Ammonium and nitrate sensors based on ion selective electrode (ISE) technology are now widely available for process monitoring of wastewater treatment. The advantage of ISE technology is that Operators can obtain continuous reliable data about nitrification and denitrification anywhere in the wastewater process without the need for replenishment of reagents or filtration mechanisms. The challenge, as with all types of equipment, is to learn the technology sufficiently to know what steps to take to achieve reliable measurements without excessive effort. This webinar will explain the technology and describe best practices for obtaining reliable, trouble-free, long-term ownership of process ISE sensors.

1. How to Get the Best Data -
Online Wastewater Process
Ammonium & Nitrate Sensors
YSI WASTEWATER WEBINAR SERIES

2. Today’s Topics
Process Monitoring of Ammonium &
Nitrate
• Sensor Design & Selection
• Applications
• Probe Operation & Care
• Calibration
- Matrix Adjustment
• YSI IQ SensorNet Features & Specs
Ion Selective Electrode (ISE) Technology
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3. Process ISE Design
Very similar in design to a pH/ORP
sensor.
• Electrochemical (potentiometric)
• 2 or more replaceable electrodes
• No reagents
• Cylindrical probe
Measures charged substances.
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4. ISE Selection
Get the right probe for your
application.
• Ammonium (A) ; Nitrate (N) ; A + N
• Compensation
- K for A
- Cl for N
- pH for A
• Individual electrodes vs. cartridge
• Acquisition cost $4,500 to $10,000
• Ownership cost $1,000 to $2,000 / yr.
Simpler, less expensive alternative to
cabinet wet chemistry analyzers.
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5. Applications
A & N ISEs are useful for control of
aeration & wasting, recirculation &
chemical (carbon) dosing.
• Nitrification
• Denitrification
• Ammonia Based Aeration Control
Many other applications possible.
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6. A & N ISE Operation & Care
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7. Operation
Ensure reliable operation by
practicing the following simple
procedures:
• Choose a representative & accessible
measurement location
- Observe max immersion
• Clean when necessary
- Utilize supplemental air cleaning if needed
• Verify measurement regularly
- Calibrate as needed (matrix adjustment /
correction)
• Replace electrodes when needed
More details to follow.
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8. Cleaning
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Slime/biomass accumulation affects measurement reliability.
• Use process water
- Never use DI water (shocks the measurement cell / long recovery time)
- Never use soaps/detergents (damages the membrane / shortens life)
• Use soft bristle brush (like a toothbrush)
Supplemental automatic air cleaning may extend cleaning intervals.

9. Verification
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Compare laboratory reference
measurements on grab samples with
monitoring system display.
Sensor value – reference = Error
Acceptable error is determined by
customer. Usually +/- 10 to 20%.
Error

10. Sampling / Sample Prep
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• Determine best time to sample
- Process is stable
- Concentration > 0.1 mg/L
• Sample near sensor
- Horizontal and vertical position
• Filter immediately into clean sample vial

11. Calibration
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59.2 mV
Ideal slope (S) is 59.2 mV / decade (logarithmic scale)
Offset (U0
ion) is influenced by unique sample properties (matrix)
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12. Calibration Methods
Cal. Method
Offset
(Uo
ion)
Slope
(S) Location Standards
Reference
(Lab) Method
Single-point Lab
Middle of
range (1)
2-point Lab
Ends of
range (2)
Standard
Addition
Bucket
High Conc.
(1)
Sample
(Matrix
Adjustment)
Process
None
required
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13. Calibration Methods
Cal. Method
Offset
(Uo
ion)
Slope
(S) Location Standards
Reference
(Lab) Method
Single-point Lab
Middle of
range (1)
2-point Lab
Ends of
range (2)
Standard
Addition
Bucket
High Conc.
(1)
Sample
(Matrix
Adjustment)
Process
None
required
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Factory slope is stable (IQSN)
Sensor stays in the process
No preparation/purchase of standards required

14. Matrix Adjustment
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15. Materials Recommended
• Long-handle sample dipper
• 10 to 30 mL syringe w/ Luer Lock tip
• 0.45 μm syringe filter(s) w/ Luer Lock fitting
• Clean sample vials
• Pipettes & tips
• Colorimeter with test kits
• Test kits for ammonium, nitrate, potassium, and chloride*
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16. IQSN Procedure
1. Clean electrodes
2. Record sample conditions
• mV signal
3. Take sample
4. Measure in lab and evaluate
• Ammonia, Nitrate, Potassium, Chloride *
• Duplicate or triplicate measurement recommended
5. Update sensor value(s) and check
• What mV value is expected? What was the actual value?
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17. Demonstration
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18. Closing Thoughts
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19. Summary
ISEs for Process Monitoring of
Ammonium & Nitrate
• Potentiometry – similar to pH/ORP
• Applications: Nitrification,
Denitrification, & ABAC
• A, N, A+N, compensation
• Measurement location, cleaning and
verification techniques
• Matrix adjustment preferred calibration
method
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20. Features of YSI IQSN ISEs
Durable stainless steel probe
SS mesh protects membrane
Longest electrode lifetime in the
industry
18 to 24 mths.
1 yr. warranty
Individually replaceable electrodes
simple replacement
Digital technology – autorecognition
Best performance
Competitive pricing
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21. IQ SensorNet Trade-In Program
20% off the YSI IQ SensorNet 2020
XT system
10% off the YSI IQ SensorNet 182
system
Offer good on competitors’ systems
Expires December 31, 2016
http://bit.ly/IQtradein
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22. Questions?
Web - www.ysi.com/wastewater
Slideshare – www.slideshare.net/YSIinc
YouTube – www.youtube.com/YSIinc
Phone: 1-800-897-4151
Email: info@ysi.com or
robert.smith@xyleminc.com
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