VWEA Education Seminar
Collaborative Biosolids: Fuel for Thought
Richmond, Virginia
May 11, 2017
Biosolids Dryer
Technology Types,
Product Types and
Market Value
By Todd O. Williams, PE, BCEE
Biosolids Dryer Technology
Types, Product Types and
Market Value
Acknowledgements:
Brian Owsenek, UOSA
Rodney Lloyd, Leesburg
Tim Gallagher, CH2M
Tim Bauer, CH2M
Peter Burrowes, CH2M
Ron Alexander, Alexander Associates
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Outline
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Drying Technologies Overview
Product Marketing Issues
Virginia Case Studies
Summary
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Why Dry Biosolids?
• Mass & Volume reduction
Trucks for Hauling
12
No. of Trucks/Day
10
8
6
Trucks for Hauling Cake
(No./Day)
4
Trucks for Hauling Dry
Product (No./Day)
2
0
0%
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25%
50%
75%
Percent of Solids Dried (2030 Basis)
100%
Why Dry Biosolids?
• Produces a Class A product (under Part 503 rules)
– unrestricted use
– flexible usages
• commercial fertilizer blend (prepared)
• fertilizer amendment (direct land application)
• fuel – cement kilns
• Can be stored easily (well, sort of….)
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Drying Technologies
• Rotary Drums (Direct)
– Jones Island, WI; UOSA, VA;
Changi, Singapore; Louisville,
KY; Corona, CA; Bonita
Springs, FL; Leesburg, VA; Blue
Lake, MN; Stamford, CT;
Philadelphia, PA
– Advantages
• Product quality
• High capacity
• Operating experience
– Disadvantages
• High cost
• High safety provisions
• Complexity, O&M
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Typical Direct Drum Dryer
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Drying Technologies
• Belt Dryers (Direct)
– Kenosha, WI
– Low temperature air is used to
heat, absorb moisture
• recycle optional
• heated by furnace or heat
exchanger
– Advantages
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Product quality (moderate)
Safety (lower temp & low dust)
Waste heat provisions
Can use waste heat from CHP
– Disadvantages
• Large footprint vs capacity
• Moderate complexity, O&M
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Drying Technologies
• Paddle & Screw (Indirect)
– Wilsonville, OR; Wilmington, DE
– hot oil or steam are used to
heat hollow paddles and shaft
• recycle not typical
• variable speed rotors
• dryers are horizontal single-pass
– Advantages
• Good for smaller plants
• Lower complexity
– Disadvantages
• Product quality
• Sludge quality adaptability
– Neutral
• Safety
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Drying Technologies
• Continuous Batch (Indirect)
– Fayetteville, AR
– Hot oil is used to heat rotor
• Recycle not typical
• Mixing augers and drum
• Fill – Dry – Discharge cycle
– Advantages
• Good for smaller plants
• Lower complexity
– Disadvantages
• Product quality
– Neutral
• Batch operation
• Safety
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Drying Technologies
• Solar Drying
– Lincoln, Rio Vista, Salida
CA; Kent County, MD
– Sun and forced ventilation
used
Chamber filling
• Climatic sensors control
airflow and mole
– Advantages
• Good for smaller plants
• Lower complexity
Drying
– Disadvantages
• Large space required
– Neutral
• Batch operation
• Safety
– Can be used in tandem with
thermal dryers to reduce
energy use by half
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End of batch – ready for unloading
Drying Technologies
– …..and others
• Thin film (Green Bay, WI)
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Drying Technologies
– …..and others
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Fluid Bed
Tray
Flash
Electric
Etc.
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Dryer Types
(2011)
Number of
Facilities
USA
Canada
Drum
38
6
Belt
7
Indirect
78
Solar
15
Total
138
1
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Product Marketing and Quality and
End Use Issues
• Seasonality of Production and Use
– Especially apparent in northern
climates
– Storage in winter is an issue
• Pellet Quality
– Big difference in product uniformity
• Direct dryers
• Indirect dryers
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Hardness
Dust
Size
Uniformity
– Contaminants (Metals, Fiber, Plastics)
– Odors
• Digested or not
• Nutrient Content (N-P-K)
– Generally N = 5 to 6
– Generally P = 3 to 8
– Generally K = 0
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Product Marketing and Quality and End Use Issues
• Fertilizer Blenders
– Require High Degree of Uniformity and will pay top $
• Agricultural Users
– Do not require uniformity and will pay much less, if at all
• Soil Blenders?
– Are they really interested in the products and willing to pay?
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WEF RBC Conducted a Survey in 2016 and Published
a Fact Sheet of Operating Dryer Facilities in 2017
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WEF Survey/Fact Sheet Highlights
• Virtually all dryer facilities sell
granulated product
• Half of respondents sell product for
$1-$20/ton
• One third of respondents sell
product for greater than $20/ton
• Most (>75%) market product in bulk
only
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Recent Survey Results from Several California Dryer
Facilities (Corona, Encina, Sacramento, Ventura)
• Only high quality pellets can be sold
for substantial price.
• High quality pellets are being sold in
relatively small quantities to golf
courses and nurseries for $100 $120/ton in super-sacks
• High quality pellets are sold in bulk to
landscapers, nurseries and
greenhouses range from $40 - $85/ton
• Bulk sales to fertilizer blenders and
brokers in the $20 - $40/ton range
• Bulk sales to farmers/agriculture value
between $12 - $17/ton and used
mainly to prevent on site storage
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Case Study – UOSA, Virginia
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Berlie/Swiss Combi (3265) installed in 2004
Andritz DDS 40 installed in 2014
Operate 24/5
Process digested primary blended with
undigested WAS
Process about 6,000 DT/Year
N-P-K = 5-3-0
Market product by third party
50/50 share in product revenues
Sold in bulk only
Wintertime, mostly agriculture at $20/T
Summer to fertilizer blenders at $40/T
After $15/T Admin fee, net +$5/T when sold
to blenders, net -$5/T when sold to
ag/farmers
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Case Study – Leesburg, Virginia
• Andritz DDS 20 installed in 2002
• Operate 2 shifts, 5 days per week
(5 am- 10 pm)
• Process digested primary blended
with undigested WAS
• Process about 1,000 DT/Year
• N-P-K = 6-3-0
• Market product themselves
• Giveaway in bags to residents
• Sold in bulk and in bags
• Published information on website
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Leesburg TLC Product Sales in 2016
Tons
50 lb bags sold
108
Bulk sold
575
50 lb bags giveaway 84
Bulk giveaway
Total
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251
1018
# bags
4320
Revenue
(including
delivery)
$26,400
$41,713
Net Revenue Net Revenue % product
($/ton)
($/bag)
distributed
3360
10.6%
56.5%
8.3%
7680
24.6%
100.0%
$68,113
$244.44
$72.54
$66.91
$6.11
Summary Thoughts
• There are many drier types that create many different
product types
– Understand your objectives
– Know what the local market is
• Before selecting a technology!
• Higher quality uniform products are sold at higher prices
• Markets are generally good for dried products
• Brokers have capacity to move product quickly and
efficiently but will pay significantly less for product
• Utilities that market their own product require dedicated
staff, but reap higher profits on product sales
• Build flexibility into your program!
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Biosolids Dryer Technology
Types, Product Types and
Market Value
QUESTIONS?
Todd O. Williams, PE, BCEE
[email protected]
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