How it works
- two different jobs — Coagulation and flocculation are opposite requirements in the same plant. The first wants G above 500 /s for seconds so the coagulant reaches every colloid. The second wants G of 20–80 /s for twenty minutes so particles collide gently and stick.
- velocity gradient — G is the Camp–Stein velocity gradient: the square root of power over viscosity times volume. It is a measure of how hard neighbouring parcels of water are shearing past each other — which is exactly what decides whether floc grows or breaks.
- Gt and tanks in series — What matters is G multiplied by time — the number of collisions each particle gets. A single tank short-circuits, so some water leaves almost immediately. Three tanks in series with tapered G gives a far tighter residence distribution for the same volume.
- shearing the floc — Above roughly 100 /s the floc you have grown is torn apart faster than it forms, and the clarifier downstream inherits fines it cannot settle. Wind the power up and watch the floc stop growing — more mixing is not more treatment.
- what governs it — G sets whether floc grows or shears; Gt sets whether it has time to reach settleable size; tanks in series set whether all the water actually gets that time. Power is the easiest thing to over-specify and the most damaging.
Design parameters
The panel opposite runs the same correlations as the T-1000 design sheet, so the animation and the calculator cannot disagree. Drag any of them and the picture responds.
- Flow — m³/h
- Tank volume — m³
- Mixing power — kW
- Temperature — °C
- Tanks in series — off
Open the full T-1000 design sheet for the governing equations, the accepted design envelopes and the worked calculation.