Coagulation is where a DAF pilot earns most of its money. The right coagulant, dose, pH and flocculation regime is the difference between a clean float that protects the membranes and a carry-over that fouls them — and on seawater it shifts week to week as the bloom develops. This page sets out how we run coagulation trials on a containerised pilot to find, and prove, the optimum on your actual intake water.
A jar test on a Tuesday tells you what worked on Tuesday's water in a beaker with no flotation. A pilot tells you what holds across a month of changing seawater, at real flotation hydraulics, with the bubble field and flocculation the full plant will actually use. We start from jar tests to bracket the chemistry, then sweep dose, pH and coagulant type on the live rig — logging clarified turbidity, residual coagulant, float quality and downstream SDI₃ for every condition. The result is a dose curve you can defend, not a single lucky data point. The chemistry behind it is set out in DAF coagulation chemistry.
The seawater default — robust across pH and excellent for TEP and organic removal. We map dose vs residual iron and float quality.
Polyaluminium chloride and pre-hydrolysed coagulants where lower dose, less sludge or temperature tolerance matter.
Low-dose anionic/non-ionic aids to toughen floc for flotation under heavy bloom load.
Acid/caustic trim to sit coagulation in its optimum window — often the single biggest lever on performance.
Online charge measurement to track and automate dose as raw-water charge demand swings.
G-value and retention time swept to grow floc that floats cleanly — see coag/floc.
| Step | What we do | Output |
|---|---|---|
| 1. Jar bracketing | Bench jar tests across coagulants, dose and pH on a grab sample | Starting envelope |
| 2. Pilot dose sweep | Step dose up/down on the live rig at fixed loading | Dose vs turbidity / SDI₃ curve |
| 3. pH optimisation | Sweep pH around the best dose | Optimum pH window |
| 4. Polymer aid trial | Add/aid trials under peak bloom load | Float robustness gain |
| 5. Seasonal tracking | Hold optimum and log demand over weeks | Demand vs bloom relationship |
| 6. Control proof | Close the loop on streaming current / flow pacing | Validated dosing control |
Desalination intake dosing → · Dosing pump selector · Instrumentation
We design the trial matrix, run it on your seawater and hand you a defensible dose curve and control strategy. Tell us about the intake.
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