203360

ASSESSMENT OF THE OTA ALTERNATIVE FOR REMEDIATION OF THE ONSITE AREA OF LIPARI

Introduct ion

We have reviewed the Congressional Office of Technology Assessment (OTA) report entitled "A Review of EPA's Decision Under the Superfund Program for an Onsite Cleanup of the LiPari Landfill". The approach as outlined in OTA's report would consist of the following sequential steps:

1. Dewatering of the contained or "onsite" portion of the LiPari site

2. Enhanced volatilization

3. Partial excavation of contaminated materials

4. Backfilling of the excavated area with clean(ed) soil

5. Onsite treatment () of the excavated contaminated materials

6. Flushing of the contaminated soil

This approach is estimated by OTA to cost approximately $65 million. The advantages associated with this increase in cost over the $8.9 million batch flushing alternative selected by EPA in the Record of Decision (ROD) are reported by OTA to be a decrease in the time required for clean-up of the site (estimated by OTA to be 5-7 years as opposed to the 15 years for the selected flushing alternative) and an increase in reliability, effectiveness, and certainty of the remedy.

Our comments concerning OTA's approach are organized to address the six sequential steps which comprise this approach.

o o •~v; . a> rH o J 0 . I o 1 272429 125 iiiiiiiinininiiii 1. Dewatering of the Containment

As outlined in the "Final Draft Report - Onsite Feasibility Study for LiPari Landfill" (FS) prepared by the REM II team and dated August 1985, dewatering of the Upper Cohansey within the containment system is a feasible step. This conclusion was reached based upon the results of the hydrogeologic investigation of the LiPari Landfill in February and March 1985 and the successful extraction of over one million gallons of leachate from the containment by IT Corporation during September and October 1984. The major cost components for completing this step are as follows:

o Capital costs for extraction wells, holding tank, prefabricated building and contingencies: $920,000.

o Operation and maintenance costs including personnel, power, vapor- phase carbon, and off—site treatment of one pore volume at a per­ mitted industrial facility: $880,000.

o Total cost • $1.8 million.

Dewatering time was estimated in the Feasibility Study at 6 months utilizing 10 extraction wells at a combined rate of 40 gallons per minute. This time period could be approximately halved utilizing 20 extraction wells at a combined rate of 80 gallons per minute without suffering yield loss in the extraction wells or pressurizing the containment system. This analysis is presented in more detail in later sections of this report which address flushing.

2. Enhanced Volatilization

After an initial site dewatering, OTA proposes using an enhanced volatilization technique to extract volatile organics from the landfill prior to the commencement of the proposed partial excavation. This

±2ti 2 126 technique would utilize a combination forced air/vacuum system to extract the volatile organics and other gases and direct them to an on-site treatment system, presumably a vapor-phase carbon adsorption unit. OTA did not provide any details as to (1) the estimated costs for such a system other than to note it is "relatively inexpensive" or (2) the time period over which this system would be required to operate to extract enough volatiles before beginning excavation. Our comments concerning this system are:

Based on experience with enhanced volatilization at a site in California, this technique was demonstrated to be effective in collecting compounds which volatilize at ambient temperatures in homogeneous soil. The effectiveness is dependent on establishing a "central flow path" consisting of air extraction and air inlet wells installed just above groundwater. The system as proposed will be operated at a negative internal pressure. Theoretically, a concentration gradient could be created by displacing the equilibrium gradient such that, in time, groundwater contaminants would also be volatilized into the soil and similarly be extracted by the wells.

Enhanced volatilization has also been applied at three California sites with demonstrated recovery rates of 1 to 2 pounds per day, 25 pounds per day, and 200 pounds per day, respectively. However, these systems have been used at industrial sites where the toxic compounds are well defined and limited in number in homogeneous soil, unlike the conditions at LiPari where a wide variety of chemical compounds exist and the fill material is heterogeneous.

Other experience to date has mainly revolved around two pilot systems. In one field experiment a homogeneous sandy soil in the unsaturated zone was contaminated with "low" concentrations of volatiles. After 17 weeks of operation over 99 percent of the volatiles were reported to have been re­ moved. In the second field demonstration a sandy soil in the unsaturated zone was contaminated with "high" concentrations of volatiles. In this instance "good" recovery was achieved after 12 months. Costs for using this technique over a 10 acre site were estimated in the $100,000-5200,000 range excluding a vapor recovery/treatment system.

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127 Although enhanced volatilization appears promising there are uncertainties regarding the length of time that such a system would be operated to effectively minimize risks during any excavation event at LiPari. In California, the systems researched have been designed to be coupled with groundwater treatment. However, the benefits of- implementa­ tion are questionable with respect to the time required to significantly decrease public health risks or reduce contaminant levels prior to excavation. If an enhanced volatilization system were to be coupled at the LiPari site with the groundwater treatment (i.e., flushing) system, then the operation of the two media treatment systems could be conducted concurrently. A combined treatment system may improve the overall cleanup by maximizing the removal of contaminants within the two media of transport.

Implementation of an enhanced volatilization system may reduce the amount of risk encountered during excavation at LiPari. Some of the volatiles currently within the interstices of the landfill would be removed and therefore not be dispersed as the landfill is opened and excavated. This is particularly important with regard to generated within the site which during an excavation process would give rise to concern about fire and/or explosions. It is anticipated that some volatile compounds will not be removed by the enhanced volatilization process and therefore still be made available to the atmosphere as the landfill material is disturbed through excavation. This release of volatiles will be greatest in those portions of the landfill where, because of short-circuiting or channeliza­ tion due to the heterogeneous makeup of the fill, volatile organics have not been removed by the enhanced volatilization process. The quantity of these volatiles and associated health risks to on-site workers and the nearby residents cannot be accurately defined because of the varied nature of the materials disposed at the LiPari landfill during the 13 year operating history. Accordingly, at the time of excavation, measures to reduce the amount of volatilization must be implemented. Several techniques are discussed in the following section.

