Blinding Media Filters
Blinding Media Filters
(OP)
We are commissioning our water treatment equipment and have found that the media filters are becoming "blinded" by a substance, probably the chemicals. The TSS of incoming water is 5-10 ppm and we are injecting both polymer (2ppm)and coagulant (3-5ppm) upstream of the filters (we do have a static mixer). Without adding chemicals we get better throughput but SDI is not <5. Any thoughts on how we can improve throughput while maintaining water quality?





RE: Blinding Media Filters
ChemE, M.E. EIT
"The only constant in life is change." -Bruce Lee
RE: Blinding Media Filters
RE: Blinding Media Filters
ChemE, M.E. EIT
"The only constant in life is change." -Bruce Lee
RE: Blinding Media Filters
What are you trying to remove and what form of treatment is being used prior to filtration?
RE: Blinding Media Filters
RE: Blinding Media Filters
The pH, water temp, etc. can play a big part on the reactiveness of the different coagulant/polymers. Different types of polymers are used for different treatments. The chemical suppliers will typically help perform the jar tests on a new plant at various pH's with different polymers to get the best floc formation/settlibility.
RE: Blinding Media Filters
In this case, since turbidity is so low, jar testing is useless. As a general rule, do not feed more than 1 grain per gallon. If you see a chalky residue on your disc filter paper, you are probably feeding too much alum.
For this direct filtration application, you should be using at least an 18 inch depth (24 inch depth or greater is better) of anthracite with an effective size of 3/16" X 3/32".
The best designs for adsorption clarification/filtration typically use two pressure vessels in series. The first contains the coarse anthracite or coarse sand; followed by the second vessel containing fine anthracite and fine sand. This approach allows you to use the deepest beds possible for longest run times.
Good luck with this challenge.
S. Bush
www.water-eg.com
RE: Blinding Media Filters
RE: Blinding Media Filters