Municipal Wastewater Treatment — 12,000 m²
Municipal Wastewater Treatment — 12,000 m²
A municipal wastewater treatment plant in eastern China operated steel walkways over clarifier tanks for 15 years. H₂S corrosion had thinned structural members, forcing annual patching and emergency replacements. The plant needed a permanent solution.What We Solved
Steel walkways corroded by H₂S within 5 years
Frequent shutdowns for emergency repairs
Slip hazards on corroded, rusted surfaces
Budget pressure for repeated replacement cycles
How ZeAllgrate Delivered
ZeAllgrate supplied 12,000 m² of molded FRP grating (38 mm, isophthalic resin) with grit-top anti-slip surface, plus FRP handrail systems — engineered to the plant's walkway layout and installed over a single shutdown window.
Zero corrosion after 3 years in service
No maintenance cost since installation
Anti-slip surface reduced incident reports
Installed in 4 weeks, on schedule
Project Parameters
| Product | Molded FRP Grating 38mm + Handrail |
| Quantity | 12,000 m² + 3,200 m handrail |
| Resin | Isophthalic polyester |
| Surface | Grit-top anti-slip |
| Client | Municipal WWTP, Eastern China |
| Year | 2023 |
In the Field
Installation and product imagery from this project type.
FRP walkway above aeration channel
Green FRP walkways between clarifiers
FRP grating access over process pipework
Project Background
A municipal wastewater treatment plant in eastern China had operated steel walkways over its clarifier tanks for 15 years — and for most of that time, it had been patching them. H₂S corrosion from the tanks had thinned structural members, forcing annual patching and emergency replacements, while corroded, rusted surfaces created slip hazards for operators working above the basins. Budget pressure made the repeated replacement cycles untenable. The plant needed a permanent solution: a material that survived continuous damp H₂S atmosphere without painting, without rusting and without becoming a slip trap.
Design Parameters
| Parameter | Value |
|---|---|
| Total area | 12,000 m² molded FRP grating |
| Panel | 38 mm molded, isophthalic resin |
| Surface | Grit-top anti-slip as standard |
| System | FRP handrail systems supplied to match |
| Service environment | Continuous damp H₂S atmosphere over clarifier tanks |
| Installation | Staged over live basins; panels hand-handled |
Engineering Approach
The specification treated the tank-top environment as the governing input: isophthalic resin for the H₂S atmosphere, 38 mm molded panels for the operator and maintenance live loads at the walkway spans, and a grit-top surface because wet, slime-coated steel had produced the plant's slip history. Handrail was supplied as an integrated system so fall protection, fastening and corrosion behaviour matched the deck. Panels were staged over live basins, and stainless hardware avoided reintroducing the fastener-corrosion path that had failed on the previous aluminium and steel walkways.
Measured Outcomes
- 12,000 m² installed over clarifier tanks with zero emergency repairs since commissioning.
- Annual patching programme eliminated — the H₂S atmosphere produces no section loss in FRP.
- Grit-top surface passed slip-resistance checks in wet service; the previous corroded steel surfaces were replaced rather than repaired.
- Staged installation over live basins caused no tank downtime and required no draining.
What Made It Work
The plant replaced a repair cycle with a permanent asset. The combination — isophthalic resin for the chemistry, adequate panel depth for the live loads, grit-top for wet slip safety and stainless hardware throughout — is the standard formula for H₂S tank-top service. It is why FRP has become the default on municipal wastewater walkways worldwide.
Engineering Notes
Plant-scale wastewater supply is managed as a package: the drawing set fixes clarifier walkways, channel covers and chemical feed platforms before manufacture, resin is mapped to each zone from the atmosphere and chemical list, and delivery is batched with certificates for site traceability. Grit-top is specified on every wet traffic line, UV-stabilised resin on the open exposure, and SS316 hardware throughout — the corrosion-proof construction removes the repaint and replacement cycle of steel across the whole plant.
What to Specify
- Drawing set: walkways, covers and platforms fixed at order.
- Resin per zone from the atmosphere/chemical list.
- Grit-top on wet traffic; UV-stabilised on exposure.
- SS316 hardware; batched delivery with certificates.
- Drawing set: walkways, covers and platforms fixed at order.
- Resin per zone from the atmosphere/chemical list.
- Grit-top on wet traffic; UV-stabilised on exposure.
- SS316 hardware; batched delivery with certificates.
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