarm relays. Input power is 110/220 Vac. It is housed in a rugged NEMA 4X enclosure.