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6 Wastewater Management and Controls


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The proper treatment and the disposal of wastewater from vehicle maintenance and refueling operations have become major concerns from both a regulatory compliance and enforcement perspective. Wastewater concerns are especially troublesome where connection to a municipal treatment system is not available. Defining what may be acceptable wastewater treatment and disposal methods varies with facility design and operations, ultimate points of discharge, wastewater contaminants and state and local regulations.

This chapter discusses wastewater from service bays, vehicle washing, stormwater and many other types of wastewaters. You will gain a better understanding of:

* Basic guidelines and recommended practices,
* Sources and characteristics of wastewaters,
* Common types of disposal and treatment methods,
* Water and wastewater reduction and recycling techniques,
* Typical problems with the design of existing facilities, and
* Compliance options and solutions.

NPSSolution5Although the objective of this chapter is to provide assistance in achieving compliance with current and future environmental rules, the information is also of value where there is a need to minimize water consumption. Where water costs and consumption rates are relatively high, a reduction of usage may result in annual cost savings which are quite attractive.

At locations where available water supplies are limited due to water-well pumping capacity or periodic droughts, conservation measures may be necessary to avoid interruption of activities.

There are numerous wastewater sources in some motor vehicle maintenance and refueling operations, and application of wastewater regulations in these facilities is relatively new and constantly evolving. As such, the topic can be a difficult issue, especially considering the practical and economic constraints of these operations, many of which are small in size.

Recommended Management Practices

The principles of wastewater management and reduction are similar to waste minimization. You may want to review Section 3.13, Minimizing Hazardous Wastes, and Chapter 7, Waste Reduction and Recycling. A reduction in the volume of wastewater and amount of contaminants in the wastewater you generate may be necessary to reduce costs or to achieve regulatory compliance. You may need to segregate and handle some wastewater streams separately or make operational changes to accomplish this.

There are several general rules of thumb to reduce or eliminate discharge of contaminated wastewaters from your facility:

* Verify sanitary and other wastewaters are connected to the publicly owned treatment works (POTW), otherwise known as the sanitary sewer. If not, determine if a connection is available and feasible.

* Where discharge to the POTW is not available, you may need to install a wastewater storage tank or recycling system.

* Avoid drainage and replacement of oil, coolant or other vehicle fluids on the ground or outdoor pavement.

* Avoid engine and vehicle washing outdoors unless there is a proper facility to divert and treat wastewaters.

* Avoid minor spills in the service bays and provide materials and incentives for immediate and thorough clean-up.

* Avoid sweeping floorwashings from the service bays to the outside pavement.

* Wastewater from bay area floor washing should be directed to a sanitary sewer or diverted to a holding tank for later disposal or an on-site recycling system.

* Require the used oil hauler to clean up any spills during pumpout of used oil from the tank area.

* Require the fuel transporter to immediately clean up any spills from tank refilling operations.

* Maintain proper absorbents and spill clean-up materials for immediate response to any indoor or outdoor spills.

* Periodically inspect and maintain OWSs to improve their performance and operation and to avoid slug discharges of oil.

* Periodically inspect stormwater catch basins for presence of oil and sludge. Clean when necessary.

This chapter contains these and many more recommended practices and solutions to wastewater problems and regulatory compliance.

Regulatory Authority and Agencies

All wastewaters are regulated by federal, state and/or local rules. With few exceptions, most discharges now require some type of permit.

Wastewaters discharged to receiving streams, surface waters, drainage ditches or storm systems are regulated by the Clean Water Act (CWA) under the NPDES. An NPDES permit (or state equivalent) is required for most discharges. (40 CFR, Part 122)

Stormwater discharges from nonretail maintenance and refueling operations are regulated under CWA, and an NPDES (or state equivalent) stormwater permit may be required. Retail automotive and car and truck rental operations are currently exempt. (40 CFR, Parts 122-124)

Wastewaters directed into a POTW are regulated directly by the local sewer authority by sewer use and pretreatment codes. You should obtain and review a copy of your local sewer use code to ensure you are meeting local requirements. Federal and state water-quality agencies are listed in Appendix A.

Septic systems and packaged treatment systems for sanitary wastes are generally regulated by the county health department.

Nonsanitary wastewaters discharged to inground disposal systems such as dry wells, soak pits and septic systems are regulated under the Safe Drinking Water Act (SDWA) by Underground Injection Control (UIC) regulations. These discharges are usually not allowed. (40 CFR, Parts 144-148)

Wastewaters which are classified as a hazardous waste may be regulated under the Resource Conservation and Recovery Act (RCRA). See Chapter 3, Hazardous Waste Management. (40 CFR, Parts 260-262)

Sources of Wastewater

Wastewaters are generated from various sources and activities as outlined below:

Restrooms (sanitary wastes)
Service bay floorwashing
Coolant changes
Steam cleaning
Engine cleaning
Vehicle washing
Tank bottom water
AST dike water
Stormwater runoff

Service facilities may also generate wastewaters from the following activities:

Radiator repair
Heavy-duty equipment cleaning
Rinsing and cleaning of trailers or tanker trucks
UST removal (see Chapter 5, Fuel and Liquid Storage Systems)
Groundwater treatment

It is important to not only understand the sources of wastewater but also the characteristics of each type of wastewater generated.

Sanitary Wastes

Sanitary wastes (also called domestic wastes) are from restrooms, restroom washbasins and drains and kitchen areas. These wastewaters may be discharged through the POTW without prior treatment. Where a connection to a POTW is not available or not required, sanitary wastes are normally treated by a septic system consisting of a septic tank and drain field. Some facilities may operate above-ground, packaged sewage treatment plants. Each of these sanitary treatment systems are typically regulated and permitted by the county health department.

* Septic Systems

Septic systems are designed for the treatment of domestic (sanitary) sewage only. Additional wastes and wastewater should not be allowed to enter the system unless specifically permitted by the regulatory agency.

Note: Where septic systems are employed for sanitary waste treatment, it is common that all other wastewaters are also discharged through the septic tank/tile fields or through a separate disposal system called dry wells or soak pits. These disposal methods, even where permitted, are not good standard practice.

In some cases, these wastewaters are knowingly or unknowingly directed to a stormwater sewer, drainage ditch, wetland or surface waters. If this is discovered, it is recommended further discharge be immediately ceased until an alternative disposal or treatment method is provided.

