Are You Prepared to Close Your Ash Ponds?

R. Kent Nilsson, P.E.

Senior Consulting Engineer

TRC Environmental Corporation

Drawbacks of Learning by Trial and Error…

Drivers for Pond Closure

Regulatory requirements

Plant retirements

Changes to facility operations

Environmental liability management

Political/social pressures

Regulatory Requirements

EPA has agreed to take final action on Coal Combustion Residuals (CCR) by December 19, 2014

Revised RCRA Subtitle “D” standards are the most likely outcome

Likely to be implemented at state level

Closure also affected by Effluent Limitation Guidelines (ELGs)

Recent developments may influence outcome

Final rule likely to be litigated

Regulatory Requirements – Ash Ponds

Anticipated RCRA Subtitle “D” requirements:

Rule effective 6 months after promulgation

Ponds not meeting liner requirements must stop accepting waste within 5 years of finalization of rules

Groundwater monitoring required within 1 year after effective date

Ponds must be closed within 2 years of last receiving waste

Strategy

Mapping out a strategic plan must consider the questions:

Close now or later?

Future end use of property?

Close in-place or remove the residuals?

What are the costs?

Strategy

A Generic Decision Matrix

Strategy – Close Now or Later?

Dictated by:

Regulatory framework and its timing

Short and long-term risk profile

Retiring plant or continuing to operate

Changes to facility operating requirements (e.g. wet ash v. dry ash handling)

Costs and funding

Strategy – Close Now or Later?

Closure schedule affected by:

Regulatory requirements/deadlines

Future site use

Pond size

Ash pond assessment and preparation of design and bid package

Regulatory approvals

Strategy – Future End Use of Property?

Retiring plants need to clearly define

Prime redevelopment locations may require stricter clean-up

Site specific conditions (e.g., wetlands)

Ash geotechnical properties

Strategy – Close In-place or Remove the Residuals?

Viable market for pond material?

Long-term obligations?

Long-term environmental liabilities?

Future land use?

Sufficient on-site borrow material?

Construct on-site landfill?

Staffing demands/outside resources?

Political/social pressures?

Cost?

Need a Plan and Schedule

Risk Considerations

Planning for potential risks and liabilities:

Geotechnical evaluation

Environmental assessment (including risk assessment)

Social/political analysis

Landfill/pond closure design

Permitting

Construction engineering

Groundwater Investigation/Remedial Options

Groundwater Investigation – Likely required to ascertain environmental impact of existing unlined

ponds

– Investigation plan should take into account Point of compliance

Constituents of concern

Well placement

Well construction

Sampling protocol

Quality assurance/quality control

Background conditions

Remedial Options – Evaluate as warranted

– Incorporate into closure plan

Closure Considerations

Pond size

Dewatering requirements/methods

Final use considerations

Remediation integration

Constructability concerns

Health and safety

Site configuration constraints

Long-term maintenance

Pond Closure – Health and Safety

Dust control and monitoring

In-place Closure

Pros:

Generally less expensive than relocation to a lined landfill

Approach keeps haul vehicles off of public roads and highways

Proximate to existing facilities

If space-constrained, can be used as landfill base

In-place Closure

Cons:

Perceived “unknowns” in the final storage conditions

Increased social/political opposition to in-place closure, especially in environmentally sensitive areas

In-place Closure

May not be feasible in an environmentally sensitive or recreational area

In-place Closure Solutions

In-place Closure Solutions

In-place Closure Solutions

Pond Closure – Final Use Considerations

Solar farm

Closure by Removal Considerations

Beneficial reuse

Disposal in off-site Subtitle “D” landfill

Disposal in on-site Subtitle “D” landfill

Consolidation with ash in existing lined pond

Closure by Removal

Beneficial reuse opportunities:

Engineered fill*

Stabilized road base

Concrete admixture

Other

* Pending EPA ruling

Removal of Residuals

Beneficial reuse as a road construction material

Closure by Removal

Closure by Removal

Closure by Removal

Closure by Removal– Final Use Considerations

Closure by Removal

Ash dewatering using geotubes

Pond Closure - Constructability

Slope stability

Pond Closure - Constructability

Ash liquefaction

Construction costs

Ash volumes–actual conditions v. designed

Moisture content – don’t pay to haul water

Haul distances – keep them short

Double handling of material

Synthetic construction materials

Long-term monitoring

On-site landfill v. off-site commercial landfill

Leachate management

Questions/Comments?