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Alternative Liner Performance, Leachate Recirculation, and Bioreactor Landfills: Request for Information and Data

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Information about this document as published in the Federal Register.

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This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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AGENCY:

Environmental Protection Agency.

ACTION:

Request for information and data.

SUMMARY:

EPA is requesting comments and information on two issues related to the Criteria for Municipal Solid Waste Landfills. First, we need data and information on the performance of alternative liner designs compared to the performance of composite liners Start Printed Page 18015when leachate is recirculated. Provisions in the municipal solid waste landfill (MSWLF) criteria prohibit leachate recirculation at an MSWLF unless the unit has a composite liner as described in these regulations. Recently, various stakeholder groups (e.g., States, local governments, solid waste associations, and industry) have suggested that there are alternative liner designs that would work as well as, if not better than, the specific liner designs currently required by the criteria.

Second, EPA is also requesting data and information on the design and performance of bioreactor landfills. In recent years, bioreactor landfills have gained recognition as a possible innovation in solid waste management. The bioreactor landfill is generally defined as a landfill operated to transform and more quickly stabilize the readily and moderately decomposable organic constituents of the waste stream by purposeful control to enhance microbiological processes. Bioreactor landfills often employ liquid addition including leachate recirculation, alternative cover designs, and state-of-the-art landfill gas collection systems.

DATES:

EPA must receive your responses on leachate recirculation and alternative liner performance by August 7, 2000. EPA must receive your responses on bioreactors by October 6, 2000.

ADDRESSES:

See section I of Supplementary Information below.

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FOR FURTHER INFORMATION CONTACT:

For general information: Contact the RCRA Hotline at 800 424-9346 or TDD 800 553-7672 (hearing impaired). In the Washington, DC, metropolitan area, call 703 412-9810 or TDD 703 412-3323.

For information on specific aspects of this document: Contact Dwight Hlustick, Municipal and Industrial Solid Waste Division of the Office of Solid Waste (mail code 5306W), U.S. Environmental Protection Agency Headquarters (EPA, HQ) 1200 Pennsylvania Ave., NW, Washington, DC 20460; 703/308-8647 [HLUSTICK.DWIGHT@EPAMAIL. EPA.GOV].

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SUPPLEMENTARY INFORMATION:

I. Submitting Responses to This Document

How May I Respond to This Document?

What Information Should I Include in My Response?

What Will EPA Do With the Information You Submit?

II. What Will Be the Official Record for This Document?

How May I See Responses to This Document?

Where May I Find Information on This Action on the Internet?

III. What Is the Authority for This Request?

IV. Description of EPA's Current Municipal Solid Waste Landfill Regulations

V. Description of Current Regulations for Landfill Liners

Performance Standard

Design Standard

VI. What Are Existing Requirements for Leachate Recirculation?

Description of Technical Guidance for Landfill Design

Description of Concerns With Respect to Leachate Recirculation

VII. What Information Would EPA Like to Have About Alternative Liner Performance and Leachate Recirculation?

VIII. Concerns With Respect to Bioreactors

Information Needs With Respect to Bioreactors

IX. Conclusion

I. Submitting Responses on This Document

How May I Respond to This Document?

You may submit your information in hard copy (paper) or using electronic mail. All comments must reference docket number F-2000-ALPA-FFFFF. You should not submit electronically any confidential business information.

  • Mail: Please submit an original and two copies to: RCRA Docket Information Center, Office of Solid Waste (5305G), U.S. Environmental Protection Agency Headquarters (EPA, HQ) 1200 Pennsylvania Ave., NW, Washington DC 20460.
  • Hand Deliveries: Please submit an original and two copies of information to: RCRA Information Center (RIC), Crystal Gateway I, First Floor, 1235 Jefferson Davis Highway, Arlington, Virginia.
  • Electronic Submittals: Please submit electronic information through the Internet to: rcra-docket@epa.gov. Your responses in electronic format must also be indentified by docket number F-2000-ALPA-FFFFF. You must provide your electronic submittals as ASCII files and avoid the use of special characters and any form of encryption. You should not submit electronically any confidential business information (CBI). An original and two copies of CBI must be submitted under separate cover to: RCRA CBI Document Control Officer, Office of Solid Waste (5305W), U.S. EPA, 1200 Pennsylvania NW, Washington, DC 20460.

What Information Should I Include in My Response?

Your comments will be most effective if you follow the suggestions below:

  • Explain your views as clearly as possible.
  • Provide solid technical data to support your views.
  • If you estimate potential costs, explain how you arrived at the estimate.
  • Provide specific examples to illustrate your concerns.
  • Offer specific alternatives.
  • Refer your comments to specific sections of this notice or MSWLF criteria.
  • Be sure to submit your information by the deadline in this notice.
  • Be sure to include the name, date, and docket number with your submittals.

