Pipe Flocculator

[Mya44]

Just wondering if anyone has any experience with pipe flocculators. Specifically for use upstream of primary separation (not DAF) with a PAC based coagulant and poly for water treatment.

Thanks!

 

[bimr]

A DAF unit has a very short residence time (~15 minutes). For equipment with short residence times, you need good flocculation upstream of the equpment. That is the reason the "pipe flocculators" is used on DAF units.

You do not need such effective flocculation with primary separation unless your are using something like a gravity plate separator. The residence time is much longer in a primary separator.

Basically, the "pipe flocculators" do work, but the use of the flocculators depends on the process application.

 

[Mya44]

Thanks for the info.
This is for a small (<8000bbl/day) mobile system and primary separation is being achieved through filtration. I want to minimize the residence time and use a pipe flocculator because of the reduced footprint of not having to use large tanks etc.

 

[bimr]

Direct Filtration with Cationic Polymers
It is often possible to eliminate or bypass conventional
flocculation and sedimentation when raw water supplies are low in turbidity on a year-round basis. For new plants, this can mean a significant savings in capital cost. Coagulant treated water is then fed directly to the filters in what is known as the direct filtration process. Cationic polymers are usually very effective in this type of service.

http://www.water.ky.gov/NR/rdonlyres/549C7092-C58D-4354-BD80-1F6DE0774F2E/0/coagulation.pdf

The direct filtration plants that I have observed have not had extensive flocculation equipment. You do not need the same type of flocculation as a DAF unit where the DAF process will not work without flocculation.