A major North American baking company is upgrading its South Carolina production facility with a new gravity grease interceptor manufactured by NWPX Park. The project required a high-capacity, corrosion-resistant solution capable of capturing and removing fats, oils and grease (FOG) from wastewater for compliant discharge. The NWPX GreaseTrooper® Model GTX-15000 — a 15,000-gallon precast concrete gravity grease interceptor with an integrally cast HDPE liner — provided a pre-engineered solution that meets performance requirements while minimizing field installation time.
Designed for Performance
The Model GTX-15000 is a multi-chambered precast concrete interceptor designed for direct burial applications. Due to its size, the interceptor was manufactured and shipped in four modular sections, each measuring approximately 21 feet by 11 feet by 12 feet. The sections were designed to stack efficiently and form a complete high-capacity system onsite.
The system includes an interior high-density polyethylene (HDPE) liner, internal baffles and piping, 6-inch inlet and outlet connections, a bitumastic exterior coating, heavy-duty access covers, and a high-grease alarm panel as part of the interceptor maintenance alert system.
Minimizing Field Labor
The studded HDPE liner is integrally cast into the concrete during manufacturing, with welded seams, and the inlet and outlet penetrations are factory lined. This detailed manufacturing approach provides seamless corrosion protection while reducing the amount of liner welding required in the field. The installation team from Plaztek initially budgeted five days for field welding. However, because the GreaseTrooper® was delivered with the HDPE liner welded on all seams except the concrete joints, field work was limited to welding the horizontal section seams only.
The contractor noted the quality of the product upon delivery, sharing that it was “the best tank they have ever come across.” Accustomed to welding walls and tops entirely in the field, the team immediately recognized that the factory-lined system would significantly accelerate the installation process.
Installation consisted of setting the base section, stacking the riser sections, and placing the lid. Butyl mastic was applied between each section to form a watertight seal. At each horizontal joint, the contractor prepared the HDPE liner by grinding the surface on either side of the seam. A strip of HDPE was tack welded over the joint, followed by extrusion welding along the strip edges using a high-temperature handheld extruder. Each weld was spark tested to verify liner integrity. After testing was complete, the unit was connected to the existing plumbing and then backfilled.
Supporting Compliance and Continued Growth
By delivering a fully lined, modular concrete grease interceptor system, NWPX Park helped streamline installation and reduce onsite labor demands. The factory-integrated liner minimizes long-term corrosion risk, while the automated alarm panel simplifies monitoring by alerting operators when pumping is required. By effectively capturing and separating fats, oils, and grease before discharge, the system helps protect the bakery’s internal plumbing from costly clogs while also safeguarding downstream municipal wastewater infrastructure. With only routine grease removal required for maintenance, the interceptor provides a durable, low-maintenance solution that supports continued production growth while maintaining compliance with municipal discharge requirements.
