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Metcalf & Eddu_ X /, // An Air & Water Technologies Company

004609-0018-010-014

July 2, 1996

Mr. David J. Newton Remedial Project Manager USEPA Region I (HBO) JFK Federal Building Boston, Massachusetts 02203-2211

Subject: Contract No. 68-W9-0036 Work Assignment No. 18-1LA5 Rose Hill Regional Landfill RI/FS Landfill Mining Memorandum

Dear Dave:

As per your request, enclosed is a memorandum presenting information compiled by M&E related to Landfill Mining for your review prior to the July 10, 1996 meeting with RIDEM.

If you have any questions or comments, do not hesitate to call me.

Very truly yours,

METCALF & EDDY, INC.

Deborah M. Simone Project Manager

Attachment

cc: M. Dennen, RIDEM C. Hagger, M&E (letter only) D. Peters, M&E B. Wyskowski, M&E N. Bergeron, M&E WA#18-1LA5

30 Harvard Mill Square Wakeheld. MA 01880-5371 • Mailing Address PO Box 4071 Wakefield. MA 01880-5371

TEL 617-246-5200 FAX 617-245-6293

ROSE HILL LANDFILL MINING MEMORANDUM

July 1996

As per EPA request, a preliminary evaluation was performed to consider landfill mining as a

potential remedial option for the Rose Hill Regional Landfill. This memorandum presents

general information on landfill mining, application of landfill mining at Rose Hill, the phases

of a mining project, and a discussion of the advantages and disadvantages of landfill mining.

General Information on Landfill Mining

Landfill mining, also known as landfill reclamation, is a process in which non-hazardous waste

domestic landfills are excavated with the aim of separating and utilizing the waste, recyclables

and soil. The reclaimed land can then be reused as necessary. The goal of the project is most

often to extend the life of the landfill by removing some of the waste completely or just

repacking the waste to free up more landfill space. The excavated waste is sometimes used as

fuel for waste to energy plants, the recyclables may raise a modest revenue and the recovered

soil can be reused. The process has been in use since 1986 in at least four states Florida,

Pennsylvania, New York and Connecticut. Several advantages and disadvantages of this

technology are listed in Table 1.

In general, the landfill mining is a simple process. The equipment used primarily consists of

backhoes or excavators, dump trucks and various screening equipment. Initially the waste is

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Rose Hill Landfill Mining Memo July 1996

ADVANTAGES

Extend the life of the landfill by

increasing the amount of available

space.

Reduce the closure costs by reducing

the area of the landfill.

Transfer of waste from unlined

landfill to a lined landfill reduces

liability.

Reclaimed land may be converted to

other uses such as municipal

recreational parks.

Mined waste can be used as a fuel

supply for waste-to-energy plants to

produce electricity.

Recovered soil may be used as

landfill cover material, capping soil

or, if suitable, for off site fill.

Revenue may be generated from sale

of recyclable materials.

DISADVANTAGES

Not all landfills are suitable for

mining implementation.

Excavation may unearth hazardous

materials which could incur

expensive disposal costs.

Subsoil and groundwater

contamination may limit the

possibilities for land reuse or require

remediation.

Odors and landfill gases could be

emitted to the atmosphere and affect

the surrounding community.

Available screening equipment is not

made to handle the diverse physical

sizes and shapes found in landfill

waste.

Difficult working conditions

associated with excavating a landfill

and the changing weather conditions.

Possibility of contaminant release


sorted through a large bar screen, usually with 3-inch spacing to screen out the larger pieces

such as refrigerators, washing machines, etc. The piles are further classified using a trommel

screen. Further screening is used as necessary to attain a higher level of purity. Magnetic

drums may be used to help separate recyclable metals.

Issues of concern for landfill mining include: health and safety, contaminant releases and

working conditions. During excavation of a landfill, the possibility of unearthing a hazardous

waste or disease causing material is possible. Well trained workers are needed to conduct this

potentially difficult waste management. The issue of odor release is also a major concern for

the community.

The landfill mining process is comprised of two phases. Phase I is the pilot study/feasibility

analysis and Phase II is the excavation/waste separation process.

Phase I - Pilot Study

Landfill mining is a site-specific technology. The conditions at any given landfill dictate the

feasibility of using this process successfully. Since not every landfill is a probable candidate for

landfill mining, some information must be gathered initially and used to determine the

applicability of the technology to each particular site. This initial data gathering and analysis

is performed in the pilot study/feasibility phase.