Discharge of service bay drain wastewaters (including spent coolant solutions) to septic systems, dry wells or soak pits is not recommended since soils and groundwater may be impacted. More important, without a UIC permit, this may be a serious violation of the SDWA and hazardous waste regulations under RCRA. Various solutions to these problems are contained in the upcoming sections.

Septic system cleanout should be scheduled on a periodic basis. The need for maintenance is commonly signaled by the slow drainage and poor operation of the system.

* Packaged Sewage Treatment Plants

Packaged treatment plants, like septic systems, are designed for the treatment of sanitary wastes only. Packaged sewage treatment plants usually consist of aeration, settling, chlorination and sand filtration. Other waters or wastewaters such as floorwashings and vehicle washwater should not enter these systems unless specifically permitted by the regulatory agency. This problem is discussed in more detail in Section 6.8, Service Bay Wastewaters.

Packaged plants require periodic inspection and maintenance, periodic sampling and analysis of the discharge and submittal of reports to the regulatory agency.1 Packaged plants can easily be upset by shock loads of antifreeze. Discharge of antifreeze can also cause chemical oxygen demand (COD) limits to be exceeded.

1 Typical analyses for the treated wastewater include total suspended soils (TSS), total dissolved solids (TDS), biological oxygen demand (BOD), oil/grease, fecal coliform and chlorine. However, if other wastewaters enter your system for treatment, additional tests may be necessary to ensure adequate treatment (lead, petroleum hydrocarbons, COD, phosphates.

* Centralized Wastewater Treatment Systems

Wastewater treatment systems other than those mentioned above are uncommon for most stand-alone maintenance facilities. However, if your fleet maintenance facility is attached to other industrial operations such as a refinery, manufacturing or power generation plant, your wastewaters may be directed to a larger and, possibly, more advanced treatment system serving the entire facility.

Other Discharges to Publicly Owned Treatment Works

Although sanitary wastes are allowed to be discharged to POTWs without treatment, local sewer authorities may not allow discharges of other wastes and wastewaters and will prohibit certain wastes.

Discharge Prohibitions

Specifically prohibited in nearly every sewer use code are:

* Oil and grease2—such as used oil and petroleum-based automotive fluids

* Strong acids and caustics3—such as battery acid

* Flammables—such as gasoline and fuels

* Explosives

* Materials which may generate toxic or explosive gases

* Extremely toxic compounds

* Unreported EPA hazardous wastes—such as spent antifreeze (see Pretreatment Requirements below)

Some local codes have specific limits on other chemical parameters such as organic compounds, metals, pH, COD, etc. Some local codes require periodic monitoring and reporting—and this is becoming more common. Some state and local codes prohibit the discharge of spent antifreeze coolants, discussed later in this chapter.

2 Typical limits for oil/grease generally range from 50-200 milligram per liter (mg/l).

3 Typical limits for pH range from 6-10 units.

Domestic Sewer Exclusion

Under the Domestic Sewer Exclusion of RCRA, the federal rules currently allow the discharge of certain hazardous wastes, if properly reported, to POTWs. This exclusion currently applies to spent coolants unless prohibited by state or local rule. For more information, see discussion of coolant (antifreeze) disposal and recycling later in this chapter, and contact the state water-quality agency.

Pretreatment Requirements

Under the General Pretreatment Standards of the CWA, dischargers to POTWs of more than 33 pounds (about 4 gallons—based on the density of water) of hazardous wastes per month must notify the regional office of the EPA, local sewer authority and state hazardous waste agency (see Appendix A). This would presumably include spent coolants, unless you have specific data which demonstrates spent coolants from your facility are nonhazardous.

Wastewater Collection and Drainage

A diagram of a typical wastewater collection system for a modern vehicle maintenance and refueling facility is shown below. Although there are variations in design features, most new and existing facilities, particularly in well-developed and urban areas, will conform to this model. Note service area bay drains are connected to a grit chamber (for trash and large solids removal and cleanout) and an oil/water separator (OWS) for removal of oil and solids prior to the connection to the main sewer line.

A sewer connection may be granted by the local authorities without any unusual requirements. At a minimum, a properly designed OWS is an NFPA standard for vehicle maintenance shops and service stations and by most sewer use and pretreatment ordinances. An animation of an OWS is shown below:

Some sewer authorities may require performance criteria for the OWS while others may, in addition, require monthly, quarterly or annual sampling and testing of the discharge to the main sewer line. Some may disallow any connection from service bays whatsoever, while others may specifically disallow discharge of spent coolants or other wastestreams. Operation, inspection and maintenance of OWSs are covered below.

Operation and Maintenance of Oil-Water Separators

OWSs are normally installed at vehicle maintenance facilities to prevent excessive discharges of oils and solids. They are required by NFPA codes.

Note: This is a minimum standard and some states may have stricter requirements. Some owners may be required to install OWSs as part of the refueling and fuel storage area drainage system to:

* Collect small amounts of oil discharges and oil sheens,

* Provide for the collection of a large release of fuel, and

* Prevent the release of petroleum to surface waters or adjacent property.

Caution: If not periodically inspected and pumped out, an OWS can cause a slug discharge of petroleum to surface waters or adjacent property.

Periodic inspection and maintenance of the OWS and associated piping and drains are necessary to eliminate plugging and backup to maintain performance and meet sewer use codes. The outlet to an OWS for service bay drains should only be connected to a POTW. Discharge to stormsewers or surface water would require an NPDES permit and is not a recommended practice.

Purpose of an Oil-Water Separator

The OWS is an underground temporary holding chamber for wastewater. The purpose of the separator is threefold:

* To settle out solid material such as dirt, sand and metal grit,
* To float out light materials, primarily oils, and
* To provide some containment in the case of a petroleum spill.

Typical holding capacity ranges from 250 to 1,000 gallons for these applications and are either a single- or double-chamber design. Restroom sanitary wastes should never pass through the OWS.


An OWS is installed between the service bay drains and the municipal sewer connection as shown in the diagram on page 6.7. It is normally located outside and is accessible and identifiable by a manhole. In cold climate regions, the OWS may be located inside to prevent freezing. Sometimes the oil which is separated in the OWS is continuously discharged by gravity through a connection to the inground used oil tank.

In some localities, periodic cleanout is a requirement of the sewer use permit and proof of maintenance must be shown every year. Separators have become a focus of attention by environmental and sewer authorities as well as landlords, owners and property managers.

