Particles, Polymers, and Performance in Filtration

Coagulation and filtration processes for water and wastewater treatment have important similarities which are useful in understanding: (1) What these processes accomplish, and how they can accomplish it; and (2) how to design and operate these processes to function effectively. For example, effective filtration requires effective chemical pretreatment to destabilize the particles to be removed. This may be done in a conventional coagulation and sedimentation process, or by a direct addition of appropriate chemicals to the filter influent. The appropriate type and dosage of destabilizing chemical to produce the most effective removal in filtration can usually be determined readily by batch (jar) coagulation tests. Filter design should then be tailored to the pretreatment process selected. Experimental evidence for these and related filtration phenomena are presented and examined.