NCD980602163_19970918_Warren County PCB Landfill_SERB C_Re Phase I Questions-OCR

SENT BY:ETG ENVIRONMENTAL me; 9-18-97 4:55pM west Chester , PA➔
ETG Providing creative environmental solutions
Envlronmental, Inc.
Facsimile Cover Sheet
To: Mr. Michael Kelly, Deputy Director
Firm: North Carolina Department of Environment
Fax: [phone]
Pages (Including Cover): 6
Message
Letter attached
Fax Status
Urgent-Deliver Without Delay Regular
From: Steve Detwiler
Date: September 18, 1997
Phone; [phone]
If you have any problems with this transmission, please contact Kerry Delaney
16 H,:igerty Boulevard, West Chester, PA 19382-7594 ■ [phone] • Fax (61 O) 431-9140
... , ..
SENT BY:ETG ENVIRONMENTAL, me; 9-18-97 4:55pM west Chester, PA➔
EiG Providing creative environmental solutions
Environmental, Int. _,,_. -------------------------------
Mr. Michael A. Kelly
Deputy Director
NCDEHNR
401 Oberlin Road
Suite 150
Raleigh, NC 27605
September 18, 1997
Subject: Warren County-Phase I Questions
Dear Mike:
As a result of your letter of September 11, 1997, ETG is pleased to provide this
letter in response to questions relative to the ETG Phase I report.
NCDEHNR Question Nurnb;t.l
ETG Response:
At the pre-bid meeting, ETG specifically asked a question about whether the air
standard applied at the stack or at the property line. The answer was "at the property
line''. Thus ETG designed an air pollution control system to meet the standard at the
property line, which was successfully achieved as shown in the report. As indicated in
the report, ETG plans on utilizing additional pollution control equipment (i.e. a wet
electrostatic precipitator) on the full scale system (the pilot unit did not have a wet ESP)
to further remove sub-micron organic droplets (aerosols) and particulates resulting in air
emissions reductions. Additionally, ETG could provide a flameless oxidizer to be used in
series with the proposed flameless oxidizer to further reduce air em.missions.
During full-scale operation, a performance test would be conducted at the site to
determine that proposed air standards would be met. ETG has utilized stack
measurements and a dispersion model (i.e. screen 3) to detennine impacts to the
environment outside of the remediation area at other project locations. The standards
specified for this project by the NCDEHNR are consistent with other state and federal
standards, as meas1m:d at the property line. The screen 3 dispersion model is typically
i6 Hagerty Boulevard. West Chester. PA 19382-7594 • 1610) 431-9 100 • Fax (610) 431 ·9 140
SENT BY:ETG ENVIRONMENTAL, me; 9-18-97 ; -4!56PM West Chester, PA-+
Mr. Mtchatl Kally Page -2· ~pttmbu 18, J997
recommended by USEP A and is standard in the industry . The low volume off-gas and
low concentrations of PCB' s and dioxins result in significant dispersion upon discharge
to the atmosphere, as indicated by the J.11odel 3 results. The maximum impact of
discharge of these contaminants would be within the ~00 foot boundary assumed in the
modeling described in the report. Contaminant concentrations would be even lower
outside of the property line.
NCDEHNR Question Number 2
ETG Response:
Thennal desorption of the contaminants of concern (i.e. PCBs, dioxins) requires
that lower boiling point compounds (i.e. water) contained in the waste be desorbed before
the contaminants of concern (i.e. PCB' s, dioxins) can be removed via thennal desorption
and BCD chemical detoxification. If the waste contains elevated moisture content,
residence time of the ·waste within the thermal desorber vessel must be increased to
ensure that water is removed. After the water is removed, the temperature of the waste is
raised and maintained at the design soil temperature for a certain period oftime such that
processing objectives are achieved and the soil treatment standards are met. Elevated
moisture content thereby increases residence time, effectively decreasing production rates
for the thermal units. Decreased production results in a longer project duration,
increasing overall project costs. Detoxification effectiveness is not impacted (positively
or negatively) by elevated moisture content.
NCDEHNR Question Numbet 3
ETG Response:
The raw waste results for sample WC 1-4 indicate the highest levels of PCB' s and
dioxins/furans of the four (4) samples received, resulting in higher residual concentrations
in the treated soil. The residual concentrations in the treated soil can be further reduced
by adjusting the key process variables including 1) reagent addition rate, 2) process
operating temperature and 3) residence time of the soil in the thermal desorber vessel. As
discussed in the report, ETG believes that 1 ppt dioxin TEQ is overly stringent and we
recommend that a cost benefit analysis of the preliminary soil treatment standards be
prepared during Phase II. As also discussed, ETG would like to reiterate that if these
samples were composited, the average of dioxin TEQ was 0.91 ppt, which meets the
preliminary targart standard. In nonnal field operations, multiple runs would be
composited for material testing purposes.
