alternative fuels from landfills

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Alternative Fuelsrom Landflls

Landfll Gas, Canola and Biodiesel:Working Towards a Sustainable System

| Terrill Chang, P.E. and Deanna Carveth |

SnohomiSh County in weStern waShington

State began converting its vehicle eet to a blend o

biodiesel in 2005. As prices or biodiesel rose due

to increased demand or this cleaner-burning uel,

Snohomish County looked to its armers to grow this

uel locally. Suitable oil seed crops or biodiesel eedstock

include canola, mustard and camelina. The residue, or

meal, has high value as an animal eed. County armers

began with 52 acres o canola and mustard crops in 2006,

increasing to 300 acres and 700 tons in 2009.

The team consisted o Snohomish County Public

Works, engineering frms (URS Corporation and

Parametrix), Washington State University Extension,

Wolkill Feed and Fertilizer (local ertilizer company)

and various equipment suppliers, It was necessary

to develop local inrastructure or the canola project

because canola is not a traditional crop in Snohomish

County. To reduce the projects cost and environmental

ootprint, the County tapped the methane content in

landfll gas rom the closed Cathcart Landfll south o

the City o Snohomish and about 35 miles north o

Seattle as the energy source or the seed dryer, in lieu

o propane or natural gas. The canola processing acility

is located at the landfll site, adjacent to the existing

landfll gas blowers and ares. Project benefts include:

Revitalization of the local agricultural

community, increasing the Countys economic

diversity, a key goal o County government

Addition of an excellent rotational, low tillage

crop that can also convert pasture into row crops

County ownership of a commercial facility

suitable or drying other grains and crushing

other seeds or oil production

A central location of the dryer and crusher that

reduces transportation to processing and to therefnery that converts the canola oil into biodiesel

A benecial use of a declining landll gas stream

that still contributes to reaching sustainability in

vehicle uel

This article discusses the challenges o the design

and equipment procurement process, permitting,

construction and startup, operational results and

lessons learned.

Project GoalsThe goals o this project are to:

Support the use of biodiesel in Snohomish

Countys vehicle eet

Support local agriculture

Benecially use landll gas, an energy source

previously wasted through aring

Create community resiliency by reducing depend-

ence on petroleum-based uels and shortening

supply lines

With SnohomishCountys commitment tothe use of biodiesel,an ongoing project

has helped to

lessen dependency

on imported

petroleum as well

as added to the

economic diversity

of the county by

creating new crops

and jobs.

36 WasteAdvantage Magazine February 2010

The distributor at the top o the elevator directs product to the dryer, storage or the crusher.Photo courtesy o Deanna Carveth, Snohomish County Public Works.

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In 2005, the Countys Fleet Management group committed

to using a cleaner uel in the Countys diesel trucks and began

converting its eet to use a 20 percent biodiesel blend (B-

20). In 2009, the County increased the blend to 40 percent

(B-40); local farmers grew 30 percent of that amount,

supporting the Countys Focus on Farming initiative (local

armers interested in growing an economically viable crop

with a local market were identifed).

A supply o unused methane gas was available as

landfll gas (LFG) currently being ared at the Cathcart

Landfll. The landfll closed in 1992, with about 1.97

million tons o waste in place. Current gas ows are about700 cm with a methane content o about 30 percent.

By growing and locally processing fuel for Snohomish

Countys diesel eet, the County has eliminated the risk

o supply line disruptions. Further, by strengthening its

local agricultural community, the County has preserved

armland or ood production.

Project Chronology2006

In January o 2006, a group o Snohomish County

armers approached the County Executive seeking a crop

to support the Countys new biodiesel initiative. Working

with Washington State University (WSU) Extension ofces,

growers planted small feld trials (52 acres) o two mustard

variants and two canola variants to determine which o

these Brassica family members would grow best in the wet,

overcast climate of the Snohomish River valley. Brassicas

were chosen because they avor moist, cooler growing

seasons and because the uel they produce can reach 28Fbeore gelling making it preerable or our cooler winters. In

contrast, soybeans preer a hotter growing climate and their

biodiesel has a cloud (gel) point o 36F.

Both crops grew better than expected. Canola had a

higher yield (pounds per acre) than mustard and more

viable markets or both the oil (35 percent o total crop

weight) and the letover meal (65 percent o total crop

weight), a sought-ater animal eed.

The County provided a grant to SnoSky Agricultural

Alliance, a growers non-proft organization, to manage

the feld trials, pay WSU sta, and otherwise promote the

project in both 2006 and 2007. The Alliance determined

that a combine was needed to eectively harvest the crop

and used grant unds to procure one.

The growers attempted to feld-dry the harvested

canola, but western Washington proved to be too rainy

and the seed germinated, rendering it useless or oil

extraction. Growers decided a crop dryer was essential

to successully harvest and market this crop. SnohomishCounty and its partners began design work or ull-scale

inrastructure.

