Large industrial sites have had permits for storm water discharges under the NPDES program of the Clean Water Act since the mid to late 80’s. Recent emphasis has been placed on regulated facilities to prepare and implement Spill Prevention, Control and Countermeasure (SPCC) plans under the Oil Pollution Prevention Act (40 CFR 112). A large iron pipe foundry in Texas has several storm water outfalls which are monitored for various water quality parameters.
Two of its outfalls (003 and 004) were identified in its recently completed SPCC plan as being susceptible to oily water discharges due to storage of oils in the two drainage basins. This paper describes the approach taken at this facility to address the dual objectives of improving storm water discharge quality and spill control with a structural Best Management Practice (BMP).
Tyler Pipe is a foundry that manufactures cast iron soil pipe and ductile iron fittings, using over 200,000 tons per year of recycled scrap iron. Located approximately 150 miles east of Dallas, Texas, its overall facility covers over 800 acres, and it employs over 900 people. The main production and storage areas cover 120 acres and are divided into a north plant (80 acres) and south plant (40 acres) which drain to permitted storm water outfalls 003 and 004, respectively. Although storm water limits for copper, lead, zinc, pH, COD, and oil and grease had not been violated, plant management wanted an extra degree of protection against receiving stream contamination from storm runoff and oil spills. Other driving forces for management’s decision to implement a structural BMP for storm water and spill control were their desires to:
- Improve storm water quality thus improving environmental compliance with its NPDES permit.
- Lower the risk of releasing reportable spilled contaminants to the environment.
- Meet the new requirements of the USEPA Spill Prevention, Control & Countermeasure Plan (SPCC) requirements.
- Protect Tyler Pipe Company’s natural resources (surface waters & groundwater).
- Improve company productivity & morale by improving plant-wide aesthetics.
- Be an industry leader in implementing innovative environmental technologies.
After evaluating different options, environmental staff decided to install vortex separators to intercept and treat first flush storm runoff. The units selected also have an oil containment feature to meet SPCC requirements.
With the Cu, Pb, and Zn limits in the storm water discharge permit, the environmental staff at the plant had been investigating for years various control strategies and removal mechanisms for heavy metals in storm runoff. They also knew from years of testing that capturing the “first flush” storm runoff would be sufficient to achieve metals removal goals.