Sidestream Treatment Overview. Kam Law, P.E. Beverley Stinson, Ph.D.

Transcription

1 Sidestream Treatment Overview Kam Law, P.E. Beverley Stinson, Ph.D. March 20, 2012

2 Presentation Outline Concerns with sidestream Treatment options Treatment processes comparison Summary

3 Concerns with sidestream Influent Primary Settling Tank Activated Sludge Final Settling Tank Effluent RAS 1% of Total Plant Influent Flow Rich in Nitrogen & Phosphorus 15 to 40% of the Total Plant TN load 50% TP load Primary Sludge Often returned in slug loads not equalized Ammonium Conc. 800 to 2,500 mg-n/l Temperature C Alkalinity insufficient for complete nitrification Poor in rbcod (rbcod :TKN = 0.4 :1) WAS Thickening Centrate / Filtrate Anaerobic Digestion Dewatering Biosolids

4 Novel Sidestream Treatment Options Sidestream Treatment Options Biological Nitrification / Denitrification & Bio-augmentation With RAS & SRT Control With RAS Without RAS Nitritation / Denitritation Chemostat SBR Deammonification Suspended Growth SBR Attached Growth MBBR Upflow Granular Process Physical-Chemical Ammonia Stripping Steam Hot Air Vacuum Distillation Ion-Exchange ARP Struvite Precipitation MAP Process

5 Novel Sidestream Treatment Options Sidestream Treatment Options Biological Nitrification / Denitrification & Bio-augmentation With RAS & SRT Control With RAS Without RAS Nitritation / Denitritation Chemostat SBR Deammonification Suspended Growth SBR Attached Growth MBBR Upflow Granular Process Physical-Chemical Ammonia Stripping Steam Hot Air Vacuum Distillation Ion-Exchange ARP Struvite Precipitation MAP Process

6 Nitrification / Denitrification & Bioaugmentation 25% O 2 1 mol Nitrate (NO 3 - ) 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 ) Nitrification / Denitrification Incubate a population of nitrifiers and then deploy them to the mainstream activated sludge (AS) system Mainstream AS volume / SRT can be reduced because of the elevated nitrifier population from this seeding process

7 Nitrification / Denitrification & Bioaugmentation AT#3 with RAS BABE BioAugmentation Batch Enhanced Process In-Nitri without RAS BAR BioAugmentation Reaeration/Regeneration RDN Reaeration Nitrification Denitrification CaRRB Centrate and RAS Reaeration Basin

8 AT#3 & BABE (Chemostat) (SBR) (BioAugmentation Batch Enhancement) Centrate treated in a small separate tank (~4 day HRT) Portion of the mainstream RAS to centrate tank Seeds nitrifiers, adds alkalinity & controls temperature Introduces Nitrite oxidizing bacteria Influent Primary Activated Sludge Final Clarifiers RAS Effluent AT#3 No dedicated clarifier or RAS system MLSS back to the main AS process BABE (Commercial) SBR built in clarifier Control on SRT WAS / Effluent back to the main AS process Clarifier effluent NOx to head of plant for odor control (Phoenix) Nitrifier & denitrifier Rich MLSS Methanol NOx denitrified in first anoxic zone of AS system Problematic in a Bio-P plant Can add methanol for denitrification and methanol degrader seeding Several full scale installations - New York City (2), Netherland. Extensive piloting and research. AT #3 Chemostat Aeration Alkalinity Clarified Effluent or Nitrifier Rich MLSS BABE SBR Nitrifier Rich WAS Sludge Centrate Centrate Dewatering Anaerobic Digestion Dewatering Anaerobic Digestion

9 In-Nitri BAR / RDN / CaRRB Raw Wastewater Primary Sedimentation Tank Aeration Tank Secondary Sedimentation Tank Treated Effluent BioAugmentation Reaeration/Regeneration (BAR) Reaeration Nitrification Denitrification (RDN) Centrate and RAS Reaeration Basin (CaRRB) Primary Sludge Thickening Nitrified Dewatering Liquid Thickened Primary Sludge Excess Nitrification Sludge Supernatant WAS Thickening Digester Influent Primary Activated Sludge RAS Centrate Final Clarifiers Effluent Dewatering Alkalinity Dewatering Return Stream Side-stream Nitrification Sludge Dewatering Sludge for Disposal Centrate aerated in a separate side stream tank with dedicated clarifier No main stream RAS Primary effluent can be added to enhance settling & add alkalinity No full scale installations Bioaugmentation potential not verified Patented Process - Royalties Anaerobic Digestion Centrate aerated in first zone of AS tanks All main stream RAS added to centrate reducing temperature & adding alkalinity PE directed to a downstream zone Many full scale installations Appleton, Czech Republic (20), Inland Empire, Blue Lake, Denver Bioaugmentation potential observed

