Tips For Cleaning A Sewage Overflow

 

Steps in an Effective Approach to Cleaning up a Sewage Spill

1. Immediate response to a sewage spill for safety of building occupants and for damage control are given
   
   at SEWAGE BACKUP, WHAT TO DO. If you have not read that article, do so, then return here. There we discuss building entry hazards such as electrical shock and other immediate risks.
2. Inspect for scope of sewage backup & contamination: an inspection of the building interior and exterior is required to make sure that the scope of cleanup and disinfection will be adequate following any sewage or plumbing drain backup or leak.
   
   An inspection for mold or other contaminants in the same area, and further cleaning needs should be made at the same time so that you do not have to do the job twice. For upper building areas 
   
   see MOLD CONTROL, FLOOD RESPONSE and for basements and crawl spaces also 
   
   see CRAWLSPACE MOLD ADVICE
   
   Watch out: in our experience [DF] when a building has been wet enough to allow water to enter even just the very bottom of a wall cavity, there is a high risk of harmful and costly mold contamination of both the interior wall cavity surfaces as well as wall insulation. 
   
   Some materials (plaster, mineral wool or cellulose insulation) resist mold growth a bit more than others (drywall, fiberglass insulation, exposed wood surfaces).
   
   More advice on handling wall and floor cavities where the floors have been wet is
   
   at Step 6. FLOOD DAMAGED BUILDING CLEAN-UP for carpeting and rugs that have been wet by area or building flooding


3. Decide who is going to perform the clean-up of the sewage spill: yourself or a professional contractor. 
   • Reasons to hire a professional water restoration company:
   • Your insurance company is paying for the clean-up.
   • The total area of contamination and scope of work are just too large for you to handle
   • Sewage spill has been in place for 24-hours or longer
   • The building HVAC system (air conditioning, forced warm air heating system) has been contaminated
   • You or building occupants are people at extra risk: asthmatic, elderly, compromised immune system, infants
   • If you are going to perform the sewage spill cleanup yourself 
     • Wear rubber gloves, eye protection, rubber boots, impervious coveralls
     • Do not directly touch sewage material; sewage spill or sewage contaminated materials such as carpets, clothing, furniture that contact bare skin can cause a serious infection
     • Take extra care that eyes, open cuts or sores or similar high-risk areas do not come in contact with sewage; be sure to keep on eye protection when spraying or washing off items outdoors during salvage operations, as sprayed sewage droplets are unsafe.
     • Wash your hands frequently; wash and disinfect clothing, gloves, boots that are to be re-used. Effective hand washing requires plenty of soap and at least 30 seconds of active scrubbing.
     • Watch out: airborne water droplets of sewage contaminated water or cleaning water carry pathogens and are dangerous. 
       
       Ensure that your vaccinations are up to date for tetanus and diphtheria. Vaccinations are also available for hepatitis A.
       
       Don't touch fecal waste nor raw sewage with bare hands
       
       Don't breathe or become wet by sewage waters
       
       Do not touch your eyes, nose, ears, nor open cuts or sores when working around sewage
       
       Do not eat, drink, apply lip balm or lipstick (!) and do not chew gum while working with sewage cleanup
       
       If you are accidentally wet by or touch sewage, stop and bathe.
       
       Clean everything: after working on sewage cleanup, change out of your work clothing and bathe; clean all clothing, equipment, tools that come into contact with sewage materials by using an appropriate sanitizer, or if appropriate, discard those materials.
     
     
4. Remove salvageable & non-salvageable contents & furnishings from the affected area.
   
   Remove non-salvageable items for disposal: wet carpets and padding should have been removed and discarded as well as wet upholstered furniture & curtains. (Valuable area rugs may be able to be salvaged by professional cleaning and sanitizing). If walls are covered with plastic or vinyl wallpaper it should be removed as well to speed drying of drywall.
   
   Use plastic bags to collect discarded materials for removal from the property. 
   
   If available, heavy-duty contractor-grade plastic bags will reduce the risk of tearing or or leaks. If you only have kitchen garbage bags available, double-bag items for added safety.
   
   Remove, clean, & store salvageable contents: wet contents that can be cleaned (hard-surfaced furniture, dishes, plastic items) should be removed from the sewage backup area and if weather permits, placed outdoors in a sheltered area. If weather or security do not permit that step, place salvageable items on a plastic-covered area of a concrete garage floor or similar area where the risk of cross-contamination of other building areas is minimized and where floor cleaning after salvage will be easy.
   
   Where weather permits, complete cleaning of salvageable materials outdoors.
   
   Be sure that cleaned salvaged items are stored dry and protected from the weather but do not bring them back into the sewage spill area until cleaning in that area and dryout of that area as well as restoration work have been completed. 
   
   For large sewage spill cleanup projects, you may require a clearance inspection and testing before contents are returned to the area as well as before it can be occupied.
   
   Tip: clothing can usually be laundered or dry-cleaned; sheets, towels, blankets and similar bedding may also be salvageable by cleaning.
   
   Tip: take photographs of the sewage spill and of sewage or water-damaged building contents and materials to assist in a later inventory of losses. Photos can be particularly helpful if insured items must be disposed-of quickly as part of damage control for the building.


5. Prevent cross-contamination: measures to assure that sewage contaminated soil was not tracked into the living area, or appropriate cleaning there if needed and that airborne sewage-contaminated dust (or mold spores) are not blown to other building spaces.
   1. Close doors between the contaminated area and other building rooms
   2. Use 6-mil plastic taped as necessary at open doorways that cannot be closed.
   3. Seal off HVAC air intake or outlet registers for systems that are (wisely) to be left shut down during the cleaning and drying procedure.
   4. Use negative air (fans blowing out through one or more windows) to keep air pressure in the contaminated area lower than in the rest of the building. This step helps prevent sewage-contaminated dust from being blown to other building areas.
   
   
6. Demolition & removal of wastewater-contaminated materials: remove any suspect or contaminated drywall, carpeting, carpet padding, paneling, building insulation or similar materials in the affected area.
   
   Remove & dispose of drywall, baseboard trim, or wall paneling that have been wet by sewage.
   
   Evaluate the porosity of remaining building materials to decide on demolition/disposal vs. cleaning. Quoting from Morey (2007):
   
   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 or replacement 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.
   
   Semiporous (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, painted drywall, and plaster, should be cleaned, disinfected, or replaced as part of the initial 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 nonpenetration 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. - Morey (2007)
   
   Remover other sewage-contaminated contents: all porous material (cardboard, paper, books cloth) carpeting, carpet padding, upholstered furniture, mattresses, curtains, stuffed animals, wet books and similar items should be discarded. Discard food that has been contaminated or is in the contaminated area. 
   
   Also discard items for which cleaning, even if technically possible, is not cost-effective - if it costs more to clean it than to replace it, it's trash.
   
   Use plastic bags to collect baggable demolition materials for removal from the property.
   
   Watch out:: while we frequently hear from readers whose building owner or cleaning company promise to "sanitize" wall to wall carpets that have been left in place, typically by using a carpet cleaning machine, steam, and spraying with a sanitizer. Those measures are unlikely to be effective.
   
   It is very difficult to adequately sanitize a thick dense material like carpeting and virtually impossible to adequately sanitize carpet padding and flooring below a sewage-spilled-on carpet.