Why is vehicle and equipment cleaning a stormwater issue?
Wash water from vehicle and equipment washing has the potential to carry nutrients, metals, and oils and greases to local water bodies, if the detergent-rich water used for washing flows into the storm drain system that leads to local streams and rivers. These pollutants can impact the aquatic animals in these water bodies.
MDOT MAA maintains an airfield vehicle and equipment wash facilities at BWI Marshall and Martin State Airports. They are located between the BWI Marshall’s Signature Vehicle Maintenance Building (#134) and the Airport Tenants Vehicle Maintenance Building (#123) along the entrance road to the Fuel Farm, and west of MTN Hanger 6 adjacent to Taxilane G respectively. The facility drains are collected by oil/water separators to eliminate contaminants from sanitary sewer drains.
Tenants are required to prevent or reduce pollutants exposed to or discharged to stormwater from vehicle and equipment cleaning. However, there is flexibility in what measures tenants can implement to accomplish this. MDOT MAA has developed Stormwater Pollution Prevention Plans (SWPPPs) for both BWI and Martin State Airport NPDES permits. The plans identify best management practices for both MAA staff and tenants related to activities such as vehicle and equipment cleaning.
As described in Tenant Directive BWI-207.2 (Washing of Airport Tenants’ Vehicles and Equipment), tenants must use the airfield vehicle and equipment wash facility unless a permit for an alternative option is approved that includes:
- Developing a contingency plan for spills
- Blocking storm drains in the vicinity of washing activities
- Collecting wastewater
- Removing wastewater from the airport property
- Using chemicals for washing with a pH between 6.0 and 9.0
Some examples of best management practices tenants can adopt include:
- Designate an area for cleaning activities.
- Use “dry” washing and surface preparation techniques when possible. Consider dry washing as an option regardless of aircraft size. Remove all materials (i.e., drippings and residue) using vacuum methods. Dispose of properly.
- Provide secondary containment, and cover if possible, for containers of washing and steam cleaning additives.
- Use pigs/mats to control the discharge of wash water.
- Use biodegradable phosphate-free detergents.
- Keep wash area clean and free of waste.
- Include proper signage to prohibit the discharge of waste oils into the drains.
- Collect and discharge wash water to an approved treatment facility (sanitary sewer system) through a permitted connection.
Physical Site Usage
- Use off-site commercial washing and steam cleaning where feasible. Using appropriate offsite facilities will decrease the potential for stormwater pollution on-site.
- Clean equipment only in designated wash areas that are covered and/or bermed to prevent contamination of stormwater through contact with wastes. Cleaning areas should be clearly demarcated on the ground.
- Gate valves at catch basins will prevent discharge to the storm drainage system during washing activities by facilitating the collection of wash water.
- Filter and recycle wash water when possible.
- Inspect, clean, and maintain sumps, oil/water separators, and on-site treatment and recycling units.
- Obtain approval prior to commencing wet washing activities in any area outside designated wash rack.
- Maintain adequate supplies of spill response equipment and materials in accessible locations near areas where spills of cleaning chemicals may be likely to occur.
Inspection and Training
- Provide the appropriate level of employee training in the following areas: spill response and prevention, stormwater pollution prevention education, right-to-know awareness training, and hazardous materials management.
- Develop regular vehicle maintenance and inspection programs.
- Characterize wastes derived from oil/water separators.
Successful implementation depends on effective training of employees on applicable BMPs and general pollution prevention strategies.
One of the requirements of tenant leases is that tenants must adhere to the requirements of the applicable tenant directives and associated regulations. Not adhering to these requirements can impact the standing of the tenant lease.
Additionally, many of the best management practices identified above are those included in the SWPPP, which is applicable to both MDOT MAA and tenants at the airport. Not implementing best management practices in association with tenant activities may result in the contamination of stormwater at the airport. MDOT MAA is legally obligated to report any illegal discharges to MDE who may issue fines or penalties for non-compliance with the Clean Water Act and the NPDES Permit. This may result in civil or criminal penalties (see Part II.C.15 and 16 of the stormwater permit for more detail).
The following provides additional information on this topic: