POTW Energy Use and Waste to Energy- Solution to Environmental Challenges
Chris Tippery, Symbiont
Energy Savings Made Easy | 2017 Business Symposium
AERATION & ENERGY
» Utility costs are expected to increase in the future
» U.S. WTPs & WWTPs account for roughly 100 billion kWh
annually (Electric Power Research Institute)
» Aeration system power requirements are often 40% to
60% of an activated sludge plant’s total energy demand
» Electricity is produced from mostly non-renewable
resources
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Example POTW – 5.5 MGD
» Aeration energy cost is approximately $260,000/yr at
$0.05/kWh
» Normalized aeration energy use:
• 1,710 kWh/MG
• 538 kWh/1,000 lb BOD (raw influent)
Energy Savings Made Easy | 2017 Business Symposium
Aeration System Review
Basins (4) Buried Concrete Tanks, Each with Anoxic and Oxic
Zones
Diffuser Type Fine Bubble Ceramic Diffusers
Blowers
(3) 600 HP and (2) 400 HP Multistage Centrifugal
Blowers
Installed in 1989
Controls
Soft Starts, DO Control of Air Flow, Surge Protection,
Time Delays
Installed in 1989
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DESIGN FOR ENERGY REDUCTION
o Air flow rate should be varied according to wastewater
oxygen demand
o Dissolved oxygen measurements used to vary air flow in
real time
o Blower surge control considerations
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DESIGN FOR ENERGY REDUCTION
» Potential aeration flow control methods:
• Flow blow-off
• Inlet throttling
• Adjustable discharge diffuser
• Variable speed drive
• Parallel operation of multiple units
Best choice
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DESIGN FOR ENERGY REDUCTION
» The two 400 HP blowers provide sufficient air flow (max.
11,260 cfm) for normal operations
» Control Modifications
Set 400 HP blowers to Lead and Lag 1
Set 600 HP blowers to Lag 2, Lag 3 & Backup
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DESIGN FOR ENERGY REDUCTION
• Two 18 pulse, IEEE 519, 460V, 400HP VFD units
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AERATION SYSTEM ELECTRICAL USAGE IMPACT
Before VFD Upgrade After VFD Upgrade Energy Reduction
45.2% of facility 39.7% of facility 12.2%
(percent change)
8,570 kWh/d 7,300 kWh/d 14.8%
1,710 kWh/MG 1,569 kWh/MG 8.2%
538 kWh/1000lb BOD 473 kWh/1000lb BOD 12.1%
Energy Savings Made Easy | 2017 Business Symposium
FINANCIAL IMPACT REVIEW
o Construction cost of approximately $115,000
o Annual utility savings of $14,800 at $.05/kWh
o Received a State Energy grant of $46,500
o Payback Period:
o 4.6 years with grant
o 7.8 years without grant
o Grant required application and justification submittals
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Food Production Creates Waste
Examples of food processing by-products
Peels
Shells
Float
Whey
Oils
Paunch
Spent Yeast
Non-Saleable Product
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Issues With Waste Disposal
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Characteristics of Optimal Waste Feedstock
» Easily biodegradable
» COD > 10,000 mg/L (higher the better)
» No heavy metals
» Low levels of toxic cleaning compounds
• Peracetic acid
• Quaternary ammonium
» Reasonable levels of N, P, and Chlorides
Energy Savings Made Easy | 2017 Business Symposium
Waste-to-Energy: The Process
Energy Savings Made Easy | 2017 Business Symposium
General Biogas Properties
50-70% CH4 / 30-50% CO2 / saturated with water / traces
of H2S and other gases
Heating value (dry) = 500 to 800 BTU/cf
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Surge
Tank
Engine
Relief
Valve
Exhaust
Heat
Recovery
Unit
Mixing
Valve
External
Radiator
Circulating
Pump
Heat
Exchanger
Process
Bypass Valve
Loop Warm up
Biogas Use - IC ENGINE HEAT RECOVERY SYSTEM
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Green Whey Energy
Turtle Lake, Wisconsin
Challenge: » Develop a regional, sustainable process to dispose of
cheese making wastes that were overloading local
POTW
» Reduce/eliminate land application
Solution: » Regional processing center for waste using anaerobic
digestion
Energy Savings Made Easy | 2017 Business Symposium
Green Whey Energy
Turtle Lake, Wisconsin
Results: » Converts cheese making waste into electricity
» Uses Upflow Anaerobic Contact process
» Processes about 300,000 gpd of waste with average
COD of 35,000 mg/L
» Produces 1.25 million cubic feet per day biogas
» Generates 3.2 MW of electricity using engines
» Heat recovery
» Discharges pretreated effluent without overloading
POTW
Energy Savings Made Easy | 2017 Business Symposium
Forest County Potawatomi Community
Milwaukee, Wisconsin
Challenge: » In accordance with tribal culture and tradition, develop
a means to protect and enhance the environment and
become energy independent
Solution: » Construct a high strength waste processing center using
anaerobic digestion to create renewable energy
Energy Savings Made Easy | 2017 Business Symposium
Forest County Potawatomi Community
Milwaukee, Wisconsin
Results:
» Flexible to receive various industrial high
strength wastes
» Anaerobic Membrane Bioreactor process
» Processes 120,000 gpd with COD of 95,000 mg/L
» Produces 778,000 cubic feet per day biogas
» Generates 2 MW of electricity plus heat
recovery for buildings, casino, and process
» Discharge to city sewer
Questions?
