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A rainy day will not keep storm water permits at bay: the metalcasting industry is beginning to see movement, especially on the state level, in storm water permit regulations.

The U.S. Environmental Protection Agency (EPA) issued a memorandum stating "storm water discharges remain a significant cause of water quality impairment" in late 2010, thus leading to its conclusion that "permitting authorities should consider including numeric benchmarks" to determine the effectiveness of storm water permits.


Changes to permitting already have started at the state level. Reviewing industrial storm water discharge permits and current storm water practices now can help metalcasters stay ahead of issues in the future.

Storm Water Regulations

Most states issue their own storm water permits based on state regulations. State storm water regulations morphed out of EPA's multi-sector general permit, first issued in 1995. New Mexico, certain sectors within Texas, and areas such as Indian lands and Puerto Rico continue under the jurisdiction of EPA. The permitting authority can issue an "individual" permit, which is rare for storm water and includes specific monitoring and compliance limits, or a "general" permit with standard language and requirements.

The typical content of a general storm water permit includes:

* A 5-year duration.

* No concentration-based numeric discharge limits for specific pollutants.

* A requirement to identify and eliminate unpermitted non-storm water discharges to storm water outfalls.

* A requirement to develop and implement a storm water pollution prevention plan (SWPPP), which emphasizes source controls and best management practices (BMPs) to reduce the potential for storm water becoming contaminated.

* Visual inspections and/or chemical monitoring to evaluate the effectiveness of the SWPPP and update it as needed.

* Submit the data and annual reports to the control authority.

States have begun to fine-tune their programs and reissue general permits, making more significant changes than in the past. Most states encourage facilities attempting to forgo the need for a storm water permit by eliminating exposures. Thousands of permits are issued by state agencies with storm water programs that are largely under-funded and staffed. Many states are focusing on the obvious storm water problems, construction permits and streamlining the permitting process.

Ohio EPA recently issued a new industrial general permit, effective Jan. 1, which includes metalcasting industry-specific "benchmark monitoring cutoff concentrations" and requires iron and steel metalcasting facilities to monitor for aluminum, total suspended solids, copper and zinc. Nonferrous facilities must monitor only copper and zinc. At the end of three years, the facility is expected to average the results from four sampling events and compare them with the benchmark concentration. If the results exceed the benchmark, it is not yet a violation. The facility must then review their BMPs and make any needed improvements.

California also considered a new general permit that utilized numeric limits as benchmark concentrations, but it has since been withdrawn. A new draft version is expected in California, which will be out for public comment in summer 2012.

EPA says numeric benchmarks are "objective and accountable" as means to determine the effectiveness of BMPs. Other states indicated they would require a rule change to add benchmarks or limits to their general permits, thus making numeric limits unlikely.

What to Do at Your Facility

To address your storm water situation, first determine if your metalcasting facility is able to opt out of the permit program by eliminating exposures of rainwater to pollutioncausing facility operations. If you are required to have a storm water permit, review the permit requirements.

Next, evaluate your current storm water sampling methods and procedures to ensure the samples are a true representation. Revive or refresh efforts to implement your SWPPP.

Consider the effectiveness of your chosen BMPs. For example, you may need to see your runoff during a rain event to determine whether it looks polluted. Examine your storm water monitoring data. Delegate responsibility and authority to correct problems and check that improvements are implemented.

Update your SWPPP if you have added or removed production processes or storage practices. Remove a stated BMP from your SWPPP if you are no longer doing it and stay informed about your state's activities if/when they respond to EPAs push for numeric limits.


Many metalcasting facilities have been dutifully and routinely collecting storm water samples, having them analyzed by a laboratory and submitting the data to their state. If this is not a current practice at your facility, check your permit to be sure you are not overlooking anything.

Indiana, tor instance, performs random spot checks of data or looks at submitted data if there is a complaint or problem, such as a fish kill situation. The state also expects facilities to look for and keep track of trends within their data. Historically, Ohio storm water data was kept by facilities and not submitted, but the permit now requires electronic data submission. Wisconsin looks for red flags and will contact a facility if the state has concerns. States typically have limited resources and therefore cannot keep a database of storm water data.

The quality of storm water monitoring data depends on a number of factors, including:

* The type of storage or materials handling activities performed outside and the cleanliness of your shop.

* The length of time between a sampling event and the last previous significant washing event.

* How representative the samples are of actual water quality.

The presence of higher metal results is strongly correlated with having high suspended solids in the runoff. Table 1 shows a permit problem--most runoff from metalcasting facilities and other developments does not meet EPA benchmarks, which are based on fish toxicity. Maintaining compliance with your permit, reviewing your own data and improving storm water runoff quality will serve you well and reduce the pressure for numeric limits. This also will keep the cost of compliance down.
Table 1. Typical Metalcasting Monitoring Results Compared to
Residential and Commercial Runoff and U.S. EPA'S Benchmark Values

 Ferrous Nonferrous Residential/Commercial

Total 100-300 100-300 10-50

Aluminum 0.05-3 0.2-0.5 NA

Copper 0.03-0.07 0.2-0.4 0.02-0.05

Zinc 0.3-0.5 0.8-1.8 0.02-0.4


Total 100

Aluminum 0.75

Copper 0.0038-0.0316+

Zinc 0.04-0.25+


A metalcasting facility also can improve the quality of storm water runoff by implementing effective BMPs. Suggested practices and the targeted pollutants controlled include:

* Eliminate outdoor storage (solids, oils, metals, organics).

* Remove empty drums, pallets and containers (oils, organics).

* Maintain equipment, such as fork trucks and baghouses (solids, oils, metals).

* Implement construction erosion controls (solids).

* Cover dumpsters (solids, oils, metals, organics).

* Construct vegetated ditches, ponds and infiltration basins (solids, oils, metals, organics).

* Train employees (solids, oils, metals, organics).


Metalcasting facilities have weathered 40 years of changing wastewater regulations and discharge permits. In the last 20 years, authorities have regulated storm water runoff from industrial properties where the potential exists for rainwater to be adversely impacted by manufacturing, storage, and shipping operations. Following is a brief timeline of storm water permitting history:

* 1972: The Clean Water Act (CWA) regulates point-source discharges to waters of the U.S.

* 1980s: Impairment of surface water by non-point sources (storm water) recognized.

* 1987: CWA amendments require EPA to issue storm water permits for industrial activity.

* 1992: EPA finalizes regulations where storm water permits are required for industrial facilities.

* 1992: Numerous metalcasting groups submit storm water permit applications.

* 1990s: States begin to develop regulations and issue storm water permits.

* 1995: EPA issues multi-sector permit with benchmark target discharge concentrations for storm water.

* 1990s-2010: State rules develop using general permits, primarily relying on best management practices to reduce pollutant discharge to waterways.

* Since 2010: EPA and an increasing number of states start to use bench-mark targets as pseudo-numeric limits in general permits.



Visit for more information on the U.S. Environmental Protection Agency's storm water program.

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Author:Turpin, Paul
Publication:Modern Casting
Date:Jul 1, 2012
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