2011-04-08_GENERAL DOCUMENTS - M1977300

• Permit No: M1977300
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Date: 4/8/2011
• Doc Name: Water Treatment Plant Residuals.
• From: CDPHE
• To: Denver Water
• Permit Index Doc Type: General Correspondence
• Email Name: DB2
• Media Type: D
• Archive: No

John W. Hickenlooper, Govemor
Christopher E. Urbina, MD, MPH
Executive Director and Chief Medical Officer
Dedicated to protecting and improving the health and environment of the people of Colorado
4300 Cherry Creek Dr. S.
Denver, Colorado 80246 -1530
Phone [phone]
Located in Glendale, Colorado
http: //www.cdphe.state.co.us
v
_April 8, 2011
Mr. Thomas Mo 1 � tfort
Denver Water
1600 West 12` Avenue
Denver, CO 80204 -3412
Dear Mr. Mountfort,
Laboratory Services Division
8100 Lowry Blvd.
Denver, Colorado 80230 -6928
[phone]
M-- /g77-30 O v
STATE OF COLORADO
Colorado Department
of Public Health
and Environment
Re: Conditional Approval for One-Ti e Acceptance at Foothills Landfill
Water Treatment Plant Residuals from Denver Water's Ralston Residuals Management Facility
Jefferson County, Colorado
The Radiation Management Unit and Permitting Unit of Solid Waste and Materials Management Program, at the
Colorado Department of Public Health and Environment ( "Department ") have reviewed your e-mail request dated
March 30, 2011, and supporting laboratory data dated March 9, 2011 relative to disposal at the Foothills Landfill
of Denver Water's water treatment residuals from Drying Bed #2 at the Ralston Residuals Management Facility.
Section 12.2 of the Regulations Pertaining to Solid Waste Sites and Facilities, 6 CCR 1007 -2, Part 1 ( "Solid
Waste Regulations ") requires generators of water treatment plant sludge to obtain disposal guidance from the
Department for sludge that exceeds 40 pCi/g gross alpha activity.
The Department published its Interim Policy and Guidance Pending Rulemaking for Control and Disposition of
Technologically - Enhanced Naturally Occurring Radioactive Materials in Colorado ( "Policy ") in February 2007.
The Policy takes a tiered approach to disposal of TENORM in various types of landfills. It makes default
recommendations of what levels of radium- or uranium- bearing materials are acceptable to the Department for
disposal at various types of facilities without a specific assessment. The levels of uranium in the residuals from
Ralston Drying Bed #2 exceed the default levels that are suggested for a municipal solid waste landfill; however,
the levels of uranium are acceptable at a suitably designed and operated industrial landfill, such as CSI, in Adams
County, or a suitable hazardous waste landfill, such as Clean Harbors Deer Trail, also in Adams County. The
Policy provides for case -by -case approval when appropriate supporting documentation is provided.
In August 2007, the City of Englewood submitted a risk assessment prepared by CDM for disposal of its water
treatment plant residuals at Foothills Landfill. The Ralston water treatment residuals are similar in nature of those
generated by the City of Englewood. Therefore, the CDM risk assessment submitted in 2007 provides part of the
required supporting documentation. The CDM risk assessment was conducted using the most recent available data
at that time. It specifically evaluates the engineering design and geology at the Foothills Landfill and uses site -
specific data for sensitive parameters. The information supplied by Denver Water on March 30, 2011 supports
disposal of the Ralston residuals at the Foothills Landfill, and is consistent with the CDM risk assessment. Based
on the data submitted, the activity concentration in the residuals ranges from approximately 175 to 220 pCi/g total