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Cost Effective Mixing and Biological Nutrient Removal (BNR)
at Warren WWTP
Presented By: Tyler Kunz, P.E. EnviroMix
Overview • 36 MGD Wastewater Treatment
Facility
• Anaerobic Zones at Front End of Four
(4) Aeration Basins.
Remove Fine Bubble Diffusers Add Baffles Install BioMixTM Compressed
Gas Mixing System • Part of Johnson Controls, Inc.
Performance Contract for Energy and Operational Savings
• Startup Spring 2014
Cost-Effective Mixing Warren, MI
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Objectives
• Achieve Biological Phosphorous Removal
• Reduce Cost of Chemicals (Ferric Chloride)
• Effectively and Efficiently Mix Anaerobic Zones
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Phosphorous Removal Through Chemical Precipitation
• Removal Mechanism • Soluble phosphorous adsorbs to Hydrous Metal Oxide (HMO) sites • Additional phosphorous (P precipitate and Bugs) are enmeshed within the HMO
• Common Chemicals • Alum, Sodium Aluminate, Ferric Chloride, Poly Aluminum Chloride
• Drawbacks • Expensive chemicals • Higher sludge production • Some chemicals consume alkalinity (may inhibit nitrification)
Cost-Effective Mixing Warren, MI
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Biological Phosphorous Removal
• Anaerobic Conditions • Phosphorous Accumulating Organisms (PAO’s) release intercellular phosphorous for energy
required to absorb Volatile Fatty Acids (VFA’s) and store as Polyhydroxybutyrate (PHB) • Aerobic Conditions
• PAO’s utilize the stored PHB as a food source for rapid cell growth • In the process they re-absorb soluble phosphorous in excess of what was released (Luxury
Uptake) • Phosphorous Removal
• Phosphorous now bound in cellular structure is removed by wasting sludge
Cost-Effective Mixing Warren, MI
PHB PHB
Poly-phosphate
Polyphosphate
Rapidly Biodegradable Substrate (VFA’s)
P Release
Excess P Uptake
Cell Synthesis
CO2 + H2O
O2 or NO3
Energy Energy
Anaerobic Aerobic
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Biological Phosphorous Removal - Simplified
Anaerobic Aerobic
• VFA uptake & storage (PHB) • Phosphorous release
• Stored “food” (PHB) oxidized • Cell synthesis • Excess phosphorous uptake
Phosphorous-rich WAS
Cost-Effective Mixing Warren, MI
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Process Modifications to Facilitate Biological Phosphorous Removal
• Pre-Anoxic Zone • Denitrification to limit the amount RAS-borne nitrates entering Anaerobic Zone
• Anaerobic Zone • Facilitate phosphorous release under anaerobic conditions
• Return Activated Sludge (RAS) • Reduced RAS from 150% down to 75% • Minimize nitrates returned to the Pre-Anoxic Zones
Cost-Effective Mixing Warren, MI
New Solutions for Old Problems
Point-Source Mixers
• Energy input is isolated
• Up to 2x the energy cost of
distributed energy model
• Submerged mechanical equipment
• Multiple mixers (maintenance
points) in large plants
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Nozzle Header System
• Distributed energy input
• Effective and efficient: 60%+ energy
savings
• No moving parts in the basin
• Many mixers replaced with a single
compressor
Distributed Energy Model
Cost-Effective Mixing Warren, MI
• Software & hardware solutions for water & wastewater treatment facilities - focused on efficient mixing systems
• Base technology- compressed gas mixing system-
intermittently firing short bursts of compressed air, nitrogen gas, or methane through engineered nozzles
• Large bubbles uniformly mix: Wastewater process tanks- Anoxic,
Anaerobic, Aerobic Digesters, channels, EQ tanks Potable water storage
• BioMix Technology creates solutions that:
Save Energy Reduce Maintenance Provide Guaranteed Mixing
Technology Overview
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BioMixTM – Compressed Gas Mixing
In-Tank Nozzles, Piping
and Anchors
Valve Panel w/ HMI Controller & Optional Remote
Monitoring
Compressor w/ Receiver
Tank(s)
Cost-Effective Mixing Warren, MI
Philadelphia (PA) SW WWTP
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Valve Control Panel (VCP) w/ Control Interface and Remote Monitoring
Cost-Effective Mixing Warren, MI
Technology Overview
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• Large compressed gas volumes expand upward and outward
• Expanding bubbles provide controlled turbulence,
fluid currents and provide mixing
• Does so with negligible amount of oxygen transfer
• Ideal for Anoxic and Anaerobic Mixing Environments
• Non-clog & high pressure design ideal for thickened sludge applications
Cost-Effective Mixing Warren, MI
Franklin County (PA) General Authority WWTP Anaerobic Pre-EQ
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• Large bubbles produced by BioMixTM deliver negligible O2 transfer
• It is a function of Bubble Size and Volume
• BioMix large bubbles have significantly less surface area than diffused aeration:
– 90% less than Coarse Bubble
– 99% less than Fine Bubble
• BioMix, anaerobic ORP values less than or equal to submersible mixers in side-by-side comparison.