Cleanout Frequency

Over a period of time, oil and solids accumulate and cleaning is required to maintain operating efficiency.

When oil levels reach maximum depth, the oil begins to discharge to the sewer system, causing a violation of discharge standards.

Solids and sludge eventually accumulate above the design level and may also pass through and cause plugging of drains and sewer lines.

Determining when an OWS needs cleaning requires periodic inspection. Cleaning frequency is dependent on the amount of solids and oils introduced into the drains and the design capacity.

Reducing Cleanout Frequency

Under the proper conditions, an OWS may require cleanout every 2 to 3 years. Due to a wide variation of operating practices, this cleanout frequency may be every 3 to 6 months, until more care is taken with what is discharged to the drains.

Minimize the amount of dirt and solids which enter the drains. Use of strainers or screens in the drains will also collect some solid materials. Under no circumstances should any oils, waste oil, solvents, acid, automotive fluids or any other liquid chemical or solid material be placed in the drains.

Contracting for Cleanout

The OWS may, at times, require only pumping of surface oils. At other times, it will need both pumping for surface oils and a cleanout of sludge and solids. These times can be determined by quarterly inspection. Facility personnel should inspect the OWS on a quarterly basis and order a cleanout of oil or solids when necessary.

Some used oil transport firms will pump out the floating oils for a fee. Some used oil transport/recycling firms will pump out oil, water and sludge and will usually charge a premium. The water can also be temporarily removed, stored in drums and returned to the OWS. Always refill the OWS with water prior to placing it back into operation.

It may be necessary to locate a firm which specializes in tank and pipe cleaning and OWS cleanout to conduct this work. Do not use unlicensed firms or firms who only pump out septic systems. A sample should be taken by the service firm to determine if the sludge/solids is an EPA hazardous waste to determine the proper disposal methods.

As necessary, inspect and clean pipes, drains and catch basins. Wastes and wastewater from the cleanout of the OWS and associated piping and drains must be disposed of in accordance with federal and state rules. See Chapter 3, Hazardous Waste Management.

Improving Oil-Water Separator Performance

After maintenance and cleanout of the OWS and implementing practices in the shop to limit the amount of oil, solids and other contaminants which enter the system, you may still be unable to meet discharge limits.

An OWS is not designed to remove certain contaminants such as emulsified oils, dissolved solids, dissolved metals such as lead, or dissolved benzene or chlorinated compounds; nor does an OWS reduce BOD or COD.

Detergents: The use of specially formulated detergents for floor washing and vehicle washing can greatly enhance OWS performance. Ask for detergents with built-in flocculents (to “float out” emulsified oils) and settling agents (to “coagulate” and settle suspended solids). Some detergents and cleaners are highly acidic or caustic and, when used in a concentrated form, can create pH and other problems. It may be a permit requirement in some areas to use a nonphosphate or low-phosphate, biodegradable detergent.

OWS Design: If the above measures cannot meet discharge limits for oil/grease, it may be necessary to install an OWS guaranteed to meet your specific limitations. A larger-capacity, double-chambered, corrugated-plated or other OWS designed for high efficiency may need to be installed. A properly designed and operated OWS should achieve 20 to 30 ppm oil/grease; whereas high-efficiency units can achieve about 10 ppm.

Other Problems: Several other problems with discharge characteristics from OWSs are given below along with possible sources.

* pH too high or too low—from improper use of detergents or cleaners, or from discharge of caustic or acidic materials

* High COD—from detergents and antifreeze

* High fluorides—from the use of hydrofluoric acid-based aluminum brighteners

* High chlorinated hydrocarbons—from the use of solvents and cleaners

* High benzene, toluene or xylene—indicates contamination with gasoline or solvents which contain these compounds

* High total petroleum hydrocarbons—indicates contamination with gasoline, diesel, used oil or petroleum products

* High lead levels—from spent coolants or radiator repair; may be from cleaning of heavily greased areas such as truck fifth-wheels; may be from leakage from batteries or washing/steam cleaning around batteries

If the above changes in operations or product substitutions are not enough to meet your discharge standards, you may need to install other wastewater treatment/recycling equipment.

See the fact sheet on Oil/Water Separators

Service Bay Wastewaters

It is very important to verify your service bay drains and sinks are connected to the POTW. This is especially important during evaluation of a facility prior to purchasing or leasing.

As mentioned earlier, the discharge of service bay wastewaters to septic systems, dry wells, soakpits, stormsewers, surface waters or the ground is a serious violation without the proper EPA permit.


Maintenance in the service bay areas generally produces these types of commingled wastes and wastewater:

* Wastewater from floor washing
* Spent coolant discharges
* Snow melt and rainwater carry-in
* Floor spills and spill residues
* Steam cleaning
* Vehicle washing wastewater


Wastewater from floor washing will contain oil/grease and solids such as sand and grit. In addition, this wastewater may contain dissolved heavy metals such as lead and possibly organic compounds from residues of minor spills. Various liquid wastes which directly enter the drain system from seemingly minor spills of chemicals and automotive fluids can greatly affect the level of contamination in the wastewater. Immediate clean-up of spills of any liquid on the floors should be mandatory. In addition, the detergents add to the pollutant loading and increase the level of oil and grease since detergents, by nature and design, emulsify and dissolve oil and grease.

Steam cleaning or washing of engines, greased parts and truck fifth-wheels not only contributes high levels of oil/grease but also metals such as lead and cadmium.

Steam cleaning or washing of batteries or battery storage areas also contributes to lead contamination.

You may be able to improve the quality of wastewater (decrease the amount of contaminants) by using a better detergent, decreasing or eliminating the use of certain materials in the shops or by other operational changes. See Improving Oil-Water Separator Performance under Section 6.11.

Disposal and Treatment Options

Proper disposal of service bay area wastewaters is of particular concern where connection to the POTW is not available, not economical or not allowable.

In 1991, EPA issued orders to ten major oil companies to halt the discharge of wastewaters associated with automotive service into sinks and drains connected to septic systems and dry wells. This order affected 1,800 company-owned-or-operated service stations and required the facilities to pay penalties totaling over $830,000, cease the discharges and implement a clean-up of soil and groundwater. The total clean-up costs were estimated at $40 million to $90 million for the 1,800 locations. In addition, EPA may seek up to $125,000 in penalties for each violation discovered in the future.

