Online Monitoring of Nitrate with Optical Sensors for Wastewater Process Control YSI WASTEWATER WEBINAR SERIES

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Optical Sensors Measure Light Intensity

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Optical Sensors Measure Light Intensity

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Beer-Lambert Law Explained

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Beer-Lambert Law Explained

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Beer-Lambert Law Explained

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Beer-Lambert Law Explained

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Beer-Lambert Law Explained

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Absorption Spectrum of Wastewater

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UV Spectrum of Wastewater

UV-Visible Spectrophotometry of Water and Wastewater, O. Thomas and C. Burgess, Ed., Elsevier Publishing, 2007

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Optical Spectral Sensor Design

• 256 wavelengths measured • Xenon flash lamp / multi-diode

array detector • 1 mm or 5 mm gap • Programmed calibrations: influent,

mixed liquor, effluent • Identical measurement &

reference channel • UltraClean™ ultrasonic cleaning

technology • Sapphire measurement windows • Titanium probe body 11

Applications

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1 mole Ammonia (NH3 / NH4

+)

1 mole Nitrite (NO2

-)

1 mole Nitrate (NO3

-)

1 mole Nitrite (NO2

-)

1/2 mole Nitrogen gas (N2)

75% O2

25% O2 40% Carbon

60% Carbon

Aerobic Anoxic

Process Control of Nitrification/Denitrification

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Requirements for Denitrification

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1. Nitrate – good nitrification 2. Anoxic conditions – low DO 3. Source of readily degradable carbon – wastewater or chemical

NitriTrak High DO Nitrification Tester

Met Council, Minnesota NitraVis 701 TS Built-in ultrasonic cleaning Supplemental air cleaning Installed April 2015 Goals: Aeration control Operate at lowest DO possible Keep nitrifiers alive Very low maintenance 15

Nitrate Monitoring

Higher rate Lower rate

Nitrate Monitoring

“The concept has been tried many times before, by us and others. It’s just that this time, it works with no maintenance! An adequate nitrate probe was needed.” Mike Rieth, Principal Research Engineer, Met Council

Denitrification Monitoring – WSSC Seneca

5 x NitraVis 701 TS (1 in each train) w/ supplemental air cleaning (MIQ/CHV) Goals: Effluent < 4.0 mg N/L (permit) Effluent < 3.0 mg N/L ($300k credit) Minimize Methanol Reasons for Selection Side-by-side trial Easy to set up; easy to use Low maintenance cost – no wipers

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Denitrification Monitoring – WSSC Seneca

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“Money is always an issue. I have a boss, too and I had to sell him on why we needed the probes. I have to have something that's reliable. This is the most reliable and easy to use equipment. We don’t have to chase them around all the time.” Marty Johnson, Chief Operator Seneca WWTP

NYCDEP Carbon Addition Project

63 x NitraVis 701 IQ Step-Feed Activated Sludge Goals: Target Effluent TN = 7 to 8 mg N/L Monitoring of oxic zone nitrate Feed forward control of carbon addition

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1 mole Ammonia (NH3 / NH4

+)

1 mole Nitrite (NO2

-)

1 mole Nitrate (NO3

-)

1 mole Nitrite (NO2

-)

1/2 mole Nitrogen gas (N2)

75% O2

25% O2 40% Carbon

60% Carbon

A Better Way to Remove Nitrogen

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1/2 mole Ammonia (NH3 / NH4

+)

1/2 mole Nitrite (NO2

-)

1/2 mole Nitrogen gas (N2)

37.5% O2

A Better Way to Remove Nitrogen

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Optical Spectral Sensors Can Resolve Nitrate and Nitrite

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wavelength [nm]

Deammonification Applications

Side-Stream Early majority stage Anaerobic digestion Nitrogen regulated areas Main-Stream Demonstration stage Alexandria Renew - Process launch 2016 Energy / Sustainability

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NiCaVis NI 701 installed in Alexandria Renew Bioreactor

Optical vs. ISE (Ion Selective Electrode)

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ISE vs. Optical Nitrate Monitoring - Cleaning

ISE Optical

ISE vs. Optical Nitrate Monitoring - Calibration

ISE – NO3 + Chloride compensation; Matrix Adjustment at commissioning/every 1 to 3 months Optical – NO3; User calibration for nitrate at commissioning* * - If needed to improve accuracy of factory calibration

ISE vs. Optical Nitrate Monitoring - Consumables

ISE Optical

ISE vs. Optical Nitrate Monitoring

Optical ISE Measuring range, mg/L as N 60 / 150 0 to 1,000 Resolution 0.01 0.1 Pressure resistance, bar 1 0.2 Power Consumption, W Up to 8 0.2 Response time (t90), min. Programmable < 3 Temperature measurement No Yes

Additional Parameters / probe COD/BOD/TOC, NO2, TSS

NH4, K, Cl

Warranty (probe), yrs 2 2 Warranty (electrodes), yrs NA 1

Optical Nitrate Sensor Types

1 mm => high concentrations, 5 mm => lower concentrations

Sensor NO3 NO2

COD/ BOD/ TOC

TSS

NitraVis √ √

NitraVis NI √ √

NiCaVis (5 mm only) √ √

NiCaVis NI √ √ √

NOx √ (NO2/3)

CarboVis √ √

Questions?

Please visit us at WEF/IWA NRR Conference in Denver, July 10 to 12. Web: www.ysi.com/wastewater Slideshare: www.slideshare.net/YSIinc YouTube: www.youtube.com/YSIinc Phone: 800-897-4151 Email: info@ysi.com or robert.smith@xyleminc.com

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