S.F. Bay Area Biosolids
How Much are We Talking About?
Presented By:
Jim Sandoval, CH2M HILL
June 2, 2008
BACWA Biosolids Workshop
Photo By:
Overview
 Infrastructure
 Production
 Management
Infrastructure
Current Biosolids Infrastructure
in the Nine-County Bay Area
 55 municipal wastewater treatment plants
(WWTPs)
– Operated by 53 wastewater treatment agencies
– Together treated an est. avg. dry weather flow
(ADWF) of 660 million gallons per day (mgd)
in 2003
– Produced est. 504 dry tons per day (dtpd)
biosolids in 2003
 i.e. 184,000 dry tons per year (dtpy)
Bay Area WWT by County (2003)
COUNTY
Alameda
ADWF
(MGD)
BIOSOLIDS PRODUCTION
(dtpy)
157.8
30,300
Contra Costa
90.8
28,200
Marin
20.3
5,300
Napa
17.2
4,300
San Francisco
89.9
22,000
San Mateo
56.6
11,300
Santa Clara
145
59,900
Solano
43.2
11,000
Sonoma
39.4
11,600
TOTALS
660
183,900
Influent Data (2003)
 Range of WW flow rates received at plants
– 0.3 mgd at the City of St. Helena
– 100 mgd at the San Jose/Santa Clara Water
Pollution Control Plant
 The average WWTP flow treated in Bay
Area was 12.5 mgd
Biosolids Data (2003)
 Range of solids contents of treated biosolids
– 4% solids at Dublin-San Ramon Services District
 biosolids are dredged from facultative lagoons & injected into a
dedicated land disposal site
– 85% solids at Oro Loma Sanitary District
 biosolids are dried in solar drying beds
 Many plants use mechanical dewatering (e.g. belt filter
presses or centrifuges)
– solids contents 15 - 26%
– Vallejo Sanitation & Flood Control District yielded 32% using limestabilized biosolids & belt filter presses
 Plants that nitrify ammonia & filter effluent had higher
biosolids production rates
– e.g. San Jose/Santa Clara WPCP - 1.15 dry tons per million
gallons treated
– Plants that do not nitrify or filter - average of 0.62 dry tons per
million gallons treated
Production
Population Projections (2003)
 Bay Area WW agencies served approx. 6.68
million people
– Approx. 95% of the nine-county population
 By 2010, 7.08 million people
 By 2030, 7.72 million people
– 15.6% increase over 2003
Breakdown of Population Served
in each County
County
Alameda
2003
2005
2010
2020
2030
Increase
(2003-2030)
1,449,000
1,544,000
1,583,000
1,645,000
1,709,000
14.8%
Contra Costa
881,000
916,000
936,000
989,000
1,041,000
18.2%
Marin
247,000
252,000
254,000
264,000
272,000
10.1%
Napa
112,000
116,000
121,000
128,000
133,000
18.8%
San Francisco
777,000
790,000
799,000
813,000
827,000
6.4%
San Mateo
669,000
686,000
694,000
715,000
741,000
10.8%
1,697,000
1,762,000
1,805,000
1,907,000
1,999,000
17.8%
Solano
380,000
407,000
426,000
458,000
496,000
30.5%
Sonoma
429,000
450,000
463,000
490,000
504,000
17.5%
TOTALS POP
SERVED
6,681,000
6,923,000
7,081,000
7,409,000
7,722,000
15.6%
BAY AREA POP.
7,030,000
7,194,000
7,405,000
8,045,000
8,657,000
23.1%
Santa Clara
Source: Association of Bay Area Governments (ABAG)
Distribution by County of
Population Served in 2003
Biosolids Production Projections
 Future biosolids production rates estimated using:
– Current biosolids production rates
– Projected population growth
 Projected biosolids production growth:
–
–
–
–
183,900 dry tons in 2003 (i.e. 504 dtpd)
192,600 dry tons in 2008 (i.e. 528 dtpd)
229,000 dry tons in 2030 (i.e. 626 dtpd)
19% increase from 2008 to 2030
 Projected biosolids production > projected
population increase…why?
