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Industrial Tank | Rectangular Tank
Corrosion-resistant, UV-resistant, impact-resistant fiberglass composite tanks

High-Quality Products

Our fiberglass composite products are corrosion-resistant, UV-resistant, and impact-resistant.

We make designing and specifying tanks easier.

Custom Projects

We offer an array of options to make designing and specifying what you need easier.


You can find our turn-key and custom tanks in a variety of settings and industries.

Multiple Industrial Applications

You can find our turn-key and custom products in a variety of settings and industries.

Request a quoteWe’ll walk you through the entire process, step by step.

Unmatched Support

Request a quote online or call us, and we’ll walk you through the entire process, step by step.

Rectangular Tank

You need a custom-designed rectangular tank that will perform better than concrete or metal. Orenco Composites can help. Our rectangular fiberglass-reinforced polymer (FRP) tanks are often the most cost-effective, long-term solution for many industrial process requirements, outperforming other materials. To meet your project needs, we manufacture single-piece tanks with capacities from 300 gallons to 50,000 gallons. 

These turn-key rectangular tank products are molded using vacuum infusion, providing a high-strength, seamless vessel. The unique foam-core structural design provides integral insulation (R24 or more) and strong, stiff walls — strong enough that tanks can be buried to grade or sit above ground. 

Orenco Composites FRP tanks can be configured with multiple baffles, weirs, slopes, access covers, and hatches. In addition, tanks can be fully outfitted with  safety railings, ladders, air diffusers, scum baffles, slide-rail systems, pumping systems, filters, and many other custom internal components. Our tanks also come fitted with lifting and mounting mechanisms. Contact us to see how we can help with your next project — from design to delivery.


  • Industrial wastewater processes
  • Various municipal wastewater treatment processes (MBR, MBBR, MABR, SBR)
  • Oil/water separators


  • Volume: from 300 gallons to 50,000 gallons (1.1 m³ to 189.3 m³)
  • Widths: 7.5′, 8, 10′, and 12′ (2.3 m, 2.4 m, 3.0 m, 3.7 m)
  • Lengths: up to 50′ (15.2 m)
  • Heights: up to 12′ (3.7 m)
  • Custom sizes available


  • Corrosion-free
  • Permanent or temporary installation
  • Above-ground or buried-to-grade installation
  • Single-piece, closed-molded vessel
  • Insulated up to R-48, depending on application
  • Internal tank coatings
  • Varied resins, based on application
  • Custom colors
  • Value-engineered vessel


  • Safety railings
  • Ladders
  • Integrated control rooms
  • Access covers and hatches
  • Baffles
  • Slide rail systems
  • Effluent pump and filter systems
  • Open top with grating

Document Resources

Here are some documents to get you started. 


Project Profile:
Industrial Wastewater

The client needed a rectangular tank to optimize their industrial treatment process. Working closely with the client, we designed an appropriate solution that met their specs and is scalable for future project needs.



The fiberglass-reinforced DuraFiber tanks contain baffles, weirs, nozzles, and other customer-specific features.  

  • 10’ wide x 11’ high x 32’ long
  • Custom colors
  • Vinyl ester resin
  • Custom cover with grading

The tank was molded using a vacuum-infusion process, which adds to its strength.