How to Handle a Sewage Contamination Disaster

Transcription

1 IAQ REMEDIATION How to Handle a Sewage Contamination Disaster PHOTO 1 Commodes were installed in September of 2005 and were in use from then until the discovery of the leaks. The family moved in during March of On May 13th, they noticed wet drywall behind the commode in the master bathroom. A plumber investigated, looking first for plumbing leaks in the wall. None were found. On detaching the commode, he found multiple stacked extenders had been used to compensate for the added floor height, rather than extending the drain line. (See photo #2, next page) This assembly had been leaking for some time, probably since installation, as completely saturated flooring materials were found. The same condition was eventually determined to affect all four commodes. See Sewage, page 38 Timothy D. Toburen Consultant Indoor Environmental Technologies Clearwater, Florida Will Spates President Indoor Environmental Technologies Clearwater, Florida This case study discusses a 3,400 square footcondominium unit that became contaminated with sewage, the challenges that were posed, the testing methods used to determine effectiveness of remediation and some unusual remediation methods that were eventually required. Building and damage The penthouse unit has three bedrooms and four bathrooms, and is located on the 20th floor of a Florida Gulf Coast complex built in The present owners purchased the unit in December of 04. Extensive remodeling began in April of 05 and was completed in March of 06. In all four bathrooms the new finish floor was travertine tile installed over the original ceramic tile. The various layers of flooring materials in the bathrooms at this point consisted of: Concrete slab Adhesive Cork Thin set Original ceramic tile Cement board Adhesive Cork Thin set Travertine tiles By the time construction was completed, the new bathroom floors were elevated well above the original floor and flange connection to the commode drain lines. (See photo #1) 37

2 Sewage, from page 37 PHOTO 2 Contamination Commode installations had leaked at their connection to the flange. Each time a commode flushed, contaminated water seeped out and began spreading on top of the concrete subfloor, under the multiple layers of flooring materials. By the time of discovery, black water had directly affected an irregular area of 100 to 250 square feet around each of the four commodes. (See Floorplan, below.) of contaminants and to protect worker health. Wall materials were contaminated by sewage in some areas, and extensive mold growth not discussed in this article, were also issues. IET developed a written protocol for the work and an experienced local mold remediation contractor was retained to do the work. Remediation To prevent cross-contamination of unaffected areas, containment was erected and negative pressure generated in the work zones. Any wall or flooring materials indicating elevated moisture content were removed down to the studs or concrete slab, which was then cleaned and treated with an EPA-registered biocide. All surfaces inside the containments were thoroughly cleaned and treated with biocide. IET was then contacted to perform a postremediation evaluation. Sewage Remediation Testing Methods As noted above, many pathogens can be present in sewage. For a number of reasons, testing for all of them is impractical: Many of the pathogens may be present in low concentration. However, it may require only a few to cause disease. The statistical likelihood of detecting a low concentration of a pathogen in a sample from a small area is low. Testing methods for particular pathogens may detect only one or a few pathogen types. Testing for all potential pathogens would require many tests, at high expense, even assuming tests were available for all of them. For these reasons and others, sewage remediation testing is usually done by testing for indicator organisms, easily detectable bacteria usually found in a sewage-contaminated environment. While some bacteria in an indicator organism group may be pathogenic, indicator organisms are also used to extrapolate whether other less easily detected pathogenic organisms are present. In other words, testing is done to determine the level of cleanliness or sanitation. If indicator organisms are absent or are present at very low levels, we assume the level of sanitation is adequate. Typically, IET uses total and/or fecal coliform bacteria and Escherichia coli (E. coli) When water penetrated under walls into adjacent areas, contamination wicked up into wall materials and also affected the black walnut hardwood strip flooring in the rest of the unit. This flooring had also been installed over previous materials, resulting again in multiple layers of flooring being affected. (See photo #3) PHOTO 3 Sewage Composition A wide variety of organisms are found in sewage. Some are human pathogens. Many pathogens may be present, including bacteria (Salmonella, Shigella, Staphyloccocus), protozoa (Giardia, Entamoeba), parasites (worms and flukes), and viruses (norovirus, echoviruses). Sewage pathogens vary in their characteristics, including resistance to desiccation, to changes in temperature or ph, and to contact with biocides. After leaving the digestive tract, some die quickly. Others may be able