Where POTW connections are not available, four methods of wastewater control may be employed as follows:

Option 1—Dry, closed system: Permanently close and seal drains. Steam clean floor and install an impermeable, durable and easily cleaned epoxy floor sealer. In large shops, purchase an industrial floor cleaner or use an outside service for periodic cleaning. For small shops, manual mop-and-bucket floor cleaning methods may be necessary. Temporarily store wastewater on site for proper off-site disposal. Wet mop or wet vac accumulated water from rain carry-in and snow melt. See the fact sheet on Floor Clean Up

Option 2—Wet, open system: Install a sump to collect the drainage from the floor drains. Collect the water in the sump and periodically pump out for off-site disposal. You can automatically pump the water from a small sump to an AST, if necessary. An underground holding tank can also be installed. Impress upon employees to minimize water usage during floorwashing to keep disposal and transportation costs to a minimum. Transportation and disposal costs can range from $.25 per gallon to $2 per gallon.

These wastewaters may be acceptable to discharge, with permission, to a POTW at another location. The wastewaters collected by these methods should not normally be hazardous. However, only testing and analysis will dictate if these wastewaters must be treated as hazardous for your particular facility.

Option 3—On-site treatment: The use of on-site wastewater treatment equipment may be necessary to allow for the pretreatment of wastes prior to entering the POTW.

a) Units are commercially available for the reduction of oil/grease, metals and organics. If properly designed, a unit may be able to meet discharge limits for discharge to the ground or to surface waters under an appropriate permit, as well as the POTW.

b) Where wastewater volumes are relatively high, particularly where vehicles are routinely washed, wastewater treatment and recycling equipment can be installed. These systems can allow 100% reuse of the treated wastewater and reduce water consumption.

Besides the high initial cost of installation, on-site treatment also has continuous operation and maintenance, making these options impractical in most small shops.

Where wastewater volumes are relatively low, evaporation equipment can be installed to reduce or eliminate wastewater. Liquid wastes and sludges can be chemically fixated (solidified) rendering the potentially hazardous waste a nonhazardous waste suitable for direct landfilling.

Option 4—Discharge to a septic system or dry well: These systems, when used to discharge motor vehicle maintenance wastes and wastewater, are Class V injection wells and may be regulated by the UIC program under the SDWA. These discharges are allowed in some areas and not allowed in others—with or without a UIC permit. You will need to check your own state and local agencies for the rules that apply at your location.

Class V wells for motor vehicle wastes could also be considered a violation under RCRA, if, at any time, the wastes were to be considered an EPA hazardous waste. Use of these systems for purposes other than domestic-waste treatment is not advisable.

In accordance with a final rule dated November 23, 1999, some Class V wells receiving motor vehicle maintenance wastes (not already banned by state rule) must be closed as follows:

All new Class V wells— banned nationwide after April 2000.
Existing Class V wells in Groundwater Protection Areas (as designated by your state) must be closed by January 1, 2005 (a one-year extension may be available in some states).
Existing Class V wells in Other Sensitive Groundwater Areas (as designated by your state) must be closed by January 1, 2007 ( a one-year extension may be available in some states).

Spent Coolants and Radiator Flushing Solutions

Spent coolants are generally 50/50 solutions of antifreeze and water. Antifreeze, is 97 to 98% ethylene glycol and the balance proprietary additives. High COD and lead concentrations are the primary concern of regulators. Although treatment of spent antifreeze at most POTWs is complete, and does not affect the POTW operation, several states and many localities prohibit antifreeze discharges.

At the time of this writing, the states of California, Delaware, Illinois, Massachusetts, Michigan, New Hampshire, New Jersey, Texas and West Virginia do not allow the discharge of antifreeze into POTWs. Many local areas also disallow the discharge.

Where discharge of antifreeze to the POTW is prohibited, it is necessary to segregate and collect this wastestream. Furthermore, it is illegal to discharge spent coolants to any other system (on the ground, underground, or directly to surface waters or stormsewers). In these cases, the options are:

1) Collection and storage of spent coolants for off-site treatment (which may include discharge to a POTW at another location, if allowable);

2) Off-site recycling; or

3) On-site recycling.

Radiator flushing wastewaters may also be of concern. Where discharge to the POTW is not available and radiator treatment and flushing is desired, a combination of radiator flushing and coolant recycling equipment will eliminate the relatively large volume of wastewater generated.

For more information on antifreeze disposal and recycling, see Chapter 7, Waste Reduction and Recycling.

Radiator Repair

In shops where complete radiator repairs are performed, as many as three distinct sources of wastes and wastewaters are present. These are the boilout tank, flush booth and test tank.

Radiator boilout tanks used to remove paint, oil and scale contain a caustic solution. Although no wastewater is discharged directly, drag-out of the solution to the floor drains and flush booth contributes to high pH and high lead, zinc and cadmium levels. Over time, sludges accumulate in the boilout tank and require removal and disposal.

Most boilout operations have been discontinued as modern automobile radiators are now made with aluminum components which are damaged by the caustic solution.

In shops without a boilout tank, wastewaters will be acidic (low pH) due to the acidic soldering fluxes used.

Most shops now use only a flush booth where the radiator is back-flushed with high-pressure water to knock out scale. Wastewater and sludges are generated in the flush booth tank.

Radiator test tanks are also a source of contaminated wastewater and sludge.

Wastewaters contain high levels of lead (up to 1,000 ppm or more), oils from transmission oil coolers, ethylene glycol and other metals.

Although discharge of these wastewaters to POTWs may still be allowable in many areas, it is being prohibited in many areas. Most facilities will eventually need to provide treatment prior to discharge or use a total closed-loop recycling system.

Treatment of wastewaters may be accomplished through filtration, pH adjustment, chemical precipitation and settling. Packaged systems designed for radiator shops are commercially available. Options include sludge dewatering by way of centrifuging or filter press. Treated water can be reused in the tanks.

Sludges must be handled as a hazardous waste. It may be possible to exempt sludges from regulation if they are sent to a primary smelter for reclamation of the metals. Sludges can also be chemically fixated and solidified rendering the sludges a nonhazardous waste suitable for direct landfilling.

Vehicle Washing

The washing of cars, trucks, buses and off-road equipment should only be conducted where wastewaters can be properly contained and treated. Wastewater from vehicle washing is considered a process wastewater. The discharge requires an NPDES permit unless it is discharged to a POTW. POTWs generally require settling and oil-water separation, but in some areas may require further treatment and limitations on the types of detergents and other chemicals used in the washing facility.

