The routes of exposure of the building occupants to these pathogens are contact, ingestion, and inhalation. An incomplete or inadequate job of cleaning and disinfection may leave residue that can be a substrate for disease-causing microorganisms. Occupants may be infected by contacting contaminated surfaces, with inadvertent transmission from hands to mouth, or aerosolization of contamination may result in the inhalation of microorganisms or their products (e.g., endotoxins). Residue and microbial contaminants also can be tracked by occupants feet to other parts of the building.
Another aspect of health impact is that the conditions caused by sewage backflow or flooding are conductive to the growth of non sewage microorganisms. These conditions include wetness, humidity, and organic matter. Microorganisms, which exist in various life stages in both indoor and outdoor environments, would then have the opportunity for exponential population growth. These species(see Table 2) can produce bioaerosols, which are potential sources for disease. For example, mold allergy is a common source of indoor air symptoms and complaints (5).
In regard to the susceptibility of building occupants, those individuals whose immune systems are in some way compromised (i.e., immunocompromised), or who are otherwise susceptible due to age, medication, or underlying illness, are considered to be at greater risk of contracting potentially fatal infections from the black water damage than those individuals who are healthy.
Fundamental Considerations for Remediation: Water Cleanup, Water Damage Restoration
The factors to be considered in remediation include the types of materials affected, assessment of the degree of damage, the extent of contaminated absorbent material, the total contact time, the humidity, and the amount of ventilation available. The primary goal of water restoration must be the complete extraction and disposal of water and contamination using the sanitary sewer system if possible. Wet extraction systems should be used to completely remove sewage and water used for cleaning. As part of this phase of the operation, removal of affected contents and structural materials may be necessary. These items could include carpet, wall covering porous wallboard, and insulation, and other substrates with the potential for mold growth. Disposal of non restorable contaminated materials requires that the materials be confined in plastic bags and transported to appropriate disposal facilities. In all cases, extraction experts must be provided with appropriate personal protective equipment such as respirators, boots, gloves, splash goggles, and coveralls, and with equipment with which to remove contamination (6).
In order to speed the drying process from water damage and the need to clean up the water, both mechanical and natural dehumidification should be employed as the gross contamination is removed and during restoration. An indoor humidity target of 40% relative humidity (RH) or less should be attained as quickly as possible (7). If possible, depending on the design of the contaminated space and the outdoor weather conditions, there should be ventilation with fans and evaporation of indoor water by introducing outside air. The use of dehumidifiers for removal of water (moisture) from inside building surfaces and air is recommended. The ACS and HVAC systems may be considered as dehumidifiers, depending on the systems mechanical capacity versus the extent of moisture load over time. Rapid drying that stresses proper management of temperature, airflow, and dehumidification is essential for success during the water cleanup process.
Desiccant dehumidifiers, using silica-gel or lithium chloride, could be employed as an adjunct to disinfection to reduce RH to as low a level as possible (8). Moisture content measurements of reclaimed materials is an important criterion of the success of adequate drying and the remediation process.
Chemical Disinfection To Black Water Clean Up
Even concrete can be colonized and broken down my microorganisms if it is allowed to remain wet and contaminated by organic matter. Chemicals categorized as disinfectants are appropriate in this application. A disinfectant may be defined as an agent that reduces significant numbers of pathogens on inanimate objects to a level below the expected to cause disease. Disinfectants may not kill spores, however, and, because some bacterial and fungal spores will always be present in the environment, it would not be feasible to attempt to kill all of the spores in an affected area. Emphasis instead should be placed on removal of the substrates, water, and organic matter needed for the growth of spores.
Choice of disinfectants depends on the degree of microbial killing required, the nature of surfaces to be treated, application safety, and the cost and ease of use of available agents. It is recommended that disinfectants be used in accordance with the manufacturer instructions for use and dilution.
