1. 2003 ASTSWMO State Solid Waste Managers Conference
An Introduction to Bioreactor Landfill Concepts and Design Concerns from a Regulatory Perspective
By: Robert J. Phaneuf, P.E.
New York State Department of Environmental Conservation Division of Solid & Hazardous Materials
Bureau of Hazardous Waste & Radiation Management
Albany, New York
Phone: (518)
Fax: (518) 1

2. 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

3. 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

4. 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: 4

5. Historical Regulatory Perspective on Bioreactor LFs (Then vs Now Or Lined vs Unlined )
Unlined condition prohibited regulatory acceptance of leachate recirculation.
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. 5

6. 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 %
Note: the above performance data is for the upper liner system only – overall performance of the double liner system is not calculated.
For more annual report data and info on NYS Landfills check out our “ftp” website at: ftp:// 6

7. 7 Optimum Waste Mass MC 40 - 70 %
> 50 % of MSW is Organic Material
Optimum Waste Mass MC %
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 % added airspace over Conventional LF = $$$$ 7

8. 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 ? 8

9. 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. 9

10. Regulatory Perspective on Landfill Bioreactors (What the Federal Regs say today)
40 CFR Part (a)(2) Liner requirement (restriction)
Only allows leachate recirculation if landfill is lined with a
standard, single composite liner system, as described in
Section 40 CFR Part (a)(2).
Means, no leachate recirculation on alternative liner systems approved by Directors of approved states.
40 CFR Part (a) Bulk liquid restriction applies.
Means that absolutely no bulk liquid addition to any landfill,
whether properly lined or not, thus restricting bioreactor
operations in arid states where leachate production is minimal. 10

11. 11 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 11

12. NYS’s 2/5/01 Notice to Landfill Owners/Operators on Bioreactor Landfill Concepts
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
Sent to all 27 MSW Lfs in NYS
Stressing need for Dept Approval 12

13. Thank you for listening. Questions
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 ?
Thank you for listening. Questions 13

14. Do we have enough leachate in NYS ?
Bioreactor Landfills Require:
Optimum Waste Mass MC %
Or, typically gallons of added moisture needed per ton of waste.
In year 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 MSW landfills generated just over 440 million gallons of leachate.
[Data from Calendar Year 2000 Annual Reports]
Individual landfill demonstration of need for additional moisture needs to be conducted. 14