What Will EPA Do With the Information You Submit?

We will review all responses to this action as well as additional information in our own data base in considering whether to propose to revise the Criteria for Municipal Solid Waste Landfills (40 CFR part 258). EPA will not respond directly on an individual basis to those providing information to the Agency as a result of this action, but will address issues raised by the respondents in future Federal Register notices. In addition, all responses to this information request notice will be incorporated into the docket for any rulemaking proposals on the subject criteria.

II. What Will Be the Official Record for This Document?

The official record for this action will be kept in paper form. Accordingly, EPA will transfer all electronic submittals into paper form and place them in the official record, which will also include all responses submitted directly in writing. The official record is the paper record maintained at the RCRA Information Center (RIC), Crystal Gateway I, First Floor, 1235 Jefferson Davis Highway, Arlington, Virginia.

How May I See Responses to This Document?

All responses to this document are available for viewing in the RCRA Information Center (RIC), located at Crystal Gateway I, First Floor, 1235 Jefferson Davis Highway, Arlington, VA. The RIC is open from 9 a.m. to 4 p.m., Monday through Friday, excluding federal holidays. To review docket materials, we recommend that the public make an appointment by calling 703 603-9230. The public may copy a maximum of 100 pages from any regulatory docket at no charge. Additional copies cost $0.15/page.

Where May I Find Information on This Action on the Internet?

Information on this action, consisting of this notice and a fact sheet, may be found at the following Internet site: http://www.epa.gov/​epaoswer/​non-hw/​muncpl/​landfill/​leachate.htm. Start Printed Page 18016

III. What Is the Authority for This Request?

Any revisions to Criteria for Municipal Solid Waste Landfills (40 CFR part 258) will be made under Sections 1008, 2002 (general rule making authority), 4004, and 4010 of the Resource Conservation and Recovery Act of 1976, as amended. Revisions may also be made under Section 405 of the Clean Water Act which addresses the disposal of sewage sludge.

IV. Description of EPA's Current Municipal Solid Waste Landfill Regulations

As specified in the Resource Conservation and Recovery Act, the federal role is to establish overall regulatory direction through the provision of minimum nationwide standards for MSWLFs. On October 9, 1991, EPA issued revised Criteria for Municipal Solid Waste Landfills (40 CFR part 258; 56 FR 50978). These criteria establish minimum national performance standards necessary to ensure that “no reasonable probability of adverse effects on health or the environment” will result from solid waste disposal facilities. MSWLFs typically receive household waste, non-hazardous commercial, institutional and industrial waste, household hazardous waste and conditionally exempt small quantity generator (CESQG) hazardous waste. The criteria are implemented in one of two ways. The first, and preferred alternative, is that each State would implement the criteria after receiving approval by EPA of its municipal solid waste landfill permit program or other system of prior approval. The criteria contain provisions that allow States to develop and rely on alternative approaches that deal with site-specific conditions. Therefore, the actual planning and direct implementation of solid waste programs is principally a function of State governments and those owners and operators, including local governments, of MSWLFs, not the federal government.

The second alternative is that the program would be self-implementing by landfill owners and operators in those States that have not received EPA approval of their MSWLF permitting programs. In this case, the regulations provide less flexibility than for approved States. As of March 1, 2000, 49 states and territories had received approval of their programs and are implementing these regulations.

V. Description of Current Regulations for Landfill Liners

The criteria set forth two methods for complying with liner requirements for municipal solid waste landfills. The first is a performance standard and the second is a specific design standard.

Performance Standard

The performance standard is set forth in § 258.40(a)(1). Under this standard, a landfill owner or operator may rely on the design of their choice, provided the design ensures that the concentration values for the constituents listed in the following table will not be exceeded in the uppermost aquifer at the relevant point of compliance as determined by the Director of an approved State.

Table 1.—Concentration Values Not To Be Exceeded at the Point of Compliance

ChemicalMCL (mg/l)
Arsenic0.05
Barium1.0
Benzene0.005
Cadmium0.01
Carbon tetrachloride0.005
Chromium (hexavalent)0.05
2,4-Dichlorophenoxy acetic acid0.1
1,4-Dichlorobenzene0.075
1,2-Dichloroethane0.005
1,2-Dichloroethylene0.007
Endrin0.0002
Fluoride4
Lindane0.004
Lead0.05
Mercury0.002
Methoxychlor0.1
Nitrate10
Selenium0.01
Silver0.05
Toxaphene0.005
1,1,1-Trichoromethane0.2
Trichloroethylene0.005
2,4,5-Trichlorophenoxy acetic acid0.01
Vinyl Chloride0.002

