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Hydrogen Sulfide Monitor

WATER TEST K100-H2S monitor and controller for continuous % [mV/mVref], ppb (or
ppm) and mVC (controllable mV) monitoring and control of dissolved Hydrogen Sulfide
(H2S) in water or watery sludges.

- Direct (in-line) monitoring of H2S or development towards H2S release in ponds, aquatic sludge, (biogas) reactors, hatcheries (variable units: mVC, % [mV/mVref] , ppb (or ppm)
- Steering aerators, water exchange pumps or any “early warning” stagnant water alarm device (variable units: “%” [mV / mVref] or “mVC”)
- Determination of Total Inorganic Sulfide (TIS) in (waste-) water and sludge (variable units: “ppb” (or “ppm”) times factor for known pH value)
- Monitoring bulking sludge by sulfide-oxidizing organisms in activated sludge processes or final clarifier (variable units: “%” [mV / mVref] or “ppb”)
- Monitoring/steering of sulfidic heavy metal purging and/or sulfide corrosion in process and waste waters (variable unit: “ppb” or “ppm”)

- Measuring principle: temperature corrected Differential Potentiometry with InReset© noise & temperature compensated sensor data processing (no electrolyte reference)
- Units: “mVC”, “%” [mV / mVref], “ppb” (or “ppm”), mV (raw input data), pH2S and oC
- Measuring/control range: 0.0 – 99.9 %, 1 – 999 ppb (or ppm) or mVC (temperature corrected controllable mV value)
- Detection limit: <0.1 ppb
- Response time (T90): < 3 min. with H2S > 10 ppb

- In-line measuring, no sampling, no reagents, minimal maintenance
- No lower signal limit enabling the monitoring of H2S
concentrations as well as the development towards H2S release (% [mV / mVref])
- Robust full plastic (PE) armature and water-proof shield cable connections
- Analog output 0/4 – 20 mA, additional alarm relay
- Illuminated LCD display

Operating principle
Both sensors, as integrated into the probe and connected to the K-100-H2S monitor, are lowered/installed directly into the media and at the site where dissolved H2S is to be measured. The 1-decimal digital display in “%”, “ppb” (or “ppm”) and of the sample temperature in “oC” is provided. Beyond monitoring tasks the setting can be used for control or steering functions (with 2 set points/ relays , proportionality and hysteresis functions). In case hydrochemicaln conditions in the media develop in favour of H2S (even in sub-ppb level) an additional alarm relay is activated.

H2S & temperature sensors
-Sensor Combined pH2S electrode type WT-573-H2S-SX8 (built-in pre-amplifier optional)
-Temperature separated Pt 100
-Display & set points mVC, ppb (or ppm), %
-Control range 0.0 – 99.9 %, 1 – 999 ppb (or ppm) or mVC
-Precision ±0.01 mV
-Response time < 3 min
-Max. pressure 1 bar
-Temp. range 0 ...... 40 oC
-Optimal pH 3 ..... 9
-Calibration default setting as free non-sulfidic or sulfidic semi-automatic buffer routines (mVref = mV[5 ppb potassium hydrogen phthalate/iodide buffer])
-Potential drift InReset© compensation with usually <1 mV/month (after initial conditioning)
-Armature full PE Superlene® with pH2S and temperature sensors built-in & 2 shield cables (<10 m)
-Working life depending on application, usually >>2 year
-Warranty 6 months

Monitor/Controller Unit
-Input high impedance >5x1012 Ohm, galvanically isolated
-Temperature Pt 100 input, 2-conductor, range 0.0 – 100.0 +/- 0.1 oC
-Temp. compensation manual or automatic
-Display alpha-numerical LCD, 2 lines 16 characters
-Analog output 0/4 – 20 mA
-Relay output 2 relays + 1 alarm relay output, SPDT contacts 250 V, 6 A, max 550 VA
-Interface optional RS485
-Ambient temparature operation: 0 – 50 storage: -20 – 65 oC
-Humidity max 90% at 40 oC non-condensing
-Power required 230 or 130 or 24 VAC,-10…+6 %, 40 – 60 Hz
-Power consumption 10 VA
-Electromagn.Comp. acc. to DIN EN 50081-1 / -2 in compliance with CE
-Casing polystyrole, spring-loaded terminals
-Protection class IP 65 (NEMA X4)

System configuration
WATER TEST Hydrogen Sulfide (pH2S) monitoring/controller panel for mVC, %, ppb (or ppm) includes:
Wall-mounted monitor and controller unit K 100-H2S , water-proof connecting shield cables (free choice up to 10 m) for
H2S & temperature, full plastic combined sensor armature with built-in pre-amplifier, combined pH2S-electrode and Pt
100 temperature sensor.

This publication is not intended to form the basis of a contract and WATER TEST Co., Ltd. reserves the right to amend
the design and specifications of the instruments without notice.


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