Chris Tippery Symbiont
Variable Refrigerant Flow (VRF)
Christopher Swallow – Thermal Mechanics, INC
Energy Savings Made Easy | 2017 Business Symposium
Development of VRF
» 1973 – Global oil crises
» 1979 – New energy efficiency laws passes in Japan
» 1980 – Chiller design engineers challenged with making a higher
efficiency chiller
» 1982 – The worlds first VRF System is launched
» MOVE REFRIGERANT THROUGH PIPE NETWORK IN LIEU OF WATER
Water
2.6 watts/lb
25 watts/lb
Refrigerant
Air
0.14 watts/lb
VAV VWV VRF
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Reduced Space Requirements
7 Ton Ductwork
28 Tons of Refrigerant Pipes
Energy Savings Made Easy | 2017 Business Symposium
VRF in the Global Market
~16%
~12%
31% 53%
45%
70%
~53%
33%
54%
~40%
23%
Energy Savings Made Easy | 2017 Business Symposium
VRF Concept
Think of a VRF system as a chiller / boiler that circulates refrigerant to each zone instead of water
A heat pump system is equivalent to a 2 pipe chiller
Major benefit is smaller heat/cool changeover zones due to the modular build up
A heat recovery system is equivalent to a 4 pipe chiller system
6 Ton
6 Ton
Heat recovery
Cooling Cooling Heating
12 Ton
Heat Pump
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Parts and Pieces
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Heat Pump
Energy Savings Made Easy | 2017 Business Symposium
Heat Recovery
Energy Savings Made Easy | 2017 Business Symposium
How Does the VRV Inverter Control the System
52~210Hz
Applied frequency
37 Applied Capacity Steps
Condenser Control
COOL Operation
HEAT Operation
14%
100%
Inverter control Adjusts
compressor speed (capacity) up or down to
correct deviation from the target pressure
values (system load)
Sets Target low & high pressure
values at the Condenser
Sets the Target evap. & cond.
Temps in the indoor Fan Coils
Local Remote Controllers initiate a
system Thermo-ON with a 1°
deviation from set point
Local Remote Controllers initiate a
system Thermo-OFF when all set
points are reached
Control System
Detects the system operating suction
pressure at Condenser once every 20
seconds
Detects the system operating high
pressure at Condenser once every 20
seconds
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Average VRV System Performance
0.02.04.06.08.0
10.012.014.016.018.020.022.024.026.0
10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
EER
Load
Partial Load Performance (VRV)
75%
595
340
680
340
170
425
510
255
85
System Operation
Hours
75% of total operation
hours- less than 70% of full load
Questions?
Chris Swallow Thermal Mechanics
Combined Heat and Power
Charlie Mayer Clarke Energy
Energy Savings Made Easy | 2017 Business Symposium
Combined heat and power (CHP) is a high
efficiency technology for generating power
in the form of electricity and heat, on site
and from a single fuel source
Recip Engine-Generator Sets in CHP
Energy Savings Made Easy | 2017 Business Symposium
Why CHP?
Fuel
(100%)
Electricity for
transmission
(35%)
Generation/heat
losses (65%)
Conventional
Power Plant
Gas-fuelled
CHP plant
90%
Efficiency
Generation/heat losses
(10%)
Fuel
(100%)
Electricity
(45%)
Useful Heat
(45%)
Transmission
Losses (1.5%)
Supplied
electricity
(efficiency)
33.5%
Energy Savings Made Easy | 2017 Business Symposium
Energy Savings Made Easy | 2017 Business Symposium
CHP solutions are applicable in a wide variety of
energy-intensive facilities
Combined heat and
power plant
Industrial manufacturers,
institutions, commercial
buildings
Residential communities, municipalities
• Industrial manufacturers - chemical,
refining, pulp and paper, food
processing, glass manufacturing,
cement, steel mills
• Institutions - colleges and universities,
hospitals, prisons, military bases
• Commercial buildings - hotels and
casinos, airports, high-tech
campuses, large office buildings,
nursing homes
• Municipal - district heating systems,
wastewater treatment facilities
• Residential - multi-family housing,
planned communities
Energy Savings Made Easy | 2017 Business Symposium
US CHP Installation Data
Energy Savings Made Easy | 2017 Business Symposium
Combined heat and power
Energy Savings Made Easy | 2017 Business Symposium
Combined heat power and cooling
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Combined heat, power and CO2 recovery
Combined heat, power and CO2 recovery
Energy Savings Made Easy | 2017 Business Symposium
Gas Engine Module Basics
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Fuel Flexibility
Landfill gas Sewage gas
Associated
petroleum gas
Special gases
Biogas
Greenhouse
applications
Cogeneration
(Natural gas)
Coal mine gas
Island mode
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Flexible Delivery Model
» Genset • Gas engine
• Generator
• Base frame
• Fuel gas train
• Genset control panel
• Design and Documentation
• Options
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Flexible Delivery Model
» Power module • Item 1 plus
• Ventilation system
• Acoustic/weatherproof enclosure
• Silencer
• Radiators
• Fire and gas detection
• Electrical and I&C
• Further options
• Co/tri-generation
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Flexible Delivery Model
» Power plant • Item 2 plus
• Civil work
• Gas conditioning plant
• Lube oil system
• HV/LV switch room, control room, electrical sub-stations , metering
and reticulation
• Black-start diesel generators
• Storage / workshops
• Further options
Energy Savings Made Easy | 2017 Business Symposium
Energy Savings Made Easy | 2017 Business Symposium
CHP is an application…not a product
Design must accommodate system complexity
• Balance fluctuations in seasonal thermal load demand
• Complete understanding of application requirements dictates plant size
• Systems integration of components and configuration to drive resiliency, flexible and reliable operation
• Optimize around financial returns and policy incentives
Energy Savings Made Easy | 2017 Business Symposium
End to End Service
Contact
Clarke Energy USA Inc.
2100 Pewaukee Road,
Waukesha, WI 53188
Tel: +1 (262) 565 5020
www.clarke-energy.com
Questions?
Charlie Mayer-Clarke Energy