brown grease to biogas at wwtps puget sound brown grease symposium april, 2009
TRANSCRIPT
Brown Grease to Biogas at WWTPs
Puget Sound Brown Grease SymposiumApril, 2009
Presentation Snapshot
Business Case (why FOG to Biogas?)
Case Study: Millbrae, CA Data from first 12 months of operation Reduced solids production
• ~30% weight reduction Improved solids dewaterability
• Increase cake density, reduced polymer usage Electricity production Digester stability Project Costs
Other Opportunities
Business Case: Why do it?
Reduce operating costs Reduce waste to landfill (diversion) To capitalize on “Green” aspects of
project (gain prestige) To help diversify local utility’s renewable
portfolio “Greener” replacement for composting
operation
Business Case: How does it help me?
Can reduce demand for outside energy source (i.e. electricity, natural gas)
Can reduce solids being hauled from plant
Can increase waste diverted from landfills
Can create a revenue stream (tipping fees)
Can reduce carbon foot print of facility Can provide good PR opportunities
“The project here in Millbrae is cutting edge,” US Rep. Tom Lantos said. “It will allow us to develop energy independently and provide energy with resources we
have not looked at in the past.”San Mateo Daily Journal, 8/31/2007
Business Case: What do we do?
Anaerobic Digester Upgrade (typically)
Add Gas Conditioning Equipment Add Cogeneration Equipment (or other
gas utilization technology) Add Waste Receiving Station
Business Case: What if I do nothing?
Continue to “lose” money on missed opportunity
May miss funding opportunities Waste streams may go to other
facilities Cost to do project will increase Flared gas will be viewed as wasted
opportunity
Project Background
Project Background & Update
2004 project planning started
January 2007 Grease receiving started
September 2008 1 million gallons received
Millbrae WPCP
Project Details
Will receive ~3000 gallons per dayGrease content = ~10% - 20%Volatile solids destruction = 60% - 65%Gas production = 15 CF/lb VS destroyedMethane Content = 60% - 65%Cost of electricity = $0.138/kWh
Tipping Fees: $0.06 per gallon (negotiated with hauler)
Reduced Solids Production
Annual loads hauled
0
20
40
60
80
100
120
Years
Num
ber
of L
oads
Loads Hauled Linear (Loads Hauled)
Digester cleaning
IKG receiving station started
Reduced Solids Production
Compare average FY 93 - 06 loads hauled to Startup to Date
0.0
5.0
10.0
Month
Loa
ds
Average monthly biosolids loads from 93-06 Startup to Date
Average from FY 93 through FY 06
Startup to date
Grease deliveries interrupted for two weeks,July 13 to August 2, 2007
Started Feeding Grease, January 18, 2007
Reduced Solids Production
1585 Wet Metric Tons
1111 Wet Metric Tons
0
200
400
600
800
1,000
1,200
1,400
1,600
WE
T W
EIG
HT
, ME
TR
IC T
ON
S
Wet metric Tons Biosolids Disposed
FY 93 - FY 06 Average 2007
Ave
rage
FY
93
- F
Y 0
6
2
007
aver
age
AF
TE
R I
KG
RE
CE
IVIN
G
Improved Dewaterability
Polymer use (per DT and total) vs cake density
0
1
2
3
4
5
6
7
8
Uni
ts
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
Pounds Polymer per DT/10 Monthly Pounds of Polymer/100 Average Cake Density
Started Feeding Grease, January 18, 2007 No Grease feed, July 13 to
August 2, 2007
Power ProductionFY 06-07 Utility vs Cogen Production
0
25,000
50,000
75,000
100,000
125,000
150,000
Jul-0
6
Aug-06
Sep-0
6
Oct-06
Nov-0
6
Dec-0
6
Jan-0
7
Feb-0
7
Mar
-07
Apr-07
May
-07
Jun-0
7
Jul-0
7
Aug-07
Sep-0
7
Month
kW
h
PG&E Co-Gen
Started receiving greaseJanuaruy 18, 2007
No grease received,July 13 through August 2, 2007
Digester StabilityCompare grease feed to digester stability
0%
5%
10%
15%
20%
25%
30%
35%
40%
Month
Per
cent
GREASE WEIGHT/TOTAL SOLID WEIGHT Primary Secondary
VA/A Ratio
Digester Grease to sludge ratio
Started receiving greaseJanuaruy 18, 2007
No Grease feed, July 13 to August 2, 2007
How much did it cost?
Total project cost ~$5.5 M Base cogen facility ~$1.9 M Switchgear upgrade ~$0.7 M Grease receiving station ~$0.7 M CNG storage facility ~$0.7 M Digester mixing ~$1.5 M
Opportunities
Note: This list is also broken down by state
Opportunities in WA
Facility Authority Influent Flow(MGD)
Potential Electric
Capacity (kW)
W. BREMERTON/ CHARLESTON STP BREMERTON, CITY OF 7.6 169
CENT. KITSAP REG. STP KITSAP CO. COMMISSIONERS 8 178
RICHLAND STP RICHLAND UTILITY SERVICES 6 133
SPOKANE STP SPOKANE, CITY OF 44 978
TACOMA CENTRAL STP #1 TACOMA, CITY OF 26 578
WALLA WALLA STP WALLA WALLA, CITY OF 6.2 137
YAKIMA REGIONAL WWTP YAKIMA, CITY OF 11.3 251
Source: 2004 Clean Watersheds Needs Survey
Opportunities in OR
Facility Authority Influent Flow(MGD)
Potential Electric
Capacity (kW)
MEDFORD STP MEDFORD, CITY OF 20.1 446
MCMINNVILLE WWTP MCMINNVILLE, CITY OF 5.5 122
Source: 2004 Clean Watersheds Needs Survey
Thank You
Greg Chung
Richard York
(former plant superintendant)
Joseph Magner