128 The capital cost to install an enhanced volatilization system at LiPari with a battery of thirty-six 6-inch PVC wells, varying from 20 to 35 feet deep at the minimal spatial distances of 100 feet apart would be approximately $150,000-$200,000. Additional costs for a vapor phase carbor recovery system utilizing granular activated carbon to treat the contaminated air prior to discharge to atmosphere is estimated at $100,000 resulting in a total cost estimate of $250,000 to $300,000. This estimate does not include operating and maintenance costs which would be dependent principally on carbon replacement requirements to meet ambient air quality criteria.

3. Partial Excavation of the Containment System

The OTA report recommends, that only a portion of the LiPari Landfill be excavated and subsequently treated on-site, based on the assumption that only about 6 acres of the total 15 acre LiPari site was used originally as a landfill. Furthermore, OTA states "enough is known about the movement of the underground water to estimate what parts of the site area might be highly contaminated." "It should be possible to establish criteria for certain key contaminants so that areas with higher concentrations can be designated for excavation."

Extent of Onsite Contamination: Examining this approach, the spatial distribution of LiPari's "indicator contaminants" may be utilized to ascertain which portions of the containment system are in fact con­ taminated. As noted in the Onsite Feasibility Study (FS), 13 indicator compounds were selected for the LiPari site based on concentration, mobility, and toxicity. These compounds were: bis (2-chloroethyl) ether; 1.2, dichloroethane; methylene chloride; toluene; benzene; phenol; chromium; nickel; lead; mercury; selenium; arsenic; and silver. Table 1 and Figure 1 indicate the distribution of these contaminants within the 15 acre containment system.

It is apparent from the information presented that the extent of con­ tamination is more widespread than the original six acre landfill. Each of

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FIGURE LIPARI LANDFILL CDM GLOUCESTER COUNTY, MONITORING WELL LOCATION rnj»n»u'ryw NEW JERSEY '' lot 131 the eight interior Cohansey wells for which analytical results are available indicates concentrations of bis (2-chloroethyl) ether well abov background. Additionally, it is also apparent from viewing the well sere locations that the contamination is no longer confined to the original waste trench depth which had been reported at 15 feet (JRB, 1984).

Surface elevations within the reported areal limits of the buried waste a currently approximately 138 feet atove Mean Sea Level (MSL). The elevati at well C-5 prior to construction of the encapsulation system was reporte to be approximately 135 feet (MSL). Allowing 3 feet for cover material, is postulated that the top of the landfilled material occurs approximatel at an elevation of 132 feet (MSL), although this is not documented other than in the boring log for well C-15 where trash was encountered at eleva tion 130 feet (MSL). Given that wastes were landfilled in trenches at depths up to 15 feet, the bottom of the original gravel pit prior to use . waste disposal site occurred at an elevation of approximately 117 feet (MSL). This logic appears reasonable in light of the fact that groundwat< can be found at about this elevation and it is reasonable to assume that excavation of the sand and gravel was halted once groundwater was en­ countered. The screen elevations in the interior Cohansey monitoring well C-10a and C-25a, are set at an elevation approximately 20 feet below the postulated depth of the originally landfilled materials. From this in­ formation it is apparent that contamination is present well below the six acre "source".

To summarize, within the containment system contamination is no longer limited to the six acres originally landfilled. Contamination is more widely spread and occurring at depths greater than the reported 15 feet of the original borrow pit trenches. The waste material landfilled included approximately 3 million gallons of liquids deposited between 1958 and 1971 After such an extended period of time, during which natural flushing mechanisms have been ongoing, contamination is presently spread beyond the original landfill area such that the effectiveness of excavating the actua landfill to alleviate the "bulk" of contamination is questionable. In light of the widely varying rate of decomposition and leaching character­ istics associated with debris typically discarded in a municipal landfill,

6 132 a determination as to whether or not a majority of the contamination still resides within the originally landfilled material is speculative. There­ fore, OTA's contention that "far less flushing would be necessary [with the OTA alternative] than in the [EPA] selected remedy because most of the contaminated soil and waste would have been removed and treated" is questionable.

Excavation Techniques: Excavation of the original landfill would result in significant health risk impacts. The major concern is the release of volatile organics during excavation of the landfilled material and soil. Opening of the landfill would give rise to concerns about health impacts on the nearby residential community due to the transport of toxic volatile organics off-site from the volatilization of chlorinated solvents from the open excavation. Because of the heterogeneous material within the landfilled area, it is unlikely that the volatile organics can be reliably removed by an enhanced volatilization technique. Further, excavation of the original landfill would be expected to result in the release of odors associated with anaerobic decomposition. The odor is expected to be comparable to "leachate odor" in character and will be especially strong luring the summer months.

More important than the issue of nuisance odors is the concern that during the excavation methane gas will be encountered, resulting in the associated risk of fire and explosion. Two fires and one explosion were reported to have occurred during landfilling operations (Chemical Manufacturers Association, 1980). According to this source, in 1969 a fire occurred at the site following an explosion which occurred as workers were in the process of dumping a drum. The landfill and the trailer being used to haul waste caught fire. It took two hours to bring this fire under control. It is also noted according to this source, that three barrels of explosive material are believed buried in the landfill. Apparently a second fire started when a bulldozer, in the process of compacting the waste materials, hit one of the drums which then exploded.