Automated car washes are commonly purchased as a total unit complete with wastewater treatment systems which meet POTW requirements. Do-it-yourself car washes generally must be equipped with an OWS before a connection to the POTW can be made. Direct discharge to stormwater sewers or surface waters is prohibited.

At trucking and transportation facilities and heavy construction equipment maintenance areas, vehicle washing presents more of a problem. Commonly, trucks and heavy equipment are washed outdoors without adequate facilities. These operations are coming under closer regulatory scrutiny. In these operations, treatment or recycling of vehicle washwaters is recommended and may be required where POTW connections are not available. If properly sized, these systems should also handle other wastewater streams.

Vehicle washing solutions are discussed in detail in Section 6.10 following stormwater controls and permitting.

Tanker Cleaning and Rinsing

Wastewaters generated by the cleaning and rinsing of bulk transport and tanker trucks which carry bulk materials and chemicals require special consideration. If the tanks have contained hazardous wastes or materials, pesticides or other substances, the rinse and washwaters can be a hazardous waste. Special rules may apply which include special employee protection and safety procedures and being permitted as a hazardous waste storage facility.

Tank Bottom Water

Water which is removed from the bottom of gasoline tanks will most likely exceed EPA limits for benzene of 5 parts per billion (ppb) and could be considered a hazardous waste. However, if the water is pumped out along with recoverable fuel, it may be considered an off-spec product and exempt from federal hazardous waste rules if it is destined for reclamation. You must not intentionally add fuel to the contaminated water to avoid regulation. Typically, it is difficult to avoid removing some amount of fuel from the tank with the water.

EPA has not issued a specific mixture ratio or designated a minimum amount of fuel in the mixture for the mixture to be considered an off-spec product. Therefore, any amount of gasoline (or fuel) in the mixture, for example, 1 gallon, should be acceptable for the return of the mixture to a refinery, petroleum terminal or used oil recycling/fuel blending plant for proper treatment without being handled and transported as a hazardous waste.

Gasoline tank bottom water containing no gasoline in the mixture would most likely exceed the benzene limits and would be a regulated hazardous waste. Treatment methods include the following:

* It is possible the discharge of this water to the POTW would be acceptable without treatment, if permission is obtained.

* Water may be pumped out and treated on site by a mobile carbon filtration unit prior to discharge to POTWs.

* You may contract with an EPA-permitted hazardous waste service firm to pump out the water for off-site treatment.

Water from diesel tanks is not likely to be hazardous due to benzene. You should be able to directly discharge this to the POTW after receiving permission or remove the water for off-site treatment. In the states of California, Florida, Michigan and South Carolina, this water may be hazardous due to other organic compounds, called polyaromatic hydrocarbons (PAHs) found in diesel fuels.

Water and sludge from tank cleaning may also be a hazardous waste. See Chapter 3, Hazardous Waste Management, for more information.

Stormwater Regulations

40 CFR, Parts 122-124

State-specific stormwater rules and resources are one click away.

swpp In 1990, the EPA established stormwater regulations which affect many truck and transportation terminals that perform either vehicle washing, refueling or maintenance. These stormwater regulations cover a variety of industries including trucking and transportation, petroleum marketing and bulk storage, utility fleets, government fleet operations, etc. Retail automotive service shops, truck stops, light truck rental and leasing and service stations are exempt, but could be affected when Phase II is implemented.

According to the regulations, stormwater means “stormwater runoff, snow melt runoff, surface runoff and drainage.” Stormwater discharge associated with industrial activity means the “discharge from any conveyance which is used for collecting and conveying stormwater and which is directly related to manufacturing, processing or raw material storage areas at an industrial plant.”

EPA has specifically targeted “transportation facilities” but only those portions of the facility that are either involved in vehicle maintenance (including vehicle rehabilitation, mechanical repairs, painting, fueling and lubrication), equipment cleaning operations or airport deicing operations . . . are defined as “associated with industrial activity.”

Regulations require a stormwater discharge permit, which is issued under the NPDES. The first step in applying for the permit is to submit a Notice of Intent to the regulatory agency that administers the NPDES program for your state. That agency then issues the stormwater discharge permit.

Three Types of Stormwater Discharge Permits

Up until October 1995, two types of stormwater discharge permits were available: an individual permit or a group permit. A multisector permit was introduced in October 1995 as a third choice. The multisector permit requires written certification that your stormwater discharge is in compliance with the Endangered Species Act and National Historic Preservation Act.

This new, 515-page permit, which addresses specific industries, is an offshoot of group permits—but it only applies to U.S. territories, the District of Columbia and 10 states that don’t issue general permits. (AZ, FL, ID, LA, ME, MA, NH, NM, OK and TX. Puerto Rico, Midway and Wake Islands, Indian reservations and federal facilities are also included.)

Permit conditions require each facility covered by the permit to develop and implement a Storm Water Pollution Prevention Plan (SWPPP). In some cases, the SWPPP must have been prepared by April 1, 1993 and implemented by October 1, 1993.

The SWPPP must contain certain elements that are detailed in the permit. The purpose of the SWPPP is to identify the sources of pollution that may affect the quality of the stormwater discharges and also to ensure the implementation of pollution prevention practices.

Typical SWPPP preparation requires a detailed site inspection, scaled site plan of the facility and evaluation of the site for the presence of nonstormwater discharges (such as vehicle washing). The plan must be maintained at the facility and available to regulators upon request. SWPPP requirements are discussed below.

In some states, periodic sampling and analysis of stormwater discharge may be required. Changes in operating practices and/or facility engineered controls may even be necessary in some cases.

Failure to obtain stormwater discharge permits and prepare/implement a SWPPP could result in civil and criminal penalties.

For more information call the Federal Stormwater Hotline (703-821-4823) and your state agency or EPA regional office administering the NPDES permit program (see Appendix A).

Storm Water Pollution Prevention Plan

The plan must include evaluation of all potential stormwater pollutants from:

* Vehicle fueling areas
* Fuel storage and loading
* Fuel spill controls and clean-up
* Outdoor storage of products (oil, salt, fuel, etc.)
* Outdoor storage of wastes (oil, batteries, etc.)
* OWS discharge location, inspection and maintenance
* Vehicle washing operations
* Outdoor servicing involving fluids
* Steam cleaning areas
* Soil erosion areas

Best management practices are to be implemented to minimize or eliminate stormwater pollutants from all sources including the above areas as well as elimination of nonstormwater pollution sources such as vehicle washing, maintenance operations or fuel area washdowns.

