Basic principles of sewage remediation include (1) prompt physical removal of sewage (black) water, (2) thorough and often repeated disinfection of interior surfaces that came in contact with sewage water, and (3) prompt drying of interior surfaces following disinfection so as to remove conditions that promote mold growth. Specific actions recommended during sewage cleanup are described in IICRC Standard S50013 and by Berry et al.37 Prompt removal of sewage water and disinfection of affected surfaces are recommended because of the presence of pathogenic microorganisms and invertebrates (e.g., hepatitis A, Escherichia coli 0157/H7, Giardia lamblia, Ascaris lumbricoides; see Ref. 38 for a description of sewage organisms).14
During sewage cleanup it is important to document which porous materials or contents were directly affected by sewage water. Materials and contents (e.g., carpet, gypsum wallboard, insulation, upholstered furniture, clothing) that came in contact with sewage water are discarded.14,37 Semiporous materials such as wood framing and concrete can be cleaned and disinfected. Nonporous materials such as sheetmetal and glass can be easily cleaned and disinfected.13,14,37 An important aspect of restoration is the identification of building components such as wall cavities, underflooring materials, HVAC ductwork, and crawlspaces that may have come in contact with sewage water. These areas should be disinfected, and this may require removal of undamaged finishes and construction material in order to gain access to contaminated materials.14
Microbial sampling to document the effectiveness of sewage remediation is seldom carried out because the primary emphasis is placed on physical removal of sewage water and disinfection and drying of affected interior surfaces. If microbial sampling is carried out, it is appropriate to compare the ecology of sewage-contacted surfaces with similar surfaces in clean, dry, and well-maintained buildings (see Table 3.9, in Chapter 3 of this book). The mere presence of a serotype E. coli in the soil around a building, in soil tracked into a building, and in niches such as cat litterboxes, does not in itself indicate the occurrence of sewage contamination. However, the occurrence of an E. coli serotype such as O157/H7 (a causal agent of hemorrhagic diarrhea) on building surfaces directly affected by sewage water is indicative of contamination needing remediation.
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