10 Plant without Bio-Aug Integration Winter TN Removal Varied from 43% - 80% Avg. 60% Stinson et al., Evaluation and Optimization of a Side Stream Centrate Treatment System Integrated with a Secondary Step-Feed Process, WEF / IWA Specialty Nutrient Conference, Baltimore 2007

11 Plant with Bio-Aug Integration Winter TN Removal Varied from 60% - 90% Avg. 75% Stinson et al., Evaluation and Optimization of a Side Stream Centrate Treatment System Integrated with a Secondary Step-Feed Process, WEF / IWA Specialty Nutrient Conference, Baltimore 2007

12 Operational Benefits Nitrifier Incubator enhanced Operational Reliability Enhanced winter performance Mitigated storm washout impacts Mitigated centrate inhibition impacts Mitigated air limitations Off-Loaded 30% TKN Load Oxidized 70-95% Centrate TKN Denitrified in main plant anoxic zone using wastewater COD >70% TN Removal Plant-Wide 26th Ward WPCP 85 MGD Nitrite Accumulation in Main Plant Suggested Selection of AOB over NOB

13 Key Design Consideration Oxygen Uptake Rate OUR (>150 mg/ l hr) can define the size of tank Select diffuser to operate at temperatures > 30C and with intermittent aeration in an SBR (clogging) Control RAS addition Provides alkalinity Develops an integrated culture of nitrifiers Cools centrate temp. difference important Too great nitrifers may not remain active in AS Too cool loose selection for AOBs over NOBs Don t want to recycle too many Nitrite Oxidizing Bacteria (NOBs) May need to provide Alkalinity & OP addition Colder side stream process More NO 3 -N Courtesy B.Wett

14 Novel Sidestream Treatment Options Sidestream Treatment Options Biological Nitrification / Denitrification & Bio-augmentation With RAS & SRT Control With RAS Without RAS Nitritation / Denitritation Chemostat SBR Deammonification Suspended Growth SBR Attached Growth MBBR Upflow Granular Process Physical-Chemical Ammonia Stripping Steam Hot Air Vacuum Distillation Ion-Exchange ARP Struvite Precipitation MAP Process

15 Nitritation / denitritation (simplified) 75% O 2 Autotrophic Aerobic Environment 25% O 2 1 mol Ammonia (NH 3 / NH + 4 ) 1 mol Nitrite (NO 2- ) Ammonia Oxidizers (e.g. Nitrosomonas) 1 mol Nitrate (NO 3- ) Nitrite Oxidizers (e.g. Nitrobacter) Nitritation / Denitritation 1 mol Nitrite (NO 2- ) 40% Carbon Heterotrophic Anoxic Environment 60% Carbon ½ mol Nitrogen Gas (N 2 ) 25% Reduction in Oxygen Demand 40% Reduction in Carbon (e - donor) Demand 40% Reduced Biomass Production

16 Nitritaton / Denitritation SHARON Process Stable and High activity Ammonia Removal Over Nitrite Strass Process batch system

17 Chemostat Tank Configurations - SHARON Process Stable and High activity Ammonia Removal Over Nitrite Completely Mixed tank with cyclical aeration ph controlled Plug flow with internal recycle Accommodates modifications for ANAMMOX process in the future Pump station Methanol Pump station ½ Q Nitritation ANAMMOX 10Q ½ Q Concentric circles feed the anoxic zone to utilize all CODs in centrate first Pump station Methanol Phosphoric acid Aerobic Anoxic Effluent Heat exchangers Courtesy: Grontmij Cooling water (treated effluent)

18 Chemostat Tank Configurations - SHARON Process Stable and High activity Ammonia Removal Over Nitrite Small Footprint 2.5 day SRT = HRT Oxic SRT = days Anoxic SRT = days No clarifiers No pre-treatment Courtesy: Grontmij 90% NH 3 -N removal Cost Reductions 25% Oxygen demand 40% COD demand 40% sludge 20% CO 2 emission

19 SHARON Experience/Installations 6 operational >10 years experience 5 planned NYC DEP Wards Island First in USA & largest in world 30-40% TKN-load WWTP Capacity (pe) SHARON kgn/day Operational Utrecht Rotterdam-Dokhaven Zwolle Beverwijk , Groningen-Garmerwolde , The Hague - Houtrust , New York-Wards Island 2,000,000 5, Whitlingham, UK , MVPC Shell Green, UK - 1, Geneva Aïre , Paris Seine Grésillons 3,