The plan must provide the following records:

* Detailed site plan showing potential pollutant sources and stormwater outfalls

* Materials inventory
* Monthly inspection checklist
* Pollution prevention team roster
* Spill report forms
* Employee training records
* Annual compliance certification

It is expected employing best management practices and principles of pollution prevention would eliminate unacceptable stormwater pollutant levels. In general, EPA or states are not expected to require engineered controls.

Exemption from Stormwater PermitsA no-exposure certification for Phase I and Phase II stormwater permits became effective February 7, 2000 as published in the December 8, 1999 Federal Register. This allows facilities to obtain an exemption from a stormwater permit. EPA will grant a certification beginning in the summer of 2000 in the non-delegated states (Maine, Massachusetts, New Hampshire, Florida, New Mexico, Texas, Arizona, Idaho, and Alaska). Other states must accept it into their programs before it is available.

A copy of the federal No-Exposure Certification Checklist is provided on the following page. The form must be completed, signed by a company officer and submitted to EPA. If approved, the facility need not obtain a stormwater permit as long as operational conditions do not cause a violation of the certification.

Proposed Stormwater Phase II Regulations

EPA has proposed stormwater Phase II regulations that require municipalities with populations between 1,000 and 100,000 to develop stormwater-control plans to limit the discharge of pollutants to surface waters. The federal Phase II regulations do not target specific industries (except construction activities), like automotive and heavy-duty repair facilities, or any other facility exempted under Phase I. It will leave that decision to the local authorities. In other words, vehicle maintenance/refueling facilities exempted under Phase I could still could be subject to local permitting/registration requirements and preparation of stormwater-management plans.

Local authorities are likely to target facilities that have illegal connections to stormwater sewers and require corrections. In addition, the Phase II rules will cover construction projects impacting 1 to 5 acres where the likelihood of stormwater exists. At new construction or expansion sites, facility owners and contractors may need NPDES discharge permits and assure best management practices are used to limit stormwater pollutants from erosion. The EPA plans to implement the regulations beginning in the year 2002.

Vehicle Washing Issues and Solutions

Pressure Wash/Power Wash Discharges

It is common practice to clean equipment and vehicles outdoors with mobile pressure wash/power wash units.

As stated before, the CWA and EPA prohibits “point source” discharges of pollutants into waters without a NPDES permit. This includes discharges from pressure wash/power wash operations. It also includes mobile pressure washers. Most NPDES permitted dischargers would also require treatment and analysis—an impracticality for most situations.

However, you can still comply with CWA by not discharging this processed water to waters of the U.S. Commom compliance methods are:

1.) Retaining the wastewater and vacuuming/pumping it to a container for later

2.) Berming the wastewater and allowing it to evaporate

3.) Pumping and discharging to a POTW

The most common form of noncompliance is to discharge this water to a storm sewer leading directly to waters of the U.S.

You should also review the section on vehicle washing for other methods of compliance.

EPA notes it recommends vehicles be washed at a properly permitted commercial vehicle wash. If this is not practical, EPA says that NPDES requirements may be avoided and impacts on waters may be minimized if vehicles are washed in a grassy area where the wash water can be absorbed into the ground. There could be additional requirements if the absorbed water will reach an underground body of water, or if waxes, detergents or other chemicals are improperly used.

You should be cautioned however, this is only a possible solution if the vehicles or equipment are soiled with mud or dust and at the most contain light films of oil, diesel soot, road salt and minimal amounts of other types of contaminants. Vehicles or equipment that are moderately or heavily soiled with oil/grease, asphalt, or any hazardous material should not be washed on the ground.

Note: The following section on vehicle washing options was contributed by D. Richard Castellano, President, FleetServ, Lake George, NY.

Vehicle Washing Options

Stormwater regulations have required fleet operators to take new approaches to meet their vehicle washing needs. In most cases, fleets can no longer just be washed in the yard where they sit. Past practices must be reevaluated and revised to ensure your washing meets all federal, state and local laws.

Presented below are the most common options available. You must be creative and adapt these options to meet your operational, budgetary and site-specific needs. The arena of available equipment and regulatory interpretation is constantly changing.

It will help if you first evaluate your site and local laws. Answering the following questions will narrow the search for the washing system that best fits your exact needs.

Are you on a sanitary sewer or septic?
Is your yard paved and in good condition or is it stone or dirt?
Are you on city water or a well?
What quality of wash do you desire?
What type of contaminants do you expect to find in the washwater?
What is your budget?

Off-Site Washing: If there is a commercial truck wash located in your area, this may be a good option dependent on your specific operations. There are automatic drive-through style washes as well as do-it-yourself truck wash bays.

* No investment in equipment or supplies
* All wastes are disposed by the truck wash
* No regulatory headaches

* Usually high cost ($40 and up)
* Commute time and cost per mile to location
* Waiting time cost if a busy location
* Logistical problems of moving vehicles

On-Site Dry Washing: This method of vehicle cleaning involves the use of a product which is sprayed onto a dirty vehicle and wiped off with a cloth. The products usually contain silicones or polymers which claim to encapsulate dirt and keep it from scratching a vehicle’s finish when wiped off.

* No wastes generated other than dirty rags
* No regulations to meet regarding stormwater
* No water use or discharge
* Provides additional paint and finish protection

* Very labor intensive method

* Usually high chemical cost per vehicle ($2 plus per tractor)

* Current chemicals do not completely remove heavy grease, oil and bugs

* Cannot be used on tires

Yard Washing (Storm Drains Capped/Area Diked): This option allows you to temporarily cap or plug stormsewer drains and dike off your paved or concrete wash area using absorbent dikes, water-filled berms or vacuum-type berms to contain washwater. The wash area must be free of cracks or breaks in the surface. After washing, the water and solids are picked up from the ground, and the area is cleaned. Wastes are hauled off, recycled or treated and discharged to the sanitary sewer with permits. Some government agencies allow this, and others do not.

Costs of this service vary according to your own system, how water is handled and treated, amount of solids produced and disposed, etc.