7 133 One technique which could be utilized to reduce the concerns about volat: organics and methane gas is the use of the enhanced volatilization tech­ nique previously discussed. The release of volatile organics is antici­ pated to be a recurring problem in spite of enhanced volatilization beca- of the uncertainties as to how effective this technique would-be in a landfill situation. Another technique would be to only open small portic of the landfill at a time, thus reducing the surface area for volatiles t escape. Nevertheless, some volatilization would be expected to occur. A third technique could be the use of an air-supported structure placed ove the open excavation. This would ostensibly halt the release of volatile organics to the outside atmosphere, however, it would add to difficulties during excavation as documented in the FS and could present safety proble associated with the concentration of methane gas. A fourth technique WOL be to excavate only during those periods of the year when ambient tempera tures are low, such as during the winter, since emission rates of volatil are temperature dependent and much lower in colder weather. A fifth technique would be to excavate only during favorable wind conditions wher. the wind is blowing away from the nearby residences. However, none of these techniques are considered practical to implement based upon con­ struction contractor continuity problems and required implementation time

Excavation Time: The time for excavation is dependent upon the excavatio technique employed and number of personnel and equipment committed to the project. For estimating purposes it is assumed that one backhoe operator outfitted in appropriate personal protective gear could fill a 20 cubic yard box container with contaminated soil and debris at an average rate c one per hour. If six acres of the site are to be excavated to an average depth of 15 feet, approximately 145,200 cubic yards of material will be removed. This would require approximately 2 years assuming 10 work hours per day, 365 days per year. At 10 hours per day and 250 days per year th time would be extended to about 3 years. If excavation were to proceed only during the winter months, within the confines of an air-supported structure, or within the limitations of a small working face these estimates would have to be increased accordingly. Likewise, if excavatio; were only to proceed when the winds were favorable (from the northeast, east, or southeast) the time required for excavation would also increase.

8 134 Utilization of additional resources could decrease the excavation time, however, the advantage of this would be limited by the feed rate to an onsite incinerator. Exceeding the incinerator feed rate would not be appropriate because of the the need to stockpile the excess hazardous material onsite and suppress the release of volatile organics- and leachate drainage.

Excavation Costs: Costs for the excavation of hazardous materials in the FS were estimated at $10.50 per cubic yard assuming Level B protection and no "special techniques" for excavating the landfill. Considering 145,200 cubic yards are to be removed, the cost for excavation of the six acre original landfill is approximately $1.5 million. These costs as well as the time required for excavation would increase should landfill debris requiring excavation be encountered at a depth below the estimated limit of 117 feet (MSL). Deep excavation would either have to proceed utilizing 2:1 side slopes or by utilizing sheeting to keep the excavation open and prevent cave-ins. Should sheeting be proposed, a geotechnical evaluation of impacts on the integrity of the nearby containment wall would be required. Employing a 2:1 side slope technique may result in a portion of the landfilled material either not being removed because of close proximity to the containment wall or removal of a portion of the wall thus compromis­ ing the integrity of the containment.

Excavation Health Risks: The health risks associated with the excavation alternative are to the nearby residences and the on-site workers. The magnitude of the health risks cannot be accurately defined at this time due to the heterogenous nature of the landfilled material. The risks due to the release of volatile organics can only be estimated based upon previous air sampling results collected in the contaminated marshland and from the on-site air vents during the Off-Site Remedial Investigation activities. However, it is anticipated that the results of these samples exhibit only a small fraction of the volatile organic compounds which would be released under an excavation option.

Another basis for estimation lies within the boring logs for well C-5 which was drilled well within the reported limits of the original landfill. From this log (Attachment 1) it is apparent that large quantities of non-methane

9 135 Attachment 1

Subject Lipari Landfill Job No. 8077 _Boring No. C-5 Location Pitman. New Jersey ^Classified by JHB Sheet 1 of 3_ Contractor Geo Facts/Empire Dri1ler R. Loqel Ground Surf. Elev. 13A.9 Method of Advancing Boring Hollow-stem augers Static Water Level 18.8 Date Started 3/16/81 Date Completed 3/17/B1

II Uc 0> 0> w u fc. c Sediment. 3 Construction Blows per Si Description and Details °U Z 3 6 In. Classification and Bemarks

a TI Q. r t 5' «3 a e I n -U 1 "» Medium Sand rill; orange-brown, layered. 17 SP Ui— A> above 2.0': OVA inn

SP Sample S2: 1" re­ covery 1? 131 4.5': Medium Sand Till: yellow- SP brown, green stained. 5.0*: WCC-S3 iTo

iTF 7.0': encountered SP As above bent nail 12B 1? 8.0': OVA 12 9.0': encoantered SP As above metal fragments i7fe 125 iA 11.0't WCC-S6 SP As above HA­ bB Sample 7: photo 12 7A UL 17 Medium Sand rill: black and light SP 13.0': OVA 121. >B 19 brown, mixed in 1/10" Sample 6A: layers. 38 Ill—

75 SP 120 65 As above 118 119 >A 51 11 SP Medium to Coarse Sand rill: light 17.0'i WCC-59 118 >B 31 brown, faintly banded, '•

100/4" 16 U° 136 ii* Attachment 1

Subject Lioari Landfill Job No. 8077 _Boring No. C-5 Location Pitman. New Jersey _C1assified by JH3 _Sheet 2 of 3_ Contractor Geo Facts/Empire Ori11er R. Loqel Ground Surf. Elev. 134.9 Method of Advancing Boring Hollow-stem augers _Static Water Level 18.8 Date Started 3/16/81 Date Completed 3/17/81

* u c & o> u W L. Sediment Q Construction k. i. t sV Blows per Description end W Details SiD 3 b V In. Clsssificstion V. and Remarks O Z c • "0 O • a -> c c. U > ¥ a « cL. O w V u s 111. 11A Medium Sand fill; light-brown, /, 20.0': moist soil -21 SS 20 SM moist. H begins 65 -114- 111 21.0*: OVA; WCC- -22 9C 61 22.5'i Fine to Medium Sand Till: 12n IB 55 dark grayish-green and 21 SK brown, silty, with 1/4* 121 35 24 31 clayey bands. 131 15 16 SM As above 13! 17 17 14 12 JJ 14 SM IB 27.5'» Fine Cravel Fill; dark 25.0'i WCC-S13 Ji 18 green chemical staining. 2B.0'; MLS Tube; ISA® OVA; photo of 29 18 SM Fine Sand Filli alternating brown,] ft SI 3. 106 151 12 ysllw, and orange, some Ifl 31.0*: WCC-S16; 3C 2! ailt and clay. _ t 1614 12 Ji 20 SM Medium Sand Pillt deep orange- 17 nzz 16! Iron staining. ll.S'i OVA 19 Ji 33.0't MLS Tube ns 171 31.75*1 Median Band: orange-brown, 32-34*1 S17 21 occasional fine gravel, Ji 24 ;p i—112. 17! ?1 hooKigeneous. 26 10L. IB; 3! 24 5M in: IB! 35.5*1 Mediin_Sand; as above, sore] 3£ ailty. 191 V 24 SM Fine Sandi alternating 1/2* bands 3«X 1". 20 slot 19! of orange-brown and orange] )< 13 gray, silty. 201 39 24 ;M 201 As above 4C ji ot 137 1 ^ Attachment 1

