Water Treatment - Flocculation
Water Treatment - Flocculation
(OP)
Hi,
I am in the process of optimising flocculator paddle speed and cannot find any information regarding paddle direction.
I understand the fundamental process design parameters affecting flocculation performance includes mixing intensity and detention time. G = SQR(P/Vu)
This does not take into consideration alum concentration, the following eqn does: G^2.8Ct = 4.4x10^6
The problem is both of these equations do not take into consideration paddle direction, counter-current or co-current.
Can anybody point me in the right direction?
Watproc
I am in the process of optimising flocculator paddle speed and cannot find any information regarding paddle direction.
I understand the fundamental process design parameters affecting flocculation performance includes mixing intensity and detention time. G = SQR(P/Vu)
This does not take into consideration alum concentration, the following eqn does: G^2.8Ct = 4.4x10^6
The problem is both of these equations do not take into consideration paddle direction, counter-current or co-current.
Can anybody point me in the right direction?
Watproc





RE: Water Treatment - Flocculation
RE: Water Treatment - Flocculation
RE: Water Treatment - Flocculation
As you know, after rapid mix, you provide a slow agitation (flocculation zone) which basically brings more particles together in a shorter time. But, you don't want to shear the particles with a high agitation. The velocity of the fluid in the chamber will vary in different locations (ie center of paddle vs. outer edge of paddle). If you are rotating against the incoming current, you will already have a velocity entering that the paddles will push against (increasing the localized velocity). As some flocculators use a back and forth sweeping motion in lieu of a circular motion, this localized velocity increase does little to harm the floc formation as long as it is not too great.
Again, as countryham said, the jar tests will give you a better indication of what will need to be done for optimization. It will be more than just checking the paddle speed. These jar tests should be run on a constant basis also. Running them once and calling it optimized will not be accurate as conditions will change.
RE: Water Treatment - Flocculation
But I use the direction that produce up-flow in the pit to avoid flocs cash agains pit bottom. Therefore rotation direction depend of paddles angle.