Project: Black Water Decontamination, Metro Office Building,

Client:  Nashville's Metropolitan General Services

Summary:  This project consisted of decontaminating and project monitoring of Metro Nashville's Howard School Building following a black water intrusion caused by a sewage/storm water line collapse. Howard School Building is Metro Nashville's Central Permitting Complex and Information Technology (IT) Center. Local storm water/sewage lines were filled to capacity and over run after an intense storm, resulting in a sewer line collapse. Back pressure in the lines forced the black water to flood the basement area of the complex, infecting IT hardware, office furnishings, architectural furnishings, mechanical systems and general air quality throughout the 25,000 sf basement.

Effected zones were determined, personnel were evacuated, and the contaminated areas were isolated. Several hundred gallons of black water was recovered and disposed. Dehumidification and force air drying techniques were utilized, preventing damage to moisture sensitive IT hardware. Quick response time prevented service failure to Metro’s service departments.

During decontamination activities, non-porous office and architectural furnishings were HEPA vacuumed, decontaminated with an EPA D listed disinfectant, and removed for onsite storage. Effected porous office and architectural furnishings were removed, wrapped in two layers of six mil poly, and placed in a waste container for disposal. Saturated gypsum board was removed up to one foot from the baseboard. Exposed wall support structure was decontaminated, disinfected and forced air /moisture reducing techniques and dehumidifiers were utilized for quick drying.

Precipitating from impacted floor covering removal, underlying asbestos floor tiles became loose requiring removal. Areas containing floor tile, were isolated with critical barriers and engineering controls were utilized with the use of HEPA filtered air scrubbers exhausting the filtered air outside. EPA certified asbestos abatement technicians used wet abatement methods during removal.

To prevent potential exposure from migrating micro-organisms and/or infectious spores, the mechanical system and associated ductwork throughout the building basement was cleaned and decontaminated. The mechanical system's intake, mixing air and filter chambers along with eliminators, air coils, and dampeners were HEPA vacuumed and disinfected., Carbon filter media was placed on the intake grill to minimize foreign VOC infiltration. Technicians entered the duct system for source removal. The ducting was HEPA vacuumed, disinfected, and liner was coated with a mold inhibiting encapsulant.

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