Subject Lipari Landfill Job No. 8077 _Boring No. C-5 Location Pitman, New Jersey _Classified by JMB Sheet 3 of 3 Contractor Geo Facts/Empire Driller R. Loqel Ground Surf. Elev. 13A.9 Method of Advancing Boring Hollow-stem auoers Static Water Level 18.8 Date Started 3/16/81 Date Completed 3/17/81

1 C c0 0 • *> c 1* k1 m Sediment u Construction k. w c S 9 « 4J Blows per >» Description end u Details e It Si k* • *4 0 u 6 In. I1 ClassiIication U Wi and Remarks • O Z > uses w4 c X 0 m *> 0 X 8 a > 0 K u i a «e a W O E a O u an to X 95 8 2 It 41.0': Pine Send; dark gray, aone 41 9 17 SH 41.5': WCC-S21 94 tilt, little clay, 11 -7" 21E occasional 1/2" clay bands. * 4? 42.0'; OVA 93 B 22t / 43 9 6 SH 92 14 Lr ' 22B 44 7* .-1 A 91 [/ f 8 23 A-tT / 9 12 SM * 45.5'i Photos of 'lr1 A 11 (/ t 523 hn 4m' <( i i; KH 45.5': Silty Clay; dark gray. 'Tf '^ / HQ 9 4 24; compact, cohesive. \ f 47 11 •i*- A 47.0': Photo of Bfi 22 HH / / 13 t ~524 241 UV' t 48 14 t 47.5*1 VCC-S24 R7 As above V t 48.0' 2S; 'r> J 49 24 KH OA Undist. 24 y 25! SO es /•/ > 4 TD at 50.0' .

•

1

• -na - —r»--> volatiles were encountered within the landfill. Total non-methane volatile organics were noted during installation of this well at 1,000 ppm with 200+ ppm constituting benzene and 200+ ppm constituting styrene. The Threshold Limit Value - Time Weighted Average (TLV-TWA) for benzene as reported by the American Conference of Governmental Industrial Hygienists is 10 ppm. This is the time-weighted average concentration for a normal 8-hour workday and a 40-hour workweek to which nearly all workers may be repeatedly ex­ posed, day after day, without adverse effect. The Threshold Limit Value Short Term Exposure Limit (TLV-STEL) for benzene is 25 ppm. A STEL is defined as a 15-minute time-weighted average which should not be exceeded at any time during a work day. The TLV-TWA for styrene is 50 ppm and the TLV-STEL for styrene is 100 ppm. Therefore, for both benzene and styrene both the TWA and STEL air guidelines were exceeded. It should also be noted from this well log that the concentration of volatiles increased in magnitude by two to three times when the soil was disturbed.

A preliminary screening analysis was prepared to assess the possible impacts of excavation of the original six acre LiPari landfill. This analysis consisted of air quality screening modeling using the Industrial Source Complex Long Term (ISCLT) Dispersion Model. The purpose of the analysis was to assess the potential for significant impacts to the offsite public from the volatilization of organic compounds during excavation at the site.

In order to prepare this analysis, a number of assumptions were required. The emission source is based on a single measurement of a well core sample emission rate taken in the field. From this sample, an assumption was made of an instantaneous and continuous emission rate based on a concentration of 200 ppm benzene and 200 ppm styrene in a fixed volume element (flux box). This resulted in an assumed continuous emission rate of 2.16 grams/second for benzene and 3.96 grams/second for styrene. This emission rate was integrated over an assumed working surface area during excavation of 400 square feet (20 ft. by 20 ft. square area) to provide the area source incorporated Into the ISCLT model. The modeling assumptions are given in Table 2 below:

. ^ n 11 139 TABLE 2

Assumptions for ISCLT Modeling

1. ISCLT area source model used removing the limitation preventing the calculation of concentrations at receptors within 100 meters of the source.

2. Meteorology consisting of a screening joint frequency distribution of wind speed, stability class and wind direction.

3. Mixing depth of 50 meters.

4. Ambient temperature of 72°F.

The results of this analysis are summarized in Table 3:

TABLE 3

AIR ANALYSIS RESULTS (ug/trT)

Benzene Styrene Receptor Recommended Recommended Location Concentration AAL* Concentration AAL*

Fenceline east 12,326 100 16,490 716 of Chestnut Branch

Howard Avenue 782 100 1,046 716 Home #1

Howard Avenue 683 100 915 716 Home #2

•AAL Acceptable Ambient Level. An AAL is the contaminant concentration which is considered to be an acceptable average concentration at a receptor on an annual basis. These values are developed as guidelines to safeguard receptors against potential chronic effects resulting from continuing exposures. Source; New York State Air Guide -1, "Guidelines for the Control of Toxic Ambient Air Contaminants 1985-1986" by New York State D.E.C.

12 140 From this analysis it can be seen that in all instances the predicted concentrations of benzene and styrene exceed the recommended AAL con­ centration limits at the receptor points. The use of recommended AAL values is consistent with evaluating public health hazards relative to remedial action alternatives proposed for sites.

The point of this assessment is not to imply the absolute certainty of a health hazard to the residential community should the LiPari landfill be excavated. Rather, its usefulness is to note that under this scenario the 1% TLV was violated. Because this value was exceeded simply magnifies the need for more data to assess the potential health risks prior to opening of the landfill via excavation.

4. Backfilling of Excavated Areas

Considering that removal of the six acre original landfill results in only partial site remediation, the remaining contaminated soil will be treated by flushing. This requires restoration of the containment system. The overall cost estimate for this portion of the OTA alternative including the cost for backfilling the excavated area with clean(ed) soil, restoration of the liner, grading and seeding is 1.3 million.