The point of compliance can be no more than 150 meters from the waste management unit boundary and must be on land owned by the owner of the MSWLF (see 40 CFR 258.40(d)). The criteria require that in determining whether the performance standard is met, the Director of the approved State program shall consider the following factors in his/her determination:

1. The hydrogeologic characteristics of the facility and the surrounding land;

2. The volume and the physical and chemical characteristics of the leachate;

3. The quantity, quality, and direction of flow of ground water;

4. The proximity of and withdrawal rate of the groundwater users;

5. The availability of alternative drinking water supplies;

6. The existing quality of the ground water, including other sources of contamination and their cumulative impacts on the ground water, and whether the ground water is currently used or reasonably expected to be used for drinking water;

7. Public health, safety, and welfare effects; and

8. Practical capability of the owner or operator.

Design Standard

The second method for compliance with the criteria is to install a liner system that meets the specific design criteria described in 40 CFR 258.40(a)(2) and set forth in 40 CFR 258.40(b). Section 258.40(a)(2) states that the liner system must contain a composite liner and Section 258.40(b) defines a composite liner as a system comprised of two components:

1. An upper component consisting of a minimum of 30 mil flexible membrane liner (60 mil if high density polyethylene (HDPE) is used); and

2. a lower component consisting of compacted soil at least two feet deep with a hydraulic conductivity of no more than 1x 10−7 cm/sec.

We based this decision on a desire to ensure that leachate reaching the liner would be efficiently collected (56 FR 51056). The design standards require that the leachate collection system be capable of maintaining a hydraulic head within the landfill of 30 cm or less.

VI. What Are the Existing Requirements for Leachate Recirculation?

The liquid restrictions in Subpart C of Part 258 only allow leachate recirculation in MSWLFs that are constructed with a composite liner and leachate recirculation system as described in 40 CFR 258.28(a)(2). The recirculation of leachate is not allowed in landfills which have an alternative liner design even if the design meets the performance standard in 40 CFR 258.40(a)(1). At the time these regulations were promulgated, we believed MSWLFs needed a composite liner and leachate control system as described at 40 CFR 258.40(a)(2) to ensure that ground water would be protected.

Description of Technical Guidance for Landfill Design

EPA published a technical manual entitled “Solid Waste Disposal Criteria” (EPA530-R-93-017, NTIS PB94-100-450, Internet site: http://www.epa.gov/​epaoswer/​non-hw/​muncpl/​landfill/​techman/​) in 1993. Chapter 4 of this manual entitled “Design Criteria” sets forth additional guidance in the Start Printed Page 18017following areas: (1) Design concepts, (2) design calculations, (3) physical properties, and (4) construction methods. This chapter of the guidance document also addresses the following:

Designs Based on the Performance Standard

  • Leachate characterization and leakage assessment;
  • Leachate migration in the subsurface;
  • Leachate migration models;
  • Relevant point of compliance assessment.

Description of Concerns With Respect to Leachate Recirculation

Many MSWLF stakeholders (e.g., States, local governments, solid waste associations, and industry) believe that under certain conditions, leachate recirculation should be allowed when alternative liners are used. In fact, some believe that alternative liner technologies can be superior to the composite liner design specified in the criteria. We are trying to determine if it is possible to design and operate MSWLFs safely when alternative liner designs are used and leachate is recirculated. As required by the regulations, such an alternative liner design must assure that the performance standard specified at 40 CFR 258.40(a)(1) and the requirement to maintain a hydraulic head within the landfill of 30 cm. or less are met.

VII. What Information Would EPA Like to Have About Alternative Liner Performance and Leachate Recirculation?

We are interested in determining whether and which types of alternative liners are capable of meeting the design performance standard described above including maintaining a hydraulic head at acceptable levels.

More specifically we are seeking data and information on the following issues and questions:

  • Should EPA revise the MSWLF regulations to allow leachate recirculation when alternative liners are used, and under what conditions should leachate recirculation be allowed?
  • Should only specified alternative liner designs be allowed if leachate is recirculated?
  • When alternative liners are used, what would be the impact of leachate recirculation on leachate quality and quantity and attainment of the concentration values specified in Table 1 in ground water at the point of compliance?
  • Does EPA need to specify other requirements in the MSWLF Criteria to ensure that landfills that recirculate leachate when using alternative liners protect ground water and maintain the hydraulic head with the landfill at 30 cm. or less?
  • To what degree does leachate recirculation accelerate the stability of the leachate and the remaining decomposable solids in a landfill? How can EPA make a determination when a landfill is sufficiently stabilized?
  • Should EPA revise the technical manual? If so, how? We are particularly interested in information on how to advise owners and operators to characterize leachate and leachate leakage rates properly when conducting leakage migration modeling to demonstrate that a landfill which recirculates leachate meets the performance standard specified in 40 CFR 258.40(a)(1). For example, should we be suggesting different methodologies to quantify input parameters? Are there non-steady state situations that we should be addressing in the guidance? What are the effects of leachate recirculation on heavy metals in the leachate, and subsequently in the ground water? Should the groundwater models identified in this guidance be updated? If so, what models are appropriate?

