Two conveyors with identical mechanical designs can have wildly different service lives in a treatment plant, and the difference is usually materials. Wastewater environments combine constant moisture, hydrogen sulfide, chlorides, and cleaning chemicals — a corrosion cocktail that finds every specification shortcut.
Know Your Environment First
Corrosivity varies enormously within one plant. A headworks gallery with poor ventilation is among the most aggressive industrial environments anywhere; a dewatering building with good air handling is far milder; an outdoor loadout is a different problem again (UV, weather, temperature swings). Specify by location, not plant-wide.
Frames and Structure
Painted carbon steel is where corrosion failures start. In H2S-exposed areas, specify stainless steel or, at minimum, coating systems designed for sewer-gas service with surface prep to match — coating quality is in the preparation, not the topcoat. Design details matter as much as alloy choice: avoid water traps, seal or drain box sections, and keep dissimilar-metal contact isolated.
Contact Surfaces and Belting
Where material rides a belt, the structure underneath is protected from abrasive contact — one of the quiet advantages belt systems hold over drag- and screw-type equipment in corrosive-plus-abrasive service. Belting itself should be specified for the chemical exposure, temperature range, and any oil or grease content in the material.
Hardware, Drives, and Electrical
- Fasteners: stainless, always, in wet areas — a stainless frame with rusting carbon bolts fails at the bolts
- Drives and bearings: sealed for washdown, with corrosion-resistant housings in exposed locations
- Electrical: enclosures and conduit rated for the area classification; H2S attacks copper and standard contacts, so component selection in headworks areas matters
Fabrication Quality Is Part of Corrosion Resistance
Welds are where corrosion concentrates when workmanship is poor — crevices, spatter, and un-passivated stainless welds all become initiation sites. Serpentix does its own fabrication, including welding to the standards wastewater service demands, so material specifications survive the trip from drawing to installed equipment.
If you’re specifying a conveyor for a corrosive location, our engineering team will review the environment and recommend materials through a free engineering review — before the specification gets locked into a bid.
