Effect of coagulation of clay on filter cake resistance

Removal of particulate matter on coated filter media

“…Three types of clays and an instant coffee material were selected for study. The clay minerals had been used in previous filtration studies (1,16,50,51,56), Some physical and chemical properties of these commercially available clays are presented in the Appendix.…”

Design requirements of precoat filters for water filtration

“…Other research has been concerned with the characteristics of different filter aids and grades (2, 26,35,49), the evaluation of the filtering properties of various suspended solids (3,15,37,44,61), and the use of polyelectrolytes and aluminum sulfate to improve the filtering characteristics of filter aids (16,17,20,52,56,60). Extensive laboratory studies have been made to determine the applicability of precoat filters for the removal of iron (2,35,43,50,70), various flocculant solids (37, 44), clays (3,20,60,61), and suspended solids from coagulated and settled surface waters (15), raw surface waters, softened waters (15,27), and trickling filter effluent (36). A summary of almost all of the precoat filter runs made by these researchers is included in Appendix A. Precoat filtration is a form of cake filtration which is a fundamentally different process than fixed-bed granular filtration.…”