VIII. Concerns With Respect to Bioreactors

Recent communications from MSWLF stakeholders indicate that there is a growing interest in bioreactor landfills. Bioreactor landfills represent a potential new approach to solid waste management. A bioreactor landfill can be generally defined as a sanitary landfill operated to transform and stabilize the readily and moderately decomposable organic constituents of the waste stream by purposeful control to enhance microbiological processes. While categorizations of bioreactor landfills vary, operational parameters often employ leachate recirculation, alternative cover designs, liquids addition to optimize moisture content in the waste, and state-of-the-art landfill gas collection systems. Bioreactor landfills have been operated under both anaerobic and aerobic conditions. Thus, the term bioreactor landfill is a management concept for MSWLFs encompassing a variety of MSWLF practices.

Information Needs With Respect to Bioreactors

At this time, EPA lacks adequate data and information on the design, operation, and performance of bioreactor landfills to evaluate this technology. We are unsure about the appropriateness of revising the MSWLF Criteria, as some stakeholders have suggested to the Agency, to allow for design and operation of bioreactor landfills (e.g., allowing the addition of additional liquids to municipal landfills to optimize waste degradation). Therefore, we are today seeking data and other information on the design, operation, and performance of bioreactor landfills. We are specifically requesting comment and data in the following areas.

  • The nature and scope of current bioreactor landfill projects both within the U.S. and abroad.
  • The impact (advantages and disadvantages) of leachate recirculation and liquids addition (with or without the addition of air) on leachate quality, waste settlement, waste slope and stability, and landfill gas yield.
  • Modifications that have been made to daily cover to optimize biodegradation.
  • Changes to final cover that have been made to optimize biodegradation or to incorporate materials which convert landfill gas to carbon dioxide and water. See, for example “Approaching Sustainable Landfilling,” Alexander Zach, et al.; and “Biological Pretreatment of MSW as a Measure to Save Landfill Volume and Deter Birds,” Florian Koelsch and Richard T. Reynolds, Proceedings of Fifteenth International Conference on Solid Waste Technology and Management, December 12-15, 1999, Philadelphia, PA. Proceedings published by Widener University School of Engineering and the University of Pennsylvania.
  • Additional monitoring requirements necessary to ensure that a bioreactor (with or without air addition) is functioning properly over the life of the landfill.
  • Approaches that have been taken to close bioreactor landfills and to care for the landfill during the post-closure care period to ensure protection of human health and the environment.
  • The potential public health, environmental, and economic impacts of adding liquid wastes, such as sewage sludge, grey water or animal feedlot liquid wastes to the MSWLF.
  • For bioreactors which have been operating in the aerobic mode, what methods have been used to provide for aeration and how to control temperature in the waste mass.
  • The appropriateness of liner designs different from the specific design described in 40 CFR 258.40(a)(2) when liquids are added to a MSWLF to enhance biodegradation.
  • Project economics for the design, construction, and operation of Start Printed Page 18018bioreactor landfills (with or without air addition).
  • The Clean Air Act Section 111(d) and greenhouse gas emissions impact of operating a municipal solid waste landfill as a bioreactor landfill, i.e., will the addition of air or liquids affect the ability of a landfill to comply with air regulations?
  • The comparative cost effectiveness and environmental benefits of the bioreactor landfill relative to managing segregated organic wastes through composting and placing non-compostable waste in a standard municipal landfill (i.e., one not operated as a bioreactor).
  • Are there management and safety issues associated with landfill gas generation and control at bioreactor landfills that need to be addressed in regulations or guidance?
  • Are there relevant patent issues associated with anaerobic, aerobic, or other bioreactor landfills of which EPA should be aware?

IX. Conclusion

After reviewing the literature on leachate recirculation, alternative liner designs, and bioreactor landfills and information and data received during this comment period, the Agency will make a determination concerning what future actions, if any, we will take on the issues discussed in this document.

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Dated: March 22, 2000.

Elizabeth Cotsworth,

Director, Office of Solid Waste.

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[FR Doc. 00-8400 Filed 4-5-00; 8:45 am]

BILLING CODE 6560-50-P