2018 Valdese MMP

Town of Valdese
Lake Rhodhiss Wastewater Treatment Facility
MODEL MUNICIPAL MERCURY MINIMIZATION PLAN
July 20, 2018
SECTION I - PURPOSE
The purpose of this Mercury Minimization Plan ("MMP") is to describe best management practices
through which the Towns of Drexel, Rutherford College and Valdese 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 Town of Valdese 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 'nay also help control some of the
mercury reaching our storm sewer system as well.
SECTION H — FACILITY DESCRIPTION
The Town of Valdese operates a publicly owned treatment works (POTW), including a collection system
and wastewater treatment plant (WWTP), which serves Drexel, Rutherford College and Valdese, North
Carolina.
Flows conveyed to the WWTP are treated microbiologically, via an extended aeration process; consisting
of primary clarification, aeration, secondary clarification, chlorination, de -chlorination and biosolids
processing.
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 industrial users, laboratories, and other businesses.
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 d 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 Town of
Valdese 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) industrial user permits and associated mercury
monitoring data; (3) Toxics Release Inventory (TRI); (4) state hazardous site registry and the National
Priority List relating to mercury contamination; and (5) historical records of industrial sites which may
have contributed mercury loadings to the sewer system.
The Town of Valdese will also survey and evaluate the following common sources of mercury in its
service area: (1) dentist offices; (2) hospitals; (3) laboratories; (4) auto recyclers; and (5) other potential
sources of mercury based on existing information.
The Town of Valdese will request that industrial users review mercury concentrations in high -volume
process chemicals and demonstrate that the mercury concentrations are below industry average. The
Town of Valdese 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.
B. ADDITIONAL CONTROL MEASURES
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.
HousekeeninSaill Control and Collection. and Education
The Town of Valdese will develop procedures to minimize the possibility of any spill or release at the
WWTP involving mercury containing substances. Town of Valdese will add mercury identification and
proper disposal to ongoing and future operator training procedures.
Public Outreach
Town of Valdese will make available educational information regarding sources of household mercury
and appropriate use/disposal practices. This information may be posted on the Town of Valdese website
and the availability of this information will be highlighted in an outreach to customers. The Town of
Valdese will also facilitate public awareness regarding community collection points for mercury-

containing products from residents/customers for proper disposal. Periodic reminders of such collection
programs will be provided as part of Town's ongoing public outreach.
Laboratory Practice
The Town of Valdese operates a laboratory for purposes of complying with state and federal monitoring
and sampling requirements. The laboratory is a potential source of small quantities of mercury -
containing compounds. 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. Additionally, a mercury spill kit is kept on site, in case of accidental breakage of
mercury filled thermometers, which may still be in use.
C. TRACKING AND MONITORING
In order to assess the implementation of the control measures, the Town of Valdese 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 least 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 Town of Valdese 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
Mercury is periodically analyzed, through the pretreatment program, via the collection of industrial
discharges on those Significant Industrial Users permitted within the program.
The Town of Valdese 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 as part of the NPDES permit renewal process.