ETG
Environmental, Inc.
Mr. Michael Kelly
NCDEHNR Question Number 4
ETG Response:
Pagr-3-
west 1,;nester , t-iA ..
Septemb,r l 8, 199 7
The ETG continuous and batch vacuum Therm-O-Detox® systems offer
numerous safety advantages over other technology approaches, as follows:
1) Low operating temperatures, less than 1000°F .
. 2) Inen operating environment, as provided by deep vacuum (removal of
available oxygen) or an inert (i.e. nitrogen or equal) sweep gas.
3) No high pressure vessels.
4) Negative pressure or vacuum operating environment. If there was a
breach of the systemi no contaminants would be released as air would be
sucked illli2 the system. No contaminated air could escape under these
conditions.
5) Less complex system design utilizing commercially available equipment
to minimize risk factors caused by system failures and/or operator errors.
6) Field proven for several years for these state-of-the-art compact systems.
7) Non-haz.ardous reagents and reaction products. (Note: Sodium hydroxide
-NaOH is considered corrosive but not toxic)
8) The system operates with an extremely low air flow, resulting in~ low
discharge of contaminants to the atmosphere as indicated in the repon.
NCDEHNR Qyestion Number 5
ETG Re~ponse:
ETG will incorporate a "hot cyclone" device into the full scale system design. The hot
cyclone will collect larger particulates exiting the thermal unit: The cyclone will be
insulated and heated to maintain the gas temperature as it exits the thermal unit.
Maintaining the gas temperature will prohibit contaminants in the vapor phase from
condensing in the hot cyclone. The dust collected from the cyclone will probably be free
of the contaminants of concern. If the dust is contaminated, the dust will be conveyed (by
screw conveyor or equivalent) to the feed hopper of the thermal unit. Thus, the
contaminated dust would be subjected to further BCD treattnent. If the dust is clean, it
would be conveyed to the cooling unit for rehydration. Please be advised that
approximately 0.08% of the original 50 lb batch (0.044 lb) was recovered as dust. Thus.
only 34 cubic yards of dust would potentially be generated for the full-scale project based
on 40,000 cubic yards of waste to be processed at Warren County.
ETG
Environmental, Inc.
SENT BY:ETG ENVIRONMENTAL1 INC: -9-18-97 4:57PM west Chester, PA-+
Mr. Michael Ke/~y Page-4-SeptembBr 18, 1997
NCDEHNR Question Number 6
ETG Response:
ETG's approach to detoxification of high hazard wastes involves both thermal
desorption and chemical detoxification via the BCD process. Straight thermal desorption
will provide a certain level of contaminant removal via volatilization and thennal
decomposition of the co.ntaminant from the media. Chemical detoxification will allow
for additional reduction and chemical decomposition of contaminants from the media,
allowing achievement of a lower soil treatment standard for the contaminants. At
Southern Maryland, dioxin was not detected in the soil. For the other contaminants (PCP
and Creosote), the soil treatment standards could be met without BCD. There are no
problems with low levels of dioxins as relating to th~ effectiveness of the BCD process.
NCDEHNR Question Number 1
ETG Response:
Estimates for full scale processing were all inclusive (mob/demob was included)
as described in the report, and estimates were based on 60,000 tons. If less material is
processed, lower total project costs would result; however, higher per ton costs would be
required. A typical contract would be bid on a specified amount with contractual pricing
adjustments for overages or underages. The 60,000 tons was calculated from 40,000
yards x the measured bulk density (111 lb/cu ft x 27 cu ft/cu yd-;-2000 lb/ton= 1.4985
ton/cu.yard. 1.4985 ton/cu.yard x 40,000 cubic yards""' 59,940 tons or 60,000 tons).
We at ETG appreciate the opportunity to respond to your questions. We believe
these responses further clarify the effectiveness of the BCD technology which would lead
to the selection of the ETG/ICF team for Phase II activities. Please advise us as to the
time and date of any conference calls with the science advisors. If you have any
additional questions, please call me at your convenience. ·
GSD/ksd
97-084
Very truly yours,
_J__j~&)~-~
G. Steven Detwiler
Vice President, Business Development
ETG
Envltonmental, Inc.