The advantages and disadvantages of each of these disinfectants are given in Table 3. For example, the use of iodophores or low-concentration chlorine compounds would require that little organic matter be present on surfaces, a condition that may be difficult to achieve. Caution should be used in mixing some disinfectants. For example, mixing chlorine-containing solutions with ammonia will produce extremely toxic vapors, and could have lethal effects on workers or building occupants. Of critical importance is contact time. Contact time is the length of time that the disinfectant is permitted to work on the contaminated surface. The contact time must be at least 15 min before additional cleaning and removal of the disinfectant is undertaken. Some disinfectants, such as phenolics and glutaraldehydes, leave a residue that continues to suppress microbial growth for some time after treatment. Water cleanup is truly a science, especially black water cleanup, and should be left to qualified professionals.
Health-Based Recommendation for Mitigation, Water Damage Restoration, Black Water Cleanup. The following specific guidelines are presented with a goal of restoring the contaminated area such that the health of occupants is protected from any risk of pathogen-caused disease.
Water Extraction, Water Damage Restoration and remediation should begin as soon as possible. The longer the contamination is allowed to persist, the greater the potential for microbial growth and resultant damage. And just remember, water that starts out as fresh will certainly attract the contaminants in carpet, ect. Fresh water cleanup does not stay that way given the materials to which they contact.
Unprotected occupants and workers should be evacuated from the affected areas during the initial stages of decontamination, cleaning, and disinfection (e.g., until sewage has been removed and disinfectants applied).
Extraction technicians in the vicinity of the sewage during the initial stages of decontamination, cleaning, and disinfection should be equipped with an organic vapor HEPA respirator, rubber gloves, splash goggles, and boots. In the case of overhead contamination, technicians should also be equipped with goggles, hard hats, and protective suits. Technicians should report any wounds that occur during restoration and take care to avoid cross-contamination from affected to unaffected areas by foot traffic or material handling.
After water extraction, all affected materials should be decontaminated by spraying with a disinfectant solution. It is not the intent of this prespray to effect full disinfection because the presence of organics precludes this. The objective is to initiate the reduction and containment of microorganismsas quickly as possible.
All affected materials should be evaluated for porosity (permeance). From this inspection, materials should be rated as highly porous (saturated), semi porous, and nonporous. Some materials may exhibit varying degrees of porosity, depending on the exposed surfaces. For example, the surface of painted drywall has very low porosity, yet the base of the wall may be unpainted or have exposed gypsum paper that is highly porous.
Highly porous (permeance factor >10) materials that have been exposed to sewage backflow and have a value that exceeds the cost of restoration such as high-value rugs and carpet, upholstery, and other textiles should be removed and restored off site. Highly porous materials with low cost orreplacement value, such as carpet cushion, carpet, cardboard, tackless strip, wicker, and straw, should be removed and discarded as soon as possible. Other materials, such as saturated mattresses and cloth upholstery, regardless of value, cannot be restored and should be discarded. If disposal is necessary, these materials should be bagged in plastic for removal to a proper disposal site. Black water cleanup is part of Water Damage Restoration.
Semi-porous (permeance factor of >1 to 10) materials, including items such as linoleum, vinyl wall covering and upholstery, and hardboard furniture, along with construction materials such as wood, restoration process. If these materials are not removed or properly disinfected, they can become reservoirs for growth of microorganisms.
Nonporous materials (permeance factor 1) such as Formica;, linoleum, vinyl, and tile finishing materials can be inspected for subsurface contamination with a non penetration moisture meter. Although these materials may be rated as nonporous, they must be evaluated carefully because contamination can migrate from the perimeter and become trapped below the surface. If migration of contamination below the surface has not occurred, these materials may be fully restored.
Heavy organic matter, especially raw sewage and silt, must be physically removed by any safe means available. This may include the use of shovels, squeegees, septic pump trucks, wet vacuums, and moisture-extraction machines. Water must also be extracted from floor-covering fabrics such as carpet and rugs. All tools and machines, especially recovery tanks, wands, and hoses, must be cleaned and disinfected after use.
Residual organic matter in cracks and crevices can be removed by pressure washing with a disinfectant solution. The solution then must be recovered with an extraction unit, immediately after Additionally, there may be cross contamination caused by pressure washing during the water cleanup process. Be sure the use the lowest pressure needed so that the black water cleanup does not affect other materials.
