HomeMy WebLinkAbout20053799.tiff v. rld, .6(0 1,,a_tlii
Weld County Planning Department
GREELEY OFFICE 5575 DTC Parkway P 303 694 6660
j EarthTech OCy X. ^ �nOF Suite 200 F3036944410
A Tyco International Ltd Company I yt ll J Englewood,CO 80111-3016 wwwearthtech corn
September 30, 2005 RECEIVED
Mr. Douglas Ikenberry, P.E.
Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division
HMWMD-SWIM-B2
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530
Re: Buffalo Ridge Landfill - First Semi-Annual 2005 Groundwater Monitoring
14-Day Notification of a Statistically Significant Increase
Dear Mr. Ikenberry:
In accordance with Colorado Regulations Pertaining to Solid Waste Disposal Sites and Facilities,6
CCR 1007-2(B4)(C)(1), Earth Tech Inc. (Earth Tech) on behalf of the Buffalo Ridge Landfill
(BRLF), is providing this 14-day notification of a confirmed statistically significant increase (SSI)
over background for sulfate in down gradient well MW06. In accordance with 6 CCR 1007-
2(B4)(C), documentation has been placed in the facility operating record, by copy of this letter,
indicating that sulfate in well MW06 has shown a confirmed statistical exceedance.
In the Second Semi-Annual 2004 Detection Monitoring Report. submitted in March 2005, sulfate
was detected at 180 milligrams per liter (mg/L) relative to a control limit of 169.78 mg/L.
Verification sampling was completed as part of the first semi-annual 2005 monitoring event. A
statistical exceedance was verified with the completion of the statistical analysis on September 16,
2005. The detections resulting in the initial exceedance and the confirmed exceedance are
summarized in the table below:
Initial Exceedances Exceed ances Verified
Control Second 2004 Event First 2005 Event Statistical
Well Limit CUSUM Detection CUSUM I Detection Exceedance
MW06 169.78 mg/1 178.30 me/1 180 mg/1 17.1.30 mg/1 I 180 mg/1 Yes
Based on the geochemical history of groundwater at this site (parameter detections have shown
relatively significant variability), and the results of leachate sampling (there has never been a
detection of sulfate in any of the five leachate samples since the site commenced operations),BRLF
in tends to proceed with an alternative source demonstration in accordance with 6 CCR 1007-
2(B4)(C)(3). This demonstration will be conducted because Earth Tech and BRLF believe that a
source other than landfill leachate caused the SSI at MW06.This demonstration will evaluate several
hydrologic and geochemical factors that may be affecting groundwater quality within the well that is
unrelated to landfill leachate, including variations in site groundwater elevations. If a successful
demonstration is not made, BRLF will establish an assessment monitoring program meeting the
2O05 3749
1•
r
EarthTech
A two International Ltd Company
Mr. Douglas Ikenberry
September 30, 2005
Page 2
requirements of 40 CFR 258.55 in accordance with 6 CCR 1007-2(B4)(C)(2)within 90 days of the
date of this letter.
If you have any questions regarding this notice,please feel free to contact me at(303) 694-6660 or
Alan Scheere at (720) 977-2107.
Very truly yours,
Earth Tech, Inc.
Randall Thomp , P.E.
Project Engineer
cc: Cindi Etcheverry, WCDPHE
Alan Scheere, WM
Kim Ogle, WCDPS
Jack Epple, BRLF
Lou Bull, WM
Len Butler, WM
work\84 158\product\BRL\l4day doc
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