Waste Water and Sludge
Auto Body Shops
Pollution Prevention Guide
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Auto body shops can generate wastewater from either cleaning service bay floors
or washing vehicles prior to body work. In most auto body shops, wastewater
drains into a sump, where dirt and sand settle out and collect at the bottom,
forming a sludge. Wastewater may then be discharged to the sanitary sewer system
where it is treated at the municipal wastewater treatment plant.
If the floors of the shop are kept clean of spills and less hazardous products
are used, the wastewater and sludge should not be hazardous. However, when good
housekeeping is not practiced, wastewater and sludge may be contaminated with
heavy metals, chlorinated solvents, and grease. The result is sludge and wastewater
that may have to be managed as hazardous waste.
To prevent pollution caused by the mismanagement of your shop's wastewater
and sludge:
- Never discharge them into a storm sewer -- storm sewers
generally flow directly into local surface waters.
- Never release waste to sumps or drains that discharge directly
to groundwater supplies -- this could pollute local groundwater supplies
(a violation of state and federal water quality regulations).
- Never release hazardous materials to your septic system
-- chemicals can pollute local groundwater supplies (a violation of state
and federal water quality regulation).
- Contact your local municipal wastewater treatment plant prior to
discharging wastewater into the sanitary sewer. The plant may require
testing or pretreatment (such as an oil/water separator) prior to accepting
your waste.
- Prior to disposal, determine if the sludge is hazardous or not.
If the sludge is hazardous, it must be disposed as such. If non-hazardous,
allow the sludge to dry and dispose in a local solid waste management facility,
such as a landfill, with its approval.
The following series of questions will help you develop ways of preventing
pollution in wastewater and sludge management:
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Wastewater And Sludge
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YES
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NO
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| 1) Do you practice good housekeeping? Good housekeeping
practices, such as cleaning up spills and leaks right away, can help prevent
your wastewater and sludge from becoming contaminated with hazardous materials. |
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| 2) Do you use less hazardous products in your shop? Using
less hazardous products not only improves worker safety but can help keep
your wastewater and sludge from being contaminated or prevent a release
of hazardous materials into the environment. |
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| 3) Do you run a "dry shop?" A "dry shop" is one that
does not have floor drains and uses dry floor cleaning methods such as sweeping
and vacuuming instead of using water. |
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| 4) If you have a sump, do you test your wastewater to determine
if it is hazardous prior to disposal? You may have to determine
if your wastewater is hazardous prior to discharging it to the municipal
wastewater treatment plant. If you do not use hazardous materials in your
shop, there is a good chance the wastewater is not hazardous. For help,
contact your local wastewater treatment plant. |
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| 5) If you have a sump, do you test your sump sludge to determine
if it is hazardous prior to disposal? You must determine if
your sump sludge is hazardous prior to disposal. If you do not use any hazardous
materials in your shop, there is a good chance the sludges are not hazardous
and could be treated as a solid waste. Note that it may have to be dried
prior to disposal before a landfill will accept it. |
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| 6) Are you on a septic system? Septic system users
have to use extreme caution when dumping fluids down the drain. Hazardous
chemicals could find their way to local water supplies, causing serious
contamination problems. Drains not connected to the city sewer should be
sealed and less hazardous products should be used. |
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| 7) Do you use an oil-water separator in your sump? Commercial
oil-water separators or oil skimmers are available that use an oil-attracting
material immersed or run over the top of the water to absorb oil only. Once
separated, the oil can be transferred to a used oil container for recycling. |
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| 8) Do you wash vehicles on-site? If you wash vehicles
on-site, use less hazardous soaps to help prevent wastewater and sludges
from becoming hazardous waste. |
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Fact sheet 12 of 18
Montana State University Extension Service
Pollution Prevention Program Taylor Hall Bozeman, Montana 59717
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