Monday, July 6, 2009

Air Transportation Facilities - SWPPP - Stormwater Permit Proposed Requirements

On July 6, 2009, the Minnesota Pollution Control Agency released its proposed multisector industrial stormwater discharge general permit. This permit, once promulgated, will replace the existing industrial stormwater permit, which expired in October of 2002.

[Read an overall summary of the proposed MPCA Industrial Stormwater Permit]

Some key changes in the July 6, 2009 proposed permit are the additional details for 29 different sector specific requirements. The requirements described below are proposed for the Air Transportation Facilities Sector (Sector S). Sector S facilities include only those portions of the site that are engaged in servicing, repairing, or maintaining aircraft and ground vehicles, equipment cleaning and maintenance, or deicing/anti-icing operations.. These requirements are in addition to permit requirements that apply to all sectors.

Employee Training:
In addition to other training requirements, employee training programs need to include training:
1. Proper handling of deicing materials and fuels.
2. Spill and leak prevention.
3. Proper recordkeeping of deicing fluids applied and stored.

[Read more about Minnesota stormwater training]

Good Housekeeping:
For agricultural aviation operations occur, the facility must prevent contact of stormwater with pesticides, herbicides, and other agricultural chemicals.

In addition to the routine inspection requirements, facilities must conduct two inspections per month during the deicing season. Operations must conduct two of the monthly inspections during runoff events. One of the inspections must be performed during a snow melt runoff event. Each inspection must include a visual assessment of the runoff to identify any visible sheens or films that indicate the presence of oil or grease in the discharge.

Preventive Maintenance:
All facilities must evaluate whether over application of deicing chemicals on runways occurs by analyzing and adjusting application rates as necessary, consistent with considerations and requirements of flight safety The site SWPPP must include measures to prevent or minimize contamination of stormwater from all areas used for aircraft, ground vehicle and equipment maintenance, and must store all aircraft, ground vehicles and equipment awaiting maintenance in designated areas only.

Leaks & Spills:
Each individual permittee is required to report spills equal to or exceeding the reportable quantity (RQ) levels. If an airport authority is the sole permittee under the permit, then the sum of all spills at the airport must be assessed against the RQ. If tenants exist at the airport, then the amount spilled by each tenant shall be assessed against the RQ determination.

Potential Pollutant Sources:
The site SWPPP must also describe potential pollutant sources including aircraft, runways, ground vehicle and equipment maintenance and cleaning, aircraft and runway deicing operations, runways and loading areas where agricultural aviation operations occur.

Stormwater Monitoring Benchmarks:
All facilities are required to conduct visual and chemical (benchmark) monitoring. The benchmark concentrations are based on deicing chemical usage:

>100,000 gallons of glycol-based deicing/anti-icing chemicals and/or >100 tons of urea on an average annual basis:
BOD 25 mg/L
COD 120 mg/L
Total Ammonia 2.8 mg/L
pH 6-9

Less than 100,000 gallons
BOD 25 mg/L
COD 120 mg/L
Total Ammonia 2.8 mg/L

Note: Benchmark for ammonia were derived based on the Aquatic Life Standards for these parameters in Minnesota Rules.

[Read more about use of Aquatic Life Standards to derive stormwater benchmarks]
[Read more about how benchmarks are used under the proposed MPCA industrial permit]

Looking for information on Minnesota SWPPP - Industrial Stormwater Training?, go to:
MPCA Industrial Stormwater Training - SWPPP Training - Stormwater Inspection Training

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

For further information contact Caltha LLP at
Caltha LLP Website

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