Monday, July 6, 2009

Oil and Gas Extraction and Refining 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 Oil and Gas Extraction and Refining Sector (Sector I). Sector I facilities are engaged in a extraction or refining of petroleum or natural gas, and related field services and drilling. These requirements are in addition to permit requirements that apply to all sectors.

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.

Routine site inspections must include equipment and vehicles that store, mix, or transport chemicals or hazardous materials.

Preventive Maintenance:
The site SWPPP must include measures to prevent or minimize contamination of stormwater from chemical mixing areas, and prevent discharge of stormwater coming into contact with wastewater pollutants from any sources associated with production, field exploration, drilling, well completion, or well treatment.

Potential Pollutant Sources:
The site SWPPP must also describe potential pollutant sources including chemical, cement, mud, or gel mixing activities; drilling or mining activities; and equipment rehabilitation activities.

Stormwater Infiltration:
Sector I facilities are prohibited from using infiltration to manage stormwater.

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

Oil and Gas Extraction (SIC 1311, 1321, 1381-1389):
TSS 100 mg/L
pH 6-9

Oil Refining (SIC 2911):
Total Zinc 0.234 mg/L
Ammonia 34.8 mg/L

Note: Benchmarks for zinc and 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]
[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 effected 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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