Case at a glance: In a municipal wastewater treatment facility, elevated walkways and platform covers around aeration basins and clarifiers had been suffering from persistent moisture and chemical exposure. HotFRP supplied molded fiberglass grating to replace the existing metal panels, with a grit-top finish in areas where foot traffic was frequent. The new grating provides a stable, corrosion-resistant surface that handles both wet conditions and routine chemical contact.

Project Background

The treatment plant operates around the clock, with walkways used daily by operators carrying tools and monitoring equipment. The original steel grating was coated, but constant humidity, occasional splashes from basin water, and the presence of hydrogen sulfide in certain zones accelerated corrosion at edges and fastener points. Some panels had become slippery, especially in areas where algae or biofilm formed on damp surfaces.

The maintenance team needed a replacement that would not require frequent repainting and would stay safe to walk on even when wet. Because the support structure was still in good condition, the project focused on changing only the grating panels.

Material Selection

After evaluating the typical loads and foot traffic patterns, Molded FRP grating is recommended as the primary replacement material. Molded grating is well suited to wastewater environments because the resin matrix resists moisture and many common chemicals found in treatment plants, and the open mesh design allows water to drain directly through the surface, reducing puddling.

For walkway sections where workers frequently pass or where the surface could become slippery from dampness or biological growth, a grit-top finish was specified. This added surface texture improves traction without significantly affecting drainage or load capacity. In a few locations where maintenance carts or heavier equipment are occasionally moved, heavier-duty panels were suggested as an option, with final selection based on the existing support spacing.

Installation Notes

Most panels were supplied in standard sizes and dropped directly onto the existing steel supports. A small number of panels had to be trimmed on site to fit around pipe risers and handrail posts. All field-cut edges were re-sealed with a compatible resin topcoat before installation to protect exposed glass fibers from moisture and chemical wicking. This step is especially important in a wastewater plant, where constant humidity can quickly degrade unprotected cut edges.

The panels were fastened with standard FRP grating clips, and support spacing was checked against the supplier’s span recommendations. Because the plant’s walkway framework was already regularly spaced, no additional structural changes were needed.

Outcome and Observations

Since installation, the new grating has remained stable under daily use. The maintenance team no longer schedules routine repainting for walkway surfaces, and the grit-top finish has reduced slip concerns during wet weather and washdown periods. The open mesh also helps keep the walkway clear of standing water and solid debris.

This case illustrates how selecting the right resin and surface finish can make a significant difference in a wastewater treatment environment. The choice of molded construction, combined with a grit-top surface where needed, allowed the facility to keep its existing support structure while improving long-term safety and reducing upkeep.