This document discusses considerations for bioreactor landfill design and operation. It outlines key design factors such as liquid collection, stability impacts from liquid addition, cell geometry, final closure integration, and gas collection integration. Operational considerations discussed include available leachate, recirculation methods (ponding, spraying, wells), automation levels, and maintaining a water balance. Recommended changes to regulations include increased leachate collection design standards, allowing long-term interim closure, and permitting use of wastewater treatment liquids.

1. SESSION 3 - BIOREACTOR DESIGN and OPERATION
Landfill Design & Operation
Gregory Richardson, Ph.D., P.E.
US EPA WORKSHOP ON BIOREACTORS
FEBRUARY 27-28, 2003

2. Landfill Design & Operation
• Design Considerations
– liquid collection
– impact of liquid on stability
– geometry of cell
– integration with final closure
– integration with LFG collection

3. Design Considerations - liquid collection
• Increased potential for
clogging (no fabric, sands
or soil in flow path)
• Suggest designing for
reduced head to provide
increased factor of safety

4. Design Considerations - impact of liquid on stability
• Evaluate impact of
elevated head on
stability
• revision of
operations manual
to reduce potential
• limited designer
control

5. Design Considerations - geometry of cell
• Recoverable air
space?
• Long-term
interim cover
• Higher is
probably not
better

6. Design Considerations - integration with final closure
• Closure costs
exceed $100k/acre
• 180-days after
final waste
placement
• Drive for “todays
airspace”

7. Design Considerations - integration with LFG
collection
• Significant cover
penetrations
• Impact on
“recoverable air
space”
• Need for final cover?
• Ability to expand
vertically?

8. Landfill Design & Operation
• Operational Considerations
– leachate availability
– leachate recirculation methods
– degree of automation
– liquids balance

9. Operational Considerations - leachate availability
• Larger facilities
will actually run
out of leachate to
recirculate
• Need to allow
permitted use of
waste water
treatment liquids

10. Operational Considerations - leachate recirculation
methods
• Ponding
• Spray on working
face
• Vertical wells
• Horizontal wells

11. Operational Considerations - degree of automation
• Dramatic range of
systems - fully
automated to
manual

12. Operational Considerations - liquids balance
Start Date (Day 1):
• Need to maintain
Day Rain Max. Leachate Leachate Injection Problems/Weather
(Inch) Temp. Generated Recirculated Galleries (Use Extra Sheet if
Used Required)
1
2
water balance 3
4
5
records
6
7
8
9
10
• No current 11
12
13
requirements
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

13. Recommended Changes to
Subtitle D for Bioreactors
• Increase design requirements for leachate
collection systems - suggest design for
maximum head of 50 cm.
• Allow for long-term interim closure
• Allow for acceptance of municipal waste
water liquids (not sludge)