INNOVATIVE LOW COST MERCURY REMEDIATION PROJECT BRINGS HOSPITAL INTO COMPLIANCE

The Lexington Fayette Urban County Government (LFUCG) has a stringent mercury limitation for all industrial users of the Publicly Owned Treatment Works (POTWs). When the 0.0005 mg/L limitation was uniformly applied to all industrial users (IUs), several IUs were determined to be non-compliant. LFUCG implemented compliance plans to identify and lessen the discharge of mercury to the POTWs.Saint Joseph Office Park (St. Joe) was one of the IUs in significant noncompliance with the 0.0005 mg/L limitation. St. Joe is an outpatient medical facility with a diverse group of tenants including doctors, dentists, and support medical testing. The three-building complex has over 270,000 square feet in 50 office suites. The tenants lease office space from a caretaker management company that maintains the facilities and is responsible for any applicable discharge permits. St. Joe's IU permit specifies a combined waste stream location downstream of the three-building complex. Monthly, composite sample data reported mercury concentrations as high as 0.09 mg/L, over 180 times higher than the permit limitation.A multi-tiered sampling and remedial action plan was implemented to address the noncompliance status of St. Joe and to lessen the discharge of mercury to the POTWs. The sampling plan included the use of a mercury vapor analyzer to screen plumbing traps for the presence of mercury vapor. Since only the elemental form of mercury is volatile, all forms of mercury in the trap were chemically reduced by aspirating stannous chloride into the trap. A hand-held vapor analyzer was used to detect mercury in the range of 0.001 to 0.999 mg/m3. Its use in this application was to identify the presence or absence of mercury in the plumbing trap. Instrument responsive tests were conducted in known concentration test solutions to assist in quantifying the degree of mercury in each trap. Through the use of this method, all 558 traps were analyzed within a short period of time and for a budget of 10,000.