B08g_Attachment_6_-_Exhibit_6_-_BMP_for_Pressure_Washing_and_Impervious_Surface_Cleaning.pdf

BMP for Pressure Washing and Impervious Surface Cleaning National Mall and Memorial Parks

This document is a guide to stormwater protections to help with maintenance or project planning in the event pressure washing is needed.

The National Mall and Memorial Parks (NAMA) is a large urban park which runs adjacent to or encompass the Tidal Basin, Washington Channel, and the Potomac River. Each of these bodies of water are considered “Waters of the United States,” (CWA Section 502(7)) and thus are subject to Clean Water Act regulations. These water bodies have also been deemed “impaired waters” (CWA Section 303 (d)) which requires additional regulations. These regulations require that permits be acquired to discharge anything other than precipitation into these bodies of water, either through the stormdrains or through runoff (contact the park Environmental Compliance Program Manager (ECPM) for more info on acquiring a permit). There are several different types of permits which could be acquired, all of which require monitoring, reporting and may not be the easiest route to solving the issue. This document will help identify ways to mitigate impacts to waterbodies during pressure washing and impervious surface cleaning.

NAMA has two conveyance systems: sanitary sewage (CSS), and storm sewer (MS4). The CSS or Combined Sewer System captures water and is treated at the wastewater treatment plant. The MS4 or Municipal Separate Storm Sewer System flows directly into the waterbodies through drains, inlets, ditches, catch basins or runoff. Majority of NAMA is within the MS4 (figure 2).

What is Pressure Washing?

Pressure washing uses mechanical equipment to create a high-pressure stream of water, typically ejected from a hand-held wand or nozzle. Depending on the application, pressure washing may be conducted with or without heated water or added cleaners.

Pressure washing is used to clean many things, including:

• Vehicles

• Equipment

• Parking lots

• Roads

• Building exteriors

• Walkways

• Roofs

• Graffiti

• Fences

As you perform your activities, we ask that you, your employees and/or contractors be proactive.

It is easier to prevent pollution than to try to clean it up once it has occurred. If you think there is a potential to create pollution, follow the 3C’s as a general guideline:

Contain: Contain your work area by preventing water and potential pollutants from leaving your work site and reaching the stormwater conveyance system. The area around your trash dumpster should be free of accumulated trash and debris. The trash dumpster itself should be free of leaks, if it is not, contact your trash service provider and request a hole free, leak free dumpster. All outside trash containers shall also have lids or covers.

Control: Better manage your work area by keeping equipment, tools and supplies organized and properly contained. Use dry cleaning methods first. Sweep up debris with a broom or use a mop to clean hard surfaces.

Capture: Clean up your work area and properly dispose of contaminated water, pollutants and debris. Use a broom, mop, or vacuum to capture any residue or pollutants that have the potential to be discharged.

Regulations

To improve the quality of water we fish and swim in, not to mention drink, the District of Columbia (DC) is subject to MS4 Permit regulations mandated by the Environmental Protection Agency (EPA). The MS4 Permit requires DC to implement elements such as a Storm Water Ordinance to reduce pollutants in stormwater runoff (directly caused by rainfall) and to effectively prohibit non-stormwater discharges, all of DC including the National Mall is covered under the DC MS4 permit, thus we have to submit for authorization through DC to discharge, and in some cases to the EPA since we are Federal. The discharge of wastewater from pressure washing, to the storm drainage system or surface waters is prohibited by this ordinance.

Currently the park holds three (3) EPA permits (LMRP, WWII, EPMY) and one (1) DOEE authorization (Banneker) to discharge into the MS4. Various project may also be granted permits or authorizations to do so but must go through an application/approval process.

Pressure Washing as Part of the Solution:

Pressure washing is an activity that can help improve the quality of our waters when done properly. By cleaning surfaces (e.g. equipment, parking lots, sidewalks, buildings, etc.), collecting the wastes (water and/or debris), and properly disposing of it, there is less chance of pollutants ending up in our waterways during a heavy rain fall event.

Disposal Requirements and Prohibitions:

Proper disposal of pressure washing wastewater, in compliance with environmental regulations, depends on the nature of the pollutants in it. It is the responsibility of the generator to determine the proper collection and disposal method for wastewater created by pressure washing.

Storm Drains:

Discharging pressure washing wastewater into any natural body of water (this will also include Con Gardens Lake and any water feature or fountain) or any storm drainage system, which includes street curb inlets, roadside ditches, gutters, and drainage channels, is prohibited by Federal, State, and local laws.

Evaporation:

Pressure washing wastewater that contains visible debris or residue, soap, detergent or other cleaning agents, or excessive amounts of any pollutant, may not be left on paved surfaces to evaporate, because the residue will eventually be discharged to the storm drain.

Land Disposal:

Wastewater may be collected and discharged or directed onto vegetated yard areas when the wastewater does not; create a nuisance, flow into a storm drain or does not contain waste or contaminants (i.e. solvents, cleaners, oils, metals, etc.). Such discharges must soak into the ground and may not flow into the storm drain. Note: Repeated discharges to landscaped areas may result in an accumulation of contaminants, thus damaging vegetation and increasing contaminant levels in the soil.

Sanitary Sewer:

Disposal of pressure washing wastewater to the CSS may require a DCWater Permit.

Best Management Practices (BMPs)

BMP-1 Planning: Determine which conveyance system you are in, where you plan to discharge wastewater and acquire necessary approvals or permits before starting. If necessary, determine what collection method you will be using and how you intend to properly dispose of the wastewater generated from each cleaning activity. Identify where all drains are situated at the wash site and which system the drain to.

BMP-2 Surface Pre-Cleaning: Consider using dry methods for surface pre-cleaning, such as using absorbents on small oil spots and sweeping up trash/debris/dirt before wet washing. Pre-cleaning is an activity that may reduce costs and simplify the wastewater disposal process. When using dry pre-cleaning methods, be sure to pick up pre-cleaning debris as soon as possible, so the materials do not have a chance to enter the storm drains.

BMP-3 Pressure Washing: Minimize the amount of water used during pressure washing activities, thus reducing the volume of wastewater that needs to be properly disposed. Avoid using cleaning products that contain hazardous substances (e.g. hydrofluoric acid, muriatic acid, sodium hydroxide, bleach, etc.) that can turn wastewater into hazardous waste. Acidic, caustic, and detergent cleaners may damage paved or coated surfaces. Consult with the Resource Management Division on environmentally friendly cleaning products, hazardous waste disposal info as well and what products may be best for the surface being cleaned.

BMP-4 Wash Water Containment & Collection: Minimize and dispose of waste properly and recycle whenever possible. Collect wash water in permanent or temporary capture facility.

Decide what is the best method of collection (e.g., berms, storm drain cover mats, containment pools, vacuums/pumps, vacuum boom, etc.). Locate property high and low spots to determine where wash water can be pooled for collection. Do not leave areas of wash water on paved surfaces for evaporation. Sweep up any visible solids and sediments remaining after all the wash water has been collected.

BMP-5 Cleaners: Avoid using solvent-based cleaners (especially chlorinated solvent cleaners).

Check the SDS for environmental issues and consult with the ECPM for more guidance.

For more information please contact, April Newman National Mall and Memorial Parks Environmental Compliance Program Manager April_newman@nps.gov 202-731-7342 mailto:April_newman@nps.gov

Types of Stormwater Protection