Monday, February 22, 2010

Stormwater Permit for Leather Tanning & Finishing

The Minnesota Pollution Control Agency (MPCA) has issued its revised multi-sector industrial stormwater discharge general permit (MSGP). This permit 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]

All manufacturing, industrial and “industrial-like” sites that require a permit to discharge stormwater will be required to come into compliance with the revised permit, and to submit an application for permit coverage between June & October 2010, depending on their industrial sector.

Click here to review a list affected industrial sectors and application deadlines for each sector

The revised Minnesota permit details requirements for 29 different industrial sectors. The requirements described below are 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 revised 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 across Minnesota 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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