Accurate monitoring of wastewater treatment effluent and surface water storage

Developed with advanced ion selective electrode (ISE) sensor technology and a highly intelligent transmitter, the family of Hydra-DS Analysers from Electro-Chemical Devices (ECD)  simplifies the accurate measurement of harmful nitrogen (nutrients) and ammonium to maintain water quality in a wide range of environments.

The Hydra-DS Nitrate Analysers are designed to monitor the nitrification process directly in a wastewater treatment plant’s aeration basin or clarifier unit. Its advanced sensor uses ISE technology to measure the Nitrate. Also featuring a self-compensating design, the Hydra DS automatically eliminates Chloride ion interference for high accuracy and reliability.

The Hydra-DS Nitrate Analysers measure 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. It is designed for use in all kinds of water ranging from municipal and industrial wastewater treatment.

For example, nitrogen typically enters a municipal wastewater treatment plant 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) 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, minimising cost, and also provides a trend of the total nitrogen in the effluent.

The nitrate ion electrode performs the primary measurement. A second electrode measures the chloride ions in the sample. The chloride ion, because of its similar size and charge to the nitrate ion, causes a positive interference in the measurement. The chloride ion electrode measures the amount of chloride ion present in the sample and the intelligent transmitter subtracts the appropriate amount of signal from the nitrate measurement.

The Hydra-DS sensor rapidly measures NO3-N and NH4-N from 0.1 to 14,000 ppm with a response time of 1 minute (T90) and an accuracy of ±3% of reading, dependent on calibration.  It operates over a wide temperature range from 32 to 122°F (0 to 50°C).  Its highly

intelligent transmitter includes an easy-to-read backlit display and comes with two 4-20mA outlets and three SPDT alarm relays.  An integral automated sensor spray cleaner reduces biofilms to enhance accuracy and reduce sensor maintenance.

The Hydra-DS Ammonium Analyser is designed to monitor the nutrient load (NH4+) directly in the aeration basin of a wastewater treatment plant. Its powerful sensor uses ISE technology to measure the ammonium, potassium and pH levels. Its self-compensating design automatically compensates for the pH-dependent concentration equilibrium and potassium ion interference on the ammonium electrode.

The ammonium sensor measures the concentration of dissolved ammonium as nitrogen (NH4+-N) in water. The sensor uses three electrodes to determine the NH4+-N concentration, an ammonium ion electrode, a potassium ion electrode and a pH electrode. It is designed for use in all kinds of municipal wastewater or wherever ammonium is present in water.

The ammonium ion electrode performs the primary measurement. Any potassium ion in the sample, however, generates a positive interference in the measurement because of its similar size and charge to the ammonium ion.  The Hydra-DS Analyser’s highly intelligent transmitter self-compensates by adjusting the signal for this potassium interference and eliminates it from the measurement of ammonium for superior accuracy and reliability.

The ammonium ion electrode 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 favor the NH4+ and the more basic values favor dissolved ammonia gas, NH3. The pH electrode measures the pH level, and the transmitter calculates the total NH4+-N concentration based on the pH versus the NH4+ concentration profile stored in the instrument.

The Hydra-DS Analyser rapidly measures NH4+-N from 0.1 to 14,000 ppm with a response time of 1 minute (T90) and an accuracy of ±3% of reading, dependent on calibration. It also operates over a wide temperature range from 32 to 122°F (0 to 50°C).  Its intelligent transmitter also includes an easy-to-read backlit display and comes with two 4-20mA outlets and three SPDT alarm relays.  An integral automated sensor spray cleaner reduces biofilms to reduce sensor maintenance.