to survive for weeks or even years in the right conditions. Investigation Indoor Environmental Technologies (IET) was retained to develop a scope of work and protocol for the necessary remediation. A primary concern of the homeowners was that they didn t want to cover up still-contaminated materials when new materials were installed. They insisted on thorough documentation of return to sanitary conditions before reconstruction. Various parties had input into the project, which led IET to perform several inspections to address different issues between June and December of Sewage screen testing indicated the presence of indicator organisms (see discussion of sewage remediation testing below) on various materials, including concrete slab subfloors, in all the areas where flooring showed elevated moisture content. Finish flooring, hardwood and travertine, as well as the various layers beneath, had to be removed in order to access and decontaminate the concrete slab subfloor, while using appropriate precautions to prevent the spread 38

3 as indicator organisms. Proper sewage remediation methods rely primarily on aggressive cleaning to physically remove contaminants, rather than on the use of biocides to kill pathogens. One reason is that Gram-negative bacteria, very common in sewage-contaminated environments, may release endotoxins when they die, with potentially serious human health effects. Physically removing bacteria by thorough cleaning helps prevent release of endotoxins. Nevertheless, biocides are extremely useful in sewage remediation, especially those biocides which provide both cleaning and biocidal capabilities. Coliform bacteria Coliform bacteria are often used as indicator organisms. A number of genera make up this group of rod-shaped, Gram-negative, nonspore forming bacteria. They include many human pathogens, as well as bacteria that form a normal part of a healthy intestinal flora and bacteria found in the general environment. The presence of coliform bacteria should not be considered a direct indicator of sewage contamination. However, the absence of coliforms on a surface that was previously contaminated with fecal material is an excellent indication that remediation has been effective and that a sanitary environment has been re-established at the point sampled. Fecal coliforms This subgroup of coliform bacteria is more directly associated with fecal contamination PROFESSIONAL EXCELLENCE BEGINS AT THE NADCA 2008 Technical Seminars and is also used as an indicator organism for sewage contamination. Escherichia coli: E. coli is one species of the coliform group and is another indicator organism IET uses when testing for sewage contamination. It is found primarily in the intestinal tracts of mammals and on surfaces contaminated with feces. E. coli can sometimes survive outside the body for extended periods. Most strains of E. coli are not pathogenic and indeed form a normal part of human intestinal flora. E. coli can even be beneficial to human health by producing vitamin K and limiting the establishment of pathogenic bacteria. When testing for residual contamination after sewage remediation, the presence of E. coli is considered a direct indication of human fecal contamination, although there are other potential sources. Screening vs. Quantitative Analysis Most of the time, IET uses a Coliform and E.coli screen. This qualitative analysis determines the presence or absence of E. coli and of total coliform bacteria. It provides no data about how many of these organisms were present. This means it is possible for a quantity slightly above the lower detection limit, an amount that doesn t necessarily indicate a significantly contaminated environment, to generate what is in effect a false positive. A quantitative Sewage Assessment/Clearance analysis provides more information and is usually used for the final post-remediation evaluation. It may quantify total coliforms, fecal coliforms and E. coli, allowing the consultant to make decisions about whether the numbers found indicate a contaminated surface or environment. Results of Post-Remediation Evaluation (PRE) and Follow- Up Work After about two months of remediation work in early 2007, which addressed mold remediation as well as sewage contamination, remediators contacted IET to perform a post-remediation evaluation. February 27 (PRE) inspection: Mold remediation was successful. Sewage remediation testing, using screening methods, showed that remediation had been successful in some areas, but not in others. IET made suggestions to the remediators on appropriate remediation methods and additional work was completed. March 15 (PRE) inspection: Sewage remediation testing, using screening methods, found that remediation had been effective in some more areas, but other areas were still contaminated. IET again discussed appropriate remediation methods with the remediators and additional work was done. April 02 (PRE) inspection: Sewage remediation testing, using screening (presence/ absence) methods indicated successful remediation in additional areas, but other samples still showed contamination. After discussion with the owners, it was decided to use quantitative analysis in case the qualitative screening was producing false positives by showing the presence of coliforms when they were present only at very low levels. See Sewage, page 45 Classroom Instruction and Hands-on Training for Cleaning HVAC Systems: AND MUCH MORE! CALL TODAY FOR DETAILS! UPCOMING CLASS SCHEDULE August 14-16, Chicago, IL September 11-13, Baltimore, MD October 2-4, Jacksonville, FL ARE YOU LOOKING TO GET CERTIFIED? Take the ASCS Certification Prep Course! 