Aggressive effluents, chlorides, and dosing chemicals attack DAF tanks, internals, and fittings. This guide covers corrosion mechanisms and material/coating selection that extend service life.
Recognise the problem fast, then work through the causes and solutions below.
What you see: A material chosen for general duty fails fast in chloride-rich, acidic, or oily-aggressive service.
What you see: Protective coatings blister, peel or undercut, exposing the substrate to rapid attack.
What you see: Concentrated coagulant/acid/biocide corrodes dosing lines, injection points and nearby internals.
| Check | Target / Action | Typical value |
|---|---|---|
| Tank/internals grade | Match to chemistry | 316L / duplex / lined |
| Chlorides | Drive grade selection | Higher Cl = higher grade |
| Coating system | Spec & prep correctly | Verified at install |
| Dosing materials | Chemically compatible | Resistant quills/seals |
| Galvanic isolation | Avoid dissimilar metals | Isolate fasteners |
Set up correctly, dissolved air flotation turns this failure mode into a controllable, high-performance process.
DAF units are specified in materials and coatings matched to the effluent, so corrosion is designed out rather than managed as failure.
Coated steel, duplex stainless, GRP and plastics give a route to long life in even aggressive, chloride-rich or acidic service.
Accessible internals let coating and corrosion be inspected and repaired on a planned cycle before leaks develop.
Correct material selection delivers decades of service, protecting the capital investment in the plant.
Wet float, poor cake solids, and downstream dewatering knock-on.
Thin or sinking float blanket — air/solids ratio, saturator, and chemistry fixes.
Cloudy effluent and solids breakthrough — hydraulic, floc, and distribution fixes.
Low dissolved air, oversized bubbles, and inconsistent white-water faults.
Dose, pH, mixing, and polymer faults that stop liftable flocs forming.
Skim frequency, re-entrainment, and float-handling problems.
Our process engineers diagnose and resolve complex DAF performance issues on site or remotely — from chemistry and air systems to hydraulics and sludge handling.
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