The pilot study information gathering consists of historical reviews and onsite investigative

operations. Historical reviews would include such activities as reviewing landfill daily logs and

evaluating available aerial photographs taken over the lifespan of the landfill. The onsite

investigation would involve test pits and drilling down into the landfill to characterize the waste

and sample the soil. The use of test pits or drilling would depend on the depth of the waste

layer in the landfill. The number of test pits or boreholes would depend on the size of the

landfill and the degree of confidence that would be required to characterize the landfill.

Some of the information that would be obtained from these activities include: 1) the type and

quantities of wastes in the landfill; 2) the location and concentration of various wastes; 3) the

condition of the waste; 4) the depth of waste in all parts of the landfill; 5) the depth to

groundwater; and 6) the possibility of hazardous waste existing in the landfill.

This information would then be evaluated to determine if landfill mining is feasible at the site.

Some of the conditions that would present a significant obstacle to the success of landfill mining

include the presence of wastes below the groundwater table, the presence of hazardous waste,

and the possibility of releasing large amounts of landfill gases and objectionable odors.

Associated activities for the pilot study would include the preparation of a site health and safety

plan, an air monitoring plan, an operational plan and a hazardous materials management plan

in case a hazardous material or condition is found.


An economic evaluation is also performed to determine the feasibility of the technology. The

cost of the project is most likely to be the major decision making criteria for the implementation

of the process. A cost benefit analysis would compare the projected costs for the existing

landfill (such as a closure or a cap) with the costs associated landfill mining and the anticipated

savings (such as reducing the size of the cap needed or extending the life of an active landfill).

Markets and disposal for material to be excavated during Phase II would also be initially

identified during the pilot study phase of the project.

Phase II - Excavation

The results of the pilot study will dictate the next steps. If the project is deemed feasible, it may

continue into the excavation phase.

For the implementation of a full scale project, the health and safety plan, air monitoring plan,

hazardous waste management plan and operational plan from the pilot study would be expanded.

Equipment needed would include a backhoe or excavator, dump truck, and screening equipment.

The size and type of screening equipment would be determined by the information found in the

pilot study.


Landfill Mining at Rose Hill Regional Landfill

Landfill mining is being considered for the bulky waste disposal area at the Rose Hill Regional

Landfill. This 11-acre disposal area which contains an estimated 100,000 yd3 of material is

located east of the solid waste area and southwest of the sewage sludge area approximately 200

feet east of Mitchell Brook and 250 feet west of the Saugatucket River. This landfill was in

operation from 1978 - 1983. Solid waste was also reportedly disposed of during this period

between closure of the solid waste area and construction of the transfer station. Currently some

vegetation, primarily grasses overlying natural fill materials, provide cover for this area (M&E,

Final RI report, 1994).

A landfill cap is required for this disposal area and applying this technology to this site might

reduce the area of the landfill and thereby reduce the size of the cap needed. In order to

determine the conditions at Rose Hill's bulky waste disposal area, a pilot study would have to

be performed. The order of magnitude cost for performing this pilot study is estimated at

approximately $75,000.

Depending on the pilot study results and the goals of the project, the entire or a portion of the

bulky waste disposal area would be excavated. The material unearthed would be separated by

the screening equipment. Most likely the only material worth salvaging would be the soil which


could be reused for the capping process. For simplicity, it is assumed that the remainder of the

excavated waste would be transported to Rhode Island's Central Landfill.

Advantages to Landfill Mining at Rose Hill

Some of the advantages that could be expected from applying this technology are summarized

below.

• Mining this area might reduce the area size that would need the Subtitle D Landfill cap.

Reducing the size of the intended landfill cap would result in a capital cost savings.

• Mining would also recover soil which could be reused in the capping process. Again,

this would result in a reduced capital cost to build the landfill cap.

• A market may be found for the recyclable material and a small amount of revenue could

be generated.

The most important advantage to implementing landfill mining at this site is reducing the size

of the bulky waste disposal area and consequently the size of the landfill cap. However, it is

not certain whether or not this size reduction is possible. The ground water table is shallow in

this area and it is quite possible that much of the waste is below the water level. Excavating


below the water table would require dewatering measures. Dewatering a landfill with a

significant possibility of hazardous contamination would be very expensive. For the cap area

to be reduced, all the waste including that below the water table would have to be removed. The

excavation cost with any required dewatering and treatment measures could far outweigh the

possible cap size reduction savings.