This is the extruder. The oil has gone through therst virgin oil crush and is now being heated andextruded to burst the oil cell walls allowing or greater

oil extraction. Ater the rst crush, the meal is passedthrough steam locks in an extruder to prepare the meal

or nal oil extraction. Photo courtesy o Matthew Goad,Snohomish County Public Works.

WasteAdvantage Magazine February 2010 37

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2007

The previous years crop trials avored Hyola canola, so three 50-acre plots

were planted. Wolkill Feed and Fertilizer ound and transported a used 8-ton

batch dryer rom Lipton, Saskatchewan, Canada to the Cathcart Landfll.

County sta connected it to the LFG system and dried the canola. The LFG-

fred dryer was deemed a successul proo-o-concept. Seed samples taken beore

and ater drying showed no changes to seed chemistry due to exposure to LFG.

It became clear that the combine and batch dryer were insufcient

inrastructure on which to base a viable enterprise. Also, lack o local processing

meant trucking the seed 300 miles east across the Cascade Mountains toSunnyside, WA, eliminating profts in 2007.

2008

2008 was the critical year. The County received a $344,400 earmark via the

Department o Energy and a $500,000 Energy Freedom Fund Grant rom the

Washington State Community Trade and Economic Development Department.

Along with unds authorized in the solid waste budget, procurement and

installation began.

The frst purchase was a 15-ton continuous ow commercial seed dryer

with centriugal ans, a 475-bushel holding capacity, screens sized or canola

(0.050 inches), natural gas burners, oversized piping for low-BTU LFG, and

digital temperature/moisture monitoring to control burners and ans. URS

Corporation and the County had hoped to recover heat rom an existing LFG

are by re-routing hot exhaust gas through an air-to-air heat exchanger toproduce clean, hot air to dry the seed. However, the are manuacturer declined

to place a fn-tube heat exchanger cross-wise in the 8-oot diameter are, citing

concerns about corrosion and restricting the vertical ow o exhaust gas.

Ductwork to capture exhaust gas at the top o the are was also considered, but

there was no precedent or such a design. Finally, quotes or a heat exchange

system approached $750,000, exceeding the available budget

The next purchase was seed storage silos (356 ton capacity) and handling

equipment. Trucks unload on a concrete pad, where the in-ground auger

conveys the seed through a seed cleaner and into the bucket elevator. The

elevator lits the seed to the top o the silos, where an 8-way distributor directs

the seed to the appropriate silo. Bottom U-trough augers and pipe augers move

Ldfll gs, Cl, d Bdsl: wk tds Ssbl Ss


Co-locating the crusher and dryer at the fare acility makes gas supply convenient and remindsvisitors o the environmental benets o the project.

Completed acility looking east to the closed landll rom which the gas is supplied.


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the seed to the dryer or the elevator. The auger and elevator system provided a

continuous eed o canola to the new dryer, which dried 286 tons o canola and

414 tons o mustard in 2008.Engineering work by URS Corporation and Parametrix included the design

o concrete slabs, roadways, drainage, power supply, agricultural equipment

specifcations and the air permit application. To reduce costs, Public Works

crews amiliar with the landfll site built the concrete pads and roads, placed the

dryer, and connected the LFG piping and electrical power supply. The project

used Department o Energy unds to pay or the access road and consulting

services, and Energy Freedom Funds or the crusher system.

Solid Waste Division and Specialty Laboratories o Texas determined that using a

gas chromatograph/mass spectrometer (GC/MS) analysis showed the most potentialcontaminants or the least cost. This type o screening would also prevent missing a

key constituent o concern by looking or all constituents rather than a ew named

isomers. Testing in 2007, 2008 and 2009 showed that wet or green seed has exactly

the same fngerprint as the dried seed, except that volatile organic compounds

that naturally occur in the green seed are signifcantly lower in the dried seed. The

landfll gas did not adhere or absorb any contaminants onto the seed.

2009

In spring 2009, a seed cleaner, crusher and extruder were installed. About

12 tons o canola rom the 2008 all harvest was used to test the crusher and

extruder, producing about 1,000 gallons o oil and eight super sacks o meal

used or animal eed. The meal contained about 7 to 9 percent oil, which means

that the incoming seed had about 42 percent oil, much higher than expected.

A second grain elevator was installed to improve unctionality. Overall, 330

tons o material was dried including 214 tons o mustard, 85 tons o canola

Canola seed is tested or moisture content ater exiting the dryer to ensure it is stable orstorage. Photos courtesy o Deanna Carveth, Snohomish County Public Works.

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and 31 tons of barley; more crops were eld dried this year due to an unusually

dry summer.

Results and FindingsTwo crops per year o canola can be grown successully in western

Washingtons cool and rainy climate. The spring harvest o the winter croptakes place around late June. The seed must be dried and the oil extracted

beore the all harvest (about mid-September) o the spring-planted crop.

Even using low-BTU LFG (~30 percent methane), the dryer functioned

properly and met air emissions requirements. A maniold tank was installed

between the LFG compressor and the dryer to accumulate enough gas at

pressure to start the ignition sequence.