– Higher surface “churn” with submersible technology induces O2 transfer
• BioMix diffuses a fraction of the air volume as conventional aerated mixing
Fine Bubble
Coarse Bubble
BioMix
Bubble Diameter
Area:Volume Ratio
(ft2/ft3)
BioMix 4” 18
Coarse Bubble 3/8” 192
Fine Bubble 0.06” (1.5 mm)
1,220
Comparative Surface Area (Bubble Area in 1 cu ft of Air)
BioMix Negligible Oxygen Transfer
Cost-Effective Mixing Warren, MI
Benefits • Uniformly Distributed Mixing Energy
• Reduces Energy Consumption
• Improves Mixing
• Enhances Biological Nutrient Removal
(BNR)
Eliminates Cost of Chemicals for
Phosphorous Precipitation
Savings of up to $200k/Year
(4 Basins Operating)
• Operator Adjustable Firing Parameters
• Accommodates Variable Mixing
Intensity
• Optimize Energy Consumption
• No In Basin-Maintenance
• Minimize and Localize Maintenance
Requirements 13
Compressor Skid
3D Rendering of Basins 1 & 2
Rotary Screw Compressor
Cost-Effective Mixing Warren, MI
Performance Results
• BioMixTM Provides Complete Mixing
of Eight (8) Anaerobic Zones with
one (1) 15 HP Compressor
• Mixing Efficiency ~0.1 HP/1000 ft3 of
Tank Volume
• Consistently Achieving Effluent Total
Phosphorous of < 0.5 mg/l with No
Chemical Addition
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Nozzle Header System
Cost-Effective Mixing Warren, MI
Municipal Wastewater Applications
Anoxic
BNR System
Channels
Sludge Storage
EQ
Sludge Digestion
Aeration
Pump
Station
Anaerobic
Swing Zone
Chlorine Contact
Chamber
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Cost-Effective Mixing Warren, MI
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Anoxic/Anaerobic Mixing BioMixTM
Low O2 Demand/Mixing Limited
Aeration Zones
(De-couple Aeration and Mixing)
Channel Mixing
Sludge Storage
Equalization/Storm Water Holding
Aerobic SHT and Digesters
(De-couple Aeration and Mixing)
Septage Receiving
Anaerobic Digesters
Cost-Effective Mixing Warren, MI
Technology Overview
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• Fits virtually any tank configuration
• Energy input can be varied to provide mixing intensity required
• Negligible O2 transfer due to low A:V ratio of large bubbles
• Equal or lower ORP compared to submersible mixers
• 60%+ Energy Savings vs. point-source mixing
• Even higher vs. diffused aeration (channels, sludge storage etc…)
• Replace many Mixers w/ 1 compressor
• No In-Tank Maintenance
Reduced Maintenance
Reduced Energy Consumption
Highly Scalable and Flexible Operation
Facilitate Anoxic/Anaerobic
Conditions
Cost-Effective Mixing Warren, MI
Warren, MI WWTP 32630 Warkop Warren, MI 48093 (586) 264-2530
• Dave Monette – Division Head
• Todd Schaedig – Facilities Engineer
• Bob Dranberg – Chief Operator
Cost-Effective Mixing Warren, MI
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Cost-Effective Mixing Warren, MI
EnviroMix - Corporate Headquarters 180 East Bay Street, Suite 200 Charleston, SC 29401 (843) 573-7510 www.enviro-mix.com
Thank You!
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