Analyzer Ideal for Reliable Surface Water Monitoring
Designed with advanced ion selective electrode (ISE) sensors and a highly intelligent transmitter, the new plug-and-play Ammonium Hydra-DS Analyzer from Electro-Chemical Devices (ECD) simplifies the accurate measurement of harmful nutrients (nitrogen) over a broad range to help assure water quality.
The Ammonium Hydra-DS Analyzer measures the nutrient load in rivers, streams and lakes as well as wastewater treatment plant aeration basins. It determines the concentration of dissolved ammonium as nitrogen (NH4+-N [nutrients]) in water. The firm states that the sensor uses three electrodes to determine NH4+-N concentrations: ammonium (NH4), potassium (K+) and pH (acidity versus alkalinity levels).
The analyzer’s dependable NH4, K+ and pH ISE sensors are fully compensated for interferences and temperature variability to ensure reliable performance. According to the company, the ISE sensors are housed in a rugged, removable PVC tube guard for easy access. A built-in spray cleaner provides in-situ cleaning for automated, predictive maintenance with pressurised water or air to prevent algae or other film growths and to avoid technician cleaning labour.
The sensor’s NH4 electrode provides primary sensing and measurement. Any potassium ion in the sample generates a positive (K+) interference in the measurement due to its similar size and charge to the NH4 ion, adds the firm. The K ion electrode measures the amount of potassium ion present in the sample, and the T80 Transmitter subtracts the appropriate amount of signal from the NH4 measurement.
The NH4 ion electrode only measures the ammonium ion (NH4+) – not ammonia (NH3). The ammonium ion and ammonia coexist in a pH dependent ratio in solution. The more acidic pH values favour the NH4+ and the more basic values favour dissolved ammonia gas (NH3). The pH electrode measures the pH, and the analyzer’s T80 Transmitter calculates the total NH4+-N level based on the pH versus NH4+ concentration proﬁle stored in the instrument.
The rugged sensor has 1.25-inch rear facing threads for attaching an extension/immersion tube for easy installation from catwalks or handrails. The sensor is submersible with an IP68 rated degree of ingress protection. Its digital sensor design supports virtually any size length of cable, explains the company.
The firm opines that the analyzer operates over a wide measurement range from 0.1 to 14,000 ppm with a T90 response time of 1 minute. Accuracy is ±3% of reading (dependent on calibration). The sensors operate over a flow rate range from 0.1 to 3.0 minutes per section (m/s). Operating temperature range is from 32 to 122°F (0 to 50°C).
The transmitter features an easy-to-read 2.5-x-1.75-inch LCD display housed in a water-resistant Nema 4X enclosure. Two 4-20A outputs are provided with Modbus compatibility (optional Hart) for integration with plant distributed control systems. Input power is 110/220 VAC/5A. There are three SPDT relay alarms (230 VAC, 5A), including one for the spray cleaner.