5. Incineration of Excavated Materials

A major difference in the remedial action proposed for the LiPari site by EPA and OTA focuses on the onsite treatment technologies. EPA has proposed and documented within the Record of Decision the use of a "batch-type" flushing of the entire (15.3 acres) containment system. OTA has agreed with the use of a flushing technique on a reduced scale (9 acres) but has preceeded flushing with the excavation and incineration of the original six acre landfill volume as their "possible cleanup approach."

The approach proposed by OTA employs the use of an onsite mobile incinera­ tor which would eliminate the cost and risk associated with the trans­ portation of hazardous materials to an off-site disposal facility.

A . 13 141 The following is an evaluation of on-site incineration as proposed by OTA.

o Applicability of the Shirco Furnace Concept

*

The Shirco furnace was originally marketed for application in the of sewage sludge (incineration) and granular activated carbon (reactivation). The Shirco system design and operational experience to date, therefore, has primarily dealt with feed materials which were relatively homogeneous, semi-fluids which could be fed to the processing belt in an even layer. Clearly, reclaimed landfill refuse will have to be processed for size reduction to be suitable for feeding to the Shirco unit. The shredding/classification for hazardous landfill material will be difficult and is technically untried for such a feed material. This represents high cost and technical uncertainty regarding the feasibility of this type of incineration equipment for the LiPari Landfill application.

The Shirco furnace concept was developed to operate such that the hot gases generated by of the waste materials which are fed to the furnace will pass over the incoming (wet) feed. By this means, a portion of the needed to dry the feed (a necessary step prior to combustion) is supplied by the waste itself. This energy recovery concept is very reasonable when regenerating carbon. However, when the material being fed to the furnace is or can be hazardous, the "benefit" of energy conserva­ tion and operating cost ( use) reduction is lost since the exhaust gases will strip volatile, hazardous substances from the incoming feed under conditions where the temperatures are too low to ignite and burn the gasified materials. Thus, the cool off-gas drawn from the feed end of the Shirco unit must be reheated (by burning fossil fuel in an afterburner).

14 142 The Shirco system experience to date has been in relatively small units. The 100 ton per day system now reported to be under con­ struction by the Shirco Company represents a very substantial scale-up and can be expected to require a significant period of testing, "debugging" etc. before it can be considered "available technology". The many problems which can be forseen in processing the reclaimed refuse raises significant questions as to whether the LiPari site is a proper application of the technology. For example, in sludge or carbon service, the bed is stoked with a rotating "paddle-wheel like" member mounted transverse to the belt. For refuse, one can extrapolate from similar trial burns of shredded refuse in multiple hearth furnaces [eg. in Concord (Contra Costa County) CA] where wire, steel banding etc. wrapped around the rabble teeth and required frequent maintenance shut­ downs. Also, the highly abrasive nature of refuse ash may be expected to greatly increase the replacement frequency of the metal mesh belts used by Shirco.

In summary, the scaled-up Shirco facility has not been demon­ strated in the field. It is presently in the developmental stage, and should not be implemented without first undergoing thorough testing with realistic feed material from relatively long operat­ ing periods (preferably, several months of continuous operation).

Applicability of Rotary Kiln

If the application of incineration technology for the processing of the landfilled material is to be considered, the rotary kiln concept is the most demonstrated incineration concept for solid hazardous wastes. The rotary kiln design offers a high degree of confidence that the hazardous constituents of the waste can be destroyed and that the process will exhibit the features of reliability, flexability, and predictability which are crucial in view of the heterogeneous nature of the feed material. The rotary kiln system has been used for a wide variety of feed materials

15 143 including "refuse" (Eastman Kodak in Rochester, New York; Dow Chemical in Midland, Michigan; and 3-M in Minnesota). The rotary kiln concept provides both the ruggedness and insensitivity to moment-to-moment variations in physical and chemical properties which is highly desirable for the processing of heterogeneous refuse.

The disadvantages of the rotary kiln concept are the high capital cost, extended design/construction period and the possible need for modest shredding (of increasing importance as the kiln dimensions are reduced consistent with portable units suitable for operation onsite).

The rotary kiln system should be equipped with a secondary combustion chamber maintained (by firing fossil fuel) at an elevated temperature. Due to the higher excess air levels common in rotary kiln systems, it is likely that the fuel consumption per unit weight of feed for this alternative would be higher than for a Shirco unit. Considering that the Shirco unit operates on electricity to provide the necessary heat input, the high cost of electricity relative to fossil will reduce or eliminate any energy cost advantages.

In addition to the type of incineration, several other factors to be con­ sidered include: material feed rate; BTU content of feed material and the need for supplemental fuel; health risks to offsite receptors, onsite workers and operating personnel; capital and operating costs, and ash disposal.

o Feed Rate: The onsite incinerator feed rate will tend to be the limiting factor in the onsite processing of the contaminated material rather than the rate of excavation. In our evaluation of onsite landfill material incineration, two types of mobile equipment were examined, a unit manufactured by ENSCO (Model MWP - 2000 Mobile Waste Processor) which

144 16 employs a rotary kiln incinerator, and Shirco Infrared Systems (as cited by OTA) which employs electrical heating elements. The following solids feed rate for each of these systems is as stated in the manufacturer's literature:

ENSO 96 tons/day (maximum) depending on heat, moisture, and ash content

Shirco 100 tons/day depending on material properties and process requirements

Assuming that six acres of contaminated material is to be excavated to an average depth of 15 feet, approximately 160,000 tons of material will require incineration. At a feed rate of 100 tons/day it will require about 4 1/2 years to incinerate all of this material assuming 365 day per year operation with no down time for maintenance or repairs. However, it must be assumed that a mobile incinerator will experience a "down time" of about 20 percent for routine maintenance and repair. Accordingly, an estimate of 5 1/2 years to complete incineration of these materials is appropriate. This estimate assumes that the materials to be incinerated exist in a suitable form for feeding into the unit. The LiPari landfill material will require pre- treatment to provide a suitable feedstock to any incinerator.

