Published by CARLOS GONZALEZ, CTO at Carlos Gonzalez
Ladies and Gentlemen,
Given we use cationic coagulants ,how positive and neutral Natural Organic Matter (NOM) can be removed on a municipal rapid sand filter?
NOM tends to be negatively charged; hence a cationic coagulant should work well, if not overdosed. However, if you are sure that the NOM particles are positive and neutral in charge, then you might want to think of using an anionic coagulant.
Published by Daniel Adeoye, Application Development Manager at Hach
You may test the dosage of cationic coagulants by jar test, and know the best to remove the NOM.
Published by Lin JYH-YAN, advanced engineer at FORMOSA PETROCHEMICAL CORPORATION
Cationic coagulants will attract or remove positive charged NOM? How?
Published by CARLOS GONZALEZ, CTO at Carlos Gonzalez
The coagulant etc are removed in the flocculation and sedimentation process before the final filter. There is not a lot of biological activity on a rapid sand filter. There is a lot of removal on a slow sand filter, but you would not have one after coagulation.
Published by Joseph Cotruvo, President at Joseph Cotruvo & Associates, Water , Environment and Public Health
So ,.can be concluded that mainly all positive charge and neutral NOM are removed before filtration step? We have seen no more of 50% removal of TOC, so the other 50% portion escapes coagulation - flocculation- sedimentation . How to explain this?
Published by CARLOS GONZALEZ, CTO at Carlos Gonzalez