20 SBR Tank Configuration - STRASS Process Control SRT and HRT independently Single unit process with clarification step Easy adjustment to the aerobic vs. anoxic cycles Invent type mixer / aerator provides both aeration & mixing no diffusers avoids clogging / cleaning concerns Beneficial to fill only during anoxic cycles to utilize available carbon for denitrification & alkalinity recovery Split WAS and effluent flow streams WAS to activated sludge for seeding Effluent to activated sludge for TN polishing Effluent to head of plant for odor control using NO 2 -N STRASS SBR Process Control Bernhard Wett, Water Science & Technology Vol 56 No 7, 2007

21 SBR Tank Configuration - STRASS Process WWTP Salzburg WWTP Strass

22 Nitritation / Denitritation Process Control Temperature (30-38 C) favors growth kinetics of Ammonia Oxidizers SRT = HRT Sludge Age; - >Minimum for Ammonia Oxidizers, but < Minimum for Nitrite Oxidizers - Selects for Ammonia Oxidizers (AOBs) & De-selects for Nitrite oxidizers (NOBs) ph in 6.6 to 7.2 range Optimal range for AOBs Methanol for denitrification & alkalinity recovery DO in the 0.3 to 2 mg/l range Min AOB SRT Nitrite Route Courtesy: Grontmij 35 C

23 Novel Sidestream Treatment Options Sidestream Treatment Options Biological Nitrification / Denitrification & Bio-augmentation With RAS & SRT Control With RAS Without RAS Nitritation / Denitritation Chemostat SBR Deammonification Suspended Growth SBR Attached Growth MBBR Upflow Granular Process Physical-Chemical Ammonia Stripping Steam Hot Air Vacuum Distillation Ion-Exchange ARP Struvite Precipitation MAP Process

24 Deammonification (simplified) 75% O 2 Autotrophic Aerobic Environment 25% O 2 Partial Nitrification 40% O2 1 mol Ammonia (NH 3 / NH + 4 ) mol Nitrite (NO 2- ) Ammonia Oxidizers (e.g. Nitrosomonas) 1 mol Nitrate (NO 3- ) Nitrite Oxidizers (e.g. Nitrobacter) Autotrophic Anaerobic Environment 1 mol Nitrite (NO 2- ) 40% Carbon Heterotrophic Anoxic Environment ANAMMOX Anaerobic Ammonium Oxidation Autotrophic Nitrite Reduction (New Planctomycete, Strous et. al. 1999) 60% Carbon ½ mol Nitrogen Gas (N 2 ) 60% reduction in Oxygen demand Almost 100% reduction in Carbon demand Much reduced in Biomass production Reduced CO 2 emissions

25 ANAMMOX Organisms Low Growth Rate approx. 10 day doubling time at 30 C <10 day has been reported (Park et. al days) SRT (>30 days) Sensitive to; Nitrite Toxic- irreversible loss of activity based on concentration & exposure time NH 4 + : NO 2 - ratio 1 : 1.32 DO - reversible inhibition Free ammonia (<10-15 mg/l) Temperature >30 C preferred ph (neutral range)

26 Keys to success The Ability to Manage Competing Demands: Manage SRT - Aerobic SRT - long enough to support AOB growth but short enough to washout NOBs (2<SRT<3) and Anaerobic SRT - long enough to support ANAMMOX growth (>30) Manage DO high enough to support partial nitritation But low enough to suppress NOB growth (Ks AOBs< Ks NOB) And also low enough so that it does not inhibit ANAMMOX (reversible) Manage Nitrite Concentration Sufficient nitrite to support ANAMMOX growth (electron acceptor) But low enough to avoid ANAMMOX inhibition (irreversible) Manage Ammonium Concentration - Sufficient ammonium to serve as energy source for ANAMMOX But avoid free ammonia inhibition of AOBs (<15 mg/l)

27 Deammonification Process Configurations DEMON Suspended Growth SBR process 12 operational facilities mainly in Europe (2011) Several under design in NA Attached growth MBBR process Hattingen, Germany (2000) Himmerfjärden, Sweden (2007) Sjölunda, Malmö, Sweden (ANITA TM Mox pilot) Sundet WWTP Sweden (Dec 2011) Upflow granulation process ANAMMOX by Paques 11 operational facilities (2011) DEMON SBR ANITA TM Mox MBBR More industrial than municipal ANAMMOX Upflow Granulation Process

