HWEA Conference March 16, 2010 ThermAer : A New Day for ATAD Thermal Process Systems

Transcription

1 HWEA Conference March 16, 2010 ThermAer : A New Day for ATAD Thermal Process Systems

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3 ThermAer Discussion 1. Definitions 2. Process 3. System Component Parts 4. Operational Information 5. Storage Nitrification/Denitrification Reactor (SNDR) 6. Why use ThermAer?

4 ATAD A - Autothermal T Thermophilic A - Aerobic D - Digestion Self-heating!! Exothermic reaction. High temperature typically above 131 F. No outside heat source is used. Oxic conditions (this is key), high mixing intensity and aeration. Independent control of mixing and aeration is imperative. Biodegradation of volatile solids microorganisms degrade to CO 2, H 2 O and ammonia. high-temperatures provide very high biokinetics!!

5 Thermophilic Microorganisms Thermopiles love high temperatures They are one of oldest microorganisms on the planet Very Resilient to changes and loadings High Endogenous Decay Coefficient and therefore Very Low Yields

6 Aerobic Sludge Digestion Micro-organisms Organic Solids + O 2 Nutrients Bioresistant Solids + Heat + CO 2 + H 2 O + NH 4 +

7 Simplified Sludge Digestion Aerobic C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Heat (2880 kj/gmol) Anaerobic C 6 H 12 O 6 3CH 4 + 3CO 2 + Heat (430 kj/gmol)

8 Autothermal Thermophilic Aerobic Digestion (ATAD) Biologically Produces Autothermal Temperature of F without an outside heat source Degrades a High Concentration of Total and Volatile Solids Produces a High Concentration of Ammonia ppm Elevated Temperature and ph, Strips Ammonia from Liquid Phase into the Off-Gas

9 Time (Hr) = 50,070,000 / 24 x *T (where T = C) 55 C = ~24 hours 60 C = ~5 hours 65 C = ~1 hour Time (hours) o C Temperature ( o C)

10 Biosolids Train Off-Gas Biofilter Land Application WWTP Primary & Secondary Thickener ATAD SNDR Dewater Compost 5-7% TS Centrate/Filtrate Recycled to WWTP 2-3% TS (50% TS Reduction) Liquid Land Application Multiple Units Provide Redundancy & Allow Flexible Operation The Mesophilic SNDR process Finishes Biosolids Processing & Allows for Campaign Dewatering Other types of waste streams such as septage, grease trap waste, etc. can be added to the ThermAer. Existing tankage can be utilized for the ThermAer and SNDR. Batch feed and transfer are utilized for the process.

11 Process Flow ATAD SNDR

12 Applications Thickened Feed Solids - Minimum of 3% 100% Waste Activated Sludge (WAS) Primary Sludge Septage High FOG wastes Other high COD wastes Industrial Wastes

13 Waste & Feed Cycle - Two Options Semi-Batch Draw & Fill Alternate Feed with Two ATADs -- Waste from ATAD to SNDR -- Feed ATAD with Raw Sludge -- Dewater from SNDR -- Waste from either ATAD into SNDR -- Feed that ATAD for 24 hours -- Waste from 2 nd ATAD -- Feed 2 nd ATAD -- Isolate 1 st ATAD for 24 hours -- Dewater from SNDR

14 Autothermal Thermophilic Aerobic Digestion Conceptual Reactor Mechanisms 1 Extremely rapid sludge digestion and biochemical breakdown of organics Biosolids!!! thermophilic bacteria

15 Rapid oxygen transfer required to satisfy the high rate of bacterial activity 2 Oxygen IN NOTE: 1 Low DOsat (~4 mg DO/L) 2 - DOs at or below 0.5 mg/l are typical 3 Under very high oxygen uptake you can go micro-aerobic in spite of aeration Biosolids

16 Oxygen 3 Rapid carbon dioxide release needed to avoid ph drop IN OUT Biosolid Carbon Dioxide

17 Foam buildup at surface (due to proteins & lower surface tension) Oxygen 4 Biosolids IN OUT Carbon Dioxide NOTE: Foam control is essential

18 Heat loss at surface is important (the foam blanket actually reduces heat loss) Oxygen 5 OUT IN OUT Heat! Biosolids Carbon Dioxide NOTE: Excessive heat loss is undesirable! Highly efficient oxygen transfer is crucial to limit heat losses and it will also help with foam production