An important factor to consider with regard to the time required for incineration is the need to pre-sort the excavated materials prior to introduction to any on-site incinerator. The LiPari Landfill was utilized for the disposition of municipal refuse in addition to industrial and chemical wastes. Therefore, materials such as construction debris, automobile tires and batteries, and appliances will be encountered. The onsite mobile incinerators cited above are not designed to handle such materials. In discussions

17 with Shirco's Chief Applications Engineer it was indicated that the Shirco unit requires particles to be no larger than two inches in diameter. Therefore, manual presorting of the excavated debris will be necessary to exclude bulk items from the Shirco process. These bulk items will subsequently either need to be transported off-site and disposed of in a RCRA-permitted facility as a hazardous waste or be decontaminated on-site at LiPari and taken to a municipal landfill for ultimate disposal.

Additionally, shredding or other types of size processing will be necessary to prepare the excavated solid waste for introduction to -the incineration unit. After pre-sorting, the remaining debris would be loaded onto a feed conveyor which introduces the material to a shredder. Refuse shredders can attain a feed capacity of up to 50 tons per hour and typically produce a material ranging from 4 to 6-inches in diameter, thus necessitating, in the case of the Shirco incinerator, the need for a second shredder for further size reduction. Of particular concern when operating shredders on municipal landfill material is the presence of partly-filled containers of gasoline, paint thinner, solvents, etc. There are many documented instances of such materials exploding in shredders due to the striking force of the shredding "hammers" resulting in the dispersal of material from within the shredder and severe injuries and loss of life to operating personnel.

BTU Content: The BTU content of the landfilled material at LiPari has not knowledge been determined. It is known that a variety of chemical wastes were disposed of in addition to municipal refuse. Rubbish and garbage from residential sources typically has a heat value of 4,800 BTU per pound. For toxic wastes to be effectively destroyed they must first be burned at about 1,800 °F. Vapors given off during this

18 combustion process are then drawn or forced into a second chamber where they are burned once again, this time at about 2,200 °F. The BTU content of the material to be burned determines the amount of additional energy or supplemental fuel which will be necessary to support combustion at these elevated temperatures. Recent studies conducted on municipal refuse landfilled in the 1960's (approximately the same time period during which the LiPari Landfill operated) indicate that the BTU content of such materials has been reduced by 60 to 80 percent. This information leads to the conclusion that supplemental fuel will be required to efficiently burn this material.

Shirco's Chief Applications Engineer indicated that because Shirco's unit is electrical, use of traditional fossil fuel is not necessary. The unit cost quoted by Shirco for incin­ eration of materials with little or no BTU content (such as at LiPari) was $150 per cubic yard. Nonetheless, the use of the Shirco system will require firing fossil fuel in an afterburner because of the countercurrent flow design previously discussed. This need for additional fuel is expected to raise Shirco's unit cost above the $150 per cubic yard figure.

Health Risks; As with all incinerators, concerns are raised about the quality of stack emissions from such a process and effects they may have on the surrounding community. At this time an evaluation of such stack emissions would be very speculative. Without performing diagnostic and test burns on representative samples of the material, technical factors influencing emissions data such as concentration of contami­ nants and appropriate feed rates to achieve highest effici­ ency of destruction cannot be quantified. Furthermore, the quantity and quality of ash produced from an Incineration process cannot be accurately stated. Residues from a hazard­ ous waste incinerator have been typically classified as a

19 147 RCRA hazardous waste requiring ultimate disposal at a RCRA - approved treatment, storage, and disposal facility. A variety of heavy metals including arsenic, cadmium, chromium, copper, nickel, lead, silver and zinc are present in the leachate at Lipari. This presence leads to the conclusion that the ash from an on-site incinerator will concentrate these heavy metals and may fail an extraction procedure (EP) toxicity test and thus be characterized as a RCRA hazardous waste. The presence of these metals must also be considered when analyzing the emissions generated from an incineration process and the subsequent need for sophisticated controls. Piloting of any incineration unit is essential to determine the degree of air pollution control to assure an acceptable level of risk. o Costs: Costs for incineration can vary widely. As in­ dicated, Shirco has verbally quoted a cost for incineration of $150 per cubic yard. Considering this unit cost, in­ cineration costs for the six acre site would be approximately $22,000,000 excluding landfill excavation, pre-sorting, shredding, ash disposal/treatment costs, and test/diagnostic burns.

At the permanent, full-scale incinerator operated by Rollins Environmental Services in Bridgeport, New Jersey (approxi­ mately 10 miles from the LiPari site) costs for incinerating the oily, PCB - contaminated sludge from the Bridgeport Rental Oil Service (BROS) hazardous waste site having a BTU value of 1000 per pound were recently quoted at $0.61 per pound. Unit costs for onsite incineration via a mobile incinerator were quoted at $0.21 per pound for the BROS site. Applied to the LiPari site, these unit costs would result in incineration costs of approximately $195 million and $67 million, respectively. Costs for landfill excavation, pre-sorting, and containerization (necessary for the Rollins facility) are not included.

20 148 Unit costs for utilizing EPA's rotary kiln mobile incinerator have been quoted at $1000 per cubic yard. This would result in an incineration cost at LiPari on the order of $145 million. o Ash Disposal: Residue (ash) from the on-site incineration process is anticipated to be considered a RCRA hazardous waste for reasons previously stated. There are currently available technologies designed to fix or encapsulate wastes in a solid matrix end product. The fixation processes chemi­ cally or physically bind the wastes. Encapsulation methods physically surround the wastes with the agent. Many indus­ tries (eg. Chemfix, Hillman Nuclear, Stablex Corp., and Research-Cottrell) combine the use of common (Portland) cement and silicates to "fix" wastes contaminated with heavy metals. Some of these technologies have been used by the radioactive waste disposal industry and they have paralleled their application to the non-nuclear hazardous waste Industry. OTA suggests employing a low cost chemical treat­ ment of the ash (such as a product from LoPat Industries of Wanamassa, NJ) to immobilize the residual toxic metals followed by using the "fixed" ash as a backfill material on-site.