28 DEMON Suspended Growth SBR 84% TN Removal 0.7 kg ammonia N per m 3 Reduced energy demand to 1.3 kw hr / kg N removed

29 DEMON SBR Process Control DEMON depends on 3 main controls ph (narrow range e.g ) DO (0 0.5 mg/l) Time Provides accurate adjustment of all three key aspects free ammonia inhibition <10 mg/l) nitrite toxicity (<5-10 mg/l) inorganic carbon limitation Measure NH 3 -N, NO 2 -N, NO 3 -N and make process control decisions, primarily wasting, based on measurements

30 Attached Growth MBBR Concept Simultaneous aerobic and anaerobic conditions in biofilm layers NH 3 -N, alkalinity & DO in the bulk liquid AOBs on the outer aerobic layer ANAMMOX on the inner anaerobic layer Courtesy Veolia ANAMMOX organisms in attached growth are less sensitive to inhibitory compounds DO: 3 mg/l vs. 0.3 mg/l suspended NO 2 -N: 50 mg/l vs. 5 mg/l suspended

31 Upflow Granulation Process: ANAMMOX Most notable WWTPs: Rotterdam (NL), Niederglatt (CH) Numerous industrial facilities Rotterdam ANAMMOX startup 2002 Initially designed as a two-step process SHARON 1,800 m 3 ANAMMOX 72 m 3 (compact!) >2 yrs before ANAMMOX activity was detected >3.5 yrs to reach full capacity Removal rate kg/m 3 /day Refers to second stage TN removal ~90% Effluent NO 2 -N < 10 mg/l NH 4 + NO 2 - Van der Star, W. R. L. et al., 2007, Startup of Reactors for Anoxic Ammonium Oxidation: Experiences from the First Full-scale Anammox Reactor in Rotterdam. Water Research, (41),

32 GHG emissions (as % of N removed) DEMON (Weissenbacher et al. 2010) NO 2 -N: <5 mg/l DO: <0.3 mg/l N 2 O: 1.5% NO x : <0.1% NO 2 >10 mg/l resulted in increase of N 2 O, stressing the importance of managing nitrite accumulation 2-Stage SHARON - ANAMMOX (Kampschreur et. al. (2008) SHARON stage: NO 2 -N: 500 mg/l DO: 2.5 mg/l ANAMMOX stage: NO 2 -N: 3 mg/l DO: unaerated N 2 O: 2.3% (85% in Stage 1) NO: 0.24% (99% in Stage 1) 1-Stage ANAMMOX (Kampshurer et al. 2009) NO 2 -N: 6-8 mg/l DO: 5 mg/l N 2 O: 1.7% NO: 0.007% ANITA TM Mox (Christensson et al. 2011) NO 2 -N: < 5 mg/l DO: mg/l N 2 O: % NO: n/r A study of 25 full scale WWTP show large variation, average N 2 O emission of 0.6% and maximum emission of 14.6% (Wicht and Beier, 1995)

33 Comparative Summary of Deammonification Processes Volumetric Loading Rates Performance TN Removal Suspended SBR (DEMON ) Attached MBBR (ANITA TM Mox) Granular Single-Stage (AMAMMOX ) kg N/m 3 /day % ~90% NH 3 -N ~85% TN ~90% NH 3 -N ~80% TN ~90% NH 3 -N ~75% TN Energy Demand kw hrs/ kg NH 3 -N removed N.R. literature data suggests higher* Operator Attention Highest Lowest Middle Sensitivity / Flexibility ph & DO control; NO 2 < 5 mg/l Pre-settling DO control; Tolerates elevated NO 2 DO control; Tolerates elevated NO 2 GHG Emissions Low Lowest Low *Kampshurer et al report normal operations of 5 mg/l DO and 22% of NH 3 -N removed to NO 3 -N

34 In summary

35 General guidelines for alternative biological sidestream treatment options Side stream treatment option Nitrification / denitrification Bioaugmentation Loading rate (kg NH 3 -N/m 3 ) SRT (days) 0.3 to HRT (days) 1.5 (Nit) 3 (Denit) Energy demand (kwh/kg N) Carbon demand (kg COD/kg N) Nitritation / denitritation ¼ Deammonification (4.5 Hattingen MBBR) 0.1

36 Novel Sustainable Centrate/Filtrate Management Options Nitrogen Removal Focus Centrate / Filtrate Management Options Biological Energy Demand Nitrification / Denitrification & Bio-augmentation Nitritation / Denitritation Deammonification / ANAMMOX Reduction in energy & chemical demands more sustainable Perceived increase in operational complexity

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