19 NOTE: At typical ph of 8+, and high temperature, reduced nitrogen tends to switch to free ammonia Free ammonia gas (NH 3 ) will be released 6 Oxygen IN OUT OUT OUT Ammonia OUT Heat! Biosolids Carbon Dioxide

20 INPUTS OUTPUTS Human Body Food & Air Survival Warm Body Warm Breath Automobile Gas & Air Transport Hot Engine Hot Exhaust

21 INPUTS OUTPUTS Human Body & Food Air Survival Warm Hot Body Warm Breath Automobile & Gas Air Transport Hot Engine Hot Exhaust Aerobic Reactor Sludge & Air New Bacteria Hot Reactor Hot Off-Gas Aerobic metabolism is more oxidative and has a higher net heat release but also loses more energy through off-gas

22 INPUTS OUTPUTS Human Body & Food Air Survival Warm Body Warm Breath Automobile & Gas Air Transport Hot Engine Hot Exhaust Aerobic Reactor Sludge & Air New Bacteria Hot Reactor Hot Off-Gas Aerobic metabolism is more oxidative and has a higher net heat release but also loses more energy through off-gas Anaerobic Reactor Sludge Air New Bacteria Hot Reactor Hot Off-Gas Anaerobic metabolism is less oxidative and has a lower heat release due to methane formation; also note important point that off-gas flow is far smaller Air Methane

23 ThermAer Process Advantages Match the O 2 Delivery to Uptake Demand High Degree of Automation: PLC Controlled ORP Control Strategy High TS and VS Reduction Quality End Product Improved Dewatering Characteristics Very Low Odor After Dewatering Cost Effective & Low Operator Time

24 System Component Parts

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28 Jet Aeration Varying Depths Continuous operation Mixing from the Tank Bottom Varying Liquid Flow Varying Air Flow

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31 Control Panel PLC Controlled with Panel View Operator Interface Reduces Operator Time System Responsibility of Program Pre-Wired SCADA Interface UL Shop O&M Manuals Available Directly from Control Panel

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33 Instrumentation Package ORP/pH Temperature Liquid Level Foam Level Incoming and Outgoing Flow Monitoring

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35 Foam Control Controlling Foam is Essential to Reactor Health Dedicated System Enhances O 2 Transfer Allows CO 2 Stripping Hydraulic Device (Out of basin)

36 Foam Control

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38 Biofilter Low Operating Costs Minimal Head Loss Minimal Electrical Requirements Low Re-acclimation Time Inorganic Layer for Longer Media Life Organic Media for Biological Culture

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42 Operational Information

43 ATAD Process Parameters

44 Weekly Feed Cycle Yorkville ATAD Response Data ORP (mv) Temperature (C) -350 ATAD1-ORP ATAD1-TEMPERATURE 54.0

45 Storage Nitrification/Denitrification Reactor (SNDR)

46 SNDR Cooling of ThermAer solids to create a Mesophilic Culture. Cycle Blower On/Off to Control ph ph Control allows Nitrification and Denitrification in a Single Reactor reducing the ammonia levels by 50-80% Satisfies the Residual Oxygen Demand Provides additional TS & VS Reduction Provides Storage for Campaign Dewatering Reduces Overall Dewatering Cost During dewatering, Nitrifiers migrate to the aeration basin

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48 SNDR Process Parameters ph/orp vs Time (SNDR) ph /27/05 2:24 PM ph ORP 6/27/05 3:36 PM 6/27/05 4:48 PM 6/27/05 6:00 PM 6/27/05 7:12 PM 6/27/05 8:24 PM Time 6/27/05 9:36 PM 6/27/05 10:48 PM 6/28/05 12:00 AM 6/28/05 1:12 AM /28/05 2:24 AM ORP(mv)

49 High Quality End Product High TKN Concentration High Phosphorus Concentration Non-Detectable Fecal Very Stable End Product Good Dewatering Characteristics: % Cake Solids

50 Total Nitrogen 29.3 pounds/ton Organic Nitrogen 24.3 pounds/ton Phosphorus (P) 21.5 pounds/ton Magnesium (Mg) 2.9 pounds/ton Total Solids %

51 Why ThermAer?? 55-70% VS Destruction Class A Biosolids and therefore many disposal opportunities. Typically 50% (or better) TS Destruction and therefore dramatically reduced disposal costs. Solids Can be Liquid Land Applied or Dewatered. If Dewatering is chosen, an Increase in Cake Solids up to 25% can be expected

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53 Yorkville, IL

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55 Brunswick County, NC

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57 Questions?? Contact Bob Wooldridge