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4 Contractors drying a new construction project for Bob Vila s Home Again with Howard Brickman. Drying contractor measuring the moisture content of a wall using a penetrating moisture meter. themselves, but for their customers. Providing a product with fewer construction defects and less risk is a great selling point for the builders who understand the importance of using professional drying contractors to remove excessive moisture from the building envelope. Why bother hiring a professional drying company to dry a job site? Many general contractors are self-sufficient and would prefer to perform as many of the tasks as they can. But consider for a moment the downside to drying your own buildings. You have no one else to turn to in the event of a problem, and there is no third party documentation regarding the actual drying of the building. It is unlikely that a builder will have the drying industry training and certifications needed to professionally do the work. And as with any profession, reading trade journals and attending educational seminars and conventions are all important to keeping up to date with the latest practices in the drying business. Finally, the status as an unbiased and expert third party can be a critical factor in proving the builders claims that the building was actually dry. Professional drying contractors can also afford to buy and maintain the most up-to-date equipment because they use the equipment on a daily basis and don t have expensive machines sitting unused. Howard Brickman is the owner of Brickman Consulting, based out of Massachusetts. Brickman has over twenty-five years of experience in wood flooring contracting and a comprehensive graduate level academic background in wood science and building materials technology. His craftsmanship includes the restoration of the Hatch Memorial Shell, Boston, MA; The Country Club, Brookline, MA; Federal Reserve Bank, Boston, MA; This Old House program, WGBH and has made several appearances on Bob Vila s Home Again as a technical consultant. Howard can be reached at info@brickmanconsulting.com or by calling More information is also available at Kelly Cressy is the Director of Marketing for Water Out Drying Corp, based out of Jackson, NJ. Water Out Drying Corp is the manufacturer of the patented Water Out Emergency Drying System. Ms. Cressy is WRT and ASD certified. She is also an instructor for the Water Out Advanced Technicians Course and a Resident Expert with Property Claims Professionals. Kelly has been published in ICS Cleaning Specialist, Cleaning and Restoration and Claims magazines. Kelly Cressy can be reached at Kelly@waterout.com or by calling For more information you can visit Cleaners, from page 42 more significant than we realize? It s likely that a combination of both particles and gases are affecting indoor air quality and our health. And consider that as chemicals offgas from building materials, they attach to dust particles. When you breathe particles you are being exposed to both particulate matter and the chemical compounds attached to the dust. What is needed is a combination of both particulate and gas removal, what most air cleaners claim to provide yet as we have seen, many cannot. In the absence of effective air cleaners on the market to remove gases and odors, Brandys recommends ventilation using air exchangers. It may be possible to filter particulates using an air filter, but an outdoor air-exchanger is required to reduce the gases indoors. As the cost of energy goes up, it seems to have become attractive to make our buildings airtight and install ventilation systems. How much energy do these air exchangers cost to operate vs. having a leakier building? Has anyone studied the cost of health effects from living in a poorly ventilated building vs. the extra cost of heating a leaky building? As more research is done on the health effects of green buildings, we may find this has been poorly thought out. Just because a green building saves energy does not mean it produces a healthy environment. As Brandys says, If it isn t healthy it isn t green. Daniel Stih is the author of Healthy Living Spaces: Top 10 Hazards Affecting Your Health. Stih is the President of Healthy Living Spaces, Indoor Environmental Testing & Solutions and the Chapter Director of the Indoor Air Quality Association in Santa Fe, New Mexico. Stih can be reached by dan@healthylivingspaces. com or (505) Sewage, from page 39 April 05 (PRE) inspection: Quantitative analysis using the Sewage Assessment and Clearance method found fecal coliform bacteria in significant quantity in some samples. We were not expecting these results, especially considering the extended time, about 9 months, since additional contamination had stopped. Previous sewage remediation projects had been successfully remediated using the techniques specified. One possible explanation is that micro-organisms had been able to form biofilms, complex microbial