After removing heavy organics, affected materials must be cleaned before a second application of disinfectant takes place. Use of many cleaning agents, such as soaps and detergents, will solubilize most organic matter.
After thoroughly cleaning all contaminated materials, a second application of disinfectant may be applied for black water cleanup.
Chemicals classified as disinfectants are appropriate for use in areas exposed to sewage backflow. These chemicals are defined as being capable of inactivating potential pathogenic microorganisms on inert substrates when it's time to cleanup water that is from toilet overflow.
Fully evaluate all factors that affect the success of decontamination. These include the organic matter present, extent of prior cleaning, type and level of microbial contamination, concentration and time of exposure to the disinfectant, and the nature of the material to be decontaminated.
Sources such as Block (9) provide information about the classes of disinfectants.
Glutaraldehydes: These helpful agents display a broad spectrum of activity and rapid rate of kill against the majority of microorganisms. Glutaraldehydes are capable of destroying all forms of microbial life including bacterial and fungal spores, tubercle bacilli, and viruses present in the black water. They are excellent sporicides and will not corrode most materials. Black water clean up disadvantages include increased peroral, percutaneous, and inhalation toxicity, along with elevated eye and skin irritation.
Iodine and Iodine Compounds (Iodophors): These agents are highly effective, have broad-spectrum antimicrobial capabilities and exhibit some residual properties. Disadvantages cleaning up black water. Some formulations may stain porous materials an orange-yellow color.
Phenolic Compounds: These agents are stable (less inactivated by organic matter), broad spectrum (generally include antiviral properties), and readily available, and leave a residue. Disadvantages include substantially increased peroral, percutaneous, and inhalation toxicity, along with eye and skin irritation.
Quaternary Ammonium Chloride Compounds (Quats): These agents have a limited spectrum of activity but are capable of killing gram-positive bacteria and fungi, and of inactivating gram-negative bacteria and some viruses. Quats have a naturally pleasant odor, counteract offensive odors, and are excellent cleaners. Ammonium chloride compounds are safer to use than most other disinfectants for black water cleanup, because they are less toxic and cause less irritation to the mucus membranes. Quats, when diluted for use, are low in toxicity and irritation. Disadvantages of this class of agents include the facts that they are neither sporicidal nor tuberculocidal and that many formulations exhibit poor results against gram-negative bacteria and some viruses. Also, these compounds are incompatible with anionic cleaners (i.e., mutual neutralization of disinfectant and cleaner) and with the dye blockers in stain-resistant carpet.
The indoor humidity in affected areas should be reduced to 40% RH as quickly as possible. When flooding has been extensive, the drying process may require several days or longer to be effective. Adequate drying should be evaluated with a moisture meter. The humidity caused by the need to cleanup water should be monitored with a hygrometer or a psychrometer.
Because the use of disinfectants such as glutaraldehydes, iodophors, and phenolics for disinfection produce irritating vapors, appropriate personal protective equipment to preclude chemical exposure is required for black water cleanup or water damage restoration. The type of safety equipment used will depend on the disinfectant used, the concentration, and the method of application. The material safety data sheet (MSDS) and label instructions on the chosen disinfectant will provide more detailed information and must be reviewed before use.
Environmental monitoring of the water cleanup process should consist of moisture measurements, rather than surface or air sampling for the presence of viable microorganisms. After the restoration process, surveillance of occupants for sickness, allergy, and sensitivity may also provide a measure of the adequacy of the black water clean-up operation. Do not hesitate to see a doctor.
Small rugs may be restored effectively through commercial laundering. If an effort is made to restore the carpet, extensive cleaning and saturation disinfection ofthe carpet should take place. All organic material must be removed, and the complex fibrous surfaces throughout the carpet must be disinfected. Following treatment, the carpet must be inspected thoroughly for cleanliness and dryness before being reinstalled in the restored environment. Carpet cushion must be removed, disposed of, and replaced with new material, without exception. Sub returned to the environment. Under no circumstances should efforts be made to restore carpet and rugs on site that have been extensively damaged by a Situation 3 sewage backup.