Presentation from the Metropolitan Council Environmental Services division on the current and planned activities for the municipal wastewater treatment facilities they manage for greater MSP..

1. MCES Wastewater Derived Energy
Production Portfolio
Metro
•Steam Turbine
•Non-Condensing Steam Turbine
•Steam Campus Heat
Blue Lake – Anaerobic Digestion/Drying
•420 CFM Digester Gas to drying
Empire – Anaerobic Digestion/Land
Application
•140 CFM Digester Gas to Boilers

2. Solids Loading by Facility
Metro; 238
Empire
; 17
Blue Lake; 39.7 –
29.4 dtpd digested
Seneca; 27.2
Solids Production in dtpd
Metro
Empire
Blue Lake
Seneca

3. Wastewater Derived Energy
Production
Empire
–
•140 cfm digester gas
•XX BTU Boilers
•Flare
Blue
Lake
•Organic Waste Direct to
Digestion – Under
Design
•Excess gas to boilers
•CNG under
consideration
Metro
•Increasing Turbine
Generator Output and
Capacity
•Recovering waste heat
Seneca •Building Heat

4. Future Energy Production
Empire
–
•CHP Under Design – 1.0
MW
•Organic Waste Direct to
Digestion – Under Design –
28 cfm digester gas
•CNG ready
Blue
Lake
•Organic Waste Direct to
Digestion – Under Design
•Excess gas to boilers
•CNG under consideration
Metro
•Increasing Turbine
Generator Output and
Capacity
•Recovering waste heat
Seneca •Recovering energy from
solids

5. Metro Ash Initiative
• Ash has high P content
• Ash has low metals content
• Ash has shown similar
performance when
compared to struvite,
commercial fertilizer, and
digested biosolids
Ash to
Fertilizer

8. Fluidized Bed Reactor – HZI FBR Capacity
Types of Waste
• Sewage Sludge (biosolids), Industrial sludges
• 50 – 80% moisture
Range of Capacity
• Throughput: 10 – 120 dtpd (biosolids)
• Thermal Capacity: 5 – 175 MMBtu/h (1.5 - 50 MW)
• Reactor Sizes: 4 – 30 feet (1 – 10 m) diameter
Features
• Combustion Temperature: 1560 ºF (850 ºC)
• No heat absorption in reactor
(good for combustion of very wet fuels)
Page 8MCES Scrubber Presentation May 12, 2014

9. 9
Wet Scrubbing - Multistage Flue Gas
Scrubber
Main Features
For flue gas from all types of
energy-from-waste facilities
Multifunctional: quenching, gas absorption, dust
separation, dioxin removal, condensation
Neutralization agent: sodium hydroxide (or hydrated
lime)
Adsorbent injection (for additional dioxin removal)
GasPoint: very low emissions achievable
Open for extensions (e.g. heat recovery by
condensation)
Capacity
Flue gas volume up to 150,000 scfm
(250,000N m3/h)
MCES Scrubber Presentation May 12, 2014

10. 10
Semi Dry System
Types
Hitachi Zosen Inova Semi Dry System
Main Features
System based on fluidized bed reactor
Reliable operation through minimization of moving
parts
High recirculation rate, therefore high buffering
capacity and low sorbent consumption
Possible modification to other additives
Safely fulfils EU stack emission guidelines
(17.BlmSchV and lower)
Capacity
Flue gas volume up to 150,000 scfm
(250,000N m3/h)
MCES Scrubber Presentation May 12, 2014

11. 11
DeNOx Systems
Main Features
SNCR
Injection of ammonia water or urea solution
into post combustion chamber
With or without ammonia recovery
Reaches NOx removal up to 80%
SCR
Catalysts for NOx-removal and dioxin
reduction
Arrangement on hot (235°-260°C) or cool
(180°- 220°C) side of flue gas scrubbing
Reaches NOx removal up to 90%
Capacity
Flue gas volume up to 150,000 scfm
(250,000N m3/h)
MCES Scrubber Presentation May 12, 2014

12. Metropolitan Council Environmental
Services | St. Paul, MN
Page12
Three independent lines supplying one steam turbine
generating 4 MWe
No auxiliary fuel required during normal operation
Combined heat and power production
Emissions surpass MACT requirements for SSI
Hitachi Zosen Inova, EPC contractor for incinerator/boiler,
flue gas treatment, and generator
Client Metropolitan Council
Environmental Services,
St. Paul, MN
Start-up 2004
Technology
Furnace 3 Incinerator Lines
Energy recovery Recuperators, Boilers
Flue gas treatment SNCR, carbon injection, fabric filter,
wet-ESP, wet scrubber heat exchangers
Technical Data
Fuel Municipal sewage sludge
Waste capacity 315 dry t/d @ 30% solids
Net calorific value 2,000 Btu/lb wet
Reactor Diameter 22 feet
Steam rate 3 x 25,000 pph (450 psi, 750 °F )
Key Data
MCES Scrubber Presentation May 12, 2014

13. MCES: Plant Context of Wet Scrubber
System
Page 13
•WET ESP
•FLUID BED
•RECUPERATOR
•WASTE HEAT
• BLR
•CARBON
•INJECTION
•BAGHOUSE
•RING JET
•SCRUBBER
STACK REHEAT
HEX
FLUIDIZED
BED REACTOR
FLUIDIZING
AIR HEAT
EXCHANGER
BOILER
STACK
REHEAT
HX
CARBON
INJECTION
BAGHOUSE
WET
SCRUBBER
RING JET
WET
ESP
HEAT
RECOVERY
COMBUSTION Hg
PCDD-F
PM Acid Gases
PM
PM
MCES Scrubber Presentation May 12, 2014