An Introduction to Bioreactor LandfillConcepts and Design Concerns from a

Regulatory PerspectiveBy: Robert J. Phaneuf, P.E.

New York State Department of Environmental ConservationDivision of Solid & Hazardous MaterialsBureau of Hazardous Waste & Radiation ManagementAlbany, New York 12233-7258Phone: (518) 402-8594Fax: (518) 402-9025E-mail: rjphaneu@gw.dec.state.ny.us

2003 ASTSWMO State Solid Waste Managers Conference

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What is a Bioreactor?

EPA’s ORD proposed the following definition: “A landfill designed and operated in a controlled manner with the express purpose of accelerating the degradation of MSW inside a landfill containment system.” 2

What Defines A Bioreactor Landfill?(Wet Cell vs Dry Cell Operation)

In the simplest form, leachate recirculation into the waste mass will encourage enhanced waste mass decomposition (even if it is being done as a form of leachate management) .

In a more complex form, the sequenced addition of liquids and/or air in combination with other operational modifications with interest of optimizing waste mass decomposition.

Both forms of “bioreactor” operation raise similar regulatory concerns. 3

The Different Bioreactor LF Types

Aerobic - In an aerobic bioreactor landfill, leachate is removed from the bottom layer, piped to liquids storage tanks, and re-circulated into the landfill in a controlled manner. Air is injected into the waste mass, using vertical or horizontal wells, to promote aerobic activity and accelerate waste stabilization.

Anaerobic - In an anaerobic bioreactor landfill, moisture is added to the waste mass in the form of re-circulated leachate and other sources to obtain optimal moisture levels. Biodegradation occurs in the absence of oxygen (anaerobically) and produces landfill gas. Landfill gas, primarily methane, can be captured to minimize greenhouse gas emissions and for energy projects.

Hybrid (Aerobic-Anaerobic) - The hybrid bioreactor landfill accelerates waste degradation by employing a sequential aerobic-anaerobic treatment to rapidly degrade organics in the upper sections of the landfill and collect gas from lower sections. Operation as a hybrid results in the earlier onset of methanogenesis compared to aerobic landfills

Source: US EPA Website: http://www.epa.gov/epaoswer/non-hw/muncpl/landfill/bioreactors.htm

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Historical Regulatory Perspective on Bioreactor LFs(Then vs Now Or Lined vs Unlined )

Lined condition affords adequate groundwater protection - leachate recirculation conditionally allowed.

Liner performance data continues to be developed supporting that modern landfill liner systems are in fact working.

Unlined condition prohibited regulatory acceptance of leachate recirculation.

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How Well Are New York State’s Double-Lined Landfill Designs Working ?

From 2001 Annual Reports

(data on 29 Landfills)

Primary LCRS Flows:

Max: 6909 gpad; Min: 84 gpad; Mean: 1088 gpad

Secondary LCRS Flows:

Max: 87 gpad; Min: 0.5 gpad;

Mean: 8.3 gpad

“Upper” Liner System Efficiency:

Max: 99.97% ; Min: 94.5% ;

Mean: 98.8 %

For more annual report data and info on NYS Landfills check out our “ftp” website at: ftp://www.dec.state.ny.us/dshm/ 6

Note: the above performance data is for the upper liner system only – overall performance of the double liner system is not calculated.

> 50 % of MSW is Organic Material

• Optimum Waste Mass MC 40 - 70 %

Generally 25 to50 gallons of added moisture needed per ton of waste.• Do you have enough leachate ? [see slide 14 at end of this presentation]• Existing Landfill (retrofit) vs Initial Bioreactor Design Landfill• Bioreactors gain 15 - 30% added airspace over Conventional LF = $$$$

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The Merits of a Bioreactor Landfill

Conserves land resources by reducing the need for more

landfills. Can result in reduced long-term pollution potential of

waste buried in the modern lined landfill. Economic/Environmental advantages.

– Reduced leachate treatment/disposal costs

– Regenerated air space = savings

– Increased revenues from recovered biomass derived energy

Enhances LF end use options. Is such a landfill different from a conventional landfill ?

Not really ! Then why not ?

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The Push is On !!!

SWANA has established a Bioreactor Landfill Task Force to help promote/educate the industry on the movement, they are also consolidating data and information on bioreactor landfills to provide to EPA for future regulatory decision making.

US EPA in response to recent industry interest and requests for regulatory changes relating to Bioreactor Landfills has solicited for comments, held two Workshops, proposed various regulatory strategies and is developing guidance on the topic.

ASTSWMO has formed a Bioreactor Landfill Work Group to track and evaluate EPA’s progress toward regulatory revisions and development of guidance on the subject.

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Regulatory Perspective on Landfill Bioreactors(What the Federal Regs say today)

40 CFR Part 258.28(a)(2) Liner requirement (restriction)Only allows leachate recirculation if landfill is lined with astandard, single composite liner system, as described in Section 40 CFR Part 258.40(a)(2).

Means, no leachate recirculation on alternative liner systems approved by Directors of approved states.

40 CFR Part 258.28(a) Bulk liquid restriction applies.Means that absolutely no bulk liquid addition to any landfill, whether properly lined or not, thus restricting bioreactoroperations in arid states where leachate production is

minimal. 10

ASTSWMO WG Regulatory Issues Limited Data (Pilot Projects) Odors & CAA Emissions Fires (CO monitoring) Surface Seeps

Stability - Waste & Liner System Performance Criteria & Monitoring Operator Training Federal Tech Guidance is Needed

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NYS’s 2/5/01 Notice to Landfill Owners/Operators on Bioreactor Landfill Concepts

Sent to all 27 MSW Lfs in NYS

Stressing need for Dept Approval

Required that all leachate recirculation or bioreactor proposals address the following :

•Geotechnical Analysis

•Air Emission & Odor Control

•Leachate Mngt System Maintenance Plan

•Details for Leach. Induction - How & How Much

•Operations Plan

•Bioreactor Landfill Monitoring Plan

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Points to think about regarding Landfill Bioreactors(Concerns to be addressed to help promote bioreactor landfills)

• Predominant regulatory approach is still “dry tomb” LF operations.– Final cover requirements tied to last receipt of waste.

• No perceived problem with the “dry tomb” LF operation.

– Landfills are forever, how long will cover & liner systems last ?

• More information on effectiveness of odor and air emission control systems for LF bioreactor operations - to overcome negative public perceptions.

• More information on what works w/ respect to leachate induction.

• How do bioreactor landfills & ISWM goals mesh ?

• More information on bioreactor costs & savings.

• How do we monitor a bioreactor landfill’s efficiency; what indicates that a landfill’s waste mass has been effectively stabilized ?

• Will we be able to reduce the 30-year post-closure monitoring period for a

bioreactor landfill ?

13Thank you for listening. Questions

Do we have enough leachate in NYS ?

Bioreactor Landfills Require:

Optimum Waste Mass MC 40-70 %

Or, typically 25-50 gallons of added moisture needed per ton of waste.

In year 2000 - 27 MSW landfills in NYS accepted 9.3 million tons of SW.

In general if all these landfills wanted conduct bioreactor operations we’d need between 232 million and 465 million gallons of leachate.

In 2000 - 27 MSW landfills generated just over 440 million gallons of leachate.

Individual landfill demonstration of need for additional moisture needs to be conducted.

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[Data from Calendar Year 2000 Annual Reports]