Shortcut Biological Nitrogen Removal for sustainable wastewater treatment and achieving energy neutrality

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1 METROPOLITAN WATER RECLAMATION DISTRICT OF GREATER CHICAGO Shortcut Biological Nitrogen Removal for sustainable wastewater treatment and achieving energy neutrality Fenghua Yang, P.E., BCEE

2 Outline Nitrogen and its removal in WWTP Shortcut biological nitrogen removal (SCBNR) fundamentals and its benefits SCBNR in sidestream SCBNR in mainstream MWRD Initiatives on implementing SCBNR on both sidestream and mainstream

3 Slides from WERF Deammonification Compendium, Dec 2012

4 Sample Nitrogen Cycle in WWTP Influent 100% PST 48% Activated Sludge Tanks FST Effluent 40% Return Activated Sludge 1.0% Thickening centrate PST sludge 11% WAS sludge 12% Thickener Biogas (?) Digester 23% Dewatering 11% 12% Sludge cake Dewatering centrate Slides from Ulu Pandan WRP, Singapore presented at 2012 IWA world water congress

5 Nitrogen in the 7 District WRP Mainstream Total nitrogen load (as ammonia and organic nitrogen) to the 7 District Water Reclamation Plants (WRPs) combined is approximately 200 dry tons/day The district annual electrical consumption is over 600 million kwh ($45 million). Aeration consumes nearly 50%, among which, approx % is used for nitrification to meet final effluent ammonia limit in the NPDEs permits Limited denitrification; most ammonia and organic nitrogen is converted to nitrate and discharged to the receiving stream Sidestream from post-digestion dewatering Small flow, but high ammonia strength, average around 1000 mg/l. Currently recycled back to the mainstream and add ammonia load to the mainstream in most plants.

6 Nitrogen Removal in Activated Sludge WWTP Conventional Biological Nitrogen Removal Nitrification and Denitrification Version I Well established Processes (MLE process, Step feed, Bardenpho process, etc) Shortcut Biological Nitrogen Removal Nitritation and Denitritation (nitrite shunt) Version II Partial Nitritation and Deammonification Version III

7 Fundamentals of Nitrification Denitrification (Ver I) Autotrophic Aerobic Environment 1 mol Nitrate (NO 3 - ) Heterotrophic Anoxic Environment 40% Carbon 25% O 2 1 mol Nitrite (NO 2 - ) 1 mol Nitrite (NO 2 - ) 60% Carbon 75% O 2 1 mol Ammonia (NH 3 / NH 4 + ) ½ mol Nitrogen Gas (N 2 ) Oxygen demand 4.57 g / g NH + 4-N Carbon demand 4.77 g COD / g NO - 3-N

8 Fundamentals of Nitritation Denitritation (Ver II) Nitrite Shunt Autotrophic Aerobic Environment 25% O 2 1 mol Nitrate (NO - 3 ) 25% reduction in Oxygen 40 % reduction in Carbon demand 40% reduction in Biomass produced Heterotrophic Anoxic Environment 40% Carbon 1 mol Nitrite (NO 2 - ) 1 mol Nitrite (NO 2 - ) 60% Carbon 75% O 2 1 mol Ammonia (NH 3 / NH 4 + ) ½ mol Nitrogen Gas (N 2 ) Oxygen demand 3.42 g / g NH + 4-N Carbon demand 2.86 g COD / g NO - 3-N

9 Fundamentals of Partial Nitritation- Deammonification (Ver III) Autotrophic Aerobic Environment Aerobic Ammonia Oxidation 25% O 2 1 mol Nitrate (NO 3 - ) 65% reduction in Oxygen Eliminate demand for supplemental carbon 80% lower Biomass produced Autotrophic Anaerobic Environment Anaerobic Ammonium Oxidation 40% (ANAMMOX) Carbon 0.57 mol NO 2 - Partial Nitrification 35% O 2 1 mol Ammonia (NH 3 / NH 4 + ) 0.44 mol N NO 3 - Oxygen demand 1.9 g / g NH + 4-N

10 Energy Savings Significant reduction in energy demand possible kw-hr / kg N removed Typical Energy Demand Ranges million kwh per year electricity reduction or 12-15% of the District WRP electricity may be possible 0 Nitrification / Denitrification Nitritation / Denitritation Deammonification (a.k.a. ANAMMOX) Slides Courtesy WERF project INFR6R11

11 SCBNR In Sidestream The first full scale sidestream SCBNR using ANAMMOX was constructed in 2001 Since 2007, installation rapidly increased. Over 50 installations (WERF, Dec 2012) The ANAMMOX Technologies Anita Mox (attached growth system with mixed biomass of nitrifiers and anammox DEMON (suspended growth system with mixed biomass of nitrifiers and anammox) OLAND (Oxygen Limited Autotrophic Nitrification Denitrification) CANON (Completely Autotrophic Nitrogen removal over Nitrite process) Pacques Sidestream SCBNR has demonstrated TN reduction of 80% or higher

12 SCBNR In Mainstream Following the success of sidestream SCBNR, there have been great interests in mainstream application Key process consideration Growth and retention of AOB and anammox Suppression or management of Heterotrophs Suppression of NOB Challenges for mainstream Low ammonia concentration in mainstream WW Low operating temp Higher C:N ratio Pioneering studies based on full, pilot, or bench scale studies around the world has demonstrated promising results

13 SCBNR in Mainstream Large Anammox Granules e.g. Paques, Nereda granular sludge blanket systems Small Flocculent Suspended Growth Anammox Granules e.g. Activated Sludge Attached Growth Biofilm e.g. RBC, MBBR, Biofilter Suspended & Attached Growth e.g. IFAS With or Without Bioaugmentation of AOB and / or Anammox Delft, Netherlands DHV, Netherlands DC Water & HRSD, USA Changqi, Singapore Ghent University Strass, Austria Glarnarland, Switzland Delft TU, Netherlands American Water (AOA / MBR) Veolia pilots

14 SCBNR MWRD Initiatives Sidestream deammonification Pilot scale study of DEMON in 2012 First AnitaMox under construction, will be online in 2015 at the Egan WRP Total N load of 2500 lbs/day Ammonia N removal eff % Total N removal eff % Plan to consider sidestream treatment in Stickney and other facilities

15 SCBNR MWRD Initiatives Mainstream SCBNR M&R led inter-departmental SCBNR research Try to address: how this process can be applied to current District facilities given our current infrastructure and capabilities How to meet current ammonia limit in NPDES permit How this process ties into our EBPR processes How to implement in cold weather 4 processes have been identified for bench scale and full scale experiments

16 OPTION 1 - ANAEROBIC + NITRITATION/ DENITRITATION THROUGH MODULATING AERATION + INTEGRATED FIXED FILM ACTIVATED SLUDGE + REAERATION FOR SHORTCUT BIOLOGICAL NITROGEN REMOVAL PROCESS

17 OPTION 2 - STEP-FEED SHORTCUT BIOLOGICAL NITROGEN REMOVAL PROCESS

18 OPTION 3 - TWO STAGE SYSTEM FOR SHORTCUT BIOLOGICAL NITROGEN REMOVAL PROCESS

19 OPTION 4 AMMONIA BASED AERATION CONTROL TO REDUCE ENERGY CONSUMPTION

20 QUESTIONS? Thanks goes to: Cindy Qin, PhD Joseph A. Kozak, PhD, P.E. Heng Zhang, PhD, P.E. Monitoring and Research Department MWRDGC