Sector Z - Leather Tanning and Finishing Sector Z - Leather Tanning and Finishing

Z. Leather Tanning and Finishing

1. Authorized Stormwater Discharges

The requirements in Sector Z apply to stormwater discharges associated with industrial activity from leather tanning and finishing facilities as identified by the industrial activity code specified in Table 5 of Appendix D.

2. Industrial Activities Authorized by Sector Z

Permittees under Sector Z are primarily engaged in leather tanning, currying, and finishing activities.

5. Stormwater Controls

a. Employee Training (No additional requirements).

b. Erosion and Sedimentation Controls (No additional requirements).

c. Good Housekeeping (No additional requirements).

d. Inspections (No additional requirements).

e. Preventive Maintenance.

1. The Permittee shall store pallets and bales of raw, semi-processed, or finished tannery by-products (e.g. splits, trimmings, shavings) indoors or these materials must be protected by polyethylene wrapping, tarpaulins, or roofed storage.

2. The Permittee shall to the extent feasible store materials on an impermeable surface and enclose or put berms (or equivalent measures) around these areas.

3. The Permittee shall describe and implement measures that prevent or minimize contamination of stormwater runoff with leather dust from buffing and shaving areas. The Permittee shall use dust collection systems and assure that they are operating properly.

f. Spills and Leaks (No additional requirements).

g. Management of Runoff (No additional requirements).

h. Other Industry Specific Stormwater Control Measures (No additional requirements).

6. SWPPP Requirements

In addition to the requirements of Part IV, the Permittee shall also comply with the following:

a. Facility Map.

The Permittee shall identify on the facility map where any of the following may be exposed to stormwater:

1. Processing and storage areas of the beamhouse.

2. Tanyard.

3. Re-tan wet finishing and dry finishing operations.

4. Haul roads and access roads.

5. Rail spurs.

b. Inventory of Exposed Materials (No additional requirements).

c. Potential Pollutant Sources.

The Permittee shall describe the following additional sources that have potential pollutants associated with them:

1. Temporary or permanent storage of fresh and brine-cured hides.

2. Extraneous hide substances and hair.

3. Leather dust, scraps, trimmings, and shavings.

4. Chemical drums, bags, containers.

5. Empty chemical containers and bags.

6. Spent solvents.

7. Floor sweepings and washings.

8. Refuse, waste piles, and sludge.

9. Significant dust/particulate generating processes (e.g. buffing).

d. Description of Stormwater Controls (No additional requirements).

7. Monitoring and Reporting Requirements In accordance with the monitoring requirements of Part V, the Permittee shall monitor the applicable parameters in Table Z-1, below:

Sector-Specific Benchmark Values and Effluent Limitations: Sector - S2: Discharges may be subject to requirements for more than one sector or subsector.
Link to this table

Subsector	Parameter	Benchmark Values
Z1 Leather Tanning and Finishing	Solids, Total Suspended (TSS)	100 mg/L 2
	Chromium, Total (as Cr)	3.5 mg/L 1
	BOD, Carbonaceous 05 Day (20 Deg C)	25 mg/L

¹The benchmark values of some metals are influenced by water hardness. For these parameters, the Permittee may determine the hardness of the stormwater discharges to identify the applicable ‘hardness range’ for determining their benchmark value. See Table 4 of Appendix B for hardness dependent benchmark values in accordance with Minn. R. 7050.0222 and Minn. R. 7052.0100.
²If the Permittee is required to comply with Appendix A, part F.1, the benchmark value for Solids, Total Suspended (TSS) is 65 mg/L, instead of 100 mg/L.

8. Use of Infiltration Devices and/or Industrial Stormwater Ponds for Stormwater Treatment and Disposal

Sector Z industrial facilities are authorized to use designed infiltration devices or industrial stormwater ponds for stormwater management.