Disadvantages to Landfill Mining at Rose Hill

Some of the disadvantages to applying landfill mining technology to Rose Hill are:

• Certainty in type and quantity of waste is not known. There is always a possibility that

hazardous materials may be encountered.

• Due to the high water table, it is most likely that dewatering and treatment of the liquid

would be necessary during excavation operations. Construction of an on-site treatment

plant to treat the liquid would be costly.

• Excavated recyclables or materials to be sent to Central Landfill would have to be rinsed

off to remove any residual accumulations on the material and this rinsate would require

on- or off-site treatment.

8


• All waste and any contaminated soil must be removed in order to reduce the area of the

cap required. Any wastes left behind would require a Subtitle D landfill cap. The high

water table may not allow all the waste to be excavated and consequently the size of the

cap would not be significantly reduced.

• Landfill mining does not have strong public support. Excavation of the landfill could

cause the release of and/or further migration of potentially hazardous materials or noxious

odors. Nearby residents are usually opposed to use of this technology for the purposes

of reopening the landfill for extended operations.

The primary goal of this project would be to reduce the size of the bulky waste disposal area.

However, several conditions exist that would inhibit the ability to achieve this goal. Since the

area is in a low lying region and next to a river, there exists a good possibility that one of these

inhibitory conditions would be a high water table. Without dewatering measures the possibility

of excavating all the waste, including that below the water table, is small. In addition to the

excavation problems is the high cost for treatment of liquids during dewatering operations.

Estimated Order of Magnitude Costs for Implementing Landfill Mining at Rose Hill

An estimate of the order of magnitude costs for conducting landfill mining at the bulky waste

disposal area is presented below.

Rose Hill Landfill Mining Memo Julv 1996

Activity Cost

Phase I - Pilot Study S 75.000

Phase n - Excavation Landfill Operations

Excavation/Sorting S 176.000(1)

Trammeling S 53.000(1>

Fuel $ 23.000(1)

Maintenance/Odor control $ 11.000U)

Refuse Transport $ 200,000 (1)

Administration/Compliance $ 27,000(1)

Central Landfill Tipping Fees $ 1,300,000

Groundwater Treatment Plant (100 gpm) $ 1,000,000

Subtitle D Cap S 895.000 (2)

(50% estimated reduction in costs) Total $ 2,865,000

These estimated costs are based on excavating an average of 2,478 yd3 per week for a total of

100,000 yd3 (Personal Communication Brooks Norris of Lancaster County Solid Waste

Authority, 1996; M&E, Final RI Report 1994). It is assumed that half of the excavated material

would be sent to Central Landfill (tipping fee is $52/ton; assuming 2 cu. yd. = 1 ton). It is

assumed that dewatering will be necessary five (5) days a week and ten (10) hours a day for

forty (40) weeks and liquid from dewatering operations would be treated on-site using a

groundwater treatment plant. For estimating purposes, it is assumed that the size of the cap will

be reduced by 50%. Thus, the cost of $1,079,000 for a Subtitle D cap as estimated for coverage

of the waste disposal (approximately 7 acres) may be considered to be reduced by 50%.

10


(1) Personal Communication Brooks Norris of Lancaster County Solid Waste Authority, 1996

(2) M&E, preliminary calculations of Subtitle D cap costs.

Conclusions

The estimated cost to implement the landfill mining project at the bulky waste landfill is

approximately $2,865,000 while the estimated cost to install a Subtitle D landfill cap in the

existing bulky waste landfill area is approximately $1,079,000 (M&E, preliminary calculations).

Based on these order of magnitude cost estimates, applying landfill mining technology at this site

may be less than economical. The benefits which may result from mining the landfill (reducing

the size of the cap) do not overcome the costs associated with implementing this technology.

Therefore, landfill mining the bulky waste disposal area at Rose Hill Regional Landfill does not

appear to be a cost effective technology. In addition, community concerns may also discourage

consideration of this as a possible remedial technology for screening in the Rose Hill Regional

Landfill Draft Final Feasibility Study. Based on the information presented in this memorandum,

it is recommended that landfill mining be eliminated from future consideration as a remedial

option for the Rose Hill Regional Landfill.

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