To examine this step in more detail, it is first necessary to estimate the quantity of ash requiring chemical treatment. It is estimated that approximately 350 pounds of dry ash will be produced for each cubic yard of material excavated and incinerated. Following these guidelines, incineration of the original six acre landfill would result in approximately 25,000 tons of ash. The LoPat Industries product consists of silicates and other proprietary materials designed to encap­ sulate soil contaminants such as chlordane, PCB's or metals to prevent them from leaching out, and in the case of metals render them non-hazardous based on the RCRA EP-toxicity test.

21 The manufacturer states that the product is typically designed for the specific treatment of a soil type. The effectiveness of the treatment is based in particular on soil porosity, metals concentration, and thorough application of the product prior to its hardening period of 4 to € hours. The manufacturer claims that the product has been effective in "very dusty soils" and in concentrations ranging from 200 ppm to 10 percent metals concentrations. However, the products effectiveness has not been demonstrated on incinerated materials. Although laboratory tests on the Missouri dioxin contaminated soil did demonstrate its effectiveness, the tests were not performed on incinerated soil, nor was the product field tested.

Some of the currently tested applications of the product involve spraying the ground surface to prevent surface water infiltration into metal (typically lead) contaminated soil at a cost of $40 per ton of soil. Applying this cost estimate directly to the situation at LiPari would result in a cost of approximately $1.0 million. However, the application of chemical treatment on the LiPari Landfill incinerated wastes would require thorough mixing of the ash with the sealant to bind a significant percentage of the metals, or binding the exterior portion of unit volumes of the soil with the sealant while assuring non-cracking to assure that metals are not leached. The handling costs associated with this operation are anticipated to result in greater costs than the above estimate which is based on simply spraying the product on the ash surface.

A technical comparison of cement-based versus encapsulation based processes are given below:

.LT . , , I 22 150 Cement-based Process

Advantages

1. Additives are available at a reasonable price.

2. Cement mixing and handling techniques are well developed.

3. Processing equipment is readily available.

4. Processing is reasonably tolerant of chemical variations (in sludges.)

5. The strength and permeability of the end-product can be varied by controlling the amount of cement added.

Disadvantages

1. Low-strength cement-waste mixtures are often vulnerable to acidic leaching solutions. Extreme conditions can result in decomposition of the fixed material and accelerated leaching of the contaminants.

2. Pretreatment, more-expensive cement types, or costly additives may be necessary for stabilization of wastes containing impurities that affect the setting and curing of cement.

3. Cement and other additives add considerably to weight and bulk of waste; and relatively large amounts of cement are required for most processes.

23 Encapsulation Process

Advantages

1. Very soluble contaminants are totally isolated from the environment.

2. Usually no secondary container is required, because the coating materials are strong and chemically inert.

Disadvantages

1. Materials used are often expensive.

2. Techniques generally require specialized equipment and heat treatment to form the isolation jackets.

6. Flushing the Encapsulation

The OTA proposed alternative suggests use of the flushing methodology selected by EPA in the Record of Decision. The OTA alternative, however, suggests that only 9-10 acres of the landfill would require flushing subsequent to the removal and incineration of the six acres originally landfilled. The rationale for this approach is not entirely clear. Removal of the six acre landfill will not remove the contaminated soil which lies beneath the original trenches, (see previous discussion on Extent of Contamination) rather it leaves this material in place throughout the original six acre site. OTA's contention that "Far less flushing would be necessary than in the [EPA] selected remedy because most of the contaminated soil and waste would have been removed and treated" is questionable. Samples of the originally landfilled materials are not available for analysis to ascertain just how much contamination would be removed from the site by excavation. All that is known is that these materials have been subjected to natural flushing and decomposition since 1958 when the landfill operation was initiated. Also, on a volume basis,

24 152 the quantity o£ soil remaining to be flushed subsequent to the OTA- recommended excavation procedure is approximately 270,000 cubic yards assuming that the "clean" soil backfill is segregated from the remainder of the contaminated material within the containment system such that it does not become contaminated during the flushing operation. The Ej>A-selected alternative would flush approximately 445,000 cubic yards. Therefore, OTA's alternative reduces the volume of material to be flushed by 40 percent. The estimate of the flushing duration enumerated in the FS was 15 years. This estimate was based on a calculation of the time required to achieve a cost-effective hydraulic exchange of 10 pore volumes within the containment system. OTA's contention that excavation of the original landfill will reduce the time necessary for cleanup to 5-7 years, a reduction of 50-60 percent less than the Feasibility Study estimate, appears unjustified. A time frame for OTA's flushing approach of about 9 years (based on a 40 percent reduction in soil volume and segregation of the "clean" fill) is more accurate. Should segregation of the fill via an internal slurry wall, for example, not be practiced, the volume of material to be flushed under both the OTA and ROD alternatives will be the same. Should flushing proceed after excavation and incineration are complete, the duration of OTA's cleanup will exceed the EPA Flushing Alternative estimate of 15 years.

The capital costs for a batch flushing system operating at 40 gpm and utilizing 10 injection and 10 extraction wells were previously estimated at $3.4 million. Operation and maintenance costs were estimated to be $5.5 million on a 15 year present worth basis for a total present worth of approximately $8.9 million.

Should a batch flushing system be designed to operate at an increased rate of 80 gpm, utilizing 20 injection and 20 extraction wells, the capital cost are estimated at $5.6 million. Operation and maintenance costs were estimated to be $6.7 million on an eight year present worth basis for a total present worth of approximately $12.3 million (see Tables 4 and 5).