communities attached to a surface and encased in a slime matrix. Microbes in a biofilm may be much more resistant to desiccation, to mechanical disruption, and to detergents and biocides. As repeated attempts to decontaminate surfaces had not been fully effective, IET decided to directly supervise further remediation work. The remediation contractor provided workers and equipment, and IET located specialized equipment for use on a rental basis. Remediation processes used 1. Thorough cleaning: IET used a large rotary scrubber with a stiff bristle brush to scrub the concrete aggressively. The solution used was a quaternary ammonium based cleaner/disinfectant. It was not EPA-registered for sewage remediation and was used primarily for its cleaning potential. Any biocidal effect was a welcome bonus. Rationale: Previous cleaning attempts may not have been aggressive enough to disrupt possible biofilms. The porous surface of concrete, as well as paint and adhesive residues, provide crevices in which bacteria can hide, and into which biocides and cleaners may not be able to penetrate effectively. Aggressive cleaning methods might be more See Sewage, page 47 with TotalCheck and MoistureCheck Proper use of a moisture meter has always been the best way to detect excess moisture and control indoor mold growth. Delmhorst introduces MoistureCheck, a 2-in-1 moisture meter, and TotalCheck, a 3-in-1 moisture meter/thermo hygrometer to help make that job even easier! Call today for more information! DELMHORST delmhorst.com 45

5 Sewage, from page 45 effective at disrupting biofilms, dislodging sewage organisms and/or encouraging penetration of biocides into pores. 2. Thorough rinsing and extracting: IET used a high-pressure washing/extraction system designed for cleaning floor tile. 900 psi rotary spray jets flushed contaminants out of pores. The spray jets were enclosed in a vacuum hood, so there was no overspray with its potential to aerosolize contaminants. Soils and contaminants were collected by the vacuum system before they could sink back into the concrete pores. To prevent aerosolization of contaminants, vacuums exhausted to the exterior. Dehumidification controlled humidity. Rationale: Effectively removing suspended soils and contaminants from a porous surface is difficult, since after being suspended in a cleaning solution soils often redeposit before they can be extracted or absorbed. Normally, a tool of this type connects to a truck-mounted carpet cleaning machine providing high heat, water pressure and vacuum. This was impractical for this project, located on the 20th floor. IET rented a portable extraction machine capable of operating the equipment. 3. True steam cleaning: After rotary extraction, the surface of the floor was allowed to dry, and then a rented true steam cleaning machine was used. This professional unit generates a significant volume of steam at 350 F. Steam is even more effective at penetrating surface pores of concrete than high-pressure rotary extraction and may also have direct biocidal effects. Micro-fiber towels over the steam jets absorbed soils released from the surface. 4. Application of disinfectant solution: IET used a phenolic-based product EPA-registered for sewage remediation. The product was applied in compliance with label instructions and allowed to dry for several hours. Sample results showed that all areas sampled were below the lower detection limit of the analysis. IER was able to contact the owners and inform them that the environment had now tested as sanitary and that reconstruction could begin. Lessons learned When a concrete slab has been soaking in sewage for weeks or months, thorough cleaning and sanitation can be challenging. It is possible that biofilms can form and significantly increase resistance to desiccation, detergents and biocides. Aggressive cleaning, including the use of efficient methods for removing suspended soils and contaminants before they redeposit, is essential. Aggressive remediation using methods such as those described, even when rental of specialty equipment is required, is likely to be a good deal more cost-effective than repetitive ineffective remediation attempts combined with repeated sampling. Mold remediation is usually done under conditions that are as dry as possible to help prevent further amplification. This approach may be counter-productive in sewage remediation, for which aggressive cleaning methods with large volumes of water may be more effective. The remediator s challenge is to use enough water for effective cleaning while still controlling it well enough to prevent wetting of adjacent materials or the development of excessive humidity. Timothy D. Toburen is an Indoor Environmental Consultant for Indoor Environmental Technologies, based in Clearwater, Florida. He has worked in the restoration, remediation and environmental consulting industries for over 35 years, serving on the committees that produced both the IICRC S Mold Remediation and S Water Damage Restoration standards. He can be reached by at ttoburen@ietbuildinghealth.com or by phone at (727) Will Spates is President of Indoor Environmental Technologies, based in Clearwater, Florida. He has over 20 years of experience in the environmental consulting industry. 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