The County Public Works system was not geared to agricultural projectsthe

atypical equipment and the urgent timing of the crops were a challenge. Because

the project was designed and constructed over several years by multiple parties,

using new and reurbished equipment rom various vendors, unded by grants

as well as County unds, the County was orced to act as the system integrator.

Farmers and other members o the local agricultural community worked

collaboratively with the County. Their support and continued interest in growing

oil seed crops is critical to the long-term success o the Countys biodiesel initiative.

A matter o great interest was whether burning LFG in the dryer would produce

compounds such as dioxins that adhered to the seed. The GC/MS methodology

allowed comparison o the chemical fngerprints o wet and dry seeds. Complex

market economics also aect the long-term viability o the biodiesel system.

One measure o success is the increase in the acres o canola grown orbiodiesel. Canola is a great rotational crop and it is anticipated that acreage

will grow to about 1,000 acres in production each season.

Future OpportunitiesAvailable unding provided the window o biodiesel opportunity in

Snohomish County. The Solid Waste Division had looked at using landfll

gas to generate electricity previously. The Pacifc Northwest power market

has a very high percentage of hydropower; electricity has historically been

inexpensive, making alternative technologies difcult to justiy fnancially. In2013, the Bonneville Dam bonds will be paid off, allowing the Bonneville

Power Administration greater ability to ship green power out o the Pacifc

Northwest. This will increase opportunities or newer technologies to compete

in the Puget Sound region as local utilities work to meet green power mandates.

The County is currently looking at Department o Energy ARRA grant

dollars to use combined landfll gas and methane rom a near by dairy arm

or energy. This same grant incentivizes the capture o waste heat which the

Division can potentially use to run the dryer, run a boiler to make steam or the

de-gummer system and potentially pre-heat the wash water in the nearby truckwash. Local production o uel promotes local jobs and economy, preserves acres

or arming not houses and ensures we have uel when we need it should supply

lines be disrupted.

ConclusionsThis project continues to be important on several levels. First, it showed that

landfll gas, even rom a landfll closed 18 years earlier, can be a viable energy

source or an industrial process, the drying o crops. Second, groups interested

in promoting local agriculture and the use o alternative, non-petroleum uels

worked together cooperatively to grow a non-traditional (or this geographicarea) crop and extract two useul products (oil and animal eed meal) that have

Ldfll gs, Cl, d Bdsl: wk tds Ssbl Ss


Mustard seed is unloaded into the dryer system moments ater construction is completed September 18, 2008.


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local markets. Third, it showed that the technology and

equipment or a crop-to-uel system could be assembled

and operated at a County solid waste acility. Fourth,because the County oers tours to interested parties,

there is an educational and public outreach component

that helps inorm students and County residents about

sustainability, alternative energy and waste management.

Fith, with the Countys commitment to the use o

biodiesel, this project helps to lessen dependency on

imported petroleum. And last but certainly not least,

it has added to the economic diversity o the County by

creating new crops and jobs. | WATerrill Chang, P.E., is a Senior Solid Waste Engineer

or URS Corporation in Seattle, WA. Hehas 35 years o

environmental and mechanical engineering experience, and

has been involved in easibility studies, planning, design,

permitting and environmental impact assessment or landflls,

incinerators, transer stations, recycling and compost acilities

or government and private sector clients. Current projects

include several county solid waste management plans and

the design o two transer stations. Terrill holds degrees

in Mechanical Engineering rom MIT and Oregon StateUniversity and is a licensed engineer in Washington, Oregon

and Idaho. He can be reached at (206) 438-2596 or e-mail

[email protected].

Deanna Carveth is a Project Specialist IV or

Snohomish County Public Works (Everett, WA). She is a

21-year solid waste proessional, starting her career in San

Francisco packing small business and household hazardous

waste. Currently a project specialist, she manages the

Canola to Biodiesel project or Snohomish County, writes and maintains the FEMA approved Disaster Debris

Management Plan, assures compliance with NPDES

permits, is starting the Greenhouse Gas reporting program

and manages the groundwater modeling program or the

Countys closed landflls. Deanna can be reached at (425)

388-7607 or [email protected].

AcknowledgementsThis material is based on work supported by the

Department o Energy under award number DE-FG36-08GO88177. Standard disclaimer applies.The authors also grateully acknowledge the support

o Washington State Department o Commerces EnergyFreedom Fund and our private partners including WolkillFeed and Fertilizer, Whole Energy, and Snohomish Farmsincluding Sno-Valley Farms and Reiner Farms.

This paper was originally presented by Terrill Chang, URSCorporation, during WASTECON 2009 in Long Beach, CA.Excerpts and inormation rom that presentation are reproducedwith the permission o the Solid Waste Associate o North America(SWANA).

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2010 Waste Advantage Magazine, All Rights Reserved.Reprinted rom Waste Advantage Magazine.Contents cannot be reprinted without permission rom the publisher.

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