Simultaneous Nitrification and Denitrification in a Sequencing Batch Reactor Will Lambert Robert Nwaokoro Stephen Russo

SND in SBR Nitrification/Denitrification Basics Nitrification/Denitrification Basics Introduction to SND Experimental Methods Results Conclusions Suggestions/Questions?

Nitrification/Denitrification Basics Why remove nitrogen? Why remove nitrogen? Limiting nutrient in oceans and estuaries. Nitrates in drinking water cause Methemoglobinemia “blue-baby” syndrome.

Nitrification/Denitrification Basics Denitrification (anaerobic) Nitrification (aerobic) Nitrosobacters Denitrification (anaerobic) Nitrification (aerobic) Nitrosomonas Ammonification Assimilation Ammonia Nitrite N 2 (gas) Organic Nitrogen Nitrate Fixation Nitrogen Cycle in Waste Treatment

SND in SBR Nitrification/Denitrification Basics Introduction to SND Introduction to SND Experimental Methods Results Conclusions Suggestions/Questions?

Introduction to SND What is SND? What is SND? Simultaneous reactions occur of: Simultaneous reactions occur of: Ammonification Ammonification Nitrification Nitrification Denitrification Denitrification Normally occur in different steps Normally occur in different steps Why use SND? Obstacles to SND Solutions

Introduction to SND What is SND? Why use SND? Why use SND? Reduction of: Reduction of: Cost Cost Energy Energy Sludge Sludge Obstacles to SND Solutions

Introduction to SND What is SND? Why use SND? Obstacles to SND Obstacles to SND Nitrification is aerobic Nitrification is aerobic Denitrification is anaerobic Denitrification is anaerobic Solutions

Introduction to SND What is SND? Why use SND? Obstacles to SND Solutions Solutions Achieve aerobic/anaerobic environment: Achieve aerobic/anaerobic environment: Low DO Low DO 0.5 – 1 mg/L 0.5 – 1 mg/L Large flocs Large flocs Biofilms Biofilms

SND in SBR Nitrification/Denitrification Basics Introduction to SND Experimental Methods Experimental Methods States States Testing Methods Testing Methods Results Conclusions Suggestions/Questions?

Experimental Methods: States Fill with Waste Fill with Waste Run for 18.3 s Run for 18.3 s 140 mL delivered 140 mL delivered Based on 459 mL/min peristaltic pump flow rate Based on 459 mL/min peristaltic pump flow rate Fill with Water Aerate Settle Drain

Experimental Methods: States Fill with Waste Fill with Water Fill with Water Run for 350 s AND… Run for 350 s AND… Reactor volume is 4 L over 5 s average Reactor volume is 4 L over 5 s average Fail safe if pump failed to deliver appropriate amount of fluid Fail safe if pump failed to deliver appropriate amount of fluid Aerate Settle Drain

Experimental Methods: States Fill with Waste Fill with Water Aerate Aerate Run time varied Run time varied 8, 18, 24 hours 8, 18, 24 hours Aeration rate controlled by PID control Aeration rate controlled by PID control Target DO = 0.5 mg/L Target DO = 0.5 mg/L Settle Drain

Experimental Methods: States: Aerate Proportional, Integral, and Derivative (PID) Control Proportional, Integral, and Derivative (PID) Control Equation: Equation: Trial and error determined P, I, and D values Trial and error determined P, I, and D values Effective control was met when DO reached 0.5 mg/L Effective control was met when DO reached 0.5 mg/L

Experimental Methods: States Fill with Waste Fill with Water Aerate Settle Settle Run for 1 hour Run for 1 hour More than enough time for settling More than enough time for settling Left unchanged Left unchanged Drain

Experimental Methods: States Fill with Waste Fill with Water Aerate Settle Drain Drain Run until 1.2 L remained in reactor Run until 1.2 L remained in reactor

SND in SBR Nitrification/Denitrification Basics Introduction to SND Experimental Methods Experimental Methods States States Testing Methods Testing Methods Results Conclusions Suggestions/Questions?

Experimental Methods: Testing Methods Micro-Phenate Method Micro-Phenate Method Determine ammonia concentration as ammonia/nitrogen Determine ammonia concentration as ammonia/nitrogen Standards consist of: Standards consist of: Phenol Solution Phenol Solution Sodium nitroprusside Sodium nitroprusside Alkaline citrate Alkaline citrate Sodium hypochlorite Sodium hypochlorite Oxidizing Solution Oxidizing Solution Standards: 0, 0.2, 0.4, 0.6 mg N-NH 4 /L Standards: 0, 0.2, 0.4, 0.6 mg N-NH 4 /L Spectrophotometer analysis at 640 nm Spectrophotometer analysis at 640 nm Nitrate-nitrogen standards Sampling

Experimental Methods: Testing Methods Micro-Phenate Method Nitrate-nitrogen standards Nitrate-nitrogen standards Cadmium gravimetric method Cadmium gravimetric method Hach Corporation: Nitriver ® and Nitraver ® reagent packets Hach Corporation: Nitriver ® and Nitraver ® reagent packets Standards: 0, 2, 6, 10 mg N-NO 3 /L Standards: 0, 2, 6, 10 mg N-NO 3 /L Spectrophotometer analysis at 542nm Spectrophotometer analysis at 542nm Sampling

Experimental Methods: Testing Methods Micro-Phenate Method Nitrate-nitrogen standards Sampling Sampling End of aeration state End of aeration state Filtered through Millipore filter Filtered through Millipore filter Refrigerated Refrigerated Ammonia samples Ammonia samples Diluted by 10x Diluted by 10x

SND in SBR Nitrification/Denitrification Basics Introduction to SND Experimental Methods Results Results Conclusions Suggestions/Questions?

Results: PID Average DO = mg/L Standard Deviation = 0.015

Results: Ammonia Standards

Results: Nitrate Standards

Results: Samples Aeration Time (hr) Absorbance (542 nm) Concentration (mg N-NO 3 /L) Nitrate Concentrations Aeration Time (hr) Absorbance (640 nm) Diluted Concentration (mg N-NH 3 /L) Actual Concentration (mg N-NH 3 /L) Ammonia Concentrations

Results: Total Nitrogen Removal Aeration Cycle (hr) Total N Remaining (mg/L) N Removal (mg/L) % Removal

SND in SBR Nitrification/Denitrification Basics Introduction to SND Experimental Methods Results Conclusions Conclusions Suggestions/Questions?

Conclusions Total nitrogen removal efficiencies appeared to make sense Total nitrogen removal efficiencies appeared to make sense Broken down to nitrate and ammonia, unclear data Broken down to nitrate and ammonia, unclear data One long aeration cycle should have been run One long aeration cycle should have been run Sampled periodically during that cycle Sampled periodically during that cycle SND is possible at laboratory scale, SND is possible at laboratory scale, Easier at full scale Easier at full scale Achieve a more heterogeneous environment Achieve a more heterogeneous environment

SND in SBR Nitrification/Denitrification Basics Introduction to SND Experimental Methods Results Conclusions Suggestions/Questions? Suggestions/Questions?

Suggestions Questions? &