Portable Mat System: This system utilizes a heavy-duty rubber wash pad with air-inflated berms which contains all truck washwater and wastes. The vehicle is positioned on the mat, washed and water is removed and hauled, recycled or treated for discharge to the sanitary sewer with permits. Solid wastes are removed by shovel and contained for proper treatment or disposal.

* Zero discharge to the ground
* All wastes are contained
* No additional wastes from the yard are accumulated
* Can be used on stone or dirt yards
* Can perform engine degreasing on a pad

* Vehicles must be moved to the pad similar to a wash bay operation

* Some extreme winter operations may be difficult

Costs will vary depending on quality of mat required and waste handling methods.

On-Site Truck Wash Facility: Installing an on-site vehicle wash facility is an option if your fleet size and wash frequency justify the costs. It involves the construction of a wash pad, plumbing and treatment systems, the actual equipment for washing and a building in most cases.

There are “touchless” systems which rely on chemicals and water temperature and pressure or fully automatic “brush” systems.

If you operate an on-site system with your own staff, be sure to micromanage your wash operation. The improper use of detergents can double your cost per vehicle.

If you are in an area with other fleets you may want to consider a shared operation to help reduce your washing costs.

Washwater Handling Options

Recycle: Washwater is contained, treated and stored for reuse. There are many different types of systems available, and their selection should be based on your filtering requirements and size of operation. Stored water should be continuously treated with ozone to prevent bacteria growth and stagnation. Fresh water should always be used to rinse a vehicle washed with recycled water to prevent spotting.

Sanitary Sewer Discharge: At a minimum, an OWS and sometimes additional treatment will be required by your local POTW.

Hauling Wastewater Off-Site: Usually costly for the actual hauling and cost per gallon charged by some treatment firms. Costs range from $.25 per gallon to over $2 per gallon depending on volume and frequency of pickup.

Waste Disposal

Some tests performed on solid residues have indicated the presence of hazardous constituents. In these cases, disposal of the solids in a municipal landfill was not allowed.

You must test and conform to all regulations pertaining to hauling and disposal of your solids.

Your Protection

If you are using an outside vendor, here are some items you should check:

* Proper insurance carried

* Necessary state and federal EPA and DOT ID numbers maintained

* Proper manifests and documents maintained

* Vehicles are properly registered, placarded and maintained

* Disposal records are available to you

* Destination of all liquid and solid wastes is known to you

* POTW permits are obtained and followed

* Proper detergents and chemicals are used

* Vendor employees are knowledgeable about laws, waste handling and spill response plans

Note: This ends the section on vehicle washing options contributed by D. Richard Castellano, FleetServ, Lake George, NY.


Source Water Protection Practices Bulletin

Managing Vehicle Washing to Prevent Contamination of Drinking Water

Vehicle washing is the cleaning of privately owned vehicles (cars and trucks), public vehicles (school buses, vans, municipal buses, fire trucks, and utility vehicles), and industrial vehicles (moving vans or trucks and tractors). The vehicle wash water can carry sediment and contaminants to surface waters, and can contaminate groundwater by infiltration or by drainage to subsurface wells and/or septic systems. This fact sheet focuses on management of vehicle washing to prevent contamination of drinking water sources.


Vehicle washing occurs at commercial car wash facilities (for both interior and exterior cleaning), public works garages, car dealerships, truck stops, and any other facility that washes vehicles. When vehicles are washed, contaminants in the wash water and the overspray can enter source water untreated through surface runoff (e.g., through storm drains) and underground discharge (e.g., through carwash wells or septic systems). Vehicle wash water contains oil, grease, metal (paint chips), phosphates, detergents, soaps, cleaners, road salts, and other chemicals that can contaminate source water.

EPA estimates that there are 7,200 carwash wells in the United States. These carwash wells, which inject wash water into the subsurface, are categorized by EPA as Class V underground injection wells. In a 1999 EPA study on Class V wells, concerns were raised about the use of carwash wells to dispose of wash water from “wand washes” such as coin-operated, manual facilities where people use hand-held hoses to wash vehicles. Because an attendant is not usually on site, individuals may wash their engines or undercarriages using degreasers, wash the exterior of their vehicles with chemicals other than common soap solutions, or may pour used oil, antifreeze, or other hazardous materials down these drains.


Managing vehicle washing near drinking water sources is important because the wash water can flow into storm water drains and enter surface water sources untreated. The wash water can also percolate through the soil or enter the subsurface through carwash wells, and contaminate ground water. The contaminants in vehicle wash water can cause a variety of health effects, including kidney damage, circulatory system problems, increased cancer risk, and delays in physical or mental development.

Once a water supply becomes contaminated, it is very difficult and costly to treat. Treating the water supply is a lengthy process and is not always successful. Using an alternative water source may also be costly and impractical.


A variety of prevention measures, including nonstructural and structural activities, are available to address vehicle washing. Please keep in mind that individual prevention measures may or may not be adequate to prevent contamination of source waters. Most likely, individual measures should be combined in an overall prevention approach that considers the nature of the potential source of contamination, the purpose, cost, operational, and maintenance requirements of the measures, the vulnerability of the source waters, the public’s acceptance of the measures, and the community’s desired degree of risk reduction. Some of the more conventional prevention measures are described below.

Local governments can use a variety of land use controls to protect source water from potential contamination. For example, zoning can restrict certain activities to specific geographic areas that are distant from drinking water sources. Localities can also prohibit certain uses within certain areas. For example, prohibition of vehicle washing activities in source water protection areas can reduce the risk that harmful contaminants may enter source water. Local governments may also require permits that impose additional requirements such as setbacks, open spaces, buffers, walls and fences; street paving and control of site access points; and regulation of hours and methods of operation. Local municipal treatment plants may have a storm water treatment program; coordinate with your local municipal treatment plant to eliminate illicit discharges. States may require vehicle washing facilities to apply for ground water discharge permits. Many of these facilities discharge wastewater containing regulated contaminants above the State’s ambient ground water standards.

Design and Operation of Washing Facilities

Warning signs should be posted for customers and employees instructing them not to dump vehicle fluids, pesticides, solvents, fertilizers, organic chemicals, or toxic chemicals into catch basins. Catch basins are chambers or sumps which collect runoff and channel it to the storm water drain or to the sanitary sewer. Vehicle wash facilities should stencil warnings on the pavement next to the grit trap or catch basin. All signs should be in a visible location and maintained for readability.

