Primary Metals - Foundry Sector - 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 a summary of the overall Minnesota permit, stormwater monitoring, and sector requirements]

Caltha LLP will be conducted seminars on the proposed sector requirements in July & August 2009. Caltha MPCA Industrial Stormwater Permit Requirements Seminars

The proposed permit details requirements for 29 different industrial sectors. The requirements described below are proposed for the Primary Metals Sector (Sector F). Sector F covers a fairly broad range of facility types, including steel works, blast furnaces, and rolling and finishing mills, iron and steel foundries, primary smelting and refining of nonferrous metals, secondary smelting and refining of nonferrous metals, rolling, drawing, and extruding of nonferrous metals, nonferrous foundries and other primary metal products These requirements are in addition to permit requirements that apply to all sectors.

Inspections:
The facility must conduct inspections addressing air pollution control equipment (e.g., baghouses, electrostatic precipitators, scrubbers, and cyclones) for any signs of degradation (e.g., leaks, corrosion, or improper operation) that could limit their efficiency and lead to excessive emissions. The operation must monitor air flow at inlets and outlets (or use equivalent measures) to check for leaks (e.g., particulate deposition) or blockage in ducts. Also inspect all process and material handling equipment (e.g., conveyors, cranes, and vehicles) for leaks, drips, or the potential loss of material.

In addition to routine inspection requirements, the operation 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.

Good Housekeeping:
Good housekeeping practices must include a cleaning and maintenance program for all impervious areas of the facility where particulate matter, dust, or debris may accumulate, especially areas where material loading and unloading, storage, handling, and processing occur. The operation must also implement a cleaning program which includes regular sweeping for the paving of areas where vehicle traffic or material storage occur but where vegetative or other stabilization methods are not practicable. For unstabilized areas where sweeping is not practicable, the operation must select an alternative stormwater management devices that effectively trap or remove sediment.

Stormwater Monitoring Benchmarks:
All facilities are required to conduct visual and chemical (benchmark) monitoring. For benchmark monitoring, the benchmark concentrations or values depend on facility type:

Steel Works, Blast Furnaces, and Rolling and Finishing Mills (SIC 3312-3317):
TSS 100 mg/L
Total Aluminum 1.5 mg/L
Total Zinc 0.234 mg/L

Iron and Steel Foundries (SIC 3321-3325):
TSS 100 mg/L
Total Aluminum 1.5 mg/L
Total Iron 1.0 mg/L
Total Zinc 0.234 mg/L
Total Copper 0.028 mg/L

Rolling, Drawing, and Extruding of Nonferrous Metals (SIC 3351-3357):
TSS 100 mg/L
Total Zinc 0.234 mg/L
Total Copper 0.028 mg/L

Nonferrous Foundries(SIC 3363-3369):
TSS 100 mg/L
Total Zinc 0.234 mg/L
Total Copper 0.028 mg/L

Others:
TSS 100 mg/L

Note: Benchmarks for zinc, copper, aluminum, iron 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]
[Read more about what a 100 mg/L benchmark for TSS relates to]


Looking for other sector information? Click here for a link to all sector requirements

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
info@calthacompany.com
or
Caltha LLP Website