T-1000Reaction, Flocculation and Mixing Tank

How it works

1. Two opposite duties — Coagulation and flocculation are opposite requirements, which is why they get separate tanks. The first wants G above 300 /s for under two minutes so the coagulant reaches every colloid before it hydrolyses. The second wants G of 20–80 /s for twenty minutes or more so particles collide gently and stick.
2. The rapid mix — A small tank with a great deal of power in it. Retention is deliberately short — seconds to a couple of minutes. Any longer and you are shearing what you have just formed, and the coagulant has hydrolysed before it met the colloid it was meant to destabilise.
3. Velocity gradient — G is the Camp–Stein velocity gradient: the square root of power over viscosity times volume. It measures how hard neighbouring parcels of water shear past each other — exactly what decides whether floc grows or breaks. Note the viscosity term: cold water needs more power for the same G.
4. Tapered flocculation — Each tank runs gentler than the one before. Strong mixing first, while the floc is small and robust; gentle mixing last, once it is large and fragile. Tanks in series also fix the short-circuiting a single basin suffers, where some water leaves almost immediately.
5. What governs it — Rapid-mix G and time decide whether the coagulant is dispersed at all. Flocculation Gt — G multiplied by time — decides whether the floc reaches settleable size. Push floc power up and watch G leave the band: more mixing is not more treatment.
6. Mechanical flocculation — Paddles or turbines on variable-speed drives. G is set by the motor, so it is independent of the flow — the plant can turn down to half duty and the velocity gradient stays exactly where you set it. That is the whole reason mechanical flocculation remains standard, and it is worth the gearboxes and the maintenance.

Design parameters

The panel opposite runs the same correlations as the T-1000 design sheet, so the animation and the calculator cannot disagree. Every parameter below is live — drag one and the picture responds.

Open the full T-1000 design sheet for the other two inputs, all twenty-one results with their envelopes, the six equations printed beside the numbers they produce, and a calculation record you can export and put in a design file.