NC0035904_Corrective Action Plan_20150610

N*C
McCain Correctional Hospital WWTP
Mercury Minimization Plan
June 10, 2015
SECTION I - PURPOSE
The purpose of this Mercury Minimization Plan ("MMP") is to describe best management practices
through which the North Carolina Department of Public Safety (NC DPS) will seek to reduce the amount
of mercury discharged into its system and, ultimately, to the environment. The MMP compiles mercury
reduction -related efforts to -date and potential future action items. It is designed to be a working
document to help guide the McCain Correctional Hospital Waste Water Treatment Plant in its efforts to
control mercury loadings discharged into its Publicly -Owned Treatment Works (POTW) by users of the
sewer system. Such a reduction in loadings to the sewer system should translate to a reduction in the
amount of mercury which is discharged from the treatment plant. The management practices summarized
below may also help control some of the mercury reaching our storm sewer system as well.
SECTION II - FACILITY DESCRIPTION
The NC DPS operates a publicly owned treatment works (POTW), including a collection system and
wastewater treatment plant (WWTP), that serves Hoke Correctional Institution, McCain Correctional
Hospital (closed), and operations at the former Sandhills Youth Center facility, all in Raeford, Hoke
County, North Carolina.
The McCain Correctional Hospital WWTP process is described as follows: a 0.2 MGD extended aeration
wastewater treatment plant consisting of a mechanical cylindrical barscreen; 296,000-gallon aeration
basin with three (3) floating aerators; two (2) 30' diameter clarifiers; a 99,000-gallon aerobic sludge
digester with two (2) diffused aerators; a 7,500 square foot sludge drying bed; UV Disinfection; and a
Parshall flume effluent flow meter.
Most municipal treatment plants are not designed to remove mercury and it is exceedingly expensive to
do so to very low levels. Incidental mercury removal occurs through typical municipal treatment with
trace levels of mercury (and other metals) ending up in solids removed from the raw wastewater.
Mercury is not used in the treatment processes at the WWTP. Mercury may be introduced into the sewer
system through a variety of sources, such as from dentist offices, hospitals, laboratories, and other
potential sources. Residual deposits of mercury are also possible in the sewer system from historic
practices. Finally, trace amounts from household products and atmospheric deposition (both wet and dry)
contribute to sewer system mercury loadings.
While there is typically some mercury contributed to public sewer systems statewide, it is usually in
minute quantities and comprises a tiny portion of the already insignificant statewide loading for all point
sources -just two percent of the annual mercury loadings to all State waters.

SECTION III —PROGRAM PLAN
A. EVALUATION OF POTENTIAL NON -DOMESTIC SOURCES CONTRIBUTING
MERCURY TO THE POTW
Within 24 months from the NPDES required 180-day period for development of an MMP, the NC DPS
McCain Correctional Hospital WWTP will evaluate available information to assess the potential for non -
domestic users of the sewer system to contribute mercury to the system. The information to be reviewed
may include: (1) POTW influent and effluent mercury data and trends; (2) Toxics Release Inventory
(TRI); and (3) state hazardous site registry and the National Priority List relating to mercury
contamination.
The NC DPS McCain Correctional Hospital WWTP will also survey and evaluate the following sources
of mercury in its service area: (1) dental clinic; (2) hospital; (3) laboratories; and (4) other potential
sources of mercury based on existing information. The NC DPS McCain Correctional Hospital WWTP
will request that alternative sources for chemicals be explored if the mercury levels are determined to be
significantly higher than would normally be expected.
The evaluation of potential non -domestic sources of mercury to the sewer system will be updated every
five years, as warranted by prior sampling results and any additional new potentially significant sources to
the system.
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This MMP identifies reasonable and cost-effective control measures to minimize mercury being
discharged into the POTW. Below is a listing of initial BMPs for this POTW.
Pollution Prevention
Substances used at the WWTP will be evaluated to determine if they contain mercury or mercury -based
compounds. Any such chemicals will be evaluated for substitution with non -mercury -containing
substances. No mercury -containing compounds were identified at the McCain Correctional Hospital
WWTP. The hospital facility is permanently closed and all activities have ceased operation.
Housekeenine. Snill Control and Collection. and Education
The NC DPS McCain Correctional Hospital WWTP will develop procedures to minimize the possibility
of any spill or release at the WWTP involving mercury containing substances. NC DPS McCain
Correctional Hospital WWTP will add mercury identification and proper disposal to ongoing and future
operator training procedures. The bulk of housekeeping and janitorial chemicals used at these
Department of Public Safety facilities are procured from the Correction Enterprises Janitorial Products
Plant. The Janitorial Products Plant uses no mercury -containing compounds in any of its manufacturing
processes.
Facilitv Education
Educational information regarding sources of household mercury and appropriate use; disposal practices
can be made available upon request to personnel at the facilities served by the McCain CH WWTP. The
NC DPS McCain Correctional Hospital WWTP can also facilitate awareness regarding appropriate
procedures for the collection and proper disposal of mercury -containing products from these facilities.
Periodic reminders of such collection procedures may be provided to facility personnel.

Laboratory Practice
The NC DPS McCain Correctional Hospital WWTP operates a Iaboratory for purposes of complying with
state and federal monitoring and sampling requirements. While some laboratories are potential sources of
small quantities of mercury -containing compounds, the McCain CH WWTP and PWS laboratories were
surveyed and no mercury -containing compounds were identified. Should any mercury -containing
chemicals ever be introduced to the laboratory operation, laboratory employees will be trained in the
proper handling and disposal of these materials. The laboratories have also replaced mercury
thermometers with non -mercury thermometers, whenever practical.
Dental Clinic Practice— Hoke Correctional Institution
The dental clinic at Hoke Correctional Institution does provide services which involve mercury;
specifically when (1) fillings containing dental amalgam are drilled out; and (2) when fillings containing
dental amalgam are placed in teeth. The use of dental amalgam is the standard of care and there are no
plans to discontinue its use. No thermometers are utilized in the dental clinic.
The dental clinic utilizes traps in its vacuum system to collect solid dental amalgam drilled out of a tooth
and any excess amalgam mixed to place in a tooth. Only the amount of amalgam needed is prepared and
with minimal excess. Dental amalgam collected in the traps is recycled; never discarded. There exists
the potential for release into the waste water stream of extremely minute bits of dental amalgam that are
physically too tiny to be collected in the traps during the process of cutting out an amalgam -containing
tilling.
C. TRACKING AND MONITORING
In order to assess the implementation of the control measures, the NC DPS McCain Correctional Hospital
WWTP proposes to undertake the following evaluations beginning after the first full year that this MMP
is implemented:
1. Survey annually at least ten percent (10%) of any non -domestic users identified as
possible significant sources of mercury to the POTW;
2. Track the implementation of the programs outlined above;
3. Monitor influent mercury at Ieast annually. Require significant non -domestic sources of
mercury to monitor periodically, as warranted; and
4. Measure effluent mercury as required by the NPDES permit.
These efforts will allow the NC DPS McCain Correctional Hospital WWTP to establish a baseline of
influent and effluent mercury levels to assist in identifying any trends in mercury contributions from
domestic and non -domestic users of the sewer system. This baseline will be tracked annually.
SECTION IV- IMPLEMENTATION OF CONTROL MEASURES
The NC DPS McCain Correctional Hospital WWTP will implement the control measures summarized in
Section III over the permit term and will update this MMP as warranted.
SECTION V - REPORTING
A summary of the MMP activities will be submitted if required as part of the NPDES permit renewal
process.