Monday, July 6, 2009

Leather Tanning and Finishing 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 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 Leather Tanning and Finishing (Sector Z). Sector Z facilities are engaged in leather tanning, currying, and finishing activities. These requirements are in addition to permit requirements that apply to all sectors.

Preventive Maintenance:
The site SWPPP must include measures to store pallets and bales of raw, semi-processed, or finished tannery by-products indoors or these materials must be protected by polyethylene wrapping, tarpaulins, or roofed storage; to the extent feasible, the facility must store materials on impermeable surfaces and enclose or put berms around these areas. The operations must also prevent or contamination of stormwater runoff with leather dust from buffing and shaving areas, and must use dust collection systems and assure that they are operating properly.

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

Leather Tanning and Finishing (SIC 3111):
TSS 100 mg/L
Chromium +3 3.5 mg/L
BOD 25 mg/L

Note: Benchmarks for chromium 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]

Caltha LLP is conducting seminars in several cities across Minnesota to provide an overview of what the proposed MPCA permit requirements are and potential impacts on affected facilities. For more information, go to:
MPCA Proposed Industrial Stormwater Requirements Seminar

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
Caltha LLP Website

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