– Much of the population growth will occur in service
areas that require nitrification of ammonia and filtration
(e.g. San Jose/Santa Clara)
Estimated Biosolids
Production Rates (dtpy)
County
2003
2005
2010
2020
2030
Increase
(2003-2030)
Alameda
30,300
30,800
32,000
34,600
37,800
24.8%
Contra Costa
28,200
28,700
30,200
33,100
34,800
23.4%
Marin
5,300
5,400
5,700
6,000
6,100
15.1%
Napa
4,300
4,400
4,600
4,900
5,000
16.3%
San Francisco
22,000
22,200
22,600
23,600
25,900
17.7%
San Mateo
11,300
11,500
11,700
12,700
13,000
15.0%
Santa Clara
59,900
61,300
64,600
71,600
77,800
29.9%
Solano
11,000
11,400
12,200
14,000
15,000
36.4%
Sonoma
11,600
11,800
12,400
13,200
13,600
17.2%
TOTALS
183,900
187,500
196,000
213,700
229,000
24.5%
504
514
537
585
627
24.5%
Daily Production
*Total volume generated in California in 2007 was 799,000 dtpy
Review of Biosolids Classes
CFR Title 40, Part 503
 Class A biosolids
– Treated to reduce pathogens to below detectable levels
– Can be used without pathogen-related restrictions at application site
– Can be bagged and sold to the public, if other requirements are met
 Class B biosolids
– Treated to reduce pathogens but still contain detectable levels
– Have site restrictions to minimize the potential for human and animal
exposure until environmental factors, such as heat, sunlight, and
desiccation, have reduced pathogens further
– Cannot be sold or given away in bags or other containers or used at sites
with public use
 Sewage sludge that is not treated to meet land-application standards
– Disposed at landfills
– Disposed at surface disposal sites that contain only sewage sludge
– Incinerated
Class A and Class B in the Bay Area
 Most Bay Area WWTPs produce Class B biosolids
 Some plants produce Class A with biosolids solar
drying beds
– Solar drying not explicitly listed as a Class A process
under Part 503 Rule
– Requires special testing to verify Class A standards met
Distribution of Class A and Class B
in the Bay Area (2006)
Class A (14%)
Class B (86%)
Source: EPA Region 9
Distribution of Class A and Class B
in the California (2006)
Class A (13%)
Class B (87%)
Source: EPA Region 9
Management
Bay Area Biosolids
Management Practices
 Bay Area WWTPs manage biosolids in
many ways
 Most biosolids managed by private
companies
– Applied to agricultural and pasture land to
improve soil conditions
– Hauled to landfills for use as alternative daily
cover (ADC) Disposed of in landfills
Bay Area Biosolids
Management Practices
 Other practices:
– Incineration
 Palo Alto RWQCP & Central Contra Costa Sanitary
District
 Ash disposed in landfills
– Dedicated land disposal sites
 DSRSD & Novato Sanitary District
 Owned/used these sites many years
Distribution of Reuse/Disposal Options
California vs. Bay Area
Long-Term Treatment
0.5%
Long-Term Storage
1.3%
Alkaline Treatment
3.8%
Pellets
0.7%
Other Disposal
0.9%
Unspecified
1.2%
Incineration
14.2%
Compost/Pellets
0.2%
Land Application
14.7%
Surface Disposal
1.6%
Compost
16.3%
Landfill Disposal
2.8%
Land Application
50.5%
Incineration
2.5%
Landfill ADC
15.4%
Landfill Disposal
4.5%
Landfill-Unspecified Use
0.4%
Surface Disposal
1.9%
Source: EPA Region 9
Landfill ADC
66.5%
California Biosolids
Management Practices
 Trends:
– Southern California agencies, rely heavily:
 Land application
 Compost
– Northern California agencies, combination:
 Landfill ADC/disposal
 Land application
 Incineration
End Uses in Bay Area by County
Unspecified
8.1%
Santa Clara
50.2%
Sonoma
5.7%
Solano County Landfill
0.4%
Solano County Land
Application
4.1%
Bulk for
landfill uses
Solano County ADC
7.1%
Alameda
4.8%
Contra Costa
13.0%
San Mateo
Merced
0.2%
Sacramento Napa 2.6%
0.9%
0.5%
Source: EPA Region 9
Marin
2.2%
Closing – The Common Thread
 Diverse array of options utilized in California for
biosolids reuse & disposal
 Frequently, agencies use multiple options for
robust programs
 Land application
– Plays a significant role in reuse
– Viewed as highest & best use for Class B biosolids
 Bay Area agencies seeking innovative new outlets
for biosolids reuse
– Changing political & regulatory trends: ADC & land app.
– Limited capacities
– Today’s subsequent presentations…
Questions?
Backup Slides
 The average cost of biosolids management in
2003:
– $21.71 per wet ton at 20% solids concentration
 or $108.55 per dry ton
– Prices ranged from $5.50 per wet ton to $52 per wet
tons
 Dedicated land disposal and incineration
operations have costs similar to the costs incurred
by agencies that dewater or dry biosolids