25 ; 153 TABLE 4

Flushing Cost Estimate (Capital Costs)

Item Cost ($)

0 Extraction Wells 355,000 o Injection Wells 331,000 0 Kirkwood Wells and Piping 123,000 o Upgradient Wells and Piping 194,000 o Flow Equalization Tank 244,000 o Chemical Treatment System 320,000 o Air Stripping Tower 128,000 o Clear Well 196,000 o Pipeline to GCUA 24,000 0 Pre-fab Building 156,000 0 Inter-process Piping 110,000 o Sludge Holding Tank 125,000 o Filtration Equipment 194,000 o Carbon Adsorption 700,000 0 Effluent Storage Tanks 918,000 Subtotal 4,118,000 0 Contingency (35%) 1,441,000

Total $5,559,000

TABLE 5

Flushing Cost Estimate (0 & M Costs)

Item Annual Cost ($)

Personnel 116,000 Maintenance 527,000 Monitoring (Groundwater) 126,000 Monitoring (Effluent) 12,000 Power 32,000 Chemicals 151,000 o Sludge Disposal 80,000 o Treatment at GCUA 220,000

Total $1,264,000

Present Worth (i>10%, n«8 yrs) » $6,743,000

26 154 Summary and Conclusions

Dewatering of the Upper Cohansey within the containment system is a feasible step and can be performed cost- effectively in six months utilizing 10 extraction wells at a combined flow rate of 40 gallons per minute. The estimated capital costs for this, assuming treatment at an off-site industrial wastewater treatment facility are approximately $920,000. Operation and maintenance costs are estimated at $880,000. The time duration for this dewatering procedure can be approximately halved by doubling the number of extraction wells.

Enhanced volatilization would be expected to reduce the amount of volatile organics currently within the soil interstices at the encapsulated site. This technique's degree of effectiveness, however, cannot be estimated particularly due to the heterogeneous nature of the landfill materials and the resulting concerns over short-circuiting and channelization. Enhanced volatilization is an unproven technology in a non-homogeneous fill such as exists at LiPari. The time period over which such a system would be in operation prior to excavation of the landfill is unknown and therefore could delay any remediation attempts with respect to excavation of the landfill. The costs for such an enhanced volatilization system are estimated at $250,000 to $300,000 excluding O&N costs.

Partial excavation (six acres) of the LiPari site has several major disadvantages:

- Contamination is widespread throughout the 15.3 acre encapsuation and is not confined to the six acre original landfill.

27 The landfilled debris has been subjected to natural flushing mechansims for a time period from 1958 to 1983. A lack of data on the decomposition and leaching of the waste material makes a determination of the contamination still residing within the originally landfilled material speculative at best.

- Opening of the landfill is expected to result in a release to the atmosphere of volatile organics associated with handling of the landfilled chemical wastes. These releases are anticipated to be persistent with possible health risk implications to the nearby residences. Excavation is also anticipated to release nuisance odors to the nearby residential community.

- Excavation of the landfill presents a possibility for fire and explosion.

Assuming no impediments to an excavation operation such as working within an air-supported structure, excavating only during certain seasons or under meteorological conditions, or operating only on a limited working face, excavation of the six acre site is estimated to require approximately 2 years depending on the number of operating personnel. With certain conditions as described above imposed on the excavation process, the estimated time required would increase. The estimated cost for an unimpeded excavation is approximately $1.5 million.

The estimated cost for backfilling the void created by excavation of the original landfilled area is $1.3 million including replacement of the synthetic membrane liner, seeding, and grading.

28 Incineration of the excavated portions of the original landfilled area using the unit manufactered by Shirco has several major disadvantages.

Design and operational experience to date has primarily dealt with feed materials which were homogeneous, which is not the situation at the LiPari Landfill.

- Any shredding or size classification of the excavated waste necessary for feeding into the unit will be costly, time consuming and technically difficult.

Shirco system experience to date has been in relatively small units. The 100 ton per day system reported to be under construction (the size envisioned to be used at LiPari), represents a very substantial scale up and can be expected to require a significant period of testing and "de-bugging".

A more appropriate application of incinerator technology for the processing of the landfilled material is the rotary kiln concept offering the greatest degree of confidence that the process can be implemented sucessfully.

The disadvantages of the rotary kiln concept are the high capital cost and possible need for modest shredding or size reduction of the feed material.

Assuming a feed rate of 100 tons per day is achievable, the six acre original landfill could be incinerated in approxi­ mately four and one-half to five and one-half years once the material to be incinerated has been pre-sorted and pre- processed as necessary. The cost associated with an on-site rotary kiln incineration process is expected to fall within the range of $60 million to $80 million excluding costs for landfill excavation, pre-sorting, shredding, ash disposal, test burns and air emmission controls. The use of the Shirco incinerator at the LiPari landfill site is not considered to be a proper application of this technology.

Ash from any on-site incineration process is anticipated to be classified as a RCRA-hazardous waste. Costs for chemically fixing this ash are estimated to exceed $1.0 million.

The Onsite Feasibility Study identified that the most cost- effective batch type flushing operation required 15 years for remediation, utilized 10 injection and 10 extraction wells, and operated at a flow rate of 40 gpm. It is estimated that by doubling the number of injection/extraction wells the time period to exchange 10 pore volumes of water (the clean-up criteria) within the encapsulation can approximately be halved. The capital costs for this accelerated approach have been estimated at $ 5.6 million. The O&M costs for this accelerated approach have been estimated on at present worth basis at $6.7 million for a total cost estimate of $12.3 million.

The costs to implement OTA's proposed alternative are summarized as follows:

Item Cost

Dewatering $ 1.8 million Enhanced Volatilization 0.3 million Partial Excavation (unimpeded) 1.5 million Backfilling 1.3 million Incineration 60 to 80 million Ash Handling 1.0 million Flushing (accelerated) 12.3 million

Total $75.2 to 98.2 million

\ 30 These costs do not include the following; O&M costs for an enhanced volatilization system, excavation costs should landfilled material be encountered at depths reaching the top of the Lower Cohansey, excavation inside an air-supported structure or with other impediments in place, costs for air monitoring during excavation, pre-sorting and shredding costs prior to incineration, and handling costs during chemical fixation of ash. Therefore, the above estimated costs can be expected to be significantly increased.

o A time line depicting the implementation period for both the OTA and ROD alternatives is presented as figure 2.

o The technical issues noted in the evaluation of the OTA partial excavation/incineration remedial alternates lead to the conclusion that the alternative is not appropriate for consideration for the LiPari Landfill site.

(DEC95/10) (92/ll)NY

159 ESTIMATED TIME LINES FOR OTA APPROACH AND ROD REMEDIAL ACTION i •*«••*« «c*

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