Wash areas should be located on well-constructed and maintained, impervious surfaces (i.e., concrete or plastic) with drains piped to the sanitary sewer or other disposal devices. The wash area should extend for at least four feet on all sides of the vehicle to trap all overspray. Enclosing wash areas with walls and properly grading wash areas prevent dirty overspray from leaving the wash area, allowing the overspray to be collected from the impermeable surface.

Enclosed carwash

The impervious surfaces should be marked to indicate the boundaries of the washing area and the area draining to the designated collection point. Washing areas should not be located near uncovered vehicle repair areas or chemical storage facilities; chemicals could be transported in wash water runoff.

Regular cleaning of wash areas and grit traps or catch basins can minimize or prevent debris such as paint chips, dirt, cleaning agents, chemicals, and oil and grease from being discharged into storm drains or injection wells.

Using alternative cleaning agents such as phosphate-free, biodegradable detergents for vehicle washing will reduce the amount of contaminants entering storm drains. Cleaning agents containing solvents and emulsifiers should be discouraged because they allow oil and grease to flow through the oil/water separator (see below) instead of being separated from the effluent. In addition, these cleaning agents will remain in the wastewater and can pollute drinking water sources.

Proper Management of Wastewater

There are several approaches for managing wastewater, depending on the size of the site and the resources available. These are described below.

Oil/water separators are tanks that collect oily vehicle wash water that flows along corrugated plates to encourage separation of solids and oil droplets. The oily solids or sludge can then be pumped out of the system through a different pipe. The sludge can be hauled off site, and the wash water can be discharged to vegetated areas or to a treatment plant. There are two types of oil/water separators, one that removes free oil that floats on top of water, and one that removes emulsified oil, a mixture of oil, water, chemicals, and dirt. Choose the separator that fits the needs of the vehicle wash facility.

Collection sumps are deep pits or reservoirs that hold liquid waste. Vehicle wash water accumulates in the collection sumps, and is pumped or siphoned to a vegetated area (such as a grassed swale or constructed wetland). Sediment traps can also be used to strain and collect the vehicle wash water, prior to pumping or siphoning the wash water to a vegetated area.

Recycling systems reduce or eliminate contaminated discharges to storm water drains and injection wells by reusing the wash water until the water reaches a certain contaminant level. The wastewater is then discharged to a collection sump or to a treatment facility.

Where wastewater is not to be disposed to a sanitary sewer, grassed swales (shallow, vegetated ditches) or constructed wetlands (retention ponds with emergent aquatic vegetation) can be used to hold wastewater and allow contaminant removal through infiltration and filtration. These devices are described in greater detail in the fact sheet on managing storm water runoff.

Carwash with vegetated area

Education and Training

Employee training is an important tool to prevent vehicle wash water from entering storm water drains and injection wells and contaminating source waters. Employees should be aware of operation and maintenance procedures, proper disposal practices, and general housekeeping activities. They should be aware of toxic chemicals, if any, with which they may come in contact, and have access to a chemical management plan, if applicable, and an emergency contact list.

At all designated washing areas, spill prevention, control, and management should be planned and designed to prevent any spills of pollutants from entering surface water, ground water, or a publicly or privately owned treatment works. A chemical management plan should be implemented for vehicle washes that use metal brighteners, caustics or acids, halogenated hydrocarbons, or solvents. The plan should include a list of the chemicals used, the method of disposal such as reclamation or contract hauling, and procedures for assuring that toxic chemicals are not discharged into source water.


Spill Prevention, Control and Countermeasures (SPCC)

Under the CWA, an SPCC plan is required (40 CFR, Part 112) for facilities that store petroleum products (including used oil) and that have an aggregate aboveground storage capacity of more than 660 gallons, including indoor storage.

New revisions to the rule were finalized in May 2002. Although the SPCC plan is a Clean Water Act requirement, the full discussion of SPCC requirements are given in Chapter 5 as it also related to fuel and liquid storage facilities.. Please refer to Section 5.5 for more information on SPCC requirements.

Transportation Equipment Cleaning Industry Effluent Guidelines and Standards

EPA has published the final Effluent Limitations Guidelines, Pretreatment Standards, and New Source Performance Standards for the Transportation Equipment Cleaning Point Source Category. (Federal Register, August 20, 2000) This regulation establishes technology-based effluent limitations guidelines for the discharge of pollutants into waters of the United States and into publicly owned treatment works (POTWs) by existing and new facilities that perform transportation equipment cleaning operations.
Transportation equipment cleaning (TEC) facilities generate wastewater from cleaning the interior of tank trucks, closed-top hopper trucks, rail tank cars, closed-top hopper rail cars, intermodal tank containers, inland tank barges, closed-top hopper barges, ocean/sea tankers, and other similar tanks used to transport materials or cargos that come into direct contact with the tank or container interior. The cleaning of drums and intermediate bulk containers are not covered by the rule.

Scope of Regulation

EPA has established effluent limitations for facilities discharging to surface waters in the following subcategories:

· Truck/Chemical & Petroleum;
· Rail/Chemical & Petroleum;
· Barge/Chemical & Petroleum;
· Food.

EPA has established pretreatment standards for facilities discharging to POTWs in the following subcategories:

· Truck/Chemical & Petroleum;
· Rail/Chemical & Petroleum;
· Barge/Chemical & Petroleum.

This regulation excludes:

· Facilities which do not engage in cleaning the interiors of tanks.

· Wastewater associated with tank cleanings operated in conjunction with other industrial, commercial, or POTW operations so long as the facility only cleans tanks that have contained raw materials, by-products, and finished products that are associated with the facility’s on-site processes.

· Wastewater generated from cleaning drums and intermediate bulk containers.

Wastewaters Covered by Guideline

The wastewater flows covered by the rule include all contact washwaters which have come into direct contact with the tank or container interior including pre-rinse cleaning solutions, chemical cleaning solutions, and final rinse solutions. Additionally, the rule covers wastewater generated from washing vehicle exteriors, equipment and floor washings, and TEC contaminated wastewater at those facilities subject to the TEC guidelines and standards.

Additional Information

The Federal Register notice and supporting development documents describing this rule are available on the Internet at: http://www.epa.gov/ost/guide. For additional information, contact John Tinger at tinger.john@epa.gov” or at 202 260-4